using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Input;

using Syntriax.Engine.Core;

namespace Syntriax.Engine.Input;

public class KeyboardInputsBehaviour : BehaviourOverride, IKeyboardInputs
{
    private IDictionary<Keys, Action<IKeyboardInputs, Keys>> OnPressed = new Dictionary<Keys, Action<IKeyboardInputs, Keys>>(256);
    private IDictionary<Keys, Action<IKeyboardInputs, Keys>> OnReleased = new Dictionary<Keys, Action<IKeyboardInputs, Keys>>(256);

    private int cachePressedCurrentlyCount = 0;
    private Keys[] cachePressedCurrently = new Keys[256];

    private int cachePressedPreviouslyCount = 0;
    private Keys[] cachePressedPreviously = new Keys[256];

    public void RegisterOnPress(Keys key, Action<IKeyboardInputs, Keys> callback)
    {
        if (OnPressed.TryGetValue(key, out var action))
        {
            action += callback;
            return;
        }

        OnPressed.Add(key, callback);
    }

    public void UnregisterOnPress(Keys key, Action<IKeyboardInputs, Keys> callback)
    {
        if (OnPressed.TryGetValue(key, out var action))
            action -= callback;
    }

    public void RegisterOnRelease(Keys key, Action<IKeyboardInputs, Keys> callback)
    {
        if (OnReleased.TryGetValue(key, out var action))
        {
            action += callback;
            return;
        }

        OnReleased.Add(key, callback);
    }

    public void UnregisterOnRelease(Keys key, Action<IKeyboardInputs, Keys> callback)
    {
        if (OnReleased.TryGetValue(key, out var action))
            action -= callback;
    }

    protected override void OnUpdate(GameTime time)
    {
        KeyboardState keyboardState = Keyboard.GetState();
        keyboardState.GetPressedKeys(cachePressedCurrently);
        cachePressedCurrentlyCount = keyboardState.GetPressedKeyCount();

        for (int i = 0; i < cachePressedCurrentlyCount; i++)
        {
            Keys currentlyPressedKey = cachePressedCurrently[i];
            if (!WasPressed(currentlyPressedKey))
                if (OnPressed.TryGetValue(currentlyPressedKey, out var action))
                    action.Invoke(this, currentlyPressedKey);
        }

        for (int i = 0; i < cachePressedPreviouslyCount; i++)
        {
            Keys previouslyPressedKey = cachePressedPreviously[i];
            if (!IsPressed(previouslyPressedKey))
                if (OnReleased.TryGetValue(previouslyPressedKey, out var action))
                    action.Invoke(this, previouslyPressedKey);
        }

        Array.Copy(cachePressedCurrently, cachePressedPreviously, cachePressedCurrentlyCount);
        cachePressedPreviouslyCount = cachePressedCurrentlyCount;
    }

    public bool IsPressed(Keys key)
    {
        for (int i = 0; i < cachePressedCurrentlyCount; i++)
            if (cachePressedCurrently[i] == key)
                return true;
        return false;
    }

    public bool WasPressed(Keys key)
    {
        for (int i = 0; i < cachePressedPreviouslyCount; i++)
            if (cachePressedPreviously[i] == key)
                return true;
        return false;
    }
}