using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using MrGameEng.Graphics;
using Xunit;

namespace MrGameEng.Tilemaps.Tests;

public class TileGridTests
{
    [Fact]
    public void NewGrid_IsEmpty()
    {
        var grid = new TileGrid(4, 3);

        Assert.Equal(4, grid.Width);
        Assert.Equal(3, grid.Height);
        for (var y = 0; y < 3; y++)
        {
            for (var x = 0; x < 4; x++)
            {
                Assert.Equal(0, grid[x, y]);
            }
        }
    }

    [Fact]
    public void SetGet_RoundtripsPerCell()
    {
        var grid = new TileGrid(3, 3);

        grid[2, 1] = 7;

        Assert.Equal(7, grid[2, 1]);
        Assert.Equal(0, grid[1, 2]);
    }

    [Fact]
    public void Fill_SetsEveryCell()
    {
        var grid = new TileGrid(5, 5);

        grid.Fill(3);

        Assert.Equal(3, grid[0, 0]);
        Assert.Equal(3, grid[4, 4]);
    }

    [Theory]
    [InlineData(-1, 0)]
    [InlineData(0, -1)]
    [InlineData(3, 0)]
    [InlineData(0, 2)]
    public void OutOfBounds_Throws(int x, int y)
    {
        var grid = new TileGrid(3, 2);

        Assert.False(grid.Contains(x, y));
        Assert.Throws<ArgumentOutOfRangeException>(() => grid[x, y]);
        Assert.Throws<ArgumentOutOfRangeException>(() => grid[x, y] = 1);
    }

    [Theory]
    [InlineData(0, 0)]
    [InlineData(-1, 1)]
    public void InvalidSize_Throws(int width, int height)
    {
        Assert.Throws<ArgumentOutOfRangeException>(() => new TileGrid(width, height));
    }
}

public class TileSetTests
{
    // Texture2D == null допустим в headless-тестах (см. Texture2DRegion).
    private static Texture2DRegion Region(int size = 16) =>
        new(null!, new Rectangle(0, 0, size, size));

    [Fact]
    public void Add_ReturnsSequentialIds_StartingAtOne()
    {
        var tiles = new TileSet();

        var first = tiles.Add(Region());
        var second = tiles.Add(Region(), Color.Red);

        Assert.Equal(1, first);
        Assert.Equal(2, second);
        Assert.Equal(3, tiles.Count);
        Assert.Equal(Color.White, tiles[first].Color);
        Assert.Equal(Color.Red, tiles[second].Color);
    }

    [Fact]
    public void EmptyTileZero_HasNoRegion()
    {
        var tiles = new TileSet();

        Assert.Null(tiles[0].Region);
    }
}

public class TilemapMathTests
{
    [Fact]
    public void CameraInsideMap_ReturnsClampedRange()
    {
        var cull = new RectF(35f, 18f, 40f, 30f); // правый край 75, нижний 48

        var visible = TilemapMath.VisibleCells(in cull, Vector2.Zero, 16f, 10, 10,
            out var x0, out var y0, out var x1, out var y1);

        Assert.True(visible);
        Assert.Equal((2, 1, 4, 3), (x0, y0, x1, y1));
    }

    [Fact]
    public void MapOffsetByOrigin_ShiftsRange()
    {
        var cull = new RectF(0f, 0f, 64f, 64f);

        var visible = TilemapMath.VisibleCells(in cull, new Vector2(-32f, -32f), 16f, 100, 100,
            out var x0, out var y0, out var x1, out var y1);

        Assert.True(visible);
        Assert.Equal((2, 2, 6, 6), (x0, y0, x1, y1));
    }

    [Fact]
    public void CameraLargerThanMap_ClampsToWholeGrid()
    {
        var cull = new RectF(-1000f, -1000f, 5000f, 5000f);

        var visible = TilemapMath.VisibleCells(in cull, Vector2.Zero, 16f, 8, 6,
            out var x0, out var y0, out var x1, out var y1);

        Assert.True(visible);
        Assert.Equal((0, 0, 7, 5), (x0, y0, x1, y1));
    }

    [Theory]
    [InlineData(200f, 0f)]    // справа от карты
    [InlineData(-200f, 0f)]   // слева
    [InlineData(0f, 200f)]    // ниже
    public void CameraOutsideMap_ReturnsFalse(float offsetX, float offsetY)
    {
        var cull = new RectF(offsetX, offsetY, 100f, 100f);

        var visible = TilemapMath.VisibleCells(in cull, new Vector2(-150f, -150f), 16f, 8, 8,
            out _, out _, out _, out _);

        Assert.False(visible);
    }
}