Engine-Template/Platforms/Desktop/Engine.Integration.SDL3/Sdl3GameInputs.cs

using System;
using System.Collections.Generic;

using Engine.Core;
using Engine.Systems.Input;

using MyUniverse.Shared.Behaviours.Abstract;

using SDL3;

namespace Engine.Integration.SDL3;

public class Sdl3GameInputs : Behaviour, IGameInputs, IFirstFrameUpdate
{
    public IButtonInputs<IGameInputs.Button>.InputEvent OnAnyButtonPressed { get; } = new();
    public IButtonInputs<IGameInputs.Button>.InputEvent OnAnyButtonReleased { get; } = new();

    private readonly Dictionary<IGameInputs.Button, IButtonInputs<IGameInputs.Button>.InputEvent> OnPressed = new(256);
    private readonly Dictionary<IGameInputs.Button, IButtonInputs<IGameInputs.Button>.InputEvent> OnReleased = new(256);

    private readonly Dictionary<IGameInputs.Button, SDL.Keycode> keyMappingReversed = [];
    private readonly Dictionary<SDL.Keycode, IGameInputs.Button> keyMapping = new() {
        { SDL.Keycode.Space, IGameInputs.Button.Interact }
    };

    private Sdl3KeyboardInputs keyboardInputs = null!;

    public void FirstActiveFrame()
    {
        keyboardInputs = BehaviourController.GetOrAddBehaviour<Sdl3KeyboardInputs>();
        keyboardInputs.OnAnyButtonPressed.AddListener(AnyPressCallback);
        keyboardInputs.OnAnyButtonReleased.AddListener(AnyReleaseCallback);

        foreach ((SDL.Keycode key, IGameInputs.Button button) in keyMapping)
            keyboardInputs.RegisterOnPress(key, PressCallback);

        foreach ((SDL.Keycode key, IGameInputs.Button button) in keyMapping)
            keyboardInputs.RegisterOnRelease(key, ReleaseCallback);
    }

    public void ExitUniverse(IUniverse universe)
    {
        keyboardInputs.OnAnyButtonPressed.RemoveListener(AnyPressCallback);
        keyboardInputs.OnAnyButtonReleased.RemoveListener(AnyReleaseCallback);

        foreach ((SDL.Keycode key, IGameInputs.Button button) in keyMapping)
            keyboardInputs.UnregisterOnPress(key, PressCallback);

        foreach ((SDL.Keycode key, IGameInputs.Button button) in keyMapping)
            keyboardInputs.UnregisterOnRelease(key, ReleaseCallback);
    }

    private void PressCallback(IButtonInputs<SDL.Keycode> sender, IButtonInputs<SDL.Keycode>.ButtonCallbackArguments args)
    {
        if (!keyMapping.TryGetValue(args.Button, out IGameInputs.Button button))
            return;

        if (!OnPressed.TryGetValue(button, out IButtonInputs<IGameInputs.Button>.InputEvent? @event))
            return;

        @event.Invoke(this, new(button));
    }

    private void ReleaseCallback(IButtonInputs<SDL.Keycode> sender, IButtonInputs<SDL.Keycode>.ButtonCallbackArguments args)
    {
        if (!keyMapping.TryGetValue(args.Button, out IGameInputs.Button button))
            return;

        if (!OnReleased.TryGetValue(button, out IButtonInputs<IGameInputs.Button>.InputEvent? @event))
            return;

        @event.Invoke(this, new(button));
    }

    private void AnyReleaseCallback(IButtonInputs<SDL.Keycode> sender, IButtonInputs<SDL.Keycode>.ButtonCallbackArguments args)
    {
        if (keyMapping.TryGetValue(args.Button, out IGameInputs.Button button))
            OnAnyButtonPressed?.Invoke(this, new(button));
    }

    private void AnyPressCallback(IButtonInputs<SDL.Keycode> sender, IButtonInputs<SDL.Keycode>.ButtonCallbackArguments args)
    {
        if (keyMapping.TryGetValue(args.Button, out IGameInputs.Button button))
            OnAnyButtonPressed?.Invoke(this, new(button));
    }

    public void RegisterOnPress(IGameInputs.Button button, IButtonInputs<IGameInputs.Button>.InputEvent.EventHandler callback)
    {
        if (!OnPressed.TryGetValue(button, out IButtonInputs<IGameInputs.Button>.InputEvent? @event))
        {
            @event = new();
            OnPressed.Add(button, @event);
        }

        @event.AddListener(callback);
    }

    public void UnregisterOnPress(IGameInputs.Button button, IButtonInputs<IGameInputs.Button>.InputEvent.EventHandler callback)
    {
        if (OnPressed.TryGetValue(button, out IButtonInputs<IGameInputs.Button>.InputEvent? @event))
            @event.RemoveListener(callback);
    }

    public void RegisterOnRelease(IGameInputs.Button button, IButtonInputs<IGameInputs.Button>.InputEvent.EventHandler callback)
    {
        if (!OnReleased.TryGetValue(button, out IButtonInputs<IGameInputs.Button>.InputEvent? @event))
        {
            @event = new();
            OnReleased.Add(button, @event);
        }

        @event.AddListener(callback);
    }

    public void UnregisterOnRelease(IGameInputs.Button button, IButtonInputs<IGameInputs.Button>.InputEvent.EventHandler callback)
    {
        if (OnReleased.TryGetValue(button, out IButtonInputs<IGameInputs.Button>.InputEvent? @event))
            @event.RemoveListener(callback);
    }

    public bool IsPressed(IGameInputs.Button button)
    {
        if (!keyMappingReversed.TryGetValue(button, out SDL.Keycode key))
            throw new($"{Enum.GetName(button)} is not mapped correctly");

        return keyboardInputs.IsPressed(key);
    }

    public Sdl3GameInputs()
    {
        foreach ((SDL.Keycode key, IGameInputs.Button button) in keyMapping)
            keyMappingReversed.Add(button, key);
    }
}