feat(#24): Rivalry compare view

Implemented by claude via .agents/dev dispatch.

.agents/skills/groom/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: groom
-description: Groom a box-box GitHub issue into a Ready spec via a seeded grill-me interrogation. Use when the user asks to groom an issue, for example "/groom <issue-number>" or "$groom <issue-number>" with optional "--lens architect". Single-issue path: asks targeted questions, writes a structured spec into the issue body, sets Effort/Priority, and leaves Stage at Research for approval.
+description: 'Groom a box-box GitHub issue into a Ready spec via a seeded grill-me interrogation. Use when the user asks to groom an issue, for example "/groom <issue-number>" or "$groom <issue-number>" with optional "--lens architect". Single-issue path: asks targeted questions, writes a structured spec into the issue body, sets Effort/Priority, and leaves Stage at Research for approval.'
 argument-hint: <issue-number> [--lens architect]
 ---
 

.agents/skills/implement/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: implement
-description: Dispatch a Ready box-box issue to a coding harness (claude/codex/opencode/pi/cursor) in an isolated git worktree, run the build gate, and open a PR. Use when supervising implementation via "/implement <issue-number> --harness <name> [--dry-run]" or from any harness terminal with .agents/bin/dev.
+description: 'Dispatch a Ready box-box issue to a coding harness (claude/codex/opencode/pi/cursor) in an isolated git worktree, run the build gate, and open a PR. Use when supervising implementation via "/implement <issue-number> --harness <name> [--dry-run]" or from any harness terminal with .agents/bin/dev.'
 argument-hint: <issue-number> --harness <claude|codex|opencode|pi|cursor> [--dry-run]
 ---
 

.agents/skills/lens-architect/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: lens-architect
-description: Grill/analyze a box-box issue or epic from a software-architecture perspective and post the findings as a comment. Use standalone as "/lens-architect <issue-number>" for an on-the-fly architecture review, or let /groom compose it via "--lens architect". Reads the base grill + architect persona and focuses on reuse, data flow, seams, testability, and risk.
+description: 'Grill/analyze a box-box issue or epic from a software-architecture perspective and post the findings as a comment. Use standalone as "/lens-architect <issue-number>" for an on-the-fly architecture review, or let /groom compose it via "--lens architect". Reads the base grill + architect persona and focuses on reuse, data flow, seams, testability, and risk.'
 argument-hint: <issue-number>
 ---
 

.agents/skills/review/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: review
-description: Locally review a box-box PR against its linked GitHub issue spec, run tests, capture visual screenshots when applicable, create a .review packet, and post a GitHub PR comment. Use when a ticket implementation is ready for independent local review before the human merge gate.
+description: 'Locally review a box-box PR against its linked GitHub issue spec, run tests, capture visual screenshots when applicable, create a .review packet, and post a GitHub PR comment. Use when a ticket implementation is ready for independent local review before the human merge gate.'
 argument-hint: <pr-number> [--harness <name>] [--publish-screenshots]
 ---
 

.agents/skills/write-spec/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: write-spec
-description: Render a groomed design into the box-box Ready-spec template and write it into a GitHub issue body, then set Effort and Priority. Called by /groom after a grill session, or run standalone as "/write-spec <issue-number>" to (re)write an issue's spec from agreed decisions. Does not change Stage.
+description: 'Render a groomed design into the box-box Ready-spec template and write it into a GitHub issue body, then set Effort and Priority. Called by /groom after a grill session, or run standalone as "/write-spec <issue-number>" to (re)write an issue''s spec from agreed decisions. Does not change Stage.'
 argument-hint: <issue-number>
 ---
 

frontend/src/api.ts

@@ -2,6 +2,7 @@ import type {
   ArticleContent,
   CarDataSample,
   ChampionshipHub,
+  DriverSummary,
   EnrichedGrid,
   EnrichedResult,
   LapsComparisonResponse,
@@ -108,6 +109,19 @@ export async function fetchChampionshipHub(year?: number): Promise<ChampionshipH
   return res.json()
 }
 
+export async function fetchDriverSummary(
+  driverNumber: number,
+  year?: number,
+): Promise<DriverSummary> {
+  const params = new URLSearchParams({ driver_number: String(driverNumber) })
+  if (year) params.set('year', String(year))
+  const res = await fetch(`/api/v1/driver/summary?${params.toString()}`)
+  if (!res.ok) {
+    throw new Error(`API ${res.status}: ${res.statusText}`)
+  }
+  return res.json()
+}
+
 export async function fetchLiveState(): Promise<LiveStateResponse> {
   const res = await fetch('/api/v1/live/state')
   if (!res.ok) {

frontend/src/components/RivalryCompare.tsx

@@ -0,0 +1,271 @@
+import { useMemo, useState } from 'react'
+import type { ChampHubDriver, ChampionshipHub } from '../types'
+import { teamColor } from '../utils'
+import { gapSeries, h2hTally, lastRounds } from '../lib/rivalry'
+import '../styles/rivalry.css'
+
+const PAD_L = 48
+const PAD_T = 16
+const PLOT_W = 882
+const PLOT_H = 316
+const GAP_PLOT_H = 200
+
+function fmtPts(n: number): string {
+  return Number.isInteger(n) ? String(n) : n.toFixed(1)
+}
+
+/** Up to ~7 evenly spaced round labels, always including the last round. */
+function xTicks(n: number, labels: string[], x: (i: number) => number): { x: number; label: string }[] {
+  const step = Math.max(1, Math.ceil(n / 7))
+  const ticks: { x: number; label: string }[] = []
+  for (let i = 0; i < n; i += step) {
+    ticks.push({ x: x(i), label: labels[i] ?? `R${i + 1}` })
+  }
+  const last = labels[n - 1] ?? `R${n}`
+  if (ticks[ticks.length - 1]?.label !== last) {
+    ticks.push({ x: x(n - 1), label: last })
+  }
+  return ticks
+}
+
+function polyline(values: number[], x: (i: number) => number, y: (v: number) => number): string {
+  return values.map((v, i) => `${x(i).toFixed(1)},${y(v).toFixed(1)}`).join(' ')
+}
+
+interface PickerProps {
+  id: 'a' | 'b'
+  label: string
+  drivers: ChampHubDriver[]
+  value: number
+  color: string
+  onChange: (driverNumber: number) => void
+}
+
+function DriverPicker({ id, label, drivers, value, color, onChange }: PickerProps) {
+  return (
+    <label className="rivalry-picker">
+      <span className="rivalry-picker-label">{label}</span>
+      <select
+        className="rivalry-picker-select"
+        style={{ borderLeft: `3px solid ${color}` }}
+        value={value}
+        data-testid={`rivalry-pick-${id}`}
+        onChange={(e) => onChange(Number(e.target.value))}
+      >
+        {drivers.map((d) => (
+          <option key={d.driver_number} value={d.driver_number}>
+            {d.name_acronym} · {d.full_name}
+          </option>
+        ))}
+      </select>
+    </label>
+  )
+}
+
+export function RivalryCompare({ hub }: { hub: ChampionshipHub }) {
+  const { drivers } = hub
+  const [pickA, setPickA] = useState<number | null>(null)
+  const [pickB, setPickB] = useState<number | null>(null)
+
+  // Default to the top two in the standings; fall back there if a picked
+  // driver disappears (e.g. season switch re-fetches the hub).
+  const a = drivers.find((d) => d.driver_number === pickA) ?? drivers[0]
+  const b = drivers.find((d) => d.driver_number === pickB) ?? drivers[1]
+
+  const tally = useMemo(
+    () => (a && b ? h2hTally(a.round_positions ?? [], b.round_positions ?? [], hub.round_labels) : null),
+    [a, b, hub.round_labels],
+  )
+
+  if (drivers.length < 2) {
+    return (
+      <div className="champ-chart-empty" data-testid="champ-view-rivalry">
+        Need at least two drivers in the standings to compare a rivalry.
+      </div>
+    )
+  }
+
+  const colorA = teamColor(a.team_colour)
+  const colorB = teamColor(b.team_colour)
+  const sameTeam = a.team_name === b.team_name
+
+  const cumA = a.cumulative ?? []
+  const cumB = b.cumulative ?? []
+  const rounds = Math.min(cumA.length, cumB.length)
+  const gaps = gapSeries(cumA, cumB)
+  const lastGap = gaps[gaps.length - 1] ?? 0
+  const strip = tally ? lastRounds(tally, 5) : []
+
+  const pickers = (
+    <div className="rivalry-pickers">
+      <DriverPicker id="a" label="Driver A" drivers={drivers} value={a.driver_number} color={colorA} onChange={setPickA} />
+      <span className="rivalry-vs mono">vs</span>
+      <DriverPicker id="b" label="Driver B" drivers={drivers} value={b.driver_number} color={colorB} onChange={setPickB} />
+    </div>
+  )
+
+  if (rounds === 0) {
+    return (
+      <div className="rivalry" data-testid="champ-view-rivalry">
+        {pickers}
+        <div className="champ-chart-empty">
+          No completed rounds yet — the rivalry will appear after the first race.
+        </div>
+      </div>
+    )
+  }
+
+  // Points race scales.
+  const peak = Math.max(...cumA.slice(0, rounds), ...cumB.slice(0, rounds), 1)
+  const maxY = Math.max(50, Math.ceil(peak / 50) * 50)
+  const px = (i: number) => (rounds <= 1 ? PAD_L : PAD_L + (i * PLOT_W) / (rounds - 1))
+  const py = (v: number) => PAD_T + PLOT_H - (v / maxY) * PLOT_H
+  const pyGrid = [0, 0.25, 0.5, 0.75, 1].map((f) => ({ y: py(maxY * f), label: Math.round(maxY * f) }))
+  const pxGrid = xTicks(rounds, hub.round_labels, px)
+
+  // Gap scales: symmetric around zero.
+  const maxAbs = Math.max(10, Math.ceil(Math.max(...gaps.map(Math.abs), 1) / 10) * 10)
+  const gy = (v: number) => PAD_T + GAP_PLOT_H / 2 - (v / maxAbs) * (GAP_PLOT_H / 2)
+  const gyGrid = [maxAbs, 0, -maxAbs].map((v) => ({ y: gy(v), label: v > 0 ? `+${v}` : String(v) }))
+  const gxGrid = xTicks(rounds, hub.round_labels, px)
+
+  const gapLeader = lastGap === 0 ? null : lastGap > 0 ? a : b
+  const gapCaption = gapLeader
+    ? `${gapLeader.name_acronym} leads by ${fmtPts(Math.abs(lastGap))} pts after ${hub.round_labels[rounds - 1] ?? `R${rounds}`}.`
+    : 'Dead level on points.'
+
+  return (
+    <div className="rivalry" data-testid="champ-view-rivalry">
+      {pickers}
+
+      <div className="rivalry-h2h" data-testid="rivalry-h2h">
+        <div className="rivalry-h2h-score">
+          <span className="rivalry-h2h-code mono" style={{ color: colorA }}>
+            {a.name_acronym}
+          </span>
+          <span className="rivalry-h2h-num mono" data-testid="rivalry-h2h-num">
+            {tally ? `${tally.a}–${tally.b}` : '—'}
+          </span>
+          <span className="rivalry-h2h-code mono" style={{ color: colorB }}>
+            {b.name_acronym}
+          </span>
+        </div>
+        <span className="rivalry-h2h-meta">
+          Race head-to-head · {tally?.rounds.length ?? 0} round{(tally?.rounds.length ?? 0) === 1 ? '' : 's'} counted
+          {tally && tally.skipped > 0 ? ` · ${tally.skipped} skipped` : ''}
+        </span>
+        {strip.length > 0 && (
+          <div className="rivalry-strip" data-testid="rivalry-strip">
+            <span className="rivalry-strip-label">Last {strip.length}</span>
+            {strip.map((r) => (
+              <span className="rivalry-chip" key={r.round} title={`${r.label}: ${a.name_acronym} P${r.posA} · ${b.name_acronym} P${r.posB}`}>
+                <span className="rivalry-chip-round mono">{r.label}</span>
+                <span className="rivalry-chip-winner mono" style={{ color: r.winner === 'a' ? colorA : colorB }}>
+                  {r.winner === 'a' ? a.name_acronym : b.name_acronym}
+                </span>
+              </span>
+            ))}
+          </div>
+        )}
+      </div>
+
+      <section className="rivalry-section" data-testid="rivalry-points-race">
+        <div className="champ-chart-head">
+          <span className="champ-chart-title mono">
+            Points race — {a.name_acronym} vs {b.name_acronym}
+          </span>
+          <span className="champ-chart-meta">
+            Rounds 1–{rounds} · {hub.season}
+          </span>
+        </div>
+        <div className="champ-chart">
+          <svg viewBox="0 0 1000 380" className="champ-chart-svg" preserveAspectRatio="none">
+            {pyGrid.map((g) => (
+              <g key={g.label}>
+                <line x1={PAD_L} y1={g.y} x2={930} y2={g.y} stroke="var(--border)" strokeWidth="1" />
+                <text x={40} y={g.y + 4} textAnchor="end" className="champ-chart-axis">
+                  {g.label}
+                </text>
+              </g>
+            ))}
+            {pxGrid.map((g, i) => (
+              <text key={i} x={g.x} y={372} textAnchor="middle" className="champ-chart-axis">
+                {g.label}
+              </text>
+            ))}
+            {[
+              { slot: 'a', d: a, color: colorA, dash: '0', values: cumA.slice(0, rounds) },
+              { slot: 'b', d: b, color: colorB, dash: sameTeam ? '5 4' : '0', values: cumB.slice(0, rounds) },
+            ].map((s) => (
+              <g key={s.slot}>
+                <polyline
+                  points={polyline(s.values, px, py)}
+                  fill="none"
+                  stroke={s.color}
+                  strokeWidth="2.4"
+                  strokeDasharray={s.dash}
+                  strokeLinejoin="round"
+                  strokeLinecap="round"
+                />
+                <circle cx={px(s.values.length - 1)} cy={py(s.values[s.values.length - 1])} r="3" fill={s.color} />
+                <text
+                  x={px(s.values.length - 1) + 8}
+                  y={py(s.values[s.values.length - 1]) + 4}
+                  fill={s.color}
+                  className="champ-chart-label"
+                >
+                  {s.d.name_acronym}
+                </text>
+              </g>
+            ))}
+          </svg>
+        </div>
+      </section>
+
+      <section className="rivalry-section" data-testid="rivalry-gap">
+        <div className="champ-chart-head">
+          <span className="champ-chart-title mono">
+            Gap over season — {a.name_acronym} − {b.name_acronym}
+          </span>
+          <span className="champ-chart-meta">{gapCaption}</span>
+        </div>
+        <div className="champ-chart">
+          <svg viewBox="0 0 1000 250" className="champ-chart-svg" preserveAspectRatio="none">
+            {gyGrid.map((g) => (
+              <g key={g.label}>
+                <line
+                  x1={PAD_L}
+                  y1={g.y}
+                  x2={930}
+                  y2={g.y}
+                  stroke={g.label === '0' ? 'var(--border-2)' : 'var(--border)'}
+                  strokeWidth={g.label === '0' ? 1.5 : 1}
+                />
+                <text x={40} y={g.y + 4} textAnchor="end" className="champ-chart-axis">
+                  {g.label}
+                </text>
+              </g>
+            ))}
+            {gxGrid.map((g, i) => (
+              <text key={i} x={g.x} y={242} textAnchor="middle" className="champ-chart-axis">
+                {g.label}
+              </text>
+            ))}
+            <polyline
+              points={polyline(gaps, px, gy)}
+              fill="none"
+              stroke={colorA}
+              strokeWidth="2.4"
+              strokeLinejoin="round"
+              strokeLinecap="round"
+            />
+            <circle cx={px(gaps.length - 1)} cy={gy(lastGap)} r="3" fill={colorA} />
+          </svg>
+        </div>
+        <p className="rivalry-caption">
+          Above the zero line: {a.name_acronym} ahead. Below: {b.name_acronym} ahead.
+        </p>
+      </section>
+    </div>
+  )
+}

frontend/src/lib/driverProfile.ts

@@ -0,0 +1,69 @@
+import type { DriverSummaryRound } from '../types'
+
+/** One round mapped for the grid-vs-finish chart and results table. */
+export interface RoundDelta {
+  round: number // 1-based round index within the completed season
+  label: string // short GP label, e.g. "Bahrain"
+  grid: number | null
+  finish: number | null
+  /** grid − finish: positive = places gained on Sunday, null when unknowable. */
+  delta: number | null
+  points: number
+  status: 'classified' | 'dnf' | 'dns' | 'dsq' | 'absent'
+}
+
+/** Strip the "Grand Prix" boilerplate so round labels fit chart axes. */
+export function shortGpLabel(meetingName: string): string {
+  const short = meetingName
+    .replace(/\s*grand prix\s*/i, ' ')
+    .replace(/\s+gp\s*$/i, ' ')
+    .trim()
+  return short || meetingName
+}
+
+function roundStatus(r: DriverSummaryRound): RoundDelta['status'] {
+  if (r.dns) return 'dns'
+  if (r.dsq) return 'dsq'
+  if (r.dnf) return 'dnf'
+  if (r.race_position <= 0 && r.grid_position <= 0) return 'absent'
+  return 'classified'
+}
+
+/**
+ * Map summary rounds to grid-vs-finish deltas. Positions of 0 mean "no data"
+ * (driver absent, pit-lane start, …) and become null; a delta is only computed
+ * when both ends are known and the driver actually started the race.
+ */
+export function gridFinishDeltas(rounds: DriverSummaryRound[]): RoundDelta[] {
+  return rounds.map((r, i) => {
+    const status = roundStatus(r)
+    const grid = r.grid_position > 0 ? r.grid_position : null
+    const finish = r.race_position > 0 ? r.race_position : null
+    const delta =
+      grid != null && finish != null && status !== 'dns' && status !== 'absent'
+        ? grid - finish
+        : null
+    return {
+      round: i + 1,
+      label: shortGpLabel(r.meeting_name),
+      grid,
+      finish,
+      delta,
+      points: r.points,
+      status,
+    }
+  })
+}
+
+/** 'P4' for known positions, '—' when unknown. */
+export function formatPosition(pos: number | null): string {
+  return pos != null && pos > 0 ? `P${pos}` : '—'
+}
+
+/** '+3' (gained), '−2' (lost), '=' (held), '—' (unknown). */
+export function formatDelta(delta: number | null): string {
+  if (delta == null) return '—'
+  if (delta > 0) return `+${delta}`
+  if (delta < 0) return `−${Math.abs(delta)}`
+  return '='
+}

frontend/src/lib/gpIdentity.ts

@@ -47,7 +47,9 @@ export function countryDecal(meeting: Meeting | undefined | null): string {
   return name.slice(0, 3).toUpperCase() || '—'
 }
 
-export function countryFlag(meeting: Meeting | undefined | null): string {
+export function countryFlag(
+  meeting: Pick<Meeting, 'country_code' | 'country_flag'> | undefined | null,
+): string {
   if (meeting?.country_flag && !/^https?:\/\//i.test(meeting.country_flag)) return meeting.country_flag
   const code = meeting?.country_code?.toUpperCase()
   const iso2 = code ? CODE3_TO_2[code] : ''

frontend/src/lib/rivalry.ts

@@ -0,0 +1,61 @@
+// Pure helpers for the championship rivalry compare view.
+
+/** One round that counted toward the head-to-head tally. */
+export interface H2HRound {
+  round: number // 1-based season round
+  label: string
+  posA: number
+  posB: number
+  winner: 'a' | 'b'
+}
+
+export interface H2HTally {
+  a: number
+  b: number
+  /** Rounds counted in the tally, in season order. */
+  rounds: H2HRound[]
+  /** Rounds skipped because either driver had no finishing position. */
+  skipped: number
+}
+
+/**
+ * Per-round points gap (a − b) across the rounds both cumulative series
+ * cover. Positive values mean driver A is ahead.
+ */
+export function gapSeries(a: number[], b: number[]): number[] {
+  const n = Math.min(a.length, b.length)
+  const out: number[] = []
+  for (let i = 0; i < n; i++) out.push(a[i] - b[i])
+  return out
+}
+
+/**
+ * Race head-to-head: per round, the lower finishing position wins. Rounds
+ * where either driver has no position (0 / missing) are skipped from the
+ * tally, as are equal positions (defensive — races can't tie).
+ */
+export function h2hTally(posA: number[], posB: number[], labels: string[]): H2HTally {
+  const n = Math.max(posA.length, posB.length)
+  const rounds: H2HRound[] = []
+  let a = 0
+  let b = 0
+  let skipped = 0
+  for (let i = 0; i < n; i++) {
+    const pa = posA[i] ?? 0
+    const pb = posB[i] ?? 0
+    if (pa <= 0 || pb <= 0 || pa === pb) {
+      skipped++
+      continue
+    }
+    const winner = pa < pb ? 'a' : 'b'
+    if (winner === 'a') a++
+    else b++
+    rounds.push({ round: i + 1, label: labels[i] ?? `R${i + 1}`, posA: pa, posB: pb, winner })
+  }
+  return { a, b, rounds, skipped }
+}
+
+/** Last n counted rounds of a tally, for the mini strip. */
+export function lastRounds(tally: H2HTally, n: number): H2HRound[] {
+  return tally.rounds.slice(-n)
+}

frontend/src/pages/ChampionshipPage.tsx

@@ -1,13 +1,15 @@
 import { useMemo, useState } from 'react'
 import { useQuery } from '@tanstack/react-query'
+import { Link } from '@tanstack/react-router'
 import { fetchChampionshipHub, fetchSeasons } from '../api'
 import { teamColor } from '../utils'
 import type { ChampHubDriver, ChampionshipHub } from '../types'
 import { ChampionshipSimulator } from '../components/ChampionshipSimulator'
+import { RivalryCompare } from '../components/RivalryCompare'
 import { Meaning } from '../components/Meaning'
 import { pointsGapMeaning } from '../lib/meaning'
 
-type View = 'drivers' | 'constructors' | 'progression' | 'simulator'
+type View = 'drivers' | 'constructors' | 'progression' | 'rivalry' | 'simulator'
 
 const GOLD = '#ffd700'
 const SILVER = '#c0c0c0'
@@ -213,6 +215,14 @@ function ChampionshipBody({ hub, view, setView }: BodyProps) {
           >
             Progression
           </button>
+          <button
+            type="button"
+            className={`champ-tab${view === 'rivalry' ? ' is-active' : ''}`}
+            onClick={() => setView('rivalry')}
+            data-testid="champ-tab-rivalry"
+          >
+            Rivalry
+          </button>
           <button
             type="button"
             className={`champ-tab${view === 'simulator' ? ' is-active' : ''}`}
@@ -242,10 +252,12 @@ function ChampionshipBody({ hub, view, setView }: BodyProps) {
           leaderPoints={leader.points}
           titleMath={titleMath}
           roundsLeft={hub.rounds_left}
+          season={hub.season}
         />
       )}
       {view === 'constructors' && <ConstructorsView hub={hub} />}
       {view === 'progression' && <ProgressionView hub={hub} />}
+      {view === 'rivalry' && <RivalryCompare hub={hub} />}
       {view === 'simulator' && <ChampionshipSimulator hub={hub} />}
     </div>
   )
@@ -271,11 +283,13 @@ function DriversView({
   leaderPoints,
   titleMath,
   roundsLeft,
+  season,
 }: {
   enriched: EnrichedDriver[]
   leaderPoints: number
   titleMath: string
   roundsLeft: number
+  season: number
 }) {
   const podium = enriched.slice(0, 3)
   return (
@@ -360,12 +374,19 @@ function DriversView({
                   P{e.pos}
                 </td>
                 <td>
-                  <div className="champ-drv">
+                  <Link
+                    to="/drivers/$driverNumber"
+                    params={{ driverNumber: String(e.d.driver_number) }}
+                    search={{ year: season }}
+                    className="champ-drv"
+                    style={{ color: 'inherit', textDecoration: 'none' }}
+                    data-testid={`champ-driver-link-${e.d.driver_number}`}
+                  >
                     <span className="champ-drv-bar" style={{ background: e.color }} />
                     <span className="champ-drv-code mono">{e.d.name_acronym}</span>
                     <span className="champ-drv-name">{e.d.full_name}</span>
                     <span className="champ-drv-num mono">#{e.d.driver_number}</span>
-                  </div>
+                  </Link>
                 </td>
                 <td className="champ-td-team">{e.d.team_name}</td>
                 <td className="r mono champ-td-pts">{fmtPts(e.d.points)}</td>

frontend/src/pages/DriverProfilePage.tsx

@@ -0,0 +1,369 @@
+import { useQuery } from '@tanstack/react-query'
+import { Link } from '@tanstack/react-router'
+import { fetchDriverSummary, fetchSeasons } from '../api'
+import { teamColor } from '../utils'
+import { countryFlag } from '../lib/gpIdentity'
+import {
+  formatDelta,
+  formatPosition,
+  gridFinishDeltas,
+  type RoundDelta,
+} from '../lib/driverProfile'
+import type { DriverSummary } from '../types'
+import '../styles/driver-profile.css'
+
+interface Props {
+  driverNumber: number
+  year?: number
+}
+
+function fmtPts(n: number): string {
+  return Number.isInteger(n) ? String(n) : n.toFixed(1)
+}
+
+export function DriverProfilePage({ driverNumber, year }: Props) {
+  // Without an explicit ?year=, default to the latest ingested season; if the
+  // seasons list is empty/unavailable the backend falls back to the current year.
+  const seasonsQuery = useQuery({
+    queryKey: ['seasons'],
+    queryFn: fetchSeasons,
+    enabled: year == null,
+  })
+  const resolvedYear = year ?? seasonsQuery.data?.[0]
+  const seasonsSettled = year != null || !seasonsQuery.isLoading
+
+  const summaryQuery = useQuery({
+    queryKey: ['driver-summary', driverNumber, resolvedYear ?? 'latest'],
+    queryFn: () => fetchDriverSummary(driverNumber, resolvedYear),
+    enabled: seasonsSettled && driverNumber > 0,
+    staleTime: 5 * 60_000,
+  })
+
+  if (driverNumber <= 0) {
+    return <div className="page error-box">Invalid driver number</div>
+  }
+  if (!seasonsSettled || summaryQuery.isLoading) {
+    return <div className="page loading-state">loading driver profile…</div>
+  }
+  if (summaryQuery.isError) {
+    return (
+      <div className="page error-box">
+        {summaryQuery.error instanceof Error
+          ? summaryQuery.error.message
+          : 'Failed to load driver profile'}
+      </div>
+    )
+  }
+  const summary = summaryQuery.data
+  if (!summary) {
+    return <div className="page error-box">No driver data</div>
+  }
+  return <DriverProfileBody summary={summary} />
+}
+
+function DriverProfileBody({ summary }: { summary: DriverSummary }) {
+  const color = teamColor(summary.team_colour)
+  const deltas = gridFinishDeltas(summary.rounds)
+
+  return (
+    <div className="dp-page" data-testid="driver-profile">
+      <header className="dp-header" data-testid="dp-header" style={{ borderLeftColor: color }}>
+        <div className="dp-identity">
+          <div className="dp-title-row">
+            <span className="dp-code mono">{summary.name_acronym || `#${summary.driver_number}`}</span>
+            <span className="dp-num mono" style={{ color }}>
+              #{summary.driver_number}
+            </span>
+          </div>
+          <h1 className="dp-name">{summary.full_name || `Driver ${summary.driver_number}`}</h1>
+          <div className="dp-team">
+            <span className="dp-team-swatch" style={{ background: color }} />
+            {summary.team_name || 'Unknown team'}
+            <span className="dp-season mono">{summary.season}</span>
+          </div>
+        </div>
+        <div className="dp-stat-rail">
+          <div className="dp-stat">
+            <div className="dp-stat-value mono">{summary.position > 0 ? `P${summary.position}` : '—'}</div>
+            <div className="dp-stat-label">Championship</div>
+          </div>
+          <div className="dp-stat">
+            <div className="dp-stat-value mono">{fmtPts(summary.points)}</div>
+            <div className="dp-stat-label">Points</div>
+          </div>
+          <div className="dp-stat">
+            <div className="dp-stat-value mono">{summary.wins}</div>
+            <div className="dp-stat-label">Wins</div>
+          </div>
+          <div className="dp-stat">
+            <div className="dp-stat-value mono">{summary.podiums}</div>
+            <div className="dp-stat-label">Podiums</div>
+          </div>
+          <div className="dp-stat">
+            <div className="dp-stat-value mono">{summary.poles}</div>
+            <div className="dp-stat-label">Poles</div>
+          </div>
+        </div>
+        <Link to="/championship" className="dp-back mono">
+          ← Championship
+        </Link>
+      </header>
+
+      <section className="dp-section" data-testid="dp-form">
+        <h2 className="dp-section-title mono">Season form</h2>
+        {summary.cumulative.length > 0 ? (
+          <div className="dp-form-grid">
+            <CumulativeLine
+              cumulative={summary.cumulative}
+              labels={summary.round_labels}
+              color={color}
+            />
+            <FormStrip form={summary.form} color={color} />
+          </div>
+        ) : (
+          <div className="dp-empty">No completed rounds yet.</div>
+        )}
+      </section>
+
+      <section className="dp-section" data-testid="dp-quali-race">
+        <h2 className="dp-section-title mono">Quali vs race</h2>
+        {deltas.some((d) => d.delta != null) ? (
+          <GridVsRaceChart deltas={deltas} color={color} />
+        ) : (
+          <div className="dp-empty">No grid-vs-finish data yet.</div>
+        )}
+      </section>
+
+      <section className="dp-section" data-testid="dp-rounds">
+        <h2 className="dp-section-title mono">Track by track</h2>
+        {summary.rounds.length > 0 ? (
+          <RoundsTable summary={summary} deltas={deltas} />
+        ) : (
+          <div className="dp-empty">No completed rounds yet.</div>
+        )}
+      </section>
+    </div>
+  )
+}
+
+const LINE_W = 640
+const LINE_H = 180
+const LINE_PL = 44
+const LINE_PR = 16
+const LINE_PT = 12
+const LINE_PB = 24
+
+function CumulativeLine({
+  cumulative,
+  labels,
+  color,
+}: {
+  cumulative: number[]
+  labels: string[]
+  color: string
+}) {
+  const n = cumulative.length
+  const maxY = Math.max(25, ...cumulative)
+  const plotW = LINE_W - LINE_PL - LINE_PR
+  const plotH = LINE_H - LINE_PT - LINE_PB
+  const x = (i: number) => (n <= 1 ? LINE_PL + plotW / 2 : LINE_PL + (i * plotW) / (n - 1))
+  const y = (v: number) => LINE_PT + plotH - (v / maxY) * plotH
+  const points = cumulative.map((v, i) => `${x(i).toFixed(1)},${y(v).toFixed(1)}`).join(' ')
+
+  const tickStep = Math.max(1, Math.ceil(n / 8))
+  const ticks: { x: number; label: string }[] = []
+  for (let i = 0; i < n; i += tickStep) {
+    ticks.push({ x: x(i), label: labels[i] ?? `R${i + 1}` })
+  }
+
+  return (
+    <figure className="dp-chart">
+      <figcaption className="dp-chart-caption mono">Cumulative points</figcaption>
+      <svg viewBox={`0 0 ${LINE_W} ${LINE_H}`} className="dp-chart-svg" role="img" aria-label="Cumulative points per round">
+        {[0, 0.5, 1].map((f) => {
+          const v = Math.round(maxY * f)
+          return (
+            <g key={f}>
+              <line x1={LINE_PL} y1={y(v)} x2={LINE_W - LINE_PR} y2={y(v)} className="dp-gridline" />
+              <text x={LINE_PL - 6} y={y(v) + 3} textAnchor="end" className="dp-axis">
+                {v}
+              </text>
+            </g>
+          )
+        })}
+        {ticks.map((t) => (
+          <text key={t.label} x={t.x} y={LINE_H - 8} textAnchor="middle" className="dp-axis">
+            {t.label}
+          </text>
+        ))}
+        <polyline
+          points={points}
+          fill="none"
+          stroke={color}
+          strokeWidth="2.2"
+          strokeLinejoin="round"
+          strokeLinecap="round"
+        />
+        <circle cx={x(n - 1)} cy={y(cumulative[n - 1])} r="3.2" fill={color} />
+      </svg>
+    </figure>
+  )
+}
+
+function FormStrip({ form, color }: { form: number[]; color: string }) {
+  const max = Math.max(25, ...form)
+  return (
+    <div className="dp-form-strip">
+      <div className="dp-chart-caption mono">Last {form.length} races</div>
+      <div className="dp-form-bars">
+        {form.map((pts, i) => (
+          <div className="dp-form-bar" key={i} title={`${fmtPts(pts)} pts`}>
+            <div
+              className="dp-form-bar-fill"
+              style={{ height: `${Math.max(4, (pts / max) * 100)}%`, background: color }}
+            />
+            <span className="dp-form-bar-val mono">{fmtPts(pts)}</span>
+          </div>
+        ))}
+      </div>
+    </div>
+  )
+}
+
+const DELTA_H = 190
+const DELTA_PT = 14
+const DELTA_PB = 30
+
+function GridVsRaceChart({ deltas, color }: { deltas: RoundDelta[]; color: string }) {
+  const maxAbs = Math.max(1, ...deltas.map((d) => Math.abs(d.delta ?? 0)))
+  const colW = 34
+  const w = Math.max(240, deltas.length * colW)
+  const plotH = DELTA_H - DELTA_PT - DELTA_PB
+  const zeroY = DELTA_PT + plotH / 2
+  const scale = plotH / 2 / maxAbs
+
+  return (
+    <figure className="dp-chart">
+      <figcaption className="dp-chart-caption mono">
+        Positions gained (▲) / lost (▼) from grid to flag, per round
+      </figcaption>
+      <div className="dp-chart-scroll">
+        <svg
+          viewBox={`0 0 ${w} ${DELTA_H}`}
+          width={w}
+          height={DELTA_H}
+          className="dp-delta-svg"
+          role="img"
+          aria-label="Positions gained or lost per round"
+        >
+          <line x1={0} y1={zeroY} x2={w} y2={zeroY} className="dp-zeroline" />
+          {deltas.map((d, i) => {
+            const cx = i * colW + colW / 2
+            if (d.delta == null) {
+              return (
+                <g key={d.round}>
+                  <text x={cx} y={zeroY - 6} textAnchor="middle" className="dp-axis">
+                    ·
+                  </text>
+                  <text x={cx} y={DELTA_H - 8} textAnchor="middle" className="dp-axis">
+                    R{d.round}
+                  </text>
+                </g>
+              )
+            }
+            const h = Math.abs(d.delta) * scale
+            const yTop = d.delta >= 0 ? zeroY - h : zeroY
+            return (
+              <g key={d.round}>
+                <title>{`${d.label}: ${formatPosition(d.grid)} → ${formatPosition(d.finish)} (${formatDelta(d.delta)})`}</title>
+                <rect
+                  x={cx - 8}
+                  y={yTop}
+                  width={16}
+                  height={Math.max(1.5, h)}
+                  rx={2}
+                  fill={color}
+                  opacity={d.delta >= 0 ? 0.95 : 0.45}
+                />
+                <text
+                  x={cx}
+                  y={d.delta >= 0 ? yTop - 4 : yTop + h + 11}
+                  textAnchor="middle"
+                  className="dp-delta-val mono"
+                >
+                  {formatDelta(d.delta)}
+                </text>
+                <text x={cx} y={DELTA_H - 8} textAnchor="middle" className="dp-axis">
+                  R{d.round}
+                </text>
+              </g>
+            )
+          })}
+        </svg>
+      </div>
+    </figure>
+  )
+}
+
+function statusNote(d: RoundDelta): string {
+  if (d.status === 'dnf') return 'DNF'
+  if (d.status === 'dns') return 'DNS'
+  if (d.status === 'dsq') return 'DSQ'
+  if (d.status === 'absent') return '—'
+  return ''
+}
+
+function RoundsTable({ summary, deltas }: { summary: DriverSummary; deltas: RoundDelta[] }) {
+  return (
+    <div className="dp-scroll">
+      <table className="dp-table">
+        <thead>
+          <tr>
+            <th className="l">Rnd</th>
+            <th className="l">Grand Prix</th>
+            <th className="r">Grid</th>
+            <th className="r">Race</th>
+            <th className="r">Δ</th>
+            <th className="r">Pts</th>
+            <th className="l"></th>
+          </tr>
+        </thead>
+        <tbody>
+          {summary.rounds.map((r, i) => {
+            const d = deltas[i]
+            return (
+              <tr key={r.meeting_key}>
+                <td className="mono dp-td-dim">R{i + 1}</td>
+                <td>
+                  <span className="dp-flag" aria-hidden="true">
+                    {countryFlag({ country_code: r.country_code, country_flag: '' })}
+                  </span>
+                  {r.meeting_name}
+                </td>
+                <td className="r mono">{formatPosition(d.grid)}</td>
+                <td className="r mono">{formatPosition(d.finish)}</td>
+                <td
+                  className="r mono"
+                  style={{
+                    color:
+                      d.delta == null
+                        ? 'var(--text-3)'
+                        : d.delta > 0
+                          ? 'var(--green)'
+                          : d.delta < 0
+                            ? 'var(--red)'
+                            : 'var(--text-2)',
+                  }}
+                >
+                  {formatDelta(d.delta)}
+                </td>
+                <td className="r mono">{fmtPts(r.points)}</td>
+                <td className="dp-td-dim mono">{statusNote(d)}</td>
+              </tr>
+            )
+          })}
+        </tbody>
+      </table>
+    </div>
+  )
+}

frontend/src/router.tsx

@@ -6,12 +6,17 @@ import { DataLibraryPage } from './pages/DataLibraryPage'
 import { LiveTimingPage } from './pages/LiveTimingPage'
 import { BriefingPage } from './pages/BriefingPage'
 import { ChampionshipPage } from './pages/ChampionshipPage'
+import { DriverProfilePage } from './pages/DriverProfilePage'
 import { RacePreviewPage } from './pages/RacePreviewPage'
 
 type RaceHubSearch = {
   session_key?: number
 }
 
+type DriverProfileSearch = {
+  year?: number
+}
+
 const rootRoute = createRootRoute({
   component: () => (
     <>
@@ -65,6 +70,20 @@ export const championshipRoute = createRoute({
   component: ChampionshipPage,
 })
 
+export const driverProfileRoute = createRoute({
+  getParentRoute: () => rootRoute,
+  path: '/drivers/$driverNumber',
+  validateSearch: (search: Record<string, unknown>): DriverProfileSearch => {
+    const year = Number(search.year)
+    return Number.isFinite(year) && year > 0 ? { year } : {}
+  },
+  component: function DriverProfileRoute() {
+    const { driverNumber } = driverProfileRoute.useParams()
+    const { year } = driverProfileRoute.useSearch()
+    return <DriverProfilePage driverNumber={Number(driverNumber) || 0} year={year} />
+  },
+})
+
 export const briefingRoute = createRoute({
   getParentRoute: () => rootRoute,
   path: '/briefing',
@@ -84,6 +103,7 @@ const routeTree = rootRoute.addChildren([
   dataLibraryRoute,
   liveTimingRoute,
   championshipRoute,
+  driverProfileRoute,
   briefingRoute,
   previewRoute,
 ])

frontend/src/styles/driver-profile.css

@@ -0,0 +1,289 @@
+/* Driver profile page (/drivers/$driverNumber) */
+
+.dp-page {
+  max-width: 1100px;
+  margin: 0 auto;
+  padding: var(--s6) var(--s5);
+  display: flex;
+  flex-direction: column;
+  gap: var(--s6);
+}
+
+/* --- header --- */
+
+.dp-header {
+  position: relative;
+  display: flex;
+  flex-wrap: wrap;
+  align-items: flex-end;
+  justify-content: space-between;
+  gap: var(--s5);
+  padding: var(--s5);
+  padding-left: var(--s6);
+  border: 1px solid var(--border);
+  border-left: 4px solid var(--red);
+  border-radius: var(--r2);
+  background: var(--surface);
+}
+
+.dp-title-row {
+  display: flex;
+  align-items: baseline;
+  gap: var(--s3);
+}
+
+.dp-code {
+  font-size: 13px;
+  letter-spacing: 0.12em;
+  color: var(--text-2);
+  text-transform: uppercase;
+}
+
+.dp-num {
+  font-size: 13px;
+  font-weight: 700;
+}
+
+.dp-name {
+  margin: var(--s2) 0;
+  font-size: 30px;
+  line-height: 1.1;
+  letter-spacing: -0.01em;
+}
+
+.dp-team {
+  display: flex;
+  align-items: center;
+  gap: var(--s3);
+  font-size: 13px;
+  color: var(--text-2);
+}
+
+.dp-team-swatch {
+  width: 10px;
+  height: 10px;
+  border-radius: 2px;
+}
+
+.dp-season {
+  color: var(--text-3);
+}
+
+.dp-stat-rail {
+  display: flex;
+  gap: var(--s5);
+}
+
+.dp-stat {
+  min-width: 72px;
+}
+
+.dp-stat-value {
+  font-size: 22px;
+  font-weight: 700;
+}
+
+.dp-stat-label {
+  font-size: 11px;
+  text-transform: uppercase;
+  letter-spacing: 0.06em;
+  color: var(--text-3);
+}
+
+.dp-back {
+  position: absolute;
+  top: var(--s4);
+  right: var(--s5);
+  font-size: 12px;
+  color: var(--text-3);
+  text-decoration: none;
+}
+
+.dp-back:hover {
+  color: var(--text);
+}
+
+/* --- sections --- */
+
+.dp-section {
+  display: flex;
+  flex-direction: column;
+  gap: var(--s4);
+}
+
+.dp-section-title {
+  font-size: 12px;
+  text-transform: uppercase;
+  letter-spacing: 0.1em;
+  color: var(--text-2);
+}
+
+.dp-empty {
+  padding: var(--s5);
+  border: 1px dashed var(--border);
+  border-radius: var(--r2);
+  color: var(--text-3);
+  font-size: 13px;
+}
+
+/* --- charts --- */
+
+.dp-form-grid {
+  display: grid;
+  grid-template-columns: minmax(0, 2fr) minmax(200px, 1fr);
+  gap: var(--s5);
+  align-items: stretch;
+}
+
+@media (max-width: 760px) {
+  .dp-form-grid {
+    grid-template-columns: 1fr;
+  }
+}
+
+.dp-chart {
+  margin: 0;
+  padding: var(--s4);
+  border: 1px solid var(--border);
+  border-radius: var(--r2);
+  background: var(--surface);
+  min-width: 0;
+}
+
+.dp-chart-caption {
+  font-size: 11px;
+  text-transform: uppercase;
+  letter-spacing: 0.06em;
+  color: var(--text-3);
+  margin-bottom: var(--s3);
+}
+
+.dp-chart-svg {
+  display: block;
+  width: 100%;
+  height: auto;
+}
+
+.dp-chart-scroll {
+  overflow-x: auto;
+}
+
+.dp-gridline {
+  stroke: var(--border);
+  stroke-width: 1;
+}
+
+.dp-zeroline {
+  stroke: var(--text-3);
+  stroke-width: 1;
+  stroke-dasharray: 3 3;
+}
+
+.dp-axis {
+  fill: var(--text-3);
+  font-family: var(--f-mono);
+  font-size: 10px;
+}
+
+.dp-delta-svg {
+  display: block;
+}
+
+.dp-delta-val {
+  fill: var(--text-2);
+  font-size: 10px;
+}
+
+/* --- form strip --- */
+
+.dp-form-strip {
+  padding: var(--s4);
+  border: 1px solid var(--border);
+  border-radius: var(--r2);
+  background: var(--surface);
+  display: flex;
+  flex-direction: column;
+}
+
+.dp-form-bars {
+  flex: 1;
+  display: flex;
+  align-items: flex-end;
+  gap: var(--s3);
+  min-height: 110px;
+}
+
+.dp-form-bar {
+  flex: 1;
+  height: 100%;
+  display: flex;
+  flex-direction: column;
+  justify-content: flex-end;
+  align-items: center;
+  gap: var(--s2);
+}
+
+.dp-form-bar-fill {
+  width: 100%;
+  max-width: 34px;
+  border-radius: 2px 2px 0 0;
+  opacity: 0.9;
+}
+
+.dp-form-bar-val {
+  font-size: 11px;
+  color: var(--text-2);
+}
+
+/* --- rounds table --- */
+
+.dp-scroll {
+  overflow-x: auto;
+  border: 1px solid var(--border);
+  border-radius: var(--r2);
+  background: var(--surface);
+}
+
+.dp-table {
+  width: 100%;
+  border-collapse: collapse;
+  font-size: 13px;
+}
+
+.dp-table th {
+  padding: var(--s3) var(--s4);
+  font-family: var(--f-mono);
+  font-size: 11px;
+  text-transform: uppercase;
+  letter-spacing: 0.06em;
+  color: var(--text-3);
+  border-bottom: 1px solid var(--border);
+}
+
+.dp-table td {
+  padding: var(--s3) var(--s4);
+  border-bottom: 1px solid var(--border);
+  white-space: nowrap;
+}
+
+.dp-table tbody tr:last-child td {
+  border-bottom: none;
+}
+
+.dp-table th.l,
+.dp-table td.l {
+  text-align: left;
+}
+
+.dp-table th.r,
+.dp-table td.r {
+  text-align: right;
+}
+
+.dp-td-dim {
+  color: var(--text-3);
+}
+
+.dp-flag {
+  margin-right: var(--s3);
+}

frontend/src/styles/rivalry.css

@@ -0,0 +1,134 @@
+.rivalry {
+  display: flex;
+  flex-direction: column;
+  gap: var(--s5);
+}
+
+.rivalry-pickers {
+  display: flex;
+  flex-wrap: wrap;
+  gap: var(--s4);
+  align-items: flex-end;
+}
+
+.rivalry-vs {
+  font-size: 11px;
+  letter-spacing: 0.06em;
+  text-transform: uppercase;
+  color: var(--text-3);
+  padding-bottom: var(--s3);
+}
+
+.rivalry-picker {
+  display: flex;
+  flex-direction: column;
+  gap: var(--s2);
+  min-width: 200px;
+}
+
+.rivalry-picker-label {
+  font-family: var(--f-mono);
+  font-size: 11px;
+  letter-spacing: 0.06em;
+  text-transform: uppercase;
+  color: var(--text-3);
+}
+
+.rivalry-picker-select {
+  font-family: var(--f-mono);
+  font-size: 13px;
+  padding: var(--s2) var(--s3);
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  background: var(--surface-2);
+  color: var(--text);
+}
+
+.rivalry-picker-select:focus {
+  outline: 2px solid var(--red);
+  outline-offset: 1px;
+}
+
+.rivalry-h2h {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: var(--s4) var(--s5);
+  padding: var(--s4) var(--s5);
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  background: var(--surface-2);
+}
+
+.rivalry-h2h-score {
+  display: flex;
+  align-items: baseline;
+  gap: var(--s3);
+}
+
+.rivalry-h2h-code {
+  font-size: 14px;
+  font-weight: 700;
+}
+
+.rivalry-h2h-num {
+  font-size: 24px;
+  font-weight: 700;
+  color: var(--text);
+}
+
+.rivalry-h2h-meta {
+  font-family: var(--f-mono);
+  font-size: 11px;
+  color: var(--text-3);
+}
+
+.rivalry-strip {
+  display: flex;
+  align-items: center;
+  gap: var(--s2);
+  margin-left: auto;
+}
+
+.rivalry-strip-label {
+  font-family: var(--f-mono);
+  font-size: 10px;
+  letter-spacing: 0.06em;
+  text-transform: uppercase;
+  color: var(--text-3);
+  margin-right: var(--s2);
+}
+
+.rivalry-chip {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  gap: 1px;
+  padding: var(--s1) var(--s3);
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  background: var(--surface);
+}
+
+.rivalry-chip-round {
+  font-size: 9px;
+  color: var(--text-3);
+}
+
+.rivalry-chip-winner {
+  font-size: 11px;
+  font-weight: 700;
+}
+
+.rivalry-section {
+  display: flex;
+  flex-direction: column;
+  gap: var(--s3);
+}
+
+.rivalry-caption {
+  font-family: var(--f-mono);
+  font-size: 11px;
+  color: var(--text-3);
+  margin: 0;
+}

frontend/src/test/ChampionshipPage.test.tsx

@@ -29,6 +29,7 @@ function driver(over: Partial<ChampHubDriver>): ChampHubDriver {
     poles: 4,
     form: [25, 18, 25, 15, 25],
     cumulative: [25, 43, 68, 83, 108, 200],
+    round_positions: [1, 2, 1, 3, 1, 1],
     teammate_wins: 9,
     teammate_losses: 1,
     ...over,
@@ -47,6 +48,7 @@ const drivers: ChampHubDriver[] = [
     position: 2,
     wins: 3,
     cumulative: [18, 36, 54, 80, 120, 160],
+    round_positions: [2, 1, 2, 2, 2, 2],
   }),
   driver({
     driver_number: 16,
@@ -58,6 +60,7 @@ const drivers: ChampHubDriver[] = [
     position: 3,
     wins: 1,
     cumulative: [15, 28, 40, 60, 90, 120],
+    round_positions: [3, 3, 3, 0, 3, 3],
   }),
 ]
 
@@ -129,6 +132,22 @@ describe('ChampionshipPage', () => {
     expect(screen.getByText('Cumulative points', { exact: false })).toBeInTheDocument()
   })
 
+  it('switches to the rivalry view with the top two drivers preselected', async () => {
+    renderPage()
+
+    await waitFor(() => expect(screen.getByTestId('championship')).toBeInTheDocument())
+
+    fireEvent.click(screen.getByTestId('champ-tab-rivalry'))
+    expect(screen.getByTestId('champ-view-rivalry')).toBeInTheDocument()
+    // Default pair is the top two in the standings: VER vs NOR.
+    expect(screen.getByTestId('rivalry-pick-a')).toHaveValue('1')
+    expect(screen.getByTestId('rivalry-pick-b')).toHaveValue('4')
+    // VER beats NOR in rounds 1, 3, 5, 6 → 4–2.
+    expect(screen.getByTestId('rivalry-h2h-num')).toHaveTextContent('4–2')
+    expect(screen.getByTestId('rivalry-points-race')).toBeInTheDocument()
+    expect(screen.getByTestId('rivalry-gap')).toBeInTheDocument()
+  })
+
   it('switches to the simulator view and projects standings', async () => {
     renderPage()
 

frontend/src/test/ChampionshipSimulator.test.tsx

@@ -17,6 +17,7 @@ function driver(over: Partial<ChampHubDriver>): ChampHubDriver {
     poles: 0,
     form: [],
     cumulative: [],
+    round_positions: [],
     teammate_wins: 0,
     teammate_losses: 0,
     ...over,

frontend/src/test/CommandCenterPage.test.tsx

@@ -156,6 +156,7 @@ describe('CommandCenterPage', () => {
       race_control: [],
       weather: [],
       laps: [],
+      chapters: [],
     })
   })
 

frontend/src/test/DriverProfilePage.test.tsx

@@ -0,0 +1,160 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { render, screen, waitFor } from '@testing-library/react'
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
+import { RouterProvider, createRouter, createRootRoute, createRoute } from '@tanstack/react-router'
+import { DriverProfilePage } from '../pages/DriverProfilePage'
+import type { DriverSummary } from '../types'
+
+vi.mock('../api', () => ({
+  fetchSeasons: vi.fn(),
+  fetchDriverSummary: vi.fn(),
+}))
+
+import { fetchSeasons, fetchDriverSummary } from '../api'
+
+const mockFetchSeasons = vi.mocked(fetchSeasons)
+const mockFetchSummary = vi.mocked(fetchDriverSummary)
+
+const summary: DriverSummary = {
+  season: 2025,
+  driver_number: 1,
+  name_acronym: 'VER',
+  full_name: 'Max Verstappen',
+  team_name: 'Red Bull',
+  team_colour: '3671c6',
+  headshot_url: '',
+  points: 50,
+  position: 1,
+  wins: 2,
+  podiums: 2,
+  poles: 1,
+  form: [25, 25],
+  cumulative: [25, 50],
+  round_labels: ['R1', 'R2'],
+  rounds: [
+    {
+      meeting_key: 1201,
+      meeting_name: 'Bahrain Grand Prix',
+      country_code: 'BHR',
+      country_name: 'Bahrain',
+      race_position: 1,
+      grid_position: 1,
+      quali_position: 1,
+      points: 25,
+      dnf: false,
+      dns: false,
+      dsq: false,
+    },
+    {
+      meeting_key: 1202,
+      meeting_name: 'Saudi Arabian Grand Prix',
+      country_code: 'SAU',
+      country_name: 'Saudi Arabia',
+      race_position: 1,
+      grid_position: 4,
+      quali_position: 4,
+      points: 25,
+      dnf: false,
+      dns: false,
+      dsq: false,
+    },
+  ],
+}
+
+function renderPage(props: { driverNumber: number; year?: number }) {
+  const queryClient = new QueryClient({ defaultOptions: { queries: { retry: false } } })
+  const rootRoute = createRootRoute({
+    component: () => (
+      <QueryClientProvider client={queryClient}>
+        <DriverProfilePage driverNumber={props.driverNumber} year={props.year} />
+      </QueryClientProvider>
+    ),
+  })
+  const indexRoute = createRoute({
+    getParentRoute: () => rootRoute,
+    path: '/',
+    component: () => null,
+  })
+  const router = createRouter({ routeTree: rootRoute.addChildren([indexRoute]) })
+  return render(<RouterProvider router={router} />)
+}
+
+describe('DriverProfilePage', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    mockFetchSeasons.mockResolvedValue([2025])
+    mockFetchSummary.mockResolvedValue(summary)
+  })
+
+  it('renders header, form, quali-vs-race, and rounds sections', async () => {
+    renderPage({ driverNumber: 1, year: 2025 })
+
+    await waitFor(() => {
+      expect(screen.getByTestId('driver-profile')).toBeInTheDocument()
+    })
+
+    // Header: identity + season stats.
+    expect(screen.getByTestId('dp-header')).toBeInTheDocument()
+    expect(screen.getByText('Max Verstappen')).toBeInTheDocument()
+    expect(screen.getByText('#1')).toBeInTheDocument()
+    expect(screen.getByText('Red Bull', { exact: false })).toBeInTheDocument()
+    // 'P1' / '50' also appear in the rounds table and chart axis.
+    expect(screen.getAllByText('P1').length).toBeGreaterThan(0)
+    expect(screen.getAllByText('50').length).toBeGreaterThan(0)
+
+    // Season form strip.
+    expect(screen.getByTestId('dp-form')).toBeInTheDocument()
+    expect(screen.getByText('Cumulative points')).toBeInTheDocument()
+
+    // Quali-vs-race chart shows the delta from the Saudi round (P4 → P1 = +3).
+    expect(screen.getByTestId('dp-quali-race')).toBeInTheDocument()
+    expect(screen.getAllByText('+3').length).toBeGreaterThan(0)
+
+    // Track-by-track table rows with flags.
+    const rounds = screen.getByTestId('dp-rounds')
+    expect(rounds).toBeInTheDocument()
+    expect(screen.getByText('Bahrain Grand Prix')).toBeInTheDocument()
+    expect(screen.getByText('Saudi Arabian Grand Prix')).toBeInTheDocument()
+    expect(rounds.textContent).toContain('🇧🇭')
+    expect(rounds.textContent).toContain('🇸🇦')
+
+    // With an explicit year, the seasons list is not needed.
+    expect(mockFetchSeasons).not.toHaveBeenCalled()
+    expect(mockFetchSummary).toHaveBeenCalledWith(1, 2025)
+  })
+
+  it('defaults to the latest season when no year is given', async () => {
+    renderPage({ driverNumber: 1 })
+
+    await waitFor(() => {
+      expect(screen.getByTestId('driver-profile')).toBeInTheDocument()
+    })
+    expect(mockFetchSummary).toHaveBeenCalledWith(1, 2025)
+  })
+
+  it('shows the API error message on failure', async () => {
+    mockFetchSummary.mockRejectedValue(new Error('API 404: Not Found'))
+    renderPage({ driverNumber: 99, year: 2025 })
+
+    await waitFor(() => {
+      expect(screen.getByText('API 404: Not Found')).toBeInTheDocument()
+    })
+  })
+
+  it('shows empty states when no rounds are completed', async () => {
+    mockFetchSummary.mockResolvedValue({
+      ...summary,
+      form: [],
+      cumulative: [],
+      round_labels: [],
+      rounds: [],
+    })
+    renderPage({ driverNumber: 1, year: 2025 })
+
+    await waitFor(() => {
+      expect(screen.getByTestId('driver-profile')).toBeInTheDocument()
+    })
+    expect(screen.getAllByText('No completed rounds yet.').length).toBe(2)
+    expect(screen.getByText('No grid-vs-finish data yet.')).toBeInTheDocument()
+  })
+})

frontend/src/test/RaceHubPage.test.tsx

@@ -155,6 +155,7 @@ const raceHub: RaceHub = {
       is_pit_out_lap: false,
     },
   ],
+  chapters: [],
 }
 
 const weekend: Weekend = {

frontend/src/test/RacePreviewPage.test.tsx

@@ -109,6 +109,7 @@ const hubDriver = (over: Partial<ChampHubDriver>): ChampHubDriver => ({
   poles: 4,
   form: [25],
   cumulative: [200],
+  round_positions: [1],
   teammate_wins: 9,
   teammate_losses: 1,
   ...over,

frontend/src/test/RivalryCompare.test.tsx

@@ -0,0 +1,114 @@
+import { describe, it, expect } from 'vitest'
+import { render, screen, fireEvent } from '@testing-library/react'
+import { RivalryCompare } from '../components/RivalryCompare'
+import type { ChampHubDriver, ChampionshipHub } from '../types'
+
+function driver(over: Partial<ChampHubDriver>): ChampHubDriver {
+  return {
+    driver_number: 1,
+    name_acronym: 'VER',
+    full_name: 'Max Verstappen',
+    team_name: 'Red Bull',
+    team_colour: '3671c6',
+    points: 100,
+    position: 1,
+    wins: 2,
+    podiums: 3,
+    poles: 1,
+    form: [25, 18, 25],
+    cumulative: [25, 43, 68],
+    round_positions: [1, 2, 1],
+    teammate_wins: 3,
+    teammate_losses: 0,
+    ...over,
+  }
+}
+
+function makeHub(drivers: ChampHubDriver[]): ChampionshipHub {
+  return {
+    season: 2025,
+    round: 3,
+    total_rounds: 10,
+    rounds_left: 7,
+    last_race: 'Japan GP',
+    round_labels: ['R1', 'R2', 'R3'],
+    drivers,
+    teams: [],
+  }
+}
+
+const hub = makeHub([
+  driver({}),
+  driver({
+    driver_number: 4,
+    name_acronym: 'NOR',
+    full_name: 'Lando Norris',
+    team_name: 'McLaren',
+    team_colour: 'ff8000',
+    points: 90,
+    position: 2,
+    cumulative: [18, 43, 61],
+    round_positions: [2, 1, 2],
+  }),
+  driver({
+    driver_number: 16,
+    name_acronym: 'LEC',
+    full_name: 'Charles Leclerc',
+    team_name: 'Ferrari',
+    team_colour: 'e8002d',
+    points: 50,
+    position: 3,
+    cumulative: [15, 28, 40],
+    round_positions: [3, 0, 3],
+  }),
+])
+
+describe('RivalryCompare', () => {
+  it('defaults to the top two drivers and shows the H2H score', () => {
+    render(<RivalryCompare hub={hub} />)
+
+    expect(screen.getByTestId('champ-view-rivalry')).toBeInTheDocument()
+    expect(screen.getByTestId('rivalry-pick-a')).toHaveValue('1')
+    expect(screen.getByTestId('rivalry-pick-b')).toHaveValue('4')
+    // VER wins R1 and R3, NOR wins R2.
+    expect(screen.getByTestId('rivalry-h2h-num')).toHaveTextContent('2–1')
+    expect(screen.getByText('3 rounds counted', { exact: false })).toBeInTheDocument()
+    expect(screen.getByTestId('rivalry-points-race')).toBeInTheDocument()
+    expect(screen.getByTestId('rivalry-gap')).toBeInTheDocument()
+    // Last gap: 68 − 61 = +7 → VER ahead.
+    expect(screen.getByText('VER leads by 7 pts', { exact: false })).toBeInTheDocument()
+  })
+
+  it('recomputes when a different driver is picked and skips missing rounds', () => {
+    render(<RivalryCompare hub={hub} />)
+
+    fireEvent.change(screen.getByTestId('rivalry-pick-b'), { target: { value: '16' } })
+
+    // VER vs LEC: R2 skipped (LEC has no position), VER wins R1 and R3.
+    expect(screen.getByTestId('rivalry-h2h-num')).toHaveTextContent('2–0')
+    expect(screen.getByText('2 rounds counted · 1 skipped', { exact: false })).toBeInTheDocument()
+  })
+
+  it('shows an empty state with fewer than two drivers', () => {
+    render(<RivalryCompare hub={makeHub([driver({})])} />)
+    expect(screen.getByTestId('champ-view-rivalry')).toHaveTextContent('at least two drivers')
+  })
+
+  it('shows an empty message when no rounds are completed', () => {
+    const empty = makeHub([
+      driver({ cumulative: [], round_positions: [], form: [] }),
+      driver({
+        driver_number: 4,
+        name_acronym: 'NOR',
+        cumulative: [],
+        round_positions: [],
+        form: [],
+      }),
+    ])
+    empty.round = 0
+    empty.round_labels = []
+
+    render(<RivalryCompare hub={empty} />)
+    expect(screen.getByTestId('champ-view-rivalry')).toHaveTextContent('No completed rounds yet')
+  })
+})

frontend/src/test/driverProfile.test.ts

@@ -0,0 +1,104 @@
+import { describe, it, expect } from 'vitest'
+import {
+  formatDelta,
+  formatPosition,
+  gridFinishDeltas,
+  shortGpLabel,
+} from '../lib/driverProfile'
+import type { DriverSummaryRound } from '../types'
+
+function round(over: Partial<DriverSummaryRound>): DriverSummaryRound {
+  return {
+    meeting_key: 1201,
+    meeting_name: 'Bahrain Grand Prix',
+    country_code: 'BHR',
+    country_name: 'Bahrain',
+    race_position: 1,
+    grid_position: 1,
+    quali_position: 1,
+    points: 25,
+    dnf: false,
+    dns: false,
+    dsq: false,
+    ...over,
+  }
+}
+
+describe('gridFinishDeltas', () => {
+  it('computes positive delta for places gained', () => {
+    const [d] = gridFinishDeltas([round({ grid_position: 5, race_position: 2, points: 18 })])
+    expect(d.grid).toBe(5)
+    expect(d.finish).toBe(2)
+    expect(d.delta).toBe(3)
+    expect(d.points).toBe(18)
+    expect(d.status).toBe('classified')
+    expect(d.round).toBe(1)
+  })
+
+  it('computes negative delta for places lost', () => {
+    const [d] = gridFinishDeltas([round({ grid_position: 1, race_position: 4 })])
+    expect(d.delta).toBe(-3)
+  })
+
+  it('returns null delta when the grid slot is unknown (position 0)', () => {
+    const [d] = gridFinishDeltas([round({ grid_position: 0, race_position: 6 })])
+    expect(d.grid).toBeNull()
+    expect(d.finish).toBe(6)
+    expect(d.delta).toBeNull()
+  })
+
+  it('flags DNS rounds and never computes a delta for them', () => {
+    const [d] = gridFinishDeltas([round({ dns: true, grid_position: 8, race_position: 0 })])
+    expect(d.status).toBe('dns')
+    expect(d.delta).toBeNull()
+  })
+
+  it('marks rounds the driver did not enter as absent', () => {
+    const [d] = gridFinishDeltas([round({ grid_position: 0, race_position: 0, points: 0 })])
+    expect(d.status).toBe('absent')
+    expect(d.grid).toBeNull()
+    expect(d.finish).toBeNull()
+    expect(d.delta).toBeNull()
+  })
+
+  it('still computes the delta for a classified DNF with known positions', () => {
+    const [d] = gridFinishDeltas([round({ dnf: true, grid_position: 3, race_position: 15 })])
+    expect(d.status).toBe('dnf')
+    expect(d.delta).toBe(-12)
+  })
+
+  it('numbers rounds sequentially and shortens labels', () => {
+    const ds = gridFinishDeltas([
+      round({}),
+      round({ meeting_name: 'Saudi Arabian Grand Prix', meeting_key: 1202 }),
+    ])
+    expect(ds.map((d) => d.round)).toEqual([1, 2])
+    expect(ds[1].label).toBe('Saudi Arabian')
+  })
+})
+
+describe('shortGpLabel', () => {
+  it('strips "Grand Prix" wherever it appears', () => {
+    expect(shortGpLabel('Bahrain Grand Prix')).toBe('Bahrain')
+    expect(shortGpLabel('Grand Prix of Monaco')).toBe('of Monaco')
+  })
+
+  it('falls back to the original name when stripping empties it', () => {
+    expect(shortGpLabel('Grand Prix')).toBe('Grand Prix')
+  })
+})
+
+describe('formatPosition / formatDelta', () => {
+  it('formats positions', () => {
+    expect(formatPosition(4)).toBe('P4')
+    expect(formatPosition(null)).toBe('—')
+    expect(formatPosition(0)).toBe('—')
+  })
+
+  it('formats deltas', () => {
+    expect(formatDelta(3)).toBe('+3')
+    expect(formatDelta(-2)).toBe('−2')
+    expect(formatDelta(0)).toBe('=')
+    expect(formatDelta(null)).toBe('—')
+  })
+})

frontend/src/test/preview.test.ts

@@ -54,6 +54,7 @@ const hubDriver = (over: Partial<ChampHubDriver>): ChampHubDriver => ({
   poles: 4,
   form: [25],
   cumulative: [200],
+  round_positions: [1],
   teammate_wins: 9,
   teammate_losses: 1,
   ...over,

frontend/src/test/rivalry.test.ts

@@ -0,0 +1,71 @@
+import { describe, it, expect } from 'vitest'
+import { gapSeries, h2hTally, lastRounds } from '../lib/rivalry'
+
+describe('gapSeries', () => {
+  it('computes per-round a − b', () => {
+    expect(gapSeries([25, 43, 68], [18, 36, 54])).toEqual([7, 7, 14])
+  })
+
+  it('handles negative gaps (b ahead)', () => {
+    expect(gapSeries([10, 20], [18, 36])).toEqual([-8, -16])
+  })
+
+  it('truncates to the shorter series', () => {
+    expect(gapSeries([25, 43, 68], [18])).toEqual([7])
+    expect(gapSeries([], [18, 36])).toEqual([])
+  })
+})
+
+describe('h2hTally', () => {
+  it('tallies lower-position wins per round', () => {
+    const t = h2hTally([1, 2, 1], [2, 1, 3], ['R1', 'R2', 'R3'])
+    expect(t.a).toBe(2)
+    expect(t.b).toBe(1)
+    expect(t.skipped).toBe(0)
+    expect(t.rounds.map((r) => r.winner)).toEqual(['a', 'b', 'a'])
+    expect(t.rounds[0]).toEqual({ round: 1, label: 'R1', posA: 1, posB: 2, winner: 'a' })
+  })
+
+  it('skips rounds where either driver has no position', () => {
+    // R2: a missing (0). R3: b missing (0). Only R1 and R4 count.
+    const t = h2hTally([1, 0, 5, 3], [4, 2, 0, 1], ['R1', 'R2', 'R3', 'R4'])
+    expect(t.a).toBe(1)
+    expect(t.b).toBe(1)
+    expect(t.skipped).toBe(2)
+    expect(t.rounds.map((r) => r.round)).toEqual([1, 4])
+  })
+
+  it('handles arrays of different lengths (missing tail = skipped)', () => {
+    const t = h2hTally([1, 2, 3], [2], ['R1', 'R2', 'R3'])
+    expect(t.a).toBe(1)
+    expect(t.b).toBe(0)
+    expect(t.skipped).toBe(2)
+  })
+
+  it('skips equal positions defensively and falls back on labels', () => {
+    const t = h2hTally([2, 1], [2, 3], ['R1'])
+    expect(t.a).toBe(1)
+    expect(t.b).toBe(0)
+    expect(t.skipped).toBe(1)
+    expect(t.rounds[0].label).toBe('R2')
+  })
+
+  it('returns an empty tally for empty inputs', () => {
+    const t = h2hTally([], [], [])
+    expect(t).toEqual({ a: 0, b: 0, rounds: [], skipped: 0 })
+  })
+})
+
+describe('lastRounds', () => {
+  it('returns the last n counted rounds in order', () => {
+    const t = h2hTally([1, 1, 1, 2, 1, 1, 2], [2, 2, 2, 1, 2, 2, 1], [])
+    const last = lastRounds(t, 5)
+    expect(last).toHaveLength(5)
+    expect(last.map((r) => r.round)).toEqual([3, 4, 5, 6, 7])
+  })
+
+  it('returns fewer when the tally has fewer counted rounds', () => {
+    const t = h2hTally([1, 0], [2, 0], [])
+    expect(lastRounds(t, 5)).toHaveLength(1)
+  })
+})

frontend/src/test/simulator.test.ts

@@ -29,6 +29,7 @@ function driver(over: Partial<ChampHubDriver>): ChampHubDriver {
     poles: 0,
     form: [],
     cumulative: [],
+    round_positions: [],
     teammate_wins: 0,
     teammate_losses: 0,
     ...over,

frontend/src/types.ts

@@ -91,6 +91,17 @@ export interface RaceHub {
   race_control: RaceControlMessage[]
   weather: WeatherSample[]
   laps: Lap[]
+  chapters: Chapter[]
+}
+
+export interface Chapter {
+  kind: 'start' | 'safety_car' | 'virtual_safety_car' | 'red_flag' | 'pit_phase' | 'decisive_swing' | 'finish' | string
+  title: string
+  start_lap: number
+  end_lap: number
+  start_time?: string
+  end_time?: string
+  driver_numbers: number[]
 }
 
 export interface Stint {
@@ -362,6 +373,7 @@ export interface ChampHubDriver {
   poles: number
   form: number[]
   cumulative: number[]
+  round_positions: number[]
   teammate_wins: number
   teammate_losses: number
 }
@@ -385,6 +397,39 @@ export interface ChampionshipHub {
   teams: ChampHubTeam[]
 }
 
+export interface DriverSummaryRound {
+  meeting_key: number
+  meeting_name: string
+  country_code: string
+  country_name: string
+  race_position: number
+  grid_position: number
+  quali_position?: number
+  points: number
+  dnf: boolean
+  dns: boolean
+  dsq: boolean
+}
+
+export interface DriverSummary {
+  season: number
+  driver_number: number
+  name_acronym: string
+  full_name: string
+  team_name: string
+  team_colour: string
+  headshot_url: string
+  points: number
+  position: number
+  wins: number
+  podiums: number
+  poles: number
+  form: number[]
+  cumulative: number[]
+  round_labels: string[]
+  rounds: DriverSummaryRound[]
+}
+
 export interface NewsItem {
   source: string
   title: string

internal/chapters/chapters.go

@@ -0,0 +1,628 @@
+package chapters
+
+import (
+	"fmt"
+	"math"
+	"sort"
+	"strings"
+	"time"
+
+	"github.com/AmanTahiliani/box-box/internal/models"
+)
+
+const (
+	KindStart            = "start"
+	KindSafetyCar        = "safety_car"
+	KindVirtualSafetyCar = "virtual_safety_car"
+	KindRedFlag          = "red_flag"
+	KindPitPhase         = "pit_phase"
+	KindDecisiveSwing    = "decisive_swing"
+	KindFinish           = "finish"
+
+	pitPhaseWindowLaps = 3
+	pitPhaseShare      = 0.30
+	minPitPhaseStops   = 2
+	maxDecisiveSwings  = 3
+	decisiveAfterLap   = 5
+	structuralPriority = 110
+	flagPriority       = 100
+	pitPhasePriority   = 50
+	decisivePriority   = 40
+)
+
+type RaceControl = models.RaceControl
+type PositionSample = models.Position
+type Lap = models.Lap
+
+// Chapter is a deterministic replay segment derived from timing and race-control data.
+type Chapter struct {
+	Kind          string `json:"kind"`
+	Title         string `json:"title"`
+	StartLap      int    `json:"start_lap"`
+	EndLap        int    `json:"end_lap"`
+	StartTime     string `json:"start_time,omitempty"`
+	EndTime       string `json:"end_time,omitempty"`
+	DriverNumbers []int  `json:"driver_numbers"`
+}
+
+// Detect builds replay chapters from already-loaded race-hub datasets.
+func Detect(rc []RaceControl, positions []PositionSample, laps []Lap, totalLaps int) []Chapter {
+	totalLaps = normalizeTotalLaps(totalLaps, laps, rc)
+	if totalLaps <= 0 && len(rc) == 0 && len(positions) == 0 && len(laps) == 0 {
+		return []Chapter{}
+	}
+	if totalLaps <= 0 {
+		totalLaps = 1
+	}
+
+	lapIndex := buildLapIndex(laps)
+	chapters := []Chapter{
+		{
+			Kind:      KindStart,
+			Title:     "Start",
+			StartLap:  1,
+			EndLap:    minInt(1, totalLaps),
+			StartTime: lapIndex.lapStart(1),
+			EndTime:   lapIndex.lapEnd(1),
+		},
+	}
+	chapters = append(chapters, detectFlagPeriods(rc, lapIndex, totalLaps)...)
+	chapters = append(chapters, detectPitPhases(laps, lapIndex)...)
+	chapters = append(chapters, detectDecisiveSwings(positions, lapIndex, totalLaps)...)
+	chapters = append(chapters, detectFinish(rc, lapIndex, totalLaps))
+
+	return resolveConflicts(chapters)
+}
+
+func normalizeTotalLaps(totalLaps int, laps []Lap, rc []RaceControl) int {
+	for _, l := range laps {
+		if l.LapNumber > totalLaps {
+			totalLaps = l.LapNumber
+		}
+	}
+	for _, msg := range rc {
+		if msg.LapNumber != nil && *msg.LapNumber > totalLaps {
+			totalLaps = *msg.LapNumber
+		}
+	}
+	return totalLaps
+}
+
+type lapIndex struct {
+	byLap  map[int]string
+	events []lapEvent
+}
+
+type lapEvent struct {
+	lap int
+	at  time.Time
+}
+
+func buildLapIndex(laps []Lap) lapIndex {
+	idx := lapIndex{byLap: map[int]string{}}
+	for _, l := range laps {
+		if l.LapNumber <= 0 || l.DateStart == "" {
+			continue
+		}
+		if _, ok := idx.byLap[l.LapNumber]; !ok {
+			idx.byLap[l.LapNumber] = l.DateStart
+		}
+		at, ok := parseTime(l.DateStart)
+		if ok {
+			idx.events = append(idx.events, lapEvent{lap: l.LapNumber, at: at})
+		}
+	}
+	sort.Slice(idx.events, func(i, j int) bool {
+		if idx.events[i].at.Equal(idx.events[j].at) {
+			return idx.events[i].lap < idx.events[j].lap
+		}
+		return idx.events[i].at.Before(idx.events[j].at)
+	})
+	return idx
+}
+
+func (idx lapIndex) lapStart(lap int) string {
+	return idx.byLap[lap]
+}
+
+func (idx lapIndex) lapEnd(lap int) string {
+	if v := idx.byLap[lap+1]; v != "" {
+		return v
+	}
+	return idx.byLap[lap]
+}
+
+func (idx lapIndex) lapForTime(raw string) int {
+	at, ok := parseTime(raw)
+	if !ok || len(idx.events) == 0 {
+		return 0
+	}
+	lap := 0
+	for _, event := range idx.events {
+		if event.at.After(at) {
+			break
+		}
+		lap = event.lap
+	}
+	if lap == 0 {
+		return idx.events[0].lap
+	}
+	return lap
+}
+
+type flagState struct {
+	startLap  int
+	startTime string
+}
+
+func detectFlagPeriods(rc []RaceControl, idx lapIndex, totalLaps int) []Chapter {
+	var chapters []Chapter
+	active := map[string]flagState{}
+	for _, msg := range rc {
+		kind, ok := flagKind(msg)
+		if !ok && greenFlagClear(msg) {
+			for activeKind, st := range active {
+				lap := messageLap(msg, idx)
+				if lap <= 0 {
+					lap = st.startLap
+				}
+				endLap := clampLap(lap, st.startLap, totalLaps)
+				chapters = append(chapters, Chapter{
+					Kind:      activeKind,
+					Title:     flagTitle(activeKind, st.startLap, endLap),
+					StartLap:  st.startLap,
+					EndLap:    endLap,
+					StartTime: st.startTime,
+					EndTime:   firstNonEmpty(msg.Date, idx.lapEnd(endLap)),
+				})
+				delete(active, activeKind)
+			}
+			continue
+		}
+		if !ok {
+			continue
+		}
+		lap := messageLap(msg, idx)
+		if lap <= 0 {
+			lap = 1
+		}
+		if flagCleared(msg) {
+			st, ok := active[kind]
+			if !ok {
+				continue
+			}
+			endLap := clampLap(lap, st.startLap, totalLaps)
+			chapters = append(chapters, Chapter{
+				Kind:      kind,
+				Title:     flagTitle(kind, st.startLap, endLap),
+				StartLap:  st.startLap,
+				EndLap:    endLap,
+				StartTime: st.startTime,
+				EndTime:   firstNonEmpty(msg.Date, idx.lapEnd(endLap)),
+			})
+			delete(active, kind)
+			continue
+		}
+		if flagStarted(msg) {
+			active[kind] = flagState{
+				startLap:  clampLap(lap, 1, totalLaps),
+				startTime: firstNonEmpty(msg.Date, idx.lapStart(lap)),
+			}
+		}
+	}
+	for kind, st := range active {
+		endLap := totalLaps
+		chapters = append(chapters, Chapter{
+			Kind:      kind,
+			Title:     flagTitle(kind, st.startLap, endLap),
+			StartLap:  st.startLap,
+			EndLap:    endLap,
+			StartTime: st.startTime,
+			EndTime:   idx.lapEnd(endLap),
+		})
+	}
+	return chapters
+}
+
+func flagKind(msg RaceControl) (string, bool) {
+	text := upperText(string(msg.Category), string(msg.Flag), msg.Message)
+	if strings.Contains(text, "VSC") || strings.Contains(text, "VIRTUAL SAFETY CAR") {
+		return KindVirtualSafetyCar, true
+	}
+	if strings.Contains(text, "RED FLAG") || string(msg.Flag) == string(models.FlagRed) {
+		return KindRedFlag, true
+	}
+	if strings.Contains(text, "SAFETY CAR") || msg.Category == models.CategorySafetyCar {
+		return KindSafetyCar, true
+	}
+	return "", false
+}
+
+func flagStarted(msg RaceControl) bool {
+	text := upperText(string(msg.Category), string(msg.Flag), msg.Message)
+	if strings.Contains(text, "CLEAR") || strings.Contains(text, "ENDING") || strings.Contains(text, "IN THIS LAP") || strings.Contains(text, "GREEN") {
+		return false
+	}
+	return strings.Contains(text, "DEPLOY") ||
+		strings.Contains(text, "RED FLAG") ||
+		strings.Contains(text, "VIRTUAL SAFETY CAR") ||
+		strings.Contains(text, "VSC") ||
+		strings.Contains(text, "SAFETY CAR") ||
+		string(msg.Flag) == string(models.FlagRed)
+}
+
+func flagCleared(msg RaceControl) bool {
+	text := upperText(string(msg.Category), string(msg.Flag), msg.Message)
+	return strings.Contains(text, "CLEAR") ||
+		strings.Contains(text, "ENDING") ||
+		strings.Contains(text, "IN THIS LAP") ||
+		strings.Contains(text, "GREEN")
+}
+
+func greenFlagClear(msg RaceControl) bool {
+	text := upperText(string(msg.Flag), msg.Message)
+	return strings.Contains(text, "GREEN")
+}
+
+func flagTitle(kind string, startLap, endLap int) string {
+	name := "Flag period"
+	switch kind {
+	case KindSafetyCar:
+		name = "Safety Car"
+	case KindVirtualSafetyCar:
+		name = "Virtual Safety Car"
+	case KindRedFlag:
+		name = "Red Flag"
+	}
+	return fmt.Sprintf("%s (L%d-L%d)", name, startLap, endLap)
+}
+
+func detectPitPhases(laps []Lap, idx lapIndex) []Chapter {
+	type pitOut struct {
+		lap    int
+		driver int
+	}
+	var stops []pitOut
+	for _, l := range laps {
+		if l.IsPitOutLap && l.LapNumber > 0 {
+			stops = append(stops, pitOut{lap: l.LapNumber, driver: l.DriverNumber})
+		}
+	}
+	if len(stops) < minPitPhaseStops {
+		return nil
+	}
+	sort.Slice(stops, func(i, j int) bool {
+		if stops[i].lap == stops[j].lap {
+			return stops[i].driver < stops[j].driver
+		}
+		return stops[i].lap < stops[j].lap
+	})
+	needed := int(math.Ceil(float64(len(stops)) * pitPhaseShare))
+	if needed < minPitPhaseStops {
+		needed = minPitPhaseStops
+	}
+
+	var windows []Chapter
+	for i := 0; i < len(stops); i++ {
+		start := stops[i].lap
+		end := start + pitPhaseWindowLaps - 1
+		drivers := map[int]bool{}
+		count := 0
+		for _, stop := range stops {
+			if stop.lap < start || stop.lap > end {
+				continue
+			}
+			count++
+			drivers[stop.driver] = true
+		}
+		if count < needed {
+			continue
+		}
+		ch := Chapter{
+			Kind:          KindPitPhase,
+			Title:         fmt.Sprintf("Pit phase (L%d-L%d)", start, end),
+			StartLap:      start,
+			EndLap:        end,
+			StartTime:     idx.lapStart(start),
+			EndTime:       idx.lapEnd(end),
+			DriverNumbers: sortedDriverNumbers(drivers),
+		}
+		if len(windows) > 0 && ch.StartLap <= windows[len(windows)-1].EndLap+1 {
+			last := &windows[len(windows)-1]
+			if ch.EndLap > last.EndLap {
+				last.EndLap = ch.EndLap
+				last.EndTime = idx.lapEnd(last.EndLap)
+			}
+			drivers := sliceToSet(last.DriverNumbers)
+			for _, driver := range ch.DriverNumbers {
+				drivers[driver] = true
+			}
+			last.DriverNumbers = sortedDriverNumbers(drivers)
+			last.Title = fmt.Sprintf("Pit phase (L%d-L%d)", last.StartLap, last.EndLap)
+			continue
+		}
+		windows = append(windows, ch)
+	}
+	return windows
+}
+
+type swingCandidate struct {
+	chapter      Chapter
+	significance int
+}
+
+func detectDecisiveSwings(positions []PositionSample, idx lapIndex, totalLaps int) []Chapter {
+	if len(positions) == 0 || len(idx.events) == 0 || totalLaps <= decisiveAfterLap {
+		return nil
+	}
+	snapshots := buildPositionSnapshots(positions, idx, totalLaps)
+	if len(snapshots) == 0 {
+		return nil
+	}
+	final := snapshots[totalLaps]
+	if len(final) == 0 {
+		for lap := totalLaps - 1; lap >= 1; lap-- {
+			if len(snapshots[lap]) > 0 {
+				final = snapshots[lap]
+				break
+			}
+		}
+	}
+	var candidates []swingCandidate
+	seenDriver := map[int]bool{}
+	for lap := decisiveAfterLap + 1; lap <= totalLaps; lap++ {
+		prev := snapshots[lap-1]
+		curr := snapshots[lap]
+		if len(prev) == 0 || len(curr) == 0 {
+			continue
+		}
+		for driver, pos := range curr {
+			prevPos, ok := prev[driver]
+			if !ok || prevPos <= pos || pos > 5 || pos <= 0 || seenDriver[driver] {
+				continue
+			}
+			finalPos, ok := final[driver]
+			if !ok || finalPos > pos {
+				continue
+			}
+			overtaken := driverAtPosition(curr, prevPos, driver)
+			drivers := []int{driver}
+			if overtaken != 0 {
+				drivers = append(drivers, overtaken)
+			}
+			candidates = append(candidates, swingCandidate{
+				chapter: Chapter{
+					Kind:          KindDecisiveSwing,
+					Title:         fmt.Sprintf("Decisive swing: #%d to P%d (L%d)", driver, pos, lap),
+					StartLap:      lap,
+					EndLap:        lap,
+					StartTime:     idx.lapStart(lap),
+					EndTime:       idx.lapEnd(lap),
+					DriverNumbers: drivers,
+				},
+				significance: (prevPos-pos)*10 + (6 - pos),
+			})
+			seenDriver[driver] = true
+		}
+	}
+	sort.Slice(candidates, func(i, j int) bool {
+		if candidates[i].significance == candidates[j].significance {
+			return candidates[i].chapter.StartLap < candidates[j].chapter.StartLap
+		}
+		return candidates[i].significance > candidates[j].significance
+	})
+	if len(candidates) > maxDecisiveSwings {
+		candidates = candidates[:maxDecisiveSwings]
+	}
+	out := make([]Chapter, 0, len(candidates))
+	for _, c := range candidates {
+		out = append(out, c.chapter)
+	}
+	return out
+}
+
+func buildPositionSnapshots(positions []PositionSample, idx lapIndex, totalLaps int) map[int]map[int]int {
+	byLap := map[int][]PositionSample{}
+	for _, p := range positions {
+		if p.Position <= 0 {
+			continue
+		}
+		lap := idx.lapForTime(p.Date)
+		if lap <= 0 || lap > totalLaps {
+			continue
+		}
+		byLap[lap] = append(byLap[lap], p)
+	}
+	last := map[int]int{}
+	snapshots := map[int]map[int]int{}
+	for lap := 1; lap <= totalLaps; lap++ {
+		for _, p := range byLap[lap] {
+			last[p.DriverNumber] = p.Position
+		}
+		if len(last) == 0 {
+			continue
+		}
+		cp := make(map[int]int, len(last))
+		for driver, pos := range last {
+			cp[driver] = pos
+		}
+		snapshots[lap] = cp
+	}
+	return snapshots
+}
+
+func driverAtPosition(snapshot map[int]int, pos int, exclude int) int {
+	for driver, driverPos := range snapshot {
+		if driver != exclude && driverPos == pos {
+			return driver
+		}
+	}
+	return 0
+}
+
+func detectFinish(rc []RaceControl, idx lapIndex, totalLaps int) Chapter {
+	finishLap := totalLaps
+	finishTime := idx.lapEnd(totalLaps)
+	for _, msg := range rc {
+		text := upperText(string(msg.Flag), msg.Message)
+		if strings.Contains(text, "CHEQUER") || string(msg.Flag) == string(models.FlagChequered) {
+			if lap := messageLap(msg, idx); lap > 0 {
+				finishLap = lap
+			}
+			finishTime = firstNonEmpty(msg.Date, finishTime)
+		}
+	}
+	startLap := finishLap - 1
+	if startLap < 1 {
+		startLap = 1
+	}
+	return Chapter{
+		Kind:      KindFinish,
+		Title:     fmt.Sprintf("Finish (L%d-L%d)", startLap, finishLap),
+		StartLap:  startLap,
+		EndLap:    finishLap,
+		StartTime: idx.lapStart(startLap),
+		EndTime:   finishTime,
+	}
+}
+
+func resolveConflicts(chapters []Chapter) []Chapter {
+	normalized := make([]Chapter, 0, len(chapters))
+	for _, ch := range chapters {
+		if ch.StartLap <= 0 {
+			ch.StartLap = 1
+		}
+		if ch.EndLap <= 0 {
+			ch.EndLap = ch.StartLap
+		}
+		if ch.EndLap < ch.StartLap {
+			ch.EndLap = ch.StartLap
+		}
+		if ch.DriverNumbers == nil {
+			ch.DriverNumbers = []int{}
+		}
+		normalized = append(normalized, ch)
+	}
+	sort.SliceStable(normalized, func(i, j int) bool {
+		if normalized[i].StartLap == normalized[j].StartLap {
+			return priority(normalized[i].Kind) > priority(normalized[j].Kind)
+		}
+		return normalized[i].StartLap < normalized[j].StartLap
+	})
+
+	out := make([]Chapter, 0, len(normalized))
+	for _, ch := range normalized {
+		if len(out) == 0 {
+			out = append(out, ch)
+			continue
+		}
+		last := &out[len(out)-1]
+		if ch.StartLap > last.EndLap {
+			out = append(out, ch)
+			continue
+		}
+		if isFlag(last.Kind) && priority(ch.Kind) < priority(last.Kind) {
+			continue
+		}
+		if priority(ch.Kind) > priority(last.Kind) {
+			if last.StartLap < ch.StartLap {
+				last.EndLap = ch.StartLap - 1
+				out = append(out, ch)
+			} else {
+				*last = ch
+			}
+			continue
+		}
+		if ch.EndLap > last.EndLap {
+			ch.StartLap = last.EndLap + 1
+			if ch.StartLap <= ch.EndLap {
+				out = append(out, ch)
+			}
+		}
+	}
+	return out
+}
+
+func isFlag(kind string) bool {
+	return kind == KindSafetyCar || kind == KindVirtualSafetyCar || kind == KindRedFlag
+}
+
+func priority(kind string) int {
+	switch kind {
+	case KindStart, KindFinish:
+		return structuralPriority
+	case KindSafetyCar, KindVirtualSafetyCar, KindRedFlag:
+		return flagPriority
+	case KindPitPhase:
+		return pitPhasePriority
+	case KindDecisiveSwing:
+		return decisivePriority
+	default:
+		return 0
+	}
+}
+
+func messageLap(msg RaceControl, idx lapIndex) int {
+	if msg.LapNumber != nil && *msg.LapNumber > 0 {
+		return *msg.LapNumber
+	}
+	return idx.lapForTime(msg.Date)
+}
+
+func clampLap(lap, minLap, maxLap int) int {
+	if lap < minLap {
+		return minLap
+	}
+	if maxLap > 0 && lap > maxLap {
+		return maxLap
+	}
+	return lap
+}
+
+func parseTime(raw string) (time.Time, bool) {
+	if raw == "" {
+		return time.Time{}, false
+	}
+	at, err := time.Parse(time.RFC3339, raw)
+	if err != nil {
+		return time.Time{}, false
+	}
+	return at, true
+}
+
+func upperText(parts ...string) string {
+	return strings.ToUpper(strings.Join(parts, " "))
+}
+
+func firstNonEmpty(values ...string) string {
+	for _, value := range values {
+		if value != "" {
+			return value
+		}
+	}
+	return ""
+}
+
+func sortedDriverNumbers(drivers map[int]bool) []int {
+	out := make([]int, 0, len(drivers))
+	for driver := range drivers {
+		out = append(out, driver)
+	}
+	sort.Ints(out)
+	return out
+}
+
+func sliceToSet(values []int) map[int]bool {
+	out := make(map[int]bool, len(values))
+	for _, value := range values {
+		out[value] = true
+	}
+	return out
+}
+
+func minInt(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}

internal/chapters/chapters_test.go

@@ -0,0 +1,218 @@
+package chapters
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/AmanTahiliani/box-box/internal/models"
+)
+
+func TestDetectStructuralChapters(t *testing.T) {
+	chapters := Detect(nil, nil, testLaps(10, nil), 10)
+
+	if len(chapters) < 2 {
+		t.Fatalf("chapters len = %d, want at least start and finish", len(chapters))
+	}
+	if got := chapters[0]; got.Kind != KindStart || got.StartLap != 1 || got.EndLap != 1 {
+		t.Fatalf("start chapter = %+v, want L1-L1", got)
+	}
+	got := chapters[len(chapters)-1]
+	if got.Kind != KindFinish || got.StartLap != 9 || got.EndLap != 10 {
+		t.Fatalf("finish chapter = %+v, want L9-L10", got)
+	}
+}
+
+func TestDetectReturnsEmptyWithoutData(t *testing.T) {
+	if chapters := Detect(nil, nil, nil, 0); len(chapters) != 0 {
+		t.Fatalf("chapters = %+v, want empty", chapters)
+	}
+}
+
+func TestDetectFlagPeriods(t *testing.T) {
+	tests := []struct {
+		name      string
+		start     RaceControl
+		end       RaceControl
+		wantKind  string
+		wantTitle string
+	}{
+		{
+			name:      "safety car",
+			start:     rc(12, models.CategorySafetyCar, "", "SAFETY CAR DEPLOYED"),
+			end:       rc(15, models.CategorySafetyCar, "", "SAFETY CAR IN THIS LAP"),
+			wantKind:  KindSafetyCar,
+			wantTitle: "Safety Car (L12-L15)",
+		},
+		{
+			name:      "virtual safety car",
+			start:     rc(22, models.CategoryOther, "", "VSC DEPLOYED"),
+			end:       rc(24, models.CategoryOther, "", "VSC ENDING"),
+			wantKind:  KindVirtualSafetyCar,
+			wantTitle: "Virtual Safety Car (L22-L24)",
+		},
+		{
+			name:      "red flag",
+			start:     rc(31, models.CategoryFlag, models.FlagRed, "RED FLAG"),
+			end:       rc(33, models.CategoryFlag, models.FlagGreen, "GREEN FLAG"),
+			wantKind:  KindRedFlag,
+			wantTitle: "Red Flag (L31-L33)",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			chapters := Detect([]RaceControl{tt.start, tt.end}, nil, testLaps(40, nil), 40)
+			got := findKind(chapters, tt.wantKind)
+			if got == nil {
+				t.Fatalf("chapters = %+v, want %s", chapters, tt.wantKind)
+			}
+			if got.StartLap != rcLap(tt.start) || got.EndLap != rcLap(tt.end) || got.Title != tt.wantTitle {
+				t.Fatalf("flag chapter = %+v, want %s", *got, tt.wantTitle)
+			}
+		})
+	}
+}
+
+func TestDetectPitPhaseFromPitOutLapCluster(t *testing.T) {
+	pitOuts := map[int][]int{
+		5:  {1},
+		10: {2},
+		20: {3},
+		21: {4},
+		22: {5},
+		30: {6},
+		35: {7},
+		40: {8},
+		45: {9},
+		50: {10},
+	}
+	chapters := Detect(nil, nil, testLaps(55, pitOuts), 55)
+
+	got := findKind(chapters, KindPitPhase)
+	if got == nil {
+		t.Fatalf("chapters = %+v, want pit phase", chapters)
+	}
+	if got.StartLap != 20 || got.EndLap != 22 {
+		t.Fatalf("pit phase = %+v, want L20-L22", *got)
+	}
+	if len(got.DriverNumbers) != 3 || got.DriverNumbers[0] != 3 || got.DriverNumbers[2] != 5 {
+		t.Fatalf("pit phase drivers = %v, want [3 4 5]", got.DriverNumbers)
+	}
+}
+
+func TestDetectDecisiveSwingPersistsToFinish(t *testing.T) {
+	positions := []PositionSample{
+		pos(1, 1, 1),
+		pos(1, 16, 4),
+		pos(1, 55, 3),
+		pos(6, 16, 3),
+		pos(6, 55, 4),
+		pos(8, 44, 5),
+		pos(8, 63, 6),
+		pos(10, 44, 6),
+	}
+
+	chapters := Detect(nil, positions, testLaps(12, nil), 12)
+	got := findKind(chapters, KindDecisiveSwing)
+	if got == nil {
+		t.Fatalf("chapters = %+v, want decisive swing", chapters)
+	}
+	if got.StartLap != 6 || got.EndLap != 6 {
+		t.Fatalf("swing lap = %+v, want L6", *got)
+	}
+	if len(got.DriverNumbers) != 2 || got.DriverNumbers[0] != 16 || got.DriverNumbers[1] != 55 {
+		t.Fatalf("swing drivers = %v, want [16 55]", got.DriverNumbers)
+	}
+}
+
+func TestDetectFlagPeriodsWinOverConflictingChapters(t *testing.T) {
+	pitOuts := map[int][]int{
+		12: {1, 2},
+		13: {3, 4},
+		14: {5, 6},
+	}
+	rcs := []RaceControl{
+		rc(12, models.CategorySafetyCar, "", "SAFETY CAR DEPLOYED"),
+		rc(15, models.CategorySafetyCar, "", "SAFETY CAR IN THIS LAP"),
+	}
+
+	chapters := Detect(rcs, nil, testLaps(20, pitOuts), 20)
+	if got := findKind(chapters, KindSafetyCar); got == nil || got.StartLap != 12 || got.EndLap != 15 {
+		t.Fatalf("chapters = %+v, want safety car L12-L15", chapters)
+	}
+	if got := findKind(chapters, KindPitPhase); got != nil {
+		t.Fatalf("pit phase = %+v, want omitted under safety car", *got)
+	}
+	for i := 1; i < len(chapters); i++ {
+		if chapters[i].StartLap <= chapters[i-1].EndLap {
+			t.Fatalf("chapters overlap at %d: %+v then %+v", i, chapters[i-1], chapters[i])
+		}
+	}
+}
+
+func rcLap(r RaceControl) int {
+	if r.LapNumber == nil {
+		return 0
+	}
+	return *r.LapNumber
+}
+
+func findKind(chapters []Chapter, kind string) *Chapter {
+	for i := range chapters {
+		if chapters[i].Kind == kind {
+			return &chapters[i]
+		}
+	}
+	return nil
+}
+
+func testLaps(total int, pitOuts map[int][]int) []Lap {
+	var laps []Lap
+	for lap := 1; lap <= total; lap++ {
+		drivers := []int{1}
+		if pitDrivers := pitOuts[lap]; len(pitDrivers) > 0 {
+			drivers = pitDrivers
+		}
+		for _, driver := range drivers {
+			laps = append(laps, Lap{
+				DriverNumber: driver,
+				LapNumber:    lap,
+				DateStart:    lapTime(lap),
+				IsPitOutLap:  containsDriver(pitOuts[lap], driver),
+			})
+		}
+	}
+	return laps
+}
+
+func rc(lap int, category models.RaceControlCategory, flag models.Flag, message string) RaceControl {
+	return RaceControl{
+		Category:  category,
+		Flag:      flag,
+		Message:   message,
+		LapNumber: &lap,
+		Date:      lapTime(lap),
+	}
+}
+
+func pos(lap int, driver int, position int) PositionSample {
+	return PositionSample{
+		DriverNumber: driver,
+		Position:     position,
+		Date:         lapTime(lap),
+	}
+}
+
+func lapTime(lap int) string {
+	minute := lap - 1
+	return fmt.Sprintf("2025-05-25T13:%02d:00Z", minute)
+}
+
+func containsDriver(drivers []int, driver int) bool {
+	for _, candidate := range drivers {
+		if candidate == driver {
+			return true
+		}
+	}
+	return false
+}

internal/query/racehub.go

@@ -4,6 +4,7 @@ import (
 	"database/sql"
 	"errors"
 
+	"github.com/AmanTahiliani/box-box/internal/chapters"
 	"github.com/AmanTahiliani/box-box/internal/models"
 	"github.com/AmanTahiliani/box-box/internal/store"
 )
@@ -52,6 +53,7 @@ type RaceHub struct {
 	RaceControl  []models.RaceControl   `json:"race_control"`
 	Weather      []models.Weather       `json:"weather"`
 	Laps         []models.Lap           `json:"laps"`
+	Chapters     []chapters.Chapter     `json:"chapters"`
 }
 
 // GetRaceHub loads ingested Race Hub datasets for a session from the local store.
@@ -80,6 +82,7 @@ func (s *Service) GetRaceHub(sessionKey int) (RaceHub, error) {
 		RaceControl:  []models.RaceControl{},
 		Weather:      []models.Weather{},
 		Laps:         []models.Lap{},
+		Chapters:     []chapters.Chapter{},
 	}
 
 	sess, err := s.store.GetSession(sessionKey)
@@ -248,6 +251,22 @@ func (s *Service) GetRaceHub(sessionKey int) (RaceHub, error) {
 		hub.Datasets["laps"] = availableLocal(len(hub.Laps))
 	}
 
+	hub.Chapters = chapters.Detect(hub.RaceControl, hub.Positions, hub.Laps, totalLaps(hub.Results, hub.Laps))
 	hub.Source = responseSource(hub.Datasets)
 	return hub, nil
 }
+
+func totalLaps(results []EnrichedResult, laps []models.Lap) int {
+	total := 0
+	for _, result := range results {
+		if result.NumberOfLaps > total {
+			total = result.NumberOfLaps
+		}
+	}
+	for _, lap := range laps {
+		if lap.LapNumber > total {
+			total = lap.LapNumber
+		}
+	}
+	return total
+}

internal/web/api.go

@@ -616,6 +616,7 @@ type champHubDriver struct {
 	Poles          int       `json:"poles"`
 	Form           []float64 `json:"form"`            // last 5 races' points
 	Cumulative     []float64 `json:"cumulative"`      // running total per completed round
+	RoundPositions []int     `json:"round_positions"` // finishing position per completed round (0 = no result)
 	TeammateWins   int       `json:"teammate_wins"`
 	TeammateLosses int       `json:"teammate_losses"`
 }
@@ -797,11 +798,6 @@ func (s *Server) localChampionshipHub(year int) (champHubResponse, bool, error)
 }
 
 func (s *Server) openF1ChampionshipHub(year int) (champHubResponse, error) {
-	meetings, err := s.client.GetMeetingsForYear(year)
-	if err != nil {
-		return champHubResponse{}, err
-	}
-
 	champ, err := s.client.GetDriverChampionshipForYear(year)
 	if err != nil {
 		return champHubResponse{}, err
@@ -816,16 +812,39 @@ func (s *Server) openF1ChampionshipHub(year int) (champHubResponse, error) {
 		driverInfo = buildDriverMapFirst(ds)
 	}
 
-	sort.Slice(meetings, func(i, j int) bool { return meetings[i].DateStart < meetings[j].DateStart })
+	races, incomplete, err := s.fetchSeasonRaces(year)
+	if err != nil {
+		return champHubResponse{}, err
+	}
 
+	resp := aggregateChampionshipHub(year, races, champ, teams, driverInfo)
+	ttl := champHubTTL(year, time.Now())
+	if incomplete {
 		// Any per-meeting fetch failure (network, rate limit) yields an incomplete
 		// aggregate: serve it so the page still renders, but cache it only briefly
 		// so a partial view of the season doesn't stick around for the full TTL.
-	var incomplete atomic.Bool
-	races := fetchMeetingRaces(meetings, champHubWorkers, func(m models.Meeting) (meetingRace, bool) {
+		ttl = champHubIncompleteTTL
+	}
+	s.hubCache.put(year, resp, time.Now(), ttl)
+	return resp, nil
+}
+
+// fetchSeasonRaces returns a season's GP meetings in date order, each bundled
+// with its race results and starting grid fetched from OpenF1. incomplete
+// reports whether any per-meeting fetch failed, so callers can avoid caching a
+// partial view of the season for long.
+func (s *Server) fetchSeasonRaces(year int) (races []meetingRace, incomplete bool, err error) {
+	meetings, err := s.client.GetMeetingsForYear(year)
+	if err != nil {
+		return nil, false, err
+	}
+	sort.Slice(meetings, func(i, j int) bool { return meetings[i].DateStart < meetings[j].DateStart })
+
+	var failed atomic.Bool
+	races = fetchMeetingRaces(meetings, champHubWorkers, func(m models.Meeting) (meetingRace, bool) {
 		sessions, serr := s.client.GetSessionsForMeeting(int(m.MeetingKey))
 		if serr != nil {
-			incomplete.Store(true)
+			failed.Store(true)
 			return meetingRace{}, false
 		}
 		raceKey := 0
@@ -841,18 +860,11 @@ func (s *Server) openF1ChampionshipHub(year int) (champHubResponse, error) {
 		results, rerr := s.client.GetSessionResult(raceKey)
 		grid, gerr := s.client.GetStartingGrid(raceKey)
 		if rerr != nil || gerr != nil {
-			incomplete.Store(true)
+			failed.Store(true)
 		}
 		return meetingRace{Meeting: m, RaceSessionKey: raceKey, Results: results, Grid: grid}, true
 	})
-
-	resp := aggregateChampionshipHub(year, races, champ, teams, driverInfo)
-	ttl := champHubTTL(year, time.Now())
-	if incomplete.Load() {
-		ttl = champHubIncompleteTTL
-	}
-	s.hubCache.put(year, resp, time.Now(), ttl)
-	return resp, nil
+	return races, failed.Load(), nil
 }
 
 // aggregateChampionshipHub is the pure aggregation core (no network) so it can be
@@ -984,6 +996,10 @@ func aggregateChampionshipHub(
 		if len(form) > 5 {
 			form = form[len(form)-5:]
 		}
+		roundPositions := make([]int, completed)
+		for round := 1; round <= completed; round++ {
+			roundPositions[round-1] = a.finishByRound[round]
+		}
 		info := driverInfo[c.DriverNumber]
 		drivers = append(drivers, champHubDriver{
 			DriverNumber:   c.DriverNumber,
@@ -998,6 +1014,7 @@ func aggregateChampionshipHub(
 			Poles:          a.poles,
 			Form:           form,
 			Cumulative:     cumulative[c.DriverNumber],
+			RoundPositions: roundPositions,
 			TeammateWins:   twins[c.DriverNumber],
 			TeammateLosses: tloss[c.DriverNumber],
 		})

internal/web/championship_hub_test.go

@@ -17,20 +17,22 @@ func TestAggregateChampionshipHub(t *testing.T) {
 		1: {DriverNumber: 1, NameAcronym: "VER", FullName: "Max Verstappen", TeamName: "Red Bull", TeamColour: "3671c6"},
 		2: {DriverNumber: 2, NameAcronym: "PER", FullName: "Sergio Perez", TeamName: "Red Bull", TeamColour: "3671c6"},
 		3: {DriverNumber: 3, NameAcronym: "HAM", FullName: "Lewis Hamilton", TeamName: "Mercedes", TeamColour: "27f4d2"},
+		4: {DriverNumber: 4, NameAcronym: "NOR", FullName: "Lando Norris", TeamName: "McLaren", TeamColour: "ff8000"},
 	}
 
 	champ := []models.ChampionshipDriver{
 		{DriverNumber: 1, PointsCurrent: 50, PositionCurrent: 1, SessionKey: 99},
 		{DriverNumber: 3, PointsCurrent: 33, PositionCurrent: 2, SessionKey: 99},
 		{DriverNumber: 2, PointsCurrent: 30, PositionCurrent: 3, SessionKey: 99},
+		{DriverNumber: 4, PointsCurrent: 12, PositionCurrent: 4, SessionKey: 99},
 	}
 	teams := []models.ChampionshipTeam{
 		{TeamName: "Red Bull", PointsCurrent: 80, PositionCurrent: 1},
 		{TeamName: "Mercedes", PointsCurrent: 33, PositionCurrent: 2},
 	}
 
-	// Round 1: VER P1(25), HAM P2(18), PER P3(15). Pole: VER.
-	// Round 2: VER P1(25), PER P2(18), HAM P3(15). Pole: HAM.
+	// Round 1: VER P1(25), HAM P2(18), PER P3(15). Pole: VER. NOR absent.
+	// Round 2: VER P1(25), PER P2(18), HAM P3(15), NOR P4(12). Pole: HAM.
 	races := []meetingRace{
 		{
 			Meeting: models.Meeting{MeetingName: "Bahrain GP"},
@@ -39,7 +41,7 @@ func TestAggregateChampionshipHub(t *testing.T) {
 		},
 		{
 			Meeting: models.Meeting{MeetingName: "Saudi GP"},
-			Results: []models.SessionResult{raceResult(1, 1, 25), raceResult(2, 2, 18), raceResult(3, 3, 15)},
+			Results: []models.SessionResult{raceResult(1, 1, 25), raceResult(2, 2, 18), raceResult(3, 3, 15), raceResult(4, 4, 12)},
 			Grid:    []models.StartingGrid{{DriverNumber: 3, Position: 1}},
 		},
 		// Round 3: not yet run (no results) — should not count as completed.
@@ -67,9 +69,9 @@ func TestAggregateChampionshipHub(t *testing.T) {
 		t.Errorf("round labels = %v, want [R1 R2]", resp.RoundLabels)
 	}
 
-	// Drivers are sorted by official position: VER, HAM, PER.
-	if len(resp.Drivers) != 3 {
-		t.Fatalf("drivers = %d, want 3", len(resp.Drivers))
+	// Drivers are sorted by official position: VER, HAM, PER, NOR.
+	if len(resp.Drivers) != 4 {
+		t.Fatalf("drivers = %d, want 4", len(resp.Drivers))
 	}
 	ver := resp.Drivers[0]
 	if ver.NameAcronym != "VER" || ver.Position != 1 {
@@ -91,6 +93,9 @@ func TestAggregateChampionshipHub(t *testing.T) {
 	if len(ver.Cumulative) != 2 || ver.Cumulative[0] != 25 || ver.Cumulative[1] != 50 {
 		t.Errorf("VER cumulative = %v, want [25 50]", ver.Cumulative)
 	}
+	if len(ver.RoundPositions) != 2 || ver.RoundPositions[0] != 1 || ver.RoundPositions[1] != 1 {
+		t.Errorf("VER round positions = %v, want [1 1]", ver.RoundPositions)
+	}
 	// VER beat teammate PER in both rounds.
 	if ver.TeammateWins != 2 || ver.TeammateLosses != 0 {
 		t.Errorf("VER h2h = %d-%d, want 2-0", ver.TeammateWins, ver.TeammateLosses)
@@ -109,6 +114,9 @@ func TestAggregateChampionshipHub(t *testing.T) {
 	if per.Poles != 0 {
 		t.Errorf("PER poles = %d, want 0", per.Poles)
 	}
+	if len(per.RoundPositions) != 2 || per.RoundPositions[0] != 3 || per.RoundPositions[1] != 2 {
+		t.Errorf("PER round positions = %v, want [3 2]", per.RoundPositions)
+	}
 
 	// HAM has no teammate in the data — no h2h recorded.
 	var ham champHubDriver
@@ -124,6 +132,17 @@ func TestAggregateChampionshipHub(t *testing.T) {
 		t.Errorf("HAM poles = %d, want 1", ham.Poles)
 	}
 
+	// NOR missed round 1 — position 0 marks the absent round.
+	var nor champHubDriver
+	for _, d := range resp.Drivers {
+		if d.NameAcronym == "NOR" {
+			nor = d
+		}
+	}
+	if len(nor.RoundPositions) != 2 || nor.RoundPositions[0] != 0 || nor.RoundPositions[1] != 4 {
+		t.Errorf("NOR round positions = %v, want [0 4]", nor.RoundPositions)
+	}
+
 	// Teams sorted by position; Red Bull wins = VER(2) + PER(0) = 2.
 	if len(resp.Teams) != 2 {
 		t.Fatalf("teams = %d, want 2", len(resp.Teams))

internal/web/driversummary.go

@@ -0,0 +1,177 @@
+package web
+
+import (
+	"fmt"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/AmanTahiliani/box-box/internal/models"
+)
+
+// --- /api/v1/driver/summary ---
+// Per-driver season summary: championship standing plus per-round race results,
+// aggregated server-side from the same sources as the championship hub. Caching
+// relies on the OpenF1 client's HTTP cache TTLs — no extra layer here.
+
+type driverSummaryRound struct {
+	MeetingKey  int    `json:"meeting_key"`
+	MeetingName string `json:"meeting_name"`
+	CountryCode string `json:"country_code"`
+	CountryName string `json:"country_name"`
+	// RacePosition and GridPosition are 0 when the driver has no entry for the
+	// round (did not enter, or data missing).
+	RacePosition int `json:"race_position"`
+	GridPosition int `json:"grid_position"`
+	// QualiPosition is derived from the starting grid in v1 (full qualifying
+	// session results are deferred); omitted when unknown.
+	QualiPosition int     `json:"quali_position,omitempty"`
+	Points        float64 `json:"points"`
+	DNF           bool    `json:"dnf"`
+	DNS           bool    `json:"dns"`
+	DSQ           bool    `json:"dsq"`
+}
+
+type driverSummaryResponse struct {
+	Season       int                  `json:"season"`
+	DriverNumber int                  `json:"driver_number"`
+	NameAcronym  string               `json:"name_acronym"`
+	FullName     string               `json:"full_name"`
+	TeamName     string               `json:"team_name"`
+	TeamColour   string               `json:"team_colour"`
+	HeadshotURL  string               `json:"headshot_url"`
+	Points       float64              `json:"points"`
+	Position     int                  `json:"position"`
+	Wins         int                  `json:"wins"`
+	Podiums      int                  `json:"podiums"`
+	Poles        int                  `json:"poles"`
+	Form         []float64            `json:"form"`
+	Cumulative   []float64            `json:"cumulative"`
+	RoundLabels  []string             `json:"round_labels"`
+	Rounds       []driverSummaryRound `json:"rounds"`
+}
+
+func (s *Server) handleDriverSummary(w http.ResponseWriter, r *http.Request) {
+	driverNumber, err := strconv.Atoi(r.URL.Query().Get("driver_number"))
+	if err != nil || driverNumber <= 0 {
+		http.Error(w, "driver_number required", http.StatusBadRequest)
+		return
+	}
+	year, _ := strconv.Atoi(r.URL.Query().Get("year"))
+	if year == 0 {
+		year = time.Now().Year()
+	}
+
+	champ, err := s.client.GetDriverChampionshipForYear(year)
+	if err != nil {
+		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		return
+	}
+	var entry *models.ChampionshipDriver
+	for i := range champ {
+		if champ[i].DriverNumber == driverNumber {
+			entry = &champ[i]
+			break
+		}
+	}
+	if entry == nil {
+		http.Error(w, fmt.Sprintf("driver %d not found in %d championship", driverNumber, year), http.StatusNotFound)
+		return
+	}
+
+	driverInfo := map[int]models.Driver{}
+	if ds, derr := s.client.GetDriversForSession(champ[0].SessionKey); derr == nil {
+		driverInfo = buildDriverMapFirst(ds)
+	}
+	if d, ok := s.championshipDriverInfo(entry.SessionKey, driverNumber, driverInfo); ok {
+		driverInfo[driverNumber] = d
+	}
+
+	races, _, err := s.fetchSeasonRaces(year)
+	if err != nil {
+		writeError(w, err, http.StatusInternalServerError, s.client.LastResponseWasStale())
+		return
+	}
+
+	resp, ok := aggregateDriverSummary(year, driverNumber, races, champ, driverInfo)
+	if !ok {
+		http.Error(w, fmt.Sprintf("driver %d not found in %d championship", driverNumber, year), http.StatusNotFound)
+		return
+	}
+	writeJSON(w, resp)
+}
+
+// aggregateDriverSummary is the pure aggregation core (no network) so it can be
+// unit-tested with synthetic data. It reuses the championship-hub aggregation
+// for the derived season stats (wins, podiums, poles, form, cumulative) and
+// adds the per-round result rows. races must be ordered ascending by date and
+// contain only GP meetings. Returns ok=false when the driver is not in champ.
+func aggregateDriverSummary(
+	year, driverNumber int,
+	races []meetingRace,
+	champ []models.ChampionshipDriver,
+	driverInfo map[int]models.Driver,
+) (driverSummaryResponse, bool) {
+	hub := aggregateChampionshipHub(year, races, champ, nil, driverInfo)
+
+	var hd *champHubDriver
+	for i := range hub.Drivers {
+		if hub.Drivers[i].DriverNumber == driverNumber {
+			hd = &hub.Drivers[i]
+			break
+		}
+	}
+	if hd == nil {
+		return driverSummaryResponse{}, false
+	}
+
+	rounds := make([]driverSummaryRound, 0, len(races))
+	for _, mr := range races {
+		if len(mr.Results) == 0 {
+			continue // round not completed yet
+		}
+		round := driverSummaryRound{
+			MeetingKey:  int(mr.Meeting.MeetingKey),
+			MeetingName: mr.Meeting.MeetingName,
+			CountryCode: mr.Meeting.CountryCode,
+			CountryName: mr.Meeting.CountryName,
+		}
+		for _, res := range mr.Results {
+			if res.DriverNumber == driverNumber {
+				round.RacePosition = res.Position
+				round.Points = res.Points
+				round.DNF = res.DNF
+				round.DNS = res.DNS
+				round.DSQ = res.DSQ
+				break
+			}
+		}
+		for _, g := range mr.Grid {
+			if g.DriverNumber == driverNumber {
+				round.GridPosition = g.Position
+				round.QualiPosition = g.Position
+				break
+			}
+		}
+		rounds = append(rounds, round)
+	}
+
+	return driverSummaryResponse{
+		Season:       year,
+		DriverNumber: hd.DriverNumber,
+		NameAcronym:  hd.NameAcronym,
+		FullName:     hd.FullName,
+		TeamName:     hd.TeamName,
+		TeamColour:   hd.TeamColour,
+		HeadshotURL:  driverInfo[driverNumber].HeadshotURL,
+		Points:       hd.Points,
+		Position:     hd.Position,
+		Wins:         hd.Wins,
+		Podiums:      hd.Podiums,
+		Poles:        hd.Poles,
+		Form:         hd.Form,
+		Cumulative:   hd.Cumulative,
+		RoundLabels:  hub.RoundLabels,
+		Rounds:       rounds,
+	}, true
+}

internal/web/driversummary_test.go

@@ -0,0 +1,136 @@
+package web
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/AmanTahiliani/box-box/internal/models"
+)
+
+func driverSummaryFixtures() ([]meetingRace, []models.ChampionshipDriver, map[int]models.Driver) {
+	driverInfo := map[int]models.Driver{
+		1: {DriverNumber: 1, NameAcronym: "VER", FullName: "Max Verstappen", TeamName: "Red Bull", TeamColour: "3671c6", HeadshotURL: "https://example.com/ver.png"},
+		3: {DriverNumber: 3, NameAcronym: "HAM", FullName: "Lewis Hamilton", TeamName: "Mercedes", TeamColour: "27f4d2"},
+	}
+
+	champ := []models.ChampionshipDriver{
+		{DriverNumber: 1, PointsCurrent: 50, PositionCurrent: 1, SessionKey: 99},
+		{DriverNumber: 3, PointsCurrent: 33, PositionCurrent: 2, SessionKey: 99},
+	}
+
+	// Round 1: VER P1 from pole, HAM P2 from P3.
+	// Round 2: VER P1 from P2, HAM P3 from pole.
+	// Round 3: not yet run — must not appear in rounds.
+	races := []meetingRace{
+		{
+			Meeting: models.Meeting{MeetingKey: 1201, MeetingName: "Bahrain GP", CountryCode: "BHR", CountryName: "Bahrain"},
+			Results: []models.SessionResult{raceResult(1, 1, 25), raceResult(3, 2, 18)},
+			Grid:    []models.StartingGrid{{DriverNumber: 1, Position: 1}, {DriverNumber: 3, Position: 3}},
+		},
+		{
+			Meeting: models.Meeting{MeetingKey: 1202, MeetingName: "Saudi GP", CountryCode: "SAU", CountryName: "Saudi Arabia"},
+			Results: []models.SessionResult{raceResult(1, 1, 25), raceResult(3, 3, 15)},
+			Grid:    []models.StartingGrid{{DriverNumber: 3, Position: 1}, {DriverNumber: 1, Position: 2}},
+		},
+		{Meeting: models.Meeting{MeetingKey: 1203, MeetingName: "Australia GP"}},
+	}
+	return races, champ, driverInfo
+}
+
+func TestAggregateDriverSummary(t *testing.T) {
+	races, champ, driverInfo := driverSummaryFixtures()
+
+	resp, ok := aggregateDriverSummary(2025, 1, races, champ, driverInfo)
+	if !ok {
+		t.Fatal("aggregateDriverSummary ok = false, want true")
+	}
+
+	if resp.Season != 2025 || resp.DriverNumber != 1 {
+		t.Errorf("season/driver = %d/%d, want 2025/1", resp.Season, resp.DriverNumber)
+	}
+	if resp.NameAcronym != "VER" || resp.FullName != "Max Verstappen" || resp.TeamName != "Red Bull" || resp.TeamColour != "3671c6" {
+		t.Errorf("driver identity = %s %s %s %s", resp.NameAcronym, resp.FullName, resp.TeamName, resp.TeamColour)
+	}
+	if resp.HeadshotURL != "https://example.com/ver.png" {
+		t.Errorf("headshot = %q", resp.HeadshotURL)
+	}
+	if resp.Points != 50 || resp.Position != 1 {
+		t.Errorf("points/position = %v/%d, want 50/1", resp.Points, resp.Position)
+	}
+	if resp.Wins != 2 || resp.Podiums != 2 || resp.Poles != 1 {
+		t.Errorf("wins/podiums/poles = %d/%d/%d, want 2/2/1", resp.Wins, resp.Podiums, resp.Poles)
+	}
+	if len(resp.Form) != 2 || resp.Form[0] != 25 || resp.Form[1] != 25 {
+		t.Errorf("form = %v, want [25 25]", resp.Form)
+	}
+	// Cumulative reconciles the last value to the official total.
+	if len(resp.Cumulative) != 2 || resp.Cumulative[0] != 25 || resp.Cumulative[1] != 50 {
+		t.Errorf("cumulative = %v, want [25 50]", resp.Cumulative)
+	}
+	if len(resp.RoundLabels) != 2 || resp.RoundLabels[0] != "R1" {
+		t.Errorf("round labels = %v, want [R1 R2]", resp.RoundLabels)
+	}
+
+	// Only completed rounds appear.
+	if len(resp.Rounds) != 2 {
+		t.Fatalf("rounds = %d, want 2", len(resp.Rounds))
+	}
+	r1 := resp.Rounds[0]
+	if r1.MeetingKey != 1201 || r1.MeetingName != "Bahrain GP" || r1.CountryCode != "BHR" || r1.CountryName != "Bahrain" {
+		t.Errorf("round 1 meeting = %+v", r1)
+	}
+	if r1.RacePosition != 1 || r1.GridPosition != 1 || r1.QualiPosition != 1 || r1.Points != 25 {
+		t.Errorf("round 1 result = %+v, want P1 from P1 with 25 pts", r1)
+	}
+	r2 := resp.Rounds[1]
+	if r2.RacePosition != 1 || r2.GridPosition != 2 || r2.Points != 25 {
+		t.Errorf("round 2 result = %+v, want P1 from P2 with 25 pts", r2)
+	}
+}
+
+func TestAggregateDriverSummaryDriverMissingFromRound(t *testing.T) {
+	races, champ, driverInfo := driverSummaryFixtures()
+	// Drop HAM from round 2's results and grid: the round still appears with
+	// zero-valued positions so round indexing stays aligned with the season.
+	races[1].Results = []models.SessionResult{raceResult(1, 1, 25)}
+	races[1].Grid = []models.StartingGrid{{DriverNumber: 1, Position: 2}}
+
+	resp, ok := aggregateDriverSummary(2025, 3, races, champ, driverInfo)
+	if !ok {
+		t.Fatal("aggregateDriverSummary ok = false, want true")
+	}
+	if len(resp.Rounds) != 2 {
+		t.Fatalf("rounds = %d, want 2", len(resp.Rounds))
+	}
+	r2 := resp.Rounds[1]
+	if r2.RacePosition != 0 || r2.GridPosition != 0 || r2.QualiPosition != 0 || r2.Points != 0 {
+		t.Errorf("round 2 for absent driver = %+v, want zero values", r2)
+	}
+}
+
+func TestAggregateDriverSummaryUnknownDriver(t *testing.T) {
+	races, champ, driverInfo := driverSummaryFixtures()
+	if _, ok := aggregateDriverSummary(2025, 44, races, champ, driverInfo); ok {
+		t.Error("unknown driver should return ok = false")
+	}
+}
+
+func TestHandleDriverSummaryBadRequest(t *testing.T) {
+	srv := testServer(t, nil)
+
+	// Missing, non-numeric, zero, and negative driver_number are all rejected.
+	for _, url := range []string{
+		"/api/v1/driver/summary?year=2025",
+		"/api/v1/driver/summary?year=2025&driver_number=abc",
+		"/api/v1/driver/summary?year=2025&driver_number=0",
+		"/api/v1/driver/summary?year=2025&driver_number=-4",
+	} {
+		req := httptest.NewRequest(http.MethodGet, url, nil)
+		rec := httptest.NewRecorder()
+		srv.handleDriverSummary(rec, req)
+		if rec.Code != http.StatusBadRequest {
+			t.Errorf("%s: status = %d, want 400", url, rec.Code)
+		}
+	}
+}

internal/web/racehub.go

@@ -4,6 +4,7 @@ import (
 	"net/http"
 	"strconv"
 
+	"github.com/AmanTahiliani/box-box/internal/chapters"
 	"github.com/AmanTahiliani/box-box/internal/models"
 	"github.com/AmanTahiliani/box-box/internal/query"
 )
@@ -42,5 +43,6 @@ func emptyRaceHub(sessionKey int) query.RaceHub {
 		Drivers:      []models.Driver{},
 		Results:      []query.EnrichedResult{},
 		StartingGrid: []query.EnrichedGrid{},
+		Chapters:     []chapters.Chapter{},
 	}
 }

internal/web/racehub_test.go

@@ -119,6 +119,66 @@ func TestHandleRaceHubWithLocalData(t *testing.T) {
 	}
 }
 
+func TestHandleRaceHubIncludesChapters(t *testing.T) {
+	st := openTestStore(t)
+	seedRaceHubStore(t, st)
+	sessionKey := 9472
+	meetingKey := 1229
+
+	for lap := 1; lap <= 12; lap++ {
+		if err := st.UpsertLap(store.Lap{
+			SessionKey:   sessionKey,
+			DriverNumber: 1,
+			MeetingKey:   meetingKey,
+			LapNumber:    lap,
+			DateStart:    time.Date(2025, 5, 25, 13, lap-1, 0, 0, time.UTC).Format(time.RFC3339),
+			LapDuration:  75,
+		}); err != nil {
+			t.Fatalf("UpsertLap(%d) error = %v", lap, err)
+		}
+	}
+	for _, sample := range []store.PositionSample{
+		{SessionKey: sessionKey, DriverNumber: 1, MeetingKey: meetingKey, Date: "2025-05-25T13:00:00Z", Position: 1},
+		{SessionKey: sessionKey, DriverNumber: 16, MeetingKey: meetingKey, Date: "2025-05-25T13:00:00Z", Position: 4},
+		{SessionKey: sessionKey, DriverNumber: 55, MeetingKey: meetingKey, Date: "2025-05-25T13:00:00Z", Position: 3},
+		{SessionKey: sessionKey, DriverNumber: 16, MeetingKey: meetingKey, Date: "2025-05-25T13:05:00Z", Position: 3},
+		{SessionKey: sessionKey, DriverNumber: 55, MeetingKey: meetingKey, Date: "2025-05-25T13:05:00Z", Position: 4},
+	} {
+		if err := st.UpsertPositionSample(sample); err != nil {
+			t.Fatalf("UpsertPositionSample() error = %v", err)
+		}
+	}
+
+	srv := testServer(t, st)
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/race-hub?session_key=9472", nil)
+	rec := httptest.NewRecorder()
+	srv.handleRaceHub(rec, req)
+
+	if rec.Code != http.StatusOK {
+		t.Fatalf("status = %d, want 200", rec.Code)
+	}
+
+	var hub query.RaceHub
+	if err := json.Unmarshal(rec.Body.Bytes(), &hub); err != nil {
+		t.Fatalf("decode response: %v", err)
+	}
+	if len(hub.Chapters) == 0 {
+		t.Fatalf("chapters = %+v, want generated chapters", hub.Chapters)
+	}
+	if hub.Chapters[0].Kind != "start" {
+		t.Fatalf("first chapter = %+v, want start", hub.Chapters[0])
+	}
+	foundSwing := false
+	for _, chapter := range hub.Chapters {
+		if chapter.Kind == "decisive_swing" {
+			foundSwing = true
+		}
+	}
+	if !foundSwing {
+		t.Fatalf("chapters = %+v, want decisive_swing", hub.Chapters)
+	}
+}
+
 func TestHandleMeetingsSourceLocal(t *testing.T) {
 	st := openTestStore(t)
 	seedRaceHubStore(t, st)

internal/web/server.go

@@ -70,6 +70,9 @@ func (s *Server) routes() (http.Handler, error) {
 	mux.HandleFunc("/api/v1/news", s.handleNews)
 	mux.HandleFunc("/api/v1/meetings", s.handleMeetings)
 	mux.HandleFunc("/api/v1/sessions", s.handleSessions)
+	// /api/v1/driver/summary before /api/v1/drivers: distinct prefixes today,
+	// but keep the more specific driver/* paths registered first.
+	mux.HandleFunc("/api/v1/driver/summary", s.handleDriverSummary)
 	mux.HandleFunc("/api/v1/drivers", s.handleDrivers)
 	mux.HandleFunc("/api/v1/results", s.handleResults)
 	mux.HandleFunc("/api/v1/grid", s.handleGrid)