Add full monorepo: virtual-banker, backend, frontend, docs, scripts, deployment

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

backend/api/track1/cache.go

@@ -0,0 +1,90 @@
+package track1
+
+import (
+	"sync"
+	"time"
+)
+
+// InMemoryCache is a simple in-memory cache
+// In production, use Redis for distributed caching
+type InMemoryCache struct {
+	items map[string]*cacheItem
+	mu    sync.RWMutex
+}
+
+// cacheItem represents a cached item
+type cacheItem struct {
+	value     []byte
+	expiresAt time.Time
+}
+
+// NewInMemoryCache creates a new in-memory cache
+func NewInMemoryCache() *InMemoryCache {
+	cache := &InMemoryCache{
+		items: make(map[string]*cacheItem),
+	}
+
+	// Start cleanup goroutine
+	go cache.cleanup()
+
+	return cache
+}
+
+// Get retrieves a value from cache
+func (c *InMemoryCache) Get(key string) ([]byte, error) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	item, exists := c.items[key]
+	if !exists {
+		return nil, ErrCacheMiss
+	}
+
+	if time.Now().After(item.expiresAt) {
+		return nil, ErrCacheMiss
+	}
+
+	return item.value, nil
+}
+
+// Set stores a value in cache with TTL
+func (c *InMemoryCache) Set(key string, value []byte, ttl time.Duration) error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	c.items[key] = &cacheItem{
+		value:     value,
+		expiresAt: time.Now().Add(ttl),
+	}
+
+	return nil
+}
+
+// cleanup removes expired items
+func (c *InMemoryCache) cleanup() {
+	ticker := time.NewTicker(1 * time.Minute)
+	defer ticker.Stop()
+
+	for range ticker.C {
+		c.mu.Lock()
+		now := time.Now()
+		for key, item := range c.items {
+			if now.After(item.expiresAt) {
+				delete(c.items, key)
+			}
+		}
+		c.mu.Unlock()
+	}
+}
+
+// ErrCacheMiss is returned when a cache key is not found
+var ErrCacheMiss = &CacheError{Message: "cache miss"}
+
+// CacheError represents a cache error
+type CacheError struct {
+	Message string
+}
+
+func (e *CacheError) Error() string {
+	return e.Message
+}