using System;

using Microsoft.Xna.Framework.Input;

using Syntriax.Engine.Core;
using Syntriax.Engine.Network;
using Syntriax.Engine.Systems.Input;

namespace Pong.Behaviours;

public class PongManagerBehaviour : Behaviour,
    IPacketListenerServer<PongManagerBehaviour.PongStartPacket>,
    IPacketListenerServer<PongManagerBehaviour.PongResetPacket>,
    IPacketListenerClient<PongManagerBehaviour.PongStartPacket>,
    IPacketListenerClient<PongManagerBehaviour.PongResetPacket>,
    IPacketListenerClient<PongManagerBehaviour.PongScoreUpdatePacket>
{
    public Action<PongManagerBehaviour>? OnReset { get; set; } = null;
    public Action<PongManagerBehaviour>? OnFinished { get; set; } = null;
    public Action<PongManagerBehaviour>? OnScored { get; set; } = null;

    private readonly Random random = new();
    private BallBehaviour ball = null!;

    private INetworkCommunicatorClient? networkClient = null!;
    private INetworkCommunicatorServer? networkServer = null;

    public int ScoreLeft { get; private set; } = 0;
    public int ScoreRight { get; private set; } = 0;
    public int ScoreSum => ScoreLeft + ScoreRight;

    public int WinScore { get; } = 5;

    public PongManagerBehaviour() => WinScore = 5;
    public PongManagerBehaviour(int winScore) => WinScore = winScore;

    protected override void OnFirstActiveFrame()
    {
        IButtonInputs<Keys> buttonInputs = Universe.FindRequired<IButtonInputs<Keys>>();
        buttonInputs.RegisterOnRelease(Keys.Space, (_, _1) => networkClient?.SendToServer(new PongResetPacket()));

        ball = Universe.FindRequiredBehaviour<BallBehaviour>();
        networkClient = Universe.Find<INetworkCommunicatorClient>();
        networkServer = Universe.Find<INetworkCommunicatorServer>();
    }

    public void ScoreToLeft()
    {
        if (networkServer is not null)
        {
            ScoreLeft++;
            OnScored?.InvokeSafe(this);
        }

        CheckFinish();
    }

    public void ScoreToRight()
    {
        if (networkServer is not null)
        {
            ScoreRight++;
            OnScored?.InvokeSafe(this);
        }

        CheckFinish();
    }

    public void Reset()
    {
        ScoreLeft = ScoreRight = 0;
        OnReset?.InvokeSafe(this);
    }

    private void CheckFinish()
    {
        int halfwayScore = (int)(WinScore * .5f);
        ball.ResetBall();

        networkServer?.SendToClient("*", new PongScoreUpdatePacket(this));
        if (ScoreLeft > halfwayScore || ScoreRight > halfwayScore)
            OnFinished?.InvokeSafe(this);
        else
            networkServer?.SendToClient("*", new PongStartPacket() { BallVelocity = GetBallLaunchDirection() });
    }

    private Vector2D GetBallLaunchDirection()
    {
        const float AllowedRadians = 45f * Syntriax.Engine.Core.Math.DegreeToRadian;
        float rotation = (float)random.NextDouble() * 2f * AllowedRadians - AllowedRadians;
        bool isBackwards = (random.Next() % 2) == 1;
        return Vector2D.Right.Rotate(isBackwards ? rotation + Syntriax.Engine.Core.Math.PI : rotation);
    }

    public void OnClientPacketArrived(PongStartPacket packet) => ball.LaunchBall(packet.BallVelocity);
    public void OnClientPacketArrived(PongResetPacket packet) => Reset();
    public void OnClientPacketArrived(PongScoreUpdatePacket packet)
    {
        ScoreLeft = packet.Left;
        ScoreRight = packet.Right;
        OnScored?.InvokeSafe(this);
    }

    public void OnServerPacketArrived(PongResetPacket packet, string from)
    {
        Reset();
        Vector2D ballVelocity = GetBallLaunchDirection();
        ball.LaunchBall(ballVelocity);
        networkServer?.SendToClient("*", new PongResetPacket());
        networkServer?.SendToClient("*", new PongStartPacket() { BallVelocity = ballVelocity });
    }

    public void OnServerPacketArrived(PongStartPacket packet, string from)
    {
        packet = new() { BallVelocity = GetBallLaunchDirection() };
        ball.LaunchBall(packet.BallVelocity);
        networkServer?.SendToClient("*", packet);
    }

    public class PongStartPacket : INetworkPacket
    {
        public Vector2D BallVelocity { get; set; } = Vector2D.Zero;
    }

    public class PongResetPacket : INetworkPacket;

    public class PongScoreUpdatePacket : INetworkPacket
    {
        public int Left { get; set; } = 0;
        public int Right { get; set; } = 0;

        public PongScoreUpdatePacket() { }
        public PongScoreUpdatePacket(PongManagerBehaviour pongManagerBehaviour)
        {
            Left = pongManagerBehaviour.ScoreLeft;
            Right = pongManagerBehaviour.ScoreRight;
        }
    }
}