kvs

type Config struct {
	// Type specifies the store type: "memory", "leveldb", or "redis"
	Type string `yaml:"type"`

	// Namespace provides logical isolation within the store.
	// - Memory: uses hierarchical map structure
	// - LevelDB: creates separate directory per namespace
	// - Redis: uses as key prefix
	Namespace string `yaml:"namespace"`

	// Memory-specific config
	Memory MemoryConfig `yaml:"memory"`

	// LevelDB-specific config
	LevelDB LevelDBConfig `yaml:"leveldb"`

	// Redis-specific config
	Redis RedisConfig `yaml:"redis"`
}

type LevelDBConfig struct {
	// Path is the directory path for LevelDB storage.
	// If empty, a temporary directory will be used (OS-dependent).
	Path string `yaml:"path"`

	// SyncWrites enables synchronous writes (slower but safer).
	SyncWrites bool `yaml:"sync_writes"`

	// CleanupInterval is how often to scan for and remove expired keys.
	// Default: 5 minutes
	CleanupInterval time.Duration `yaml:"cleanup_interval"`
}

type LevelDBStore struct {
	// contains filtered or unexported fields
}

type MemoryConfig struct {
	// CleanupInterval is how often to scan for and remove expired keys.
	// Default: 5 minutes
	CleanupInterval time.Duration `yaml:"cleanup_interval"`
}

type MemoryStore struct {
	// contains filtered or unexported fields
}

type RedisConfig struct {
	// Addr is the Redis server address (host:port)
	Addr string `yaml:"addr"`

	// Password is the Redis password (optional)
	Password string `yaml:"password"`

	// DB is the Redis database number (0-15)
	DB int `yaml:"db"`

	// PoolSize is the maximum number of socket connections (0 = default 10 * runtime.NumCPU)
	PoolSize int `yaml:"pool_size"`
}

type RedisStore struct {
	// contains filtered or unexported fields
}

type Store interface {
	// Get retrieves a value by key.
	// Returns ErrNotFound if the key does not exist or has expired.
	Get(ctx context.Context, key string) ([]byte, error)

	// Set stores a value with optional TTL.
	// If ttl is 0, the key will not expire.
	// If ttl is negative, the behavior is implementation-defined (typically treated as 0).
	Set(ctx context.Context, key string, value []byte, ttl time.Duration) error

	// Delete removes a key.
	// Does not return an error if the key does not exist.
	Delete(ctx context.Context, key string) error

	// Exists checks if a key exists and has not expired.
	Exists(ctx context.Context, key string) (bool, error)

	// List returns all keys matching a prefix.
	// Empty prefix returns all keys in the store.
	// The order of keys is not guaranteed.
	List(ctx context.Context, prefix string) ([]string, error)

	// Count returns the number of keys matching a prefix.
	// Empty prefix returns the total count of all keys.
	Count(ctx context.Context, prefix string) (int, error)

	// Close closes the store and releases resources.
	// After Close is called, all operations should return ErrClosed.
	Close() error
}