using Raylib_cs;
using Sand.ChunkPrototype;

const int screenWidth = 1280;
const int screenHeight = 800;
const int sidebarWidth = 220;
const int particleSize = 4;
const int simWidth = (screenWidth - sidebarWidth) / particleSize;
const int simHeight = screenHeight / particleSize;
const int brushRadius = 3;

var adapter = new PrototypeSparseSandAdapter(simWidth, simHeight);
var accumulator = 0f;
var fixedStep = 1f / 60f;
var stepCounter = 0;
var currentParticle = PrototypeParticleType.Sand;
var frameBuffer = new byte[simWidth * simHeight * 4];

Raylib.SetConfigFlags(ConfigFlags.ResizableWindow);
Raylib.InitWindow(screenWidth, screenHeight, "Sand Chunk Prototype");
Raylib.SetTargetFPS(120);
var frameImage = Raylib.GenImageColor(simWidth, simHeight, Color.Black);
var frameTexture = Raylib.LoadTextureFromImage(frameImage);
Raylib.UnloadImage(frameImage);

while (!Raylib.WindowShouldClose())
{
    var dt = Raylib.GetFrameTime();
    var mouse = Raylib.GetMousePosition();
    var simMouseX = Math.Clamp((int)((mouse.X - sidebarWidth) / particleSize), 0, simWidth - 1);
    var simMouseY = Math.Clamp((int)(mouse.Y / particleSize), 0, simHeight - 1);
    var overWorld = mouse.X >= sidebarWidth;

    if (Raylib.IsKeyPressed(KeyboardKey.C))
    {
        adapter = new PrototypeSparseSandAdapter(simWidth, simHeight);
        accumulator = 0f;
        stepCounter = 0;
    }

    if (Raylib.IsKeyPressed(KeyboardKey.One))
    {
        currentParticle = PrototypeParticleType.Sand;
    }

    if (Raylib.IsKeyPressed(KeyboardKey.Two))
    {
        currentParticle = PrototypeParticleType.Water;
    }

    if (Raylib.IsKeyPressed(KeyboardKey.Three))
    {
        currentParticle = PrototypeParticleType.Steam;
    }

    if (Raylib.IsKeyPressed(KeyboardKey.Four))
    {
        currentParticle = PrototypeParticleType.Wall;
    }

    if (Raylib.IsMouseButtonDown(MouseButton.Left) && overWorld)
    {
        PaintCircle(adapter, simMouseX, simMouseY, brushRadius, currentParticle, add: true);
    }

    if (Raylib.IsMouseButtonDown(MouseButton.Right) && overWorld)
    {
        PaintCircle(adapter, simMouseX, simMouseY, brushRadius, currentParticle, add: false);
    }

    accumulator += dt;
    var maxSteps = 8;
    while (accumulator >= fixedStep && maxSteps-- > 0)
    {
        adapter.World.ClearDirtyChunks();
        adapter.Step();
        stepCounter++;
        if ((stepCounter % 30) == 0)
        {
            adapter.TrimResidency(marginChunks: 1);
        }

        accumulator -= fixedStep;
    }

    if (accumulator > fixedStep * 4f)
    {
        accumulator = fixedStep;
    }

    var rgbaFrame = adapter.BuildRgbaFrame();
    rgbaFrame.CopyTo(frameBuffer);
    unsafe
    {
        fixed (byte* pixels = frameBuffer)
        {
            Raylib.UpdateTexture(frameTexture, pixels);
        }
    }

    Raylib.BeginDrawing();
    Raylib.ClearBackground(new Color(8, 10, 14, 255));
    Raylib.DrawRectangle(0, 0, sidebarWidth, screenHeight, new Color(20, 24, 30, 255));
    Raylib.DrawTextureEx(frameTexture, new System.Numerics.Vector2(sidebarWidth, 0), 0f, particleSize, Color.White);
    if (overWorld)
    {
        Raylib.DrawCircleLines((int)mouse.X, (int)mouse.Y, brushRadius * particleSize, new Color(255, 255, 255, 180));
    }

    DrawPanel(adapter, currentParticle);
    Raylib.EndDrawing();
}

Raylib.UnloadTexture(frameTexture);
Raylib.CloseWindow();

static void PaintCircle(PrototypeSparseSandAdapter adapter, int centerX, int centerY, int radius, PrototypeParticleType type, bool add)
{
    for (var dx = -radius; dx <= radius; dx++)
    {
        for (var dy = -radius; dy <= radius; dy++)
        {
            if ((dx * dx) + (dy * dy) > radius * radius)
            {
                continue;
            }

            var x = centerX + dx;
            var y = centerY + dy;
            if (x < 0 || y < 0 || x >= adapter.Width || y >= adapter.Height)
            {
                continue;
            }

            if (add)
            {
                adapter.AddParticle(x, y, type);
            }
            else
            {
                adapter.RemoveParticle(x, y);
            }
        }
    }
}

static void DrawPanel(PrototypeSparseSandAdapter adapter, PrototypeParticleType currentParticle)
{
    Raylib.DrawText("Chunk Proto", 12, 14, 28, new Color(110, 172, 228, 255));
    DrawParticleButton(12, 60, "1 Sand", currentParticle == PrototypeParticleType.Sand, new Color(214, 188, 96, 255));
    DrawParticleButton(12, 96, "2 Water", currentParticle == PrototypeParticleType.Water, new Color(72, 132, 232, 255));
    DrawParticleButton(12, 132, "3 Steam", currentParticle == PrototypeParticleType.Steam, new Color(182, 196, 214, 255));
    DrawParticleButton(12, 168, "4 Wall", currentParticle == PrototypeParticleType.Wall, new Color(96, 96, 104, 255));
    Raylib.DrawText($"FPS {Raylib.GetFPS()}", 12, 228, 20, Color.White);
    Raylib.DrawText($"Particles {adapter.ParticleCount}", 12, 252, 20, Color.White);
    Raylib.DrawText($"Loaded Chunks {adapter.World.LoadedChunkCount}", 12, 276, 20, Color.White);
    Raylib.DrawText($"Active Chunks {adapter.World.ActiveChunkCount}", 12, 300, 20, Color.White);
    Raylib.DrawText($"Dirty Chunks {adapter.World.DirtyChunkCount}", 12, 324, 20, Color.White);
    Raylib.DrawText("LMB paint", 12, 372, 18, Color.LightGray);
    Raylib.DrawText("RMB erase", 12, 394, 18, Color.LightGray);
    Raylib.DrawText("C clear", 12, 416, 18, Color.LightGray);
}

static void DrawParticleButton(int x, int y, string label, bool selected, Color color)
{
    Raylib.DrawRectangleRounded(new Rectangle(x, y, 188, 28), 0.2f, 6, selected ? new Color(236, 236, 242, 255) : color);
    Raylib.DrawText(label, x + 10, y + 5, 18, selected ? Color.Black : Color.Black);
}