using System;
using System.IO;
using RadicadeServer.Images;
using Xunit;

namespace RadicadeServer.Tests;

/// <summary>
/// The image route answers by name, and the name a client asks for is not always the name on
/// disk. Two real cases drove this: a custom-avatar design is stored as
/// <c>&lt;guid&gt;.bin</c> while its bytes are a PNG, and the default room image ships as
/// <c>DefaultRoomImage.png</c> while the server asks for the bare <c>DefaultRoomImage</c>.
/// Both resolved to nothing, and nothing is not "no picture" -- it is an empty 404 body, which
/// the 2023 client turns into a broken surface (and, for a room image, a fatal load failure).
/// </summary>
public class ImageAssetResolutionTests : IDisposable
{
    private readonly string root = Directory.CreateTempSubdirectory("radicade-images-test-").FullName;

    public void Dispose()
    {
        try
        {
            Directory.Delete(root, true);
        }
        catch (IOException)
        {
        }
    }

    private string Write(string name, string content = "x")
    {
        var path = Path.Join(root, name);
        File.WriteAllText(path, content);
        return path;
    }

    [Fact]
    public void TheRequestedNameIsFoundFirst()
    {
        var expected = Write("photo.png");

        Assert.Equal(expected, ImageAPI.ResolveAsset("photo.png", new[] { root }));
    }

    [Fact]
    public void ADesignStoredAsBinIsFoundByTheNameTheClientAsksFor()
    {
        // Exactly what the customizer wrote before designs moved to the image CDN: the bytes
        // are a PNG, the name on disk ends in .bin, and the client asks for that name.
        var expected = Write("a07188bb-9f99-442d-a2ff-2aebad2ca7fe.bin");

        Assert.Equal(expected, ImageAPI.ResolveAsset("a07188bb-9f99-442d-a2ff-2aebad2ca7fe.bin", new[] { root }));
    }

    [Fact]
    public void AMissingExtensionIsTriedOnTheSameStem()
    {
        // The default-image case: the server asks for "DefaultRoomImage", the deployment ships
        // "DefaultRoomImage.png", and the extension search used to be skipped for this name.
        var expected = Write("DefaultRoomImage.png");

        Assert.Equal(expected, ImageAPI.ResolveAsset("DefaultRoomImage", new[] { root }));
    }

    [Fact]
    public void AnExtensionThatDoesNotDescribeTheContentStillFindsTheFile()
    {
        var expected = Write("design.png");

        Assert.Equal(expected, ImageAPI.ResolveAsset("design.bin", new[] { root }));
        Assert.Equal(expected, ImageAPI.ResolveAsset("design.jpeg", new[] { root }));
    }

    [Fact]
    public void RootsAreSearchedInOrder()
    {
        var first = Directory.CreateDirectory(Path.Join(root, "images")).FullName;
        var second = Directory.CreateDirectory(Path.Join(root, "custom")).FullName;
        var expected = Path.Join(first, "shirt.png");
        File.WriteAllText(expected, "x");
        File.WriteAllText(Path.Join(second, "shirt.png"), "x");

        Assert.Equal(expected, ImageAPI.ResolveAsset("shirt.png", new[] { first, second }));
    }

    [Fact]
    public void ANamedRootIsPreferredOverALaterRootsVariant()
    {
        var images = Directory.CreateDirectory(Path.Join(root, "images")).FullName;
        var custom = Directory.CreateDirectory(Path.Join(root, "custom")).FullName;
        var expected = Path.Join(custom, "shirt.bin");
        File.WriteAllText(expected, "x");
        File.WriteAllText(Path.Join(images, "shirt.png"), "x");

        Assert.Equal(expected, ImageAPI.ResolveAsset("shirt.bin", new[] { images, custom }));
    }

    [Theory]
    [InlineData("")]
    [InlineData(".")]
    [InlineData("..")]
    [InlineData("../outside.png")]
    [InlineData("..\\outside.png")]
    [InlineData("sub/../outside.png")]
    public void NamesThatDoNotNameAFileInsideARootResolveToNothing(string name)
    {
        Assert.Null(ImageAPI.ResolveAsset(name, new[] { root }));
    }

    [Fact]
    public void AnUnknownNameResolvesToNothing()
    {
        Assert.Null(ImageAPI.ResolveAsset("definitely-missing.png", new[] { root }));
        Assert.Null(ImageAPI.ResolveAsset("definitely-missing.bin", new[] { root }));
    }

    [Fact]
    public void TheServedRootsStillIncludeTheDesignRoot()
    {
        // A design written before designs moved to the image CDN only stays reachable while
        // CDN/Custom is still searched, so dropping it here would silently blank old shirts.
        var roots = ImageAPI.AssetRoots();

        Assert.Contains(roots, r => r.EndsWith(Path.Join("CDN", "Images")));
        Assert.Contains(roots, r => r.EndsWith(Path.Join("CDN", "Custom")));
        Assert.Contains(roots, r => r.EndsWith(Path.Join("CDN", "Storage")));
    }
}