UI Refresh

internal/api/cache.go

@@ -5,12 +5,33 @@ import (
 	"encoding/hex"
 	"os"
 	"path/filepath"
+	"strings"
+	"sync/atomic"
+	"time"
 )
 
-type FileCache struct {
-	dir string
+// CacheStats tracks cache hit/miss statistics.
+type CacheStats struct {
+	Hits   int64
+	Misses int64
 }
 
+// FileCache implements a file-backed HTTP response cache with TTL expiry.
+type FileCache struct {
+	dir   string
+	stats CacheStats
+}
+
+// Default TTL values.
+const (
+	// CacheTTLShort is for current-season, frequently changing data (meetings, sessions, results).
+	CacheTTLShort = 15 * time.Minute
+	// CacheTTLMedium is for semi-stable data (championship standings, driver lists).
+	CacheTTLMedium = 1 * time.Hour
+	// CacheTTLLong is for historical data that rarely changes (past season data).
+	CacheTTLLong = 24 * time.Hour
+)
+
 func NewFileCache() *FileCache {
 	var cacheDir string
 	userCacheDir, err := os.UserCacheDir()
@@ -35,13 +56,56 @@ func (c *FileCache) getCachePath(key string) string {
 	return filepath.Join(c.dir, filename)
 }
 
-// Get retrieves data from the cache. Returns nil, false if not found.
+// ttlForURL determines the appropriate TTL based on the URL pattern.
+func ttlForURL(url string) time.Duration {
+	// Historical data (specific year queries for past years)
+	if strings.Contains(url, "year=2023") || strings.Contains(url, "year=2024") {
+		return CacheTTLLong
+	}
+
+	// Frequently changing endpoints
+	if strings.Contains(url, "/position") ||
+		strings.Contains(url, "/intervals") ||
+		strings.Contains(url, "/car_data") ||
+		strings.Contains(url, "/location") {
+		return CacheTTLShort
+	}
+
+	// Semi-stable data
+	if strings.Contains(url, "/championship") ||
+		strings.Contains(url, "/drivers") {
+		return CacheTTLMedium
+	}
+
+	// Default: medium TTL for everything else
+	return CacheTTLMedium
+}
+
+// Get retrieves data from the cache. Returns nil, false if not found or expired.
 func (c *FileCache) Get(key string) ([]byte, bool) {
 	path := c.getCachePath(key)
-	data, err := os.ReadFile(path)
+	info, err := os.Stat(path)
 	if err != nil {
+		atomic.AddInt64(&c.stats.Misses, 1)
 		return nil, false
 	}
+
+	// Check TTL based on file modification time
+	ttl := ttlForURL(key)
+	if time.Since(info.ModTime()) > ttl {
+		// Expired — remove the stale file
+		_ = os.Remove(path)
+		atomic.AddInt64(&c.stats.Misses, 1)
+		return nil, false
+	}
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		atomic.AddInt64(&c.stats.Misses, 1)
+		return nil, false
+	}
+
+	atomic.AddInt64(&c.stats.Hits, 1)
 	return data, true
 }
 
@@ -50,3 +114,45 @@ func (c *FileCache) Set(key string, data []byte) error {
 	path := c.getCachePath(key)
 	return os.WriteFile(path, data, 0644)
 }
+
+// Stats returns current cache hit/miss stats.
+func (c *FileCache) Stats() CacheStats {
+	return CacheStats{
+		Hits:   atomic.LoadInt64(&c.stats.Hits),
+		Misses: atomic.LoadInt64(&c.stats.Misses),
+	}
+}
+
+// Clear removes all cached files.
+func (c *FileCache) Clear() error {
+	entries, err := os.ReadDir(c.dir)
+	if err != nil {
+		return err
+	}
+	for _, entry := range entries {
+		if strings.HasSuffix(entry.Name(), ".json") {
+			_ = os.Remove(filepath.Join(c.dir, entry.Name()))
+		}
+	}
+	return nil
+}
+
+// Size returns the number of cached files and total size in bytes.
+func (c *FileCache) Size() (int, int64) {
+	entries, err := os.ReadDir(c.dir)
+	if err != nil {
+		return 0, 0
+	}
+	count := 0
+	var totalSize int64
+	for _, entry := range entries {
+		if strings.HasSuffix(entry.Name(), ".json") {
+			count++
+			info, err := entry.Info()
+			if err == nil {
+				totalSize += info.Size()
+			}
+		}
+	}
+	return count, totalSize
+}