using Friflo.Engine.ECS;
using Friflo.Engine.ECS.Systems;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Input;
using MrGameEng.Audio;
using MrGameEng.Core;
using MrGameEng.Graphics;
using MrGameEng.Input;

namespace MrGameEng.Sample;

/// <summary>Управление игроком (WASD/стрелки) и прыжок-писк на пробел.</summary>
public sealed class PlayerControlSystem(
    Entity player, ActionMap<SampleAction> actions, AudioManager audio, SoundEffect beep) : BaseSystem
{
    protected override void OnUpdateGroup()
    {
        ref var transform = ref player.GetComponent<Transform2D>();
        var move = new Vector2(
            actions.GetAxis(SampleAction.MoveLeft, SampleAction.MoveRight),
            actions.GetAxis(SampleAction.MoveUp, SampleAction.MoveDown));

        if (move != Vector2.Zero)
        {
            move.Normalize();
            transform.Position += move * 260f * Tick.deltaTime;
        }

        if (actions.IsPressed(SampleAction.Jump))
        {
            audio.Play(beep);
        }
    }
}

/// <summary>Камера следует за игроком; колесо — зум, Q/E — поворот.</summary>
public sealed class CameraControlSystem(Entity cameraEntity, Entity player, InputManager input) : BaseSystem
{
    protected override void OnUpdateGroup()
    {
        ref var camera = ref cameraEntity.GetComponent<Camera>();
        var target = player.GetComponent<Transform2D>().Position;

        camera.Position = Vector2.Lerp(camera.Position, target, Math.Min(1f, 6f * Tick.deltaTime));
        camera.Zoom = Math.Clamp(camera.Zoom * (1f + input.WheelDelta * 0.001f), 0.2f, 5f);

        var rotate = (input.IsKeyDown(Keys.E) ? 1f : 0f) - (input.IsKeyDown(Keys.Q) ? 1f : 0f);
        camera.Rotation += rotate * 1.2f * Tick.deltaTime;
    }
}

/// <summary>Отскок сущностей со скоростью от границ мира.</summary>
public sealed class BounceSystem(RectF bounds) : QuerySystem<Transform2D, Velocity>
{
    protected override void OnUpdate()
    {
        var delta = Tick.deltaTime;
        foreach (var (transforms, velocities, _) in Query.Chunks)
        {
            var t = transforms.Span;
            var v = velocities.Span;
            for (var i = 0; i < t.Length; i++)
            {
                ref var position = ref t[i].Position;
                ref var velocity = ref v[i].Value;
                position += velocity * delta;

                if (position.X < bounds.Left || position.X > bounds.Right)
                {
                    velocity.X = -velocity.X;
                    position.X = Math.Clamp(position.X, bounds.Left, bounds.Right);
                }

                if (position.Y < bounds.Top || position.Y > bounds.Bottom)
                {
                    velocity.Y = -velocity.Y;
                    position.Y = Math.Clamp(position.Y, bounds.Top, bounds.Bottom);
                }
            }
        }
    }
}

/// <summary>Пауза (P), музыка (M), переключение сцены с переходом (Tab).</summary>
public sealed class SceneHotkeysSystem(
    EngineContext context, ActionMap<SampleAction> actions, Func<Scene> nextScene, Transition transition) : BaseSystem
{
    protected override void OnUpdateGroup()
    {
        if (actions.IsPressed(SampleAction.Pause))
        {
            context.Clock.TimeScale = context.Clock.TimeScale > 0f ? 0f : 1f;
        }

        if (actions.IsPressed(SampleAction.ToggleMusic))
        {
            var music = context.Services.Get<AudioManager>().Music;
            if (music.IsPlaying)
            {
                music.Pause();
            }
            else
            {
                music.Resume();
            }
        }

        if (actions.IsPressed(SampleAction.SwitchScene) && !context.Scenes.IsTransitioning)
        {
            context.Scenes.Switch(nextScene(), transition);
        }
    }
}

/// <summary>FPS и статистика рендера: в HUD-лейбл и в заголовок окна (4 раза в секунду).</summary>
public sealed class StatsSystem(
    EngineContext context, Renderer2D renderer, string sceneName, Myra.Graphics2D.UI.Label? hudLabel = null) : BaseSystem
{
    private float _accumulated;
    private int _frames;

    protected override void OnUpdateGroup()
    {
        _accumulated += context.Clock.UnscaledDeltaTime;
        _frames++;
        if (_accumulated < 0.25f)
        {
            return;
        }

        var fps = _frames / _accumulated;
        _accumulated = 0f;
        _frames = 0;
        var stats =
            $"{fps:F0} FPS | sprites: {renderer.SubmittedSprites} | culled: {renderer.CulledSprites} | draw calls: {renderer.DrawCalls}";
        context.Services.Get<GameWindow>().Title = $"MrGameEng Sample — {sceneName} | {stats}";
        if (hudLabel is not null)
        {
            hudLabel.Text = $"{sceneName}\n{stats}";
        }
    }
}

/// <summary>Общая настройка ввода для сцен сэмпла.</summary>
public static class SampleInput
{
    public static ActionMap<SampleAction> CreateActions(InputManager input) =>
        new ActionMap<SampleAction>(input)
            .Bind(SampleAction.MoveLeft, Keys.A)
            .Bind(SampleAction.MoveLeft, Keys.Left)
            .Bind(SampleAction.MoveRight, Keys.D)
            .Bind(SampleAction.MoveRight, Keys.Right)
            .Bind(SampleAction.MoveUp, Keys.W)
            .Bind(SampleAction.MoveUp, Keys.Up)
            .Bind(SampleAction.MoveDown, Keys.S)
            .Bind(SampleAction.MoveDown, Keys.Down)
            .Bind(SampleAction.Jump, Keys.Space)
            .Bind(SampleAction.Pause, Keys.P)
            .Bind(SampleAction.ToggleMusic, Keys.M)
            .Bind(SampleAction.SwitchScene, Keys.Tab);
}