package session

// Store defines the persistence interface for session message storage.
//
// Implementations must be safe for concurrent use. The default implementation
// uses JSONL files (one file per session) with O(1) append writes.
type Store interface {
	// Save appends a single message to a session's history.
	// Creates the session file if it does not exist.
	Save(sessionID string, msg SessionMessage) error

	// Load retrieves all messages for a session in chronological order.
	// Returns an error if the session does not exist.
	Load(sessionID string) ([]SessionMessage, error)

	// List returns all known session IDs.
	List() ([]string, error)

	// Exists checks whether a session exists in the store.
	Exists(sessionID string) (bool, error)

	// Archive marks a session as archived (read-only).
	// This is a soft delete that preserves the data.
	Archive(sessionID string) error

	// Delete removes a session permanently from the store.
	Delete(sessionID string) error
}