SceneManager.cs

using Love;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SceneManager
{
    public class SceneWatchdog : Scene
    {
        readonly Dictionary<string, GameScene> gameSceneDict = new Dictionary<string, GameScene>();
        public void Add(string uniqueName, GameScene gameScene) => gameSceneDict.Add(uniqueName, gameScene);

        public void Change(string name)
        {
            if (!gameSceneDict.ContainsKey(name))
                throw new Exception("have no scene name: " + name);
            foreach (var gs in gameSceneDict.Where(kv => kv.Key != name).ToArray())
            {
                gs.Value.Pause();
            }
            currentGameScene = gameSceneDict[name];
            currentGameSceneName = name;
        }
        GameScene currentGameScene;
        string currentGameSceneName;

        public GameScene CurrentScene => currentGameScene;
        public string CurrentSceneName => currentGameSceneName;

        public override void KeyPressed(KeyConstant key, Scancode scancode, bool isRepeat) => currentGameScene?.KeyPressed(key, scancode, isRepeat);
        public override void KeyReleased(KeyConstant key, Scancode scancode) => currentGameScene?.KeyReleased(key, scancode);
        public override void MouseMoved(float x, float y, float dx, float dy, bool isTouch) => currentGameScene?.MouseMoved(x, y, dx, dy, isTouch);
        public override void MousePressed(float x, float y, int button, bool isTouch) => currentGameScene?.MousePressed(x, y, button, isTouch);
        public override void MouseReleased(float x, float y, int button, bool isTouch) => currentGameScene?.MouseReleased(x, y, button, isTouch);
        public override void MouseFocus(bool focus) => currentGameScene?.MouseFocus(focus);
        public override void WheelMoved(int x, int y) => currentGameScene?.WheelMoved(x, y);
        public override void JoystickPressed(Joystick joystick, int button) => currentGameScene?.JoystickPressed(joystick, button);
        public override void JoystickReleased(Joystick joystick, int button) => currentGameScene?.JoystickReleased(joystick, button);
        public override void JoystickAxis(Joystick joystick, float axis, float value) => currentGameScene?.JoystickAxis(joystick, axis, value);
        public override void JoystickHat(Joystick joystick, int hat, JoystickHat direction) => currentGameScene?.JoystickHat(joystick, hat, direction);
        public override void JoystickGamepadPressed(Joystick joystick, GamepadButton button) => currentGameScene?.JoystickGamepadPressed(joystick, button);
        public override void JoystickGamepadReleased(Joystick joystick, GamepadButton button) => currentGameScene?.JoystickGamepadReleased(joystick, button);
        public override void JoystickGamepadAxis(Joystick joystick, GamepadAxis axis, float value) => currentGameScene?.JoystickGamepadAxis(joystick, axis, value);
        public override void JoystickAdded(Joystick joystick) => currentGameScene?.JoystickAdded(joystick);
        public override void JoystickRemoved(Joystick joystick) => currentGameScene?.JoystickRemoved(joystick);
        public override void TouchMoved(long id, float x, float y, float dx, float dy, float pressure) => currentGameScene?.TouchMoved(id, x, y, dx, dy, pressure);
        public override void TouchPressed(long id, float x, float y, float dx, float dy, float pressure) => currentGameScene?.TouchPressed(id, x, y, dx, dy, pressure);
        public override void TouchReleased(long id, float x, float y, float dx, float dy, float pressure) => currentGameScene?.TouchReleased(id, x, y, dx, dy, pressure);
        public override void TextEditing(string text, int start, int end) => currentGameScene?.TextEditing(text, start, end);
        public override void TextInput(string text) => currentGameScene?.TextInput(text);
        public override void WindowFocus(bool focus) => currentGameScene?.WindowFocus(focus);
        public override void WindowVisible(bool visible) => currentGameScene?.WindowVisible(visible);
        public override void WindowResize(int w, int h) => currentGameScene?.WindowResize(w, h);
        public override void DirectoryDropped(string path) => currentGameScene?.DirectoryDropped(path);
        public override void FileDropped(string fileFilePath) => currentGameScene?.FileDropped(fileFilePath);
        public override bool Quit() => currentGameScene.Quit();
        public override void LowMemory() => currentGameScene?.LowMemory();
        public override void Load() => currentGameScene?.Load();
        public override void Update(float dt) => currentGameScene?.Ticks(dt);
        public override void Draw() => currentGameScene?.Draw();
    }

    public class GameScene
    {
        public virtual void KeyPressed(KeyConstant key, Scancode scancode, bool isRepeat) { }
        public virtual void KeyReleased(KeyConstant key, Scancode scancode) { }
        public virtual void MouseMoved(float x, float y, float dx, float dy, bool isTouch) { }
        public virtual void MousePressed(float x, float y, int button, bool isTouch) { }
        public virtual void MouseReleased(float x, float y, int button, bool isTouch) { }
        public virtual void MouseFocus(bool focus) { }
        public virtual void WheelMoved(int x, int y) { }
        public virtual void JoystickPressed(Joystick joystick, int button) { }
        public virtual void JoystickReleased(Joystick joystick, int button) { }
        public virtual void JoystickAxis(Joystick joystick, float axis, float value) { }
        public virtual void JoystickHat(Joystick joystick, int hat, JoystickHat direction) { }
        public virtual void JoystickGamepadPressed(Joystick joystick, GamepadButton button) { }
        public virtual void JoystickGamepadReleased(Joystick joystick, GamepadButton button) { }
        public virtual void JoystickGamepadAxis(Joystick joystick, GamepadAxis axis, float value) { }
        public virtual void JoystickAdded(Joystick joystick) { }
        public virtual void JoystickRemoved(Joystick joystick) { }
        public virtual void TouchMoved(long id, float x, float y, float dx, float dy, float pressure) { }
        public virtual void TouchPressed(long id, float x, float y, float dx, float dy, float pressure) { }
        public virtual void TouchReleased(long id, float x, float y, float dx, float dy, float pressure) { }
        public virtual void TextEditing(string text, int start, int end) { }
        public virtual void TextInput(string text) { }
        public virtual void WindowFocus(bool focus) { }
        public virtual void WindowVisible(bool visible) { }
        public virtual void WindowResize(int w, int h) { }
        public virtual void DirectoryDropped(string path) { }
        public virtual void FileDropped(string fileFilePath) { }
        public virtual bool Quit() { return true; }
        public virtual void LowMemory() { }
        public virtual void Load() { }
        public virtual void Update(float dt) { }
        public virtual void Draw() { }



        protected virtual void OnExit()
        {
        }

        protected virtual void OnResume()
        {
        }

        protected virtual void OnPause()
        {
        }

        public RunState CurrentState { get; private set; } = RunState.NotStart;


        public enum RunState
        {
            NotStart,
            Runing,
            Paused,
            End,
        }

        public void Pause()
        {
            if (CurrentState == RunState.Runing)
            {
                CurrentState = RunState.Paused;
                OnPause();
            }
        }

        public void Exit()
        {
            if (CurrentState != RunState.End)
            {
                CurrentState = RunState.End;
                OnExit();
            }
        }

        public void Ticks(float dt)
        {
            if (CurrentState == RunState.NotStart)
            {
                Load();
                CurrentState = RunState.Runing;
                Update(dt);
            }
            else if (CurrentState == RunState.Runing)
            {
                Update(dt);
            }
            else if (CurrentState == RunState.Paused)
            {
                CurrentState = RunState.Runing;
                OnResume();
                Update(dt);
            }
        }
    }
}