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

namespace MrGameEng.Sample.Scenes;

/// <summary>
/// Стресс-сцена: 100 000 спрайтов скачут в мире 4000×4000. Колесо — зум (чем дальше,
/// тем больше спрайтов в кадре), Tab — обратно в основную сцену. Цель: 60 FPS.
/// </summary>
public sealed class StressScene : Scene
{
    private const int SpriteCount = 100_000;
    private static readonly RectF WorldBounds = new(-2000f, -2000f, 4000f, 4000f);

    protected override void OnLoad()
    {
        var assets = Context.Services.Get<AssetManager>();
        var input = this.UseInput();
        var actions = SampleInput.CreateActions(input);

        var renderer = this.UseRenderer2D();
        SampleLayers.EnsureRegistered(renderer);

        var shapesTexture = assets.Load(GameAssets.Textures.Shapes);
        var regions = new[]
        {
            new Texture2DRegion(shapesTexture, new Rectangle(0, 0, 32, 32)),
            new Texture2DRegion(shapesTexture, new Rectangle(32, 0, 32, 32)),
            new Texture2DRegion(shapesTexture, new Rectangle(0, 32, 32, 32)),
            new Texture2DRegion(shapesTexture, new Rectangle(32, 32, 32, 32)),
        };

        var random = new Random(7);
        for (var i = 0; i < SpriteCount; i++)
        {
            var sprite = new Sprite(regions[random.Next(regions.Length)]);
            sprite.CenterOrigin();
            var angle = random.NextSingle() * MathF.Tau;
            Store.CreateEntity(
                new Transform2D(
                    new Vector2(
                        random.NextSingle() * WorldBounds.Width + WorldBounds.Left,
                        random.NextSingle() * WorldBounds.Height + WorldBounds.Top),
                    scale: new Vector2(0.4f + random.NextSingle() * 0.6f)),
                sprite,
                new Velocity { Value = new Vector2(MathF.Cos(angle), MathF.Sin(angle)) * (30f + random.Next(150)) });
        }

        var camera = Store.CreateEntity(new Camera(Vector2.Zero, zoom: 0.3f));

        UpdateSystems.Add(new BounceSystem(WorldBounds));
        UpdateSystems.Add(new StressCameraSystem(camera, input));
        UpdateSystems.Add(new SceneHotkeysSystem(Context, actions, () => new MainScene()));
        UpdateSystems.Add(new TitleStatsSystem(Context, renderer, $"Stress {SpriteCount:N0}"));
    }

    /// <summary>Только зум колесом — чтобы регулировать число видимых спрайтов.</summary>
    private sealed class StressCameraSystem(Entity cameraEntity, InputManager input)
        : Friflo.Engine.ECS.Systems.BaseSystem
    {
        protected override void OnUpdateGroup()
        {
            ref var camera = ref cameraEntity.GetComponent<Camera>();
            camera.Zoom = Math.Clamp(camera.Zoom * (1f + input.WheelDelta * 0.001f), 0.05f, 5f);
        }
    }
}