using DisplayCommands;
using SixLabors.ImageSharp;
using SixLabors.ImageSharp.PixelFormats;
using TanksServer.GameLogic;

namespace TanksServer.Graphics;

internal sealed class TankDrawer : IDrawStep
{
    private readonly TankManager _tanks;
    private readonly bool[] _tankSprite;
    private readonly int _tankSpriteWidth;

    public TankDrawer(TankManager tanks)
    {
        _tanks = tanks;

        using var tankImage = Image.Load<Rgba32>("assets/tank.png");
        _tankSprite = new bool[tankImage.Height * tankImage.Width];

        var whitePixel = new Rgba32(byte.MaxValue, byte.MaxValue, byte.MaxValue, byte.MaxValue);
        var i = 0;
        for (var y = 0; y < tankImage.Height; y++)
        for (var x = 0; x < tankImage.Width; x++, i++)
        {
            _tankSprite[i] = tankImage[x, y] == whitePixel;
        }

        _tankSpriteWidth = tankImage.Width;
    }

    public void Draw(PixelGrid buffer)
    {
        foreach (var tank in _tanks)
        {
            var tankPosition = tank.Position.ToPixelPosition();
            var orientation = (int)Math.Round(tank.Rotation * 16d) % 16;

            for (byte dy = 0; dy < MapService.TileSize; dy++)
            for (byte dx = 0; dx < MapService.TileSize; dx++)
            {
                if (!TankSpriteAt(dx, dy, orientation))
                    continue;

                var position = tankPosition.GetPixelRelative(dx, dy);
                buffer[position.X, position.Y] = true;
            }
        }
    }

    private bool TankSpriteAt(int dx, int dy, int tankRotation)
    {
        var x = tankRotation % 4 * (MapService.TileSize + 1);
        var y = (int)Math.Floor(tankRotation / 4d) * (MapService.TileSize + 1);
        var index = (y + dy) * _tankSpriteWidth + x + dx;

        return _tankSprite[index];
    }
}