using System;

using Framework.Services;
using Framework.Storage.Containers;

namespace Framework.Storage {

  /// <summary>Stores the persistent state of the game</summary>
  /// <remarks>
  ///   <para>
  ///     The recommended usage is to write a game-specific persistent settings accessor
  ///     that will
  ///   </para>
  /// </remarks>
  [
    ServiceScope(Scope.Session),
    DefaultBinding(typeof(PersistentGameStateManager))
  ]
  public interface IPersistentGameStateStore {

    /// <summary>Called when the persistent state store has been initialized</summary>
    event Action Initialized;

    /// <summary>Initializes the types that will be used by the store</summary>
    /// <typeparam name="TGameState">
    ///   Type that holds the current state of the game as it is stored in a save slot
    /// </typeparam>
    /// <remarks>
    ///   The default implementation of the persistent store requires this method to be called
    ///   before any of the other properties and methods of the persistent store will work.
    ///   It will load the game's current settings from their default locations if available
    ///   and create new default instances of no saved settings exist.
    /// </remarks>
    void Initialize<TGameState>(IPersistentStateSerializer<TGameState> gameStateSerializer = null)
      where TGameState : class, IGameState, new();

    /// <summary>Whether the persistent data store has been initialized already</summary>
    bool IsInitialized { get; }

    /// <summary>Container for the current state of the game</summary>
    IVerifiedPersistentContainer<IGameState> GameState { get; }

    /// <summary>Save slot that is currently being played, -1 if none</summary>
    int ActiveSaveSlot { get; }

    /// <summary>Starts a new game state in the specified slot</summary>
    /// <param name="slotIndex">Index of the slot a new game will be started in</param>
    void StartNewGame(int slotIndex);

    /// <summary>Loads the game state from the specified slot</summary>
    /// <param name="slotIndex">Index of hte slot from which the game will be loaded</param>
    void LoadGame(int slotIndex);

    /// <summary>Saves the game in the active slot</summary>
    void SaveGame();

    /// <summary>Whether a saved game exists in the specified slot</summary>
    /// <param name="slotIndex">Index of the slot that will be checked</param>
    /// <returns>True if a saved game exists in the specified slot</returns>
    bool HasSavedGame(int slotIndex);

    /// <summary>Deletes the game state in the specified slot</summary>
    /// <param name="slotIndex">Index of the slot in which the game will be deleted</param>
    /// <returns>
    ///   True if a saved state existed in the specified slot and was deleted, false otherwise
    /// </returns>
    bool DeleteGame(int slotIndex);

  }

} // namespace Framework.Storage