using System.Collections.Generic;
using BaseGames.Core;
using BaseGames.Core.Events;

namespace BaseGames.Core.States
{
    /// <summary>初始化状态（应用启动时的第一个状态）。</summary>
    public class InitializingState : IGameState
    {
        public GameStateId Id => GameStates.Initializing;

        public IReadOnlyCollection<GameStateId> ValidNextStates { get; } =
            new HashSet<GameStateId> { GameStates.MainMenu };

        public void OnEnter(GameStateId prev) { }
        public void OnExit(GameStateId next) { }
        public void Tick(float dt) { }
    }

    /// <summary>主菜单状态。</summary>
    public class MainMenuState : IGameState
    {
        public GameStateId Id => GameStates.MainMenu;

        public IReadOnlyCollection<GameStateId> ValidNextStates { get; } =
            new HashSet<GameStateId> { GameStates.LoadingScene };

        public void OnEnter(GameStateId prev) { }
        public void OnExit(GameStateId next) { }
        public void Tick(float dt) { }
    }

    /// <summary>场景加载中状态。</summary>
    public class LoadingSceneState : IGameState
    {
        public GameStateId Id => GameStates.LoadingScene;

        public IReadOnlyCollection<GameStateId> ValidNextStates { get; } =
            new HashSet<GameStateId> { GameStates.MainMenu, GameStates.Gameplay };

        public void OnEnter(GameStateId prev) { }
        public void OnExit(GameStateId next) { }
        public void Tick(float dt) { }
    }

    /// <summary>正常游玩状态。</summary>
    public class GameplayState : IGameState
    {
        public GameStateId Id => GameStates.Gameplay;

        public IReadOnlyCollection<GameStateId> ValidNextStates { get; } =
            new HashSet<GameStateId>
            {
                GameStates.LoadingScene,
                GameStates.BossFight,
                GameStates.Paused,
                GameStates.Dead,
                GameStates.Cutscene,
            };

        public void OnEnter(GameStateId prev) { }
        public void OnExit(GameStateId next) { }
        public void Tick(float dt) { }
    }

    /// <summary>Boss 战状态。</summary>
    public class BossFightState : IGameState
    {
        public GameStateId Id => GameStates.BossFight;

        public IReadOnlyCollection<GameStateId> ValidNextStates { get; } =
            new HashSet<GameStateId>
            {
                GameStates.LoadingScene,
                GameStates.Gameplay,
                GameStates.Paused,
                GameStates.Dead,
            };

        public void OnEnter(GameStateId prev) { }
        public void OnExit(GameStateId next) { }
        public void Tick(float dt) { }
    }

    /// <summary>暂停状态。</summary>
    public class PausedState : IGameState
    {
        public GameStateId Id => GameStates.Paused;

        public IReadOnlyCollection<GameStateId> ValidNextStates { get; } =
            new HashSet<GameStateId>
            {
                GameStates.Gameplay,
                GameStates.BossFight,
                GameStates.MainMenu,
            };

        public void OnEnter(GameStateId prev) { }
        public void OnExit(GameStateId next) { }
        public void Tick(float dt) { }
    }

    /// <summary>死亡状态。</summary>
    public class DeadState : IGameState
    {
        public GameStateId Id => GameStates.Dead;

        public IReadOnlyCollection<GameStateId> ValidNextStates { get; } =
            new HashSet<GameStateId> { GameStates.LoadingScene, GameStates.GameOver };

        public void OnEnter(GameStateId prev) { }
        public void OnExit(GameStateId next) { }
        public void Tick(float dt) { }
    }

    /// <summary>过场动画状态。</summary>
    public class CutsceneState : IGameState
    {
        public GameStateId Id => GameStates.Cutscene;

        public IReadOnlyCollection<GameStateId> ValidNextStates { get; } =
            new HashSet<GameStateId> { GameStates.Gameplay };

        public void OnEnter(GameStateId prev) { }
        public void OnExit(GameStateId next) { }
        public void Tick(float dt) { }
    }

    /// <summary>Game Over 状态（SteelSoul 清档用）。</summary>
    public class GameOverState : IGameState
    {
        public GameStateId Id => GameStates.GameOver;

        public IReadOnlyCollection<GameStateId> ValidNextStates { get; } =
            new HashSet<GameStateId> { GameStates.MainMenu };

        public void OnEnter(GameStateId prev) { }
        public void OnExit(GameStateId next) { }
        public void Tick(float dt) { }
    }
}