using System.Text.Json;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using RadicadeServer;
using RadicadeServer.API.Studio;
using RadicadeServer.CDN;
using RadicadeServer.DB;
using Xunit;

namespace RadicadeServer.Tests;

/// <summary>
/// Step one of the client's bundle download is
/// <c>GET /rooms/unity_assets/{assetId}/{target}/{version}</c> for a file name, step two is
/// <c>/data/{Filename}</c> for the bytes. An id arrives in two shapes and the room load needs
/// the one the subroom carries:
///
/// - a Studio manifest id (40 alphanumerics), whose bundles are named in the manifest's own
///   metadata;
/// - a legacy bundle stored under its file name, with or without the <c>.assetbundle</c> suffix
///   an import appends - which is every imported room, every built-in room and every bundle the
///   admin panel binds.
///
/// Gating both shapes on the 40-character test answered <c>400 {"success":false,"error":"bad
/// request"}</c> for every legacy bundle on the server, and the client reports one such answer as
/// "Error downloading room assets! Try again later or on a better connection." for the whole
/// room - the failure looked like a connection problem and hit every player, because it was
/// server-side and room-independent. These pin both shapes and the two names that must never be
/// served at all.
/// </summary>
[Collection(DbFactoryCollection.Name)]
public class UnityAssetMetadataTests : IDisposable
{
    private const string LegacyBundle = "Showdown_0_1.assetbundle";
    private const string StudioManifestId = "0123456789abcdef0123456789abcdef01234567";
    private static readonly string BakedBundle = new('a', 40);
    private static readonly string RejectedBundle = new('b', 40);

    private readonly string root = Directory.CreateTempSubdirectory("radicade-unity-assets-").FullName;
    private readonly string? previousStorage;

    public UnityAssetMetadataTests()
    {
        previousStorage = DBConfig.CDNStorage;
        DBConfig.CDNStorage = root;
    }

    public void Dispose()
    {
        DBConfig.CDNStorage = previousStorage!;

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

    private string Write(string name, string contents = "bundle")
    {
        var path = Path.Join(root, name);
        var directory = Path.GetDirectoryName(path);
        if (!string.IsNullOrEmpty(directory)) Directory.CreateDirectory(directory);
        File.WriteAllText(path, contents);
        return path;
    }

    private static UnityAssetsCDN Metadata() => new()
    {
        ControllerContext = new ControllerContext { HttpContext = new DefaultHttpContext() }
    };

    private static T WithHttpContext<T>(T controller) where T : Controller
    {
        controller.ControllerContext = new ControllerContext { HttpContext = new DefaultHttpContext() };
        return controller;
    }

    private static JsonElement Body(IActionResult result)
    {
        var content = Assert.IsType<ContentResult>(result);
        Assert.Equal("application/json", content.ContentType);
        return JsonSerializer.Deserialize<JsonElement>(content.Content!);
    }

    // ---------------------------------------------------------------- legacy ids

    [Theory]
    [InlineData("Showdown_0_1.assetbundle", "Showdown_0_1.assetbundle")]
    [InlineData("Showdown_0_1", "Showdown_0_1.assetbundle")]
    [InlineData("8aas7b5ivtaggn9swhe3wkgdj.assetbundle", "8aas7b5ivtaggn9swhe3wkgdj.assetbundle")]
    [InlineData("8aas7b5ivtaggn9swhe3wkgdj", "8aas7b5ivtaggn9swhe3wkgdj.assetbundle")]
    public async Task ALegacyBundleResolvesUnderBothSpellingsOfItsId(string requested, string expected)
    {
        Write("Showdown_0_1.assetbundle");
        Write("8aas7b5ivtaggn9swhe3wkgdj.assetbundle");

        var json = Body(await Metadata().GetUnityAsset(requested, 0, 1));

        Assert.Equal(requested, json.GetProperty("UnityAssetId").GetString());
        Assert.Equal(expected, json.GetProperty("Filename").GetString());
        Assert.Equal(0, json.GetProperty("Target").GetInt32());
        Assert.Equal(1, json.GetProperty("Version").GetInt32());
    }

    [Fact]
    public async Task TheFilenameTheClientIsHandedIsTheFileItCanDownload()
    {
        // The two steps have to agree: step two has no other way to reach the bytes.
        Write(LegacyBundle);
        var filename = Body(await Metadata().GetUnityAsset(LegacyBundle, 0, 1)).GetProperty("Filename").GetString()!;

        var file = Assert.IsType<PhysicalFileResult>(new DataCDN().GetDataBlob(filename));

        Assert.Equal(Path.Join(root, LegacyBundle), file.FileName);
        Assert.True(file.EnableRangeProcessing);
    }

    [Fact]
    public async Task AnUnknownBundleStillAnswersNotFound()
    {
        Write(LegacyBundle);

        Assert.IsType<NotFoundResult>(await Metadata().GetUnityAsset("not-on-disk", 0, 1));
        Assert.IsType<NotFoundResult>(await Metadata().GetUnityAsset("not-on-disk.assetbundle", 0, 1));
    }

    [Fact]
    public async Task TheIdsWithoutTargetOrVersionAnswersTheDefaultPair()
    {
        // /rooms/unity_assets/{assetId} is the short form; it must not silently be a 400 either.
        Write(LegacyBundle);

        var json = Body(await Metadata().GetUnityAsset(LegacyBundle));

        Assert.Equal(LegacyBundle, json.GetProperty("Filename").GetString());
        Assert.Equal(1, json.GetProperty("Version").GetInt32());
    }

    // ---------------------------------------------------------------- Studio manifests

    [Fact]
    public async Task AStudioManifestStillAnswersTheBundleItsMetadataNames()
    {
        Write(StudioManifestId, "{\"Version\":2,\"MainSceneProjectRelativePath\":\"Assets/Room.unity\",\"Files\":[]}");
        Write(BakedBundle);
        Write(RejectedBundle);
        await StudioUnityAssetRegistry.AddBakedAssetAsync(StudioManifestId,
            new StudioBakedUnityAsset(StudioManifestId, 0, 1, BakedBundle, RejectedBundle));

        var json = Body(await Metadata().GetUnityAsset(StudioManifestId, 0, 1));

        Assert.Equal(BakedBundle, json.GetProperty("Filename").GetString());
        Assert.Equal(RejectedBundle, json.GetProperty("RejectedDependenciesFilename").GetString());
    }

    [Fact]
    public async Task AStudioManifestIsNeverHandedOverAsItsOwnBundle()
    {
        // The manifest is the file stored under the id, so a target/version it does not name
        // must be a 404: answering with the manifest would have the client parse JSON metadata
        // as an asset bundle.
        Write(StudioManifestId, "{\"Version\":2,\"MainSceneProjectRelativePath\":\"Assets/Room.unity\",\"Files\":[]}");
        Write(LegacyBundle);

        Assert.IsType<NotFoundResult>(await Metadata().GetUnityAsset(StudioManifestId, 0, 1));
        Assert.IsType<NotFoundResult>(await Metadata().GetUnityAsset(StudioManifestId, 5, 9));
    }

    [Fact]
    public async Task ALegacyBundleWhoseIdLooksLikeAManifestStillResolves()
    {
        // 40 alphanumerics with no manifest file behind it is a bundle name like any other, and
        // a 40-character id is exactly what the importer names a Studio asset, so this is the
        // shape a bare-id bundle arrives in.
        Write(BakedBundle + ".assetbundle");

        var json = Body(await Metadata().GetUnityAsset(BakedBundle, 0, 1));

        Assert.Equal(BakedBundle + ".assetbundle", json.GetProperty("Filename").GetString());
    }

    // ---------------------------------------------------------------- names never served

    [Theory]
    [InlineData("sub/" + LegacyBundle)]
    [InlineData("..\\" + LegacyBundle)]
    [InlineData(LegacyBundle + ".uploading")]
    [InlineData("Showdown_0_1.uploading")]
    public async Task ANameThatMustNotBeServedIsRefused(string requested)
    {
        // Every one of these is on disk as literally as the platform allows, so the refusal has
        // to be the rule rather than the file being absent.
        Write(LegacyBundle);
        Write(LegacyBundle + ".uploading");
        Write("Showdown_0_1.uploading");
        Write("sub/" + LegacyBundle);

        Assert.IsType<BadRequestResult>(await Metadata().GetUnityAsset(requested, 0, 1));
    }

    [Fact]
    public async Task ANameThatLeavesTheStorageDirectoryIsRefused()
    {
        // This one escapes the storage root and re-enters it, so the file is genuinely reachable
        // by path and only the rule stands between the request and the bytes.
        Write(LegacyBundle);
        var escaping = "../" + Path.GetFileName(root) + "/" + LegacyBundle;

        Assert.IsType<BadRequestResult>(await Metadata().GetUnityAsset(escaping, 0, 1));
    }

    [Theory]
    [InlineData(256, 1)]
    [InlineData(-1, 1)]
    [InlineData(0, -1)]
    public async Task ATargetOrVersionOutsideTheContractIsRefused(int target, int version)
    {
        Write(LegacyBundle);

        Assert.IsType<BadRequestResult>(await Metadata().GetUnityAsset(LegacyBundle, target, version));
    }

    // ---------------------------------------------------------------- the bytes routes

    [Fact]
    public void TheBytesRouteAnswersBothSpellingsOfABundle()
    {
        Write(LegacyBundle);

        var exact = Assert.IsType<PhysicalFileResult>(
            WithHttpContext(new RoomsCDN()).GetUnityAssetRaw(LegacyBundle, 0, 1));
        Assert.Equal(Path.Join(root, LegacyBundle), exact.FileName);

        // /unity/{id} is the id with no extension, while an import stores <id>.assetbundle.
        var bare = Assert.IsType<PhysicalFileResult>(
            WithHttpContext(new RoomsCDN()).GetUnityAssetRaw("Showdown_0_1", 0, 1));
        Assert.Equal(Path.Join(root, LegacyBundle), bare.FileName);
    }

    [Fact]
    public void NoBlobRouteServesAHalfImportedPart()
    {
        // Admin part uploads stage <name>.uploading beside the final file and promote it only
        // when the last part lands, so a truncated bundle must be unreachable by name even
        // though it is sitting in the storage directory.
        Write(LegacyBundle);
        Write(LegacyBundle + ".uploading");

        Assert.IsType<BadRequestResult>(new DataCDN().GetDataBlob(LegacyBundle + ".uploading"));
        Assert.IsType<BadRequestResult>(new RoomsCDN().GetDataBlob(LegacyBundle + ".uploading"));
        Assert.IsType<BadRequestResult>(WithHttpContext(new RoomsCDN()).GetUnityAssetRaw(LegacyBundle + ".uploading", 0, 1));
        Assert.IsType<BadRequestResult>(new InventionCDN().GetDataBlob(LegacyBundle + ".uploading"));

        // ... while the promoted file beside it is served as usual.
        Assert.IsType<PhysicalFileResult>(new DataCDN().GetDataBlob(LegacyBundle));
    }

    [Fact]
    public void NoBlobRouteServesANameThatLeavesTheStorageDirectory()
    {
        Write(LegacyBundle);

        Assert.IsType<BadRequestResult>(new DataCDN().GetDataBlob("../" + LegacyBundle));
        Assert.IsType<BadRequestResult>(new DataCDN().GetDataBlob("sub/" + LegacyBundle));
        Assert.IsType<BadRequestResult>(new RoomsCDN().GetDataBlob("../" + LegacyBundle));
        Assert.IsType<BadRequestResult>(WithHttpContext(new RoomsCDN()).GetUnityAssetRaw("../" + LegacyBundle, 0, 1));
    }
}