cache

type Config[V any] struct {
	// TTL is the time-to-live for cache entries
	TTL time.Duration
	// RefreshInterval is the interval at which cache entries are refreshed in the background
	// If 0, no background refresh is performed
	RefreshInterval time.Duration
	// CallbackTimeout is the timeout for the data callback function
	// Defaults to 30 seconds if not specified
	CallbackTimeout time.Duration
	// RefreshTimeout is the timeout for refresh operations
	// Defaults to 30 seconds if not specified
	RefreshTimeout time.Duration
	// ExtractKeyFunc is an optional function to extract a key from the value
	ExtractKeyFunc ExtractKeyFunc[V]
}

type DataCallback[V any] func(ctx context.Context, key string) (V, error)

type ExtractKeyFunc[V any] func(value V) string

type Item[V any] struct {
	// contains filtered or unexported fields
}

type MemoryCache[V any] struct {
	// contains filtered or unexported fields
}

type RedisCache[V any] struct {
	// contains filtered or unexported fields
}

type RedisConfig[V any] struct {
	RedisClient redis.UniversalClient
	TTL         time.Duration
	// RefreshInterval triggers a background refresh of a Redis entry
	// when its age exceeds this duration. 0 = no background refresh.
	RefreshInterval time.Duration
	// RefreshTimeout is the timeout for the callback during Redis refresh.
	// Defaults to 30s.
	RefreshTimeout time.Duration
	RedisTimeout   time.Duration // default 2s
	RedisPrefix    string        // e.g. "template:build"
	// ExtractKeyFunc is an optional function to extract a key from the value.
	// When set, the key used for Redis storage is derived from the fetched value
	// rather than the original lookup key.
	ExtractKeyFunc ExtractKeyFunc[V]
	// LockTTL controls distributed locking for cache updates.
	// Lock is acquired before calling the data callback to prevent thundering herd across instances.
	// TTL is auto-computed as RefreshTimeout + 2*RedisTimeout
	LockTTL time.Duration
	// LockRetryInterval is the interval between lock acquisition retries.
	// Defaults to 50ms.
	LockRetryInterval time.Duration
}