feat(frontend): add reusable TyreStintTimeline component (#16)

Extract stint timeline SVG from StrategyView into a data-source-agnostic
chart primitive with compound legend, lap-axis ticks, and hover titles.
StrategyView maps race-hub stint data into the new props contract.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/components/StrategyView.tsx

@@ -1,28 +1,9 @@
 import type { EnrichedResult, Stint, PitStop } from '../types'
 import { compareFinishPosition } from '../utils'
-
-const COMPOUND_COLORS: Record<string, string> = {
-  SOFT: '#e8002d',
-  MEDIUM: '#ffd600',
-  HARD: '#e8e8e4',
-  INTERMEDIATE: '#39b54a',
-  WET: '#0067ff',
-}
-
-function compoundColor(c: string): string {
-  return COMPOUND_COLORS[c.toUpperCase()] ?? '#666'
-}
-
-function compoundInitial(c: string): string {
-  const abbr: Record<string, string> = {
-    SOFT: 'S',
-    MEDIUM: 'M',
-    HARD: 'H',
-    INTERMEDIATE: 'I',
-    WET: 'W',
-  }
-  return abbr[c.toUpperCase()] ?? c[0] ?? '?'
-}
+import {
+  TyreStintTimeline,
+  type StintTimelineRow,
+} from './charts/TyreStintTimeline'
 
 interface Props {
   results: EnrichedResult[]
@@ -31,7 +12,7 @@ interface Props {
   hasStints: boolean
 }
 
-export function StrategyView({ results, stints, pit_stops, hasStints }: Props) {
+export function StrategyView({ results, stints, pit_stops: _pitStops, hasStints }: Props) {
   if (!hasStints) {
     return (
       <div>
@@ -89,147 +70,29 @@ export function StrategyView({ results, stints, pit_stops, hasStints }: Props) {
     const cmp = compareFinishPosition(a.position, b.position)
     return cmp !== 0 ? cmp : a.driver_number - b.driver_number
   })
+
   const totalLaps = Math.max(
     ...stints.map((s) => s.lap_end),
     ...results.map((r) => r.number_of_laps),
-    1
+    1,
   )
 
-  const SVG_W = 640
-  const LEFT = 48
-  const RIGHT = 12
-  const ROW_H = 28
-  const BAR_H = 14
-  const BAR_Y = 7
-  const BAR_W = SVG_W - LEFT - RIGHT
-  const SVG_H = sortedDrivers.length * ROW_H + 8
-
-  const lapX = (lap: number) => LEFT + ((lap - 1) / totalLaps) * BAR_W
-  const stintW = (s: Stint) =>
-    Math.max(2, ((s.lap_end - s.lap_start + 1) / totalLaps) * BAR_W)
-
-  const usedCompounds = [...new Set(stints.map((s) => s.compound.toUpperCase()))].filter(
-    (c) => c in COMPOUND_COLORS
-  )
+  const timelineRows: StintTimelineRow[] = sortedDrivers.map((driver) => ({
+    label: driver.name_acronym || String(driver.driver_number),
+    color: driver.team_colour ? `#${driver.team_colour}` : '#888',
+    stints: stints
+      .filter((s) => s.driver_number === driver.driver_number)
+      .map((s) => ({
+        compound: s.compound,
+        lapStart: s.lap_start,
+        lapEnd: s.lap_end,
+        isNew: s.tyre_age_at_start === 0,
+      })),
+  }))
 
   return (
     <div data-testid="strategy-chart">
-      <div className="scroll-x">
-        <svg
-          viewBox={`0 0 ${SVG_W} ${SVG_H}`}
-          style={{ width: '100%', minWidth: 280, maxWidth: SVG_W, display: 'block' }}
-          role="img"
-          aria-label="Race strategy stint chart"
-        >
-          {sortedDrivers.map((driver, i) => {
-            const rowY = i * ROW_H
-            const color = driver.team_colour ? `#${driver.team_colour}` : '#888'
-            const dStints = stints.filter((s) => s.driver_number === driver.driver_number)
-            const dPits = pit_stops.filter((p) => p.driver_number === driver.driver_number)
-
-            return (
-              <g key={driver.driver_number} transform={`translate(0,${rowY})`}>
-                <text
-                  x={LEFT - 5}
-                  y={BAR_Y + BAR_H / 2 + 4}
-                  textAnchor="end"
-                  fill={color}
-                  fontFamily="var(--f-mono)"
-                  fontWeight={700}
-                  fontSize={10}
-                >
-                  {driver.name_acronym}
-                </text>
-
-                {dStints.map((stint, si) => {
-                  const x = lapX(stint.lap_start)
-                  const w = stintW(stint)
-                  const fill = compoundColor(stint.compound)
-                  return (
-                    <g key={si}>
-                      <rect x={x} y={BAR_Y} width={w} height={BAR_H} fill={fill} rx={1.5} />
-                      {w > 18 && (
-                        <text
-                          x={x + w / 2}
-                          y={BAR_Y + BAR_H / 2 + 4}
-                          textAnchor="middle"
-                          fill="#111"
-                          fontFamily="var(--f-mono)"
-                          fontWeight={700}
-                          fontSize={8}
-                        >
-                          {compoundInitial(stint.compound)}
-                        </text>
-                      )}
-                    </g>
-                  )
-                })}
-
-                {dPits.map((pit, pi) => {
-                  const x = lapX(pit.lap_number)
-                  return (
-                    <line
-                      key={pi}
-                      x1={x}
-                      x2={x}
-                      y1={BAR_Y - 3}
-                      y2={BAR_Y + BAR_H + 3}
-                      stroke="var(--text)"
-                      strokeWidth={1.5}
-                      opacity={0.7}
-                    />
-                  )
-                })}
-              </g>
-            )
-          })}
-        </svg>
-      </div>
-
-      <div
-        style={{
-          display: 'flex',
-          gap: 'var(--s4)',
-          flexWrap: 'wrap',
-          marginTop: 'var(--s4)',
-          fontSize: 11,
-          color: 'var(--text-3)',
-          alignItems: 'center',
-        }}
-      >
-        {usedCompounds.map((c) => (
-          <span key={c} style={{ display: 'inline-flex', alignItems: 'center', gap: 4 }}>
-            <span
-              style={{
-                width: 10,
-                height: 10,
-                background: COMPOUND_COLORS[c],
-                borderRadius: 2,
-                display: 'inline-block',
-                border: c === 'HARD' ? '1px solid #555' : undefined,
-              }}
-            />
-            {c.charAt(0) + c.slice(1).toLowerCase()}
-          </span>
-        ))}
-        {pit_stops.length > 0 && (
-          <span style={{ display: 'inline-flex', alignItems: 'center', gap: 5, marginLeft: 4 }}>
-            <span
-              style={{
-                width: 1,
-                height: 12,
-                background: 'var(--text)',
-                display: 'inline-block',
-                opacity: 0.7,
-              }}
-            />
-            Pit stop
-          </span>
-        )}
-        <span style={{ marginLeft: 'auto', fontFamily: 'var(--f-mono)', fontSize: 10 }}>
-          {totalLaps} laps
-        </span>
-      </div>
+      <TyreStintTimeline rows={timelineRows} totalLaps={totalLaps} />
     </div>
   )
 }

frontend/src/components/charts/TyreStintTimeline.tsx

@@ -0,0 +1,182 @@
+import { compoundClass } from '../../lib/live'
+import '../../styles/stint-timeline.css'
+
+export interface StintTimelineStint {
+  compound: string
+  lapStart: number
+  lapEnd: number
+  isNew?: boolean
+}
+
+export interface StintTimelineRow {
+  label: string
+  color: string
+  stints: StintTimelineStint[]
+}
+
+interface TyreStintTimelineProps {
+  rows: StintTimelineRow[]
+  totalLaps: number
+}
+
+const SVG_W = 640
+const LEFT = 48
+const RIGHT = 12
+const ROW_H = 28
+const BAR_H = 14
+const BAR_Y = 7
+const AXIS_H = 20
+const BAR_W = SVG_W - LEFT - RIGHT
+
+const COMPOUND_ORDER = ['SOFT', 'MEDIUM', 'HARD', 'INTERMEDIATE', 'WET'] as const
+
+function compoundLabel(compound: string): string {
+  const upper = compound.toUpperCase()
+  if (upper === 'INTERMEDIATE') return 'Intermediate'
+  return upper.charAt(0) + upper.slice(1).toLowerCase()
+}
+
+function stintLength(stint: StintTimelineStint): number {
+  return stint.lapEnd - stint.lapStart + 1
+}
+
+function stintTitle(stint: StintTimelineStint): string {
+  const length = stintLength(stint)
+  return `${compoundLabel(stint.compound)} · L${stint.lapStart}–${stint.lapEnd} · ${length} lap${length === 1 ? '' : 's'}`
+}
+
+function lapX(lap: number, totalLaps: number): number {
+  return LEFT + (lap / totalLaps) * BAR_W
+}
+
+function stintBarX(stint: StintTimelineStint, totalLaps: number): number {
+  return LEFT + ((stint.lapStart - 1) / totalLaps) * BAR_W
+}
+
+function stintBarW(stint: StintTimelineStint, totalLaps: number): number {
+  return Math.max(2, (stintLength(stint) / totalLaps) * BAR_W)
+}
+
+function axisTicks(totalLaps: number): number[] {
+  const ticks: number[] = []
+  for (let lap = 0; lap <= totalLaps; lap += 10) {
+    ticks.push(lap)
+  }
+  return ticks
+}
+
+function collectUsedCompounds(rows: StintTimelineRow[]): string[] {
+  const seen = new Set<string>()
+  for (const row of rows) {
+    for (const stint of row.stints) {
+      seen.add(stint.compound.toUpperCase())
+    }
+  }
+  const ordered = COMPOUND_ORDER.filter((c) => seen.has(c))
+  const extras = [...seen]
+    .filter((c) => !COMPOUND_ORDER.includes(c as (typeof COMPOUND_ORDER)[number]))
+    .sort()
+  return [...ordered, ...extras]
+}
+
+export function TyreStintTimeline({ rows, totalLaps }: TyreStintTimelineProps) {
+  const safeTotal = Math.max(totalLaps, 1)
+  const usedCompounds = collectUsedCompounds(rows)
+  const ticks = axisTicks(safeTotal)
+  const chartH = rows.length * ROW_H
+  const svgH = chartH + AXIS_H + 4
+
+  if (rows.length === 0) {
+    return (
+      <div className="stint-timeline" data-testid="stint-timeline-empty">
+        <div className="stint-timeline__empty">No stint data to display.</div>
+      </div>
+    )
+  }
+
+  return (
+    <div className="stint-timeline" data-testid="stint-timeline">
+      <div className="stint-timeline__scroll">
+        <svg
+          viewBox={`0 0 ${SVG_W} ${svgH}`}
+          className="stint-timeline__svg"
+          role="img"
+          aria-label="Tyre stint timeline"
+        >
+          {rows.map((row, i) => {
+            const rowY = i * ROW_H
+            return (
+              <g key={`${row.label}-${i}`} transform={`translate(0,${rowY})`}>
+                <text
+                  x={LEFT - 5}
+                  y={BAR_Y + BAR_H / 2 + 4}
+                  textAnchor="end"
+                  fill={row.color}
+                  className="stint-timeline__label"
+                >
+                  {row.label}
+                </text>
+
+                {row.stints.map((stint, si) => (
+                  <rect
+                    key={si}
+                    x={stintBarX(stint, safeTotal)}
+                    y={BAR_Y}
+                    width={stintBarW(stint, safeTotal)}
+                    height={BAR_H}
+                    rx={3}
+                    className={`stint-timeline__bar ${compoundClass(stint.compound)}${stint.isNew ? ' stint-timeline__bar--new' : ''}`}
+                  >
+                    <title>{stintTitle(stint)}</title>
+                  </rect>
+                ))}
+              </g>
+            )
+          })}
+
+          <g transform={`translate(0,${chartH})`}>
+            <line
+              x1={LEFT}
+              x2={LEFT + BAR_W}
+              y1={0}
+              y2={0}
+              className="stint-timeline__axis-line"
+            />
+            {ticks.map((lap) => (
+              <g key={lap}>
+                <line
+                  x1={lapX(lap, safeTotal)}
+                  x2={lapX(lap, safeTotal)}
+                  y1={0}
+                  y2={4}
+                  className="stint-timeline__axis-line"
+                />
+                <text
+                  x={lapX(lap, safeTotal)}
+                  y={14}
+                  textAnchor="middle"
+                  className="stint-timeline__axis-tick"
+                >
+                  {lap}
+                </text>
+              </g>
+            ))}
+          </g>
+        </svg>
+      </div>
+
+      <div className="stint-timeline__legend">
+        {usedCompounds.map((compound) => (
+          <span key={compound} className="stint-timeline__legend-item">
+            <span
+              className={`stint-timeline__legend-swatch ${compoundClass(compound)}`}
+              data-testid={`legend-${compound.toLowerCase()}`}
+            />
+            {compoundLabel(compound)}
+          </span>
+        ))}
+        <span className="stint-timeline__meta">{safeTotal} laps</span>
+      </div>
+    </div>
+  )
+}

frontend/src/styles/stint-timeline.css

@@ -0,0 +1,94 @@
+.stint-timeline {
+  --stint-left: 48px;
+  --stint-right: 12px;
+  --stint-row-h: 28px;
+  --stint-bar-h: 14px;
+  --stint-axis-h: 20px;
+}
+
+.stint-timeline__scroll {
+  overflow-x: auto;
+}
+
+.stint-timeline__svg {
+  width: 100%;
+  min-width: 280px;
+  max-width: 640px;
+  display: block;
+}
+
+.stint-timeline__label {
+  font-family: var(--f-mono);
+  font-weight: 700;
+  font-size: 10px;
+}
+
+.stint-timeline__bar {
+  stroke: none;
+}
+
+.stint-timeline__bar.tyre-soft { fill: var(--tyre-soft); }
+.stint-timeline__bar.tyre-medium { fill: var(--tyre-medium); }
+.stint-timeline__bar.tyre-hard { fill: var(--tyre-hard); stroke: #555; stroke-width: 0.5; }
+.stint-timeline__bar.tyre-inter { fill: var(--tyre-inter); }
+.stint-timeline__bar.tyre-wet { fill: var(--tyre-wet); }
+.stint-timeline__bar.tyre-unknown { fill: var(--surface-2); stroke: var(--border-2); stroke-width: 0.5; }
+
+.stint-timeline__bar--new {
+  stroke: var(--text);
+  stroke-width: 1;
+  stroke-dasharray: 2 1;
+}
+
+.stint-timeline__axis-tick {
+  font-family: var(--f-mono);
+  font-size: 9px;
+  fill: var(--text-3);
+}
+
+.stint-timeline__axis-line {
+  stroke: var(--border-2);
+  stroke-width: 1;
+}
+
+.stint-timeline__legend {
+  display: flex;
+  gap: var(--s4);
+  flex-wrap: wrap;
+  margin-top: var(--s4);
+  font-size: 11px;
+  color: var(--text-3);
+  align-items: center;
+}
+
+.stint-timeline__legend-swatch {
+  width: 10px;
+  height: 10px;
+  border-radius: 2px;
+  display: inline-block;
+}
+
+.stint-timeline__legend-swatch.tyre-hard {
+  border: 1px solid #555;
+}
+
+.stint-timeline__legend-item {
+  display: inline-flex;
+  align-items: center;
+  gap: 4px;
+}
+
+.stint-timeline__meta {
+  margin-left: auto;
+  font-family: var(--f-mono);
+  font-size: 10px;
+}
+
+.stint-timeline__empty {
+  padding: var(--s5);
+  color: var(--text-3);
+  font-size: 13px;
+  text-align: center;
+  border: 1px dashed var(--border-2);
+  border-radius: var(--r2);
+}

frontend/src/test/tyre-stint-timeline.test.tsx

@@ -0,0 +1,149 @@
+import { describe, it, expect } from 'vitest'
+import { render, screen } from '@testing-library/react'
+import { TyreStintTimeline, type StintTimelineRow } from '../components/charts/TyreStintTimeline'
+import { StrategyView } from '../components/StrategyView'
+import type { EnrichedResult, Stint, PitStop } from '../types'
+
+const sampleRows: StintTimelineRow[] = [
+  {
+    label: 'VER',
+    color: '#3671C6',
+    stints: [
+      { compound: 'MEDIUM', lapStart: 1, lapEnd: 30 },
+      { compound: 'SOFT', lapStart: 31, lapEnd: 78 },
+    ],
+  },
+  {
+    label: 'HAM',
+    color: '#E8002D',
+    stints: [{ compound: 'SOFT', lapStart: 1, lapEnd: 18 }],
+  },
+]
+
+describe('TyreStintTimeline', () => {
+  it('renders one rect per stint', () => {
+    const { container } = render(
+      <TyreStintTimeline rows={sampleRows} totalLaps={78} />,
+    )
+    expect(container.querySelectorAll('.stint-timeline__bar')).toHaveLength(3)
+  })
+
+  it('maps compounds to color classes', () => {
+    const { container } = render(
+      <TyreStintTimeline rows={sampleRows} totalLaps={78} />,
+    )
+    const bars = container.querySelectorAll('.stint-timeline__bar')
+    expect(bars[0]).toHaveClass('tyre-medium')
+    expect(bars[1]).toHaveClass('tyre-soft')
+    expect(bars[2]).toHaveClass('tyre-soft')
+  })
+
+  it('shows native title with compound, lap range, and stint length', () => {
+    const { container } = render(
+      <TyreStintTimeline rows={sampleRows} totalLaps={78} />,
+    )
+    const titles = [...container.querySelectorAll('title')].map((t) => t.textContent)
+    expect(titles).toContain('Medium · L1–30 · 30 laps')
+    expect(titles).toContain('Soft · L31–78 · 48 laps')
+    expect(titles).toContain('Soft · L1–18 · 18 laps')
+  })
+
+  it('renders lap-axis ticks every 10 laps', () => {
+    render(<TyreStintTimeline rows={sampleRows} totalLaps={78} />)
+    expect(screen.getByText('0')).toBeInTheDocument()
+    expect(screen.getByText('10')).toBeInTheDocument()
+    expect(screen.getByText('20')).toBeInTheDocument()
+    expect(screen.getByText('70')).toBeInTheDocument()
+  })
+
+  it('shows legend only for used compounds', () => {
+    render(<TyreStintTimeline rows={sampleRows} totalLaps={78} />)
+    expect(screen.getByTestId('legend-soft')).toBeInTheDocument()
+    expect(screen.getByTestId('legend-medium')).toBeInTheDocument()
+    expect(screen.queryByTestId('legend-hard')).not.toBeInTheDocument()
+    expect(screen.queryByTestId('legend-wet')).not.toBeInTheDocument()
+    expect(screen.getByText('Soft')).toBeInTheDocument()
+    expect(screen.getByText('Medium')).toBeInTheDocument()
+  })
+
+  it('renders empty state when rows are empty', () => {
+    render(<TyreStintTimeline rows={[]} totalLaps={50} />)
+    expect(screen.getByTestId('stint-timeline-empty')).toBeInTheDocument()
+    expect(screen.getByText(/No stint data/i)).toBeInTheDocument()
+  })
+})
+
+const results: EnrichedResult[] = [
+  {
+    driver_number: 1,
+    position: 1,
+    name_acronym: 'VER',
+    full_name: 'Max Verstappen',
+    team_name: 'Red Bull Racing',
+    team_colour: '3671C6',
+    dnf: false,
+    dns: false,
+    dsq: false,
+    duration: null,
+    gap_to_leader: null,
+    number_of_laps: 78,
+    points: 25,
+    session_key: 9472,
+    meeting_key: 1229,
+  },
+  {
+    driver_number: 44,
+    position: 2,
+    name_acronym: 'HAM',
+    full_name: 'Lewis Hamilton',
+    team_name: 'Ferrari',
+    team_colour: 'E8002D',
+    dnf: false,
+    dns: false,
+    dsq: false,
+    duration: null,
+    gap_to_leader: 5.1,
+    number_of_laps: 78,
+    points: 18,
+    session_key: 9472,
+    meeting_key: 1229,
+  },
+]
+
+const stints: Stint[] = [
+  {
+    session_key: 9472,
+    driver_number: 1,
+    meeting_key: 1229,
+    stint_number: 1,
+    compound: 'MEDIUM',
+    lap_start: 1,
+    lap_end: 30,
+    tyre_age_at_start: 0,
+  },
+  {
+    session_key: 9472,
+    driver_number: 44,
+    meeting_key: 1229,
+    stint_number: 1,
+    compound: 'SOFT',
+    lap_start: 1,
+    lap_end: 18,
+    tyre_age_at_start: 0,
+  },
+]
+
+const pitStops: PitStop[] = []
+
+describe('StrategyView integration', () => {
+  it('renders timeline when stints exist', () => {
+    const { container } = render(
+      <StrategyView results={results} stints={stints} pit_stops={pitStops} hasStints={true} />,
+    )
+    expect(container.querySelector('[data-testid="strategy-chart"]')).toBeInTheDocument()
+    expect(screen.getByTestId('stint-timeline')).toBeInTheDocument()
+    expect(screen.getByText('VER')).toBeInTheDocument()
+    expect(screen.getByText('HAM')).toBeInTheDocument()
+    expect(container.querySelectorAll('.stint-timeline__bar')).toHaveLength(2)
+  })
+})