using System.Net;
using Paca.Core.Config;
using Paca.Core.Hls;
using Paca.Core.Platform;
using Xunit;

namespace Paca.Tests.Core;

public class DownloadFolderCleanlinessAndPacaIsolationGateTests
{
    [Fact]
    public void Gate_DownloadMetaPathResolver_CreatesHiddenPacaFolder_AndSubdirectories()
    {
        var tempRoot = Path.Combine(Path.GetTempPath(), "paca_clean_test_" + Guid.NewGuid().ToString("N"));
        Directory.CreateDirectory(tempRoot);
        try
        {
            var outputBase = Path.Combine(tempRoot, "test_video");
            var partsDir = DownloadMetaPathResolver.GetPartsDirectory(outputBase);
            var tempPartFile = DownloadMetaPathResolver.GetTempPartFilePath(outputBase);
            var pacaDir = DownloadMetaPathResolver.GetPacaDirectory(tempRoot);

            Assert.True(Directory.Exists(pacaDir), ".paca 폴더가 생성되어야 한다.");
            var di = new DirectoryInfo(pacaDir);
            Assert.True((di.Attributes & FileAttributes.Hidden) != 0, ".paca 폴더는 Hidden 속성을 가져야 한다.");

            // partsDir은 .paca/parts 하위에 존재해야 함
            Assert.Contains(Path.Combine(".paca", "parts"), partsDir);
            Assert.DoesNotContain(tempRoot + Path.DirectorySeparatorChar + "test_video.parts", partsDir);

            // tempPartFile은 .paca/temp 하위에 존재해야 함
            Assert.Contains(Path.Combine(".paca", "temp"), tempPartFile);
        }
        finally
        {
            if (Directory.Exists(tempRoot))
            {
                try { Directory.Delete(tempRoot, recursive: true); } catch { }
            }
        }
    }

    [Fact]
    public async Task Gate_DownloadFolder_HlsDownloader_StoresPartsInsidePacaHiddenFolder()
    {
        var tempRoot = Path.Combine(Path.GetTempPath(), "paca_hls_clean_" + Guid.NewGuid().ToString("N"));
        Directory.CreateDirectory(tempRoot);

        // Fake HTTP Listener for sample m3u8
        var listener = new HttpListener();
        var port = 58921;
        listener.Prefixes.Add($"http://127.0.0.1:{port}/");
        listener.Start();

        var serverTask = Task.Run(async () =>
        {
            while (listener.IsListening)
            {
                try
                {
                    var ctx = await listener.GetContextAsync();
                    var path = ctx.Request.Url?.AbsolutePath ?? "";
                    if (path.EndsWith("playlist.m3u8"))
                    {
                        var m3u8 = "#EXTM3U\n#EXT-X-TARGETDURATION:2\n#EXTINF:2.0,\nseg0.ts\n#EXT-X-ENDLIST\n";
                        var bytes = System.Text.Encoding.UTF8.GetBytes(m3u8);
                        ctx.Response.ContentType = "application/vnd.apple.mpegurl";
                        ctx.Response.OutputStream.Write(bytes);
                        ctx.Response.Close();
                    }
                    else if (path.EndsWith("seg0.ts"))
                    {
                        var seg = new byte[1024];
                        new Random(42).NextBytes(seg);
                        ctx.Response.ContentType = "video/MP2T";
                        ctx.Response.OutputStream.Write(seg);
                        ctx.Response.Close();
                    }
                }
                catch { break; }
            }
        });

        try
        {
            using var http = new HttpClient();
            var config = new AppConfig { Concurrency = 1, OutputFolder = tempRoot };
            var fakeMuxer = new FakeMediaMuxer();
            var hls = new HlsDownloader(http, config, fakeMuxer);

            var outputBase = Path.Combine(tempRoot, "my_video");
            var res = await hls.DownloadAsync(new Uri($"http://127.0.0.1:{port}/playlist.m3u8"), outputBase);

            // 1. 루트 폴더에 .parts 폴더나 .json 파일이 절대 없어야 한다!
            var rootDirs = Directory.GetDirectories(tempRoot).Select(Path.GetFileName).ToList();
            Assert.DoesNotContain("my_video.parts", rootDirs);

            var rootFiles = Directory.GetFiles(tempRoot).Select(Path.GetFileName).ToList();
            Assert.DoesNotContain(".chunkcache.json", rootFiles);
            Assert.DoesNotContain("chunkcache.json", rootFiles);

            // 2. 최종 mp4 파일은 루트에 존재해야 한다
            Assert.True(File.Exists(outputBase + ".mp4"), "최종 mp4는 루트에 있어야 함");
        }
        finally
        {
            listener.Stop();
            try { await serverTask; } catch { }
            if (Directory.Exists(tempRoot))
            {
                try { Directory.Delete(tempRoot, recursive: true); } catch { }
            }
        }
    }

    [Fact]
    public async Task Gate_DownloadFolder_DirectDownloader_IsolatesPartFileInPacaHiddenDir()
    {
        var tempRoot = Path.Combine(Path.GetTempPath(), "paca_direct_clean_" + Guid.NewGuid().ToString("N"));
        Directory.CreateDirectory(tempRoot);

        try
        {
            var fakeHandler = new SimpleMockHandler(new byte[512]);
            using var client = new HttpClient(fakeHandler);
            var config = new AppConfig { OutputFolder = tempRoot };
            var downloader = new DirectDownloader(client, config);

            var outputBase = Path.Combine(tempRoot, "direct_file");
            var final = await downloader.DownloadAsync(new Uri("https://test.paca/video.mp4"), outputBase);

            Assert.True(File.Exists(final));
            // 루트 폴더에 .part 파일이 없어야 함
            Assert.False(File.Exists(outputBase + ".part"), "루트 폴더에 .part 파일이 존재해서는 안 됨");

            var rootFiles = Directory.GetFiles(tempRoot).Select(Path.GetFileName).ToList();
            Assert.DoesNotContain("direct_file.part", rootFiles);
        }
        finally
        {
            if (Directory.Exists(tempRoot))
            {
                try { Directory.Delete(tempRoot, recursive: true); } catch { }
            }
        }
    }

    private sealed class SimpleMockHandler : HttpMessageHandler
    {
        private readonly byte[] _data;
        public SimpleMockHandler(byte[] data) => _data = data;
        protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
        {
            var resp = new HttpResponseMessage(HttpStatusCode.OK)
            {
                Content = new ByteArrayContent(_data)
            };
            resp.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("video/mp4");
            return Task.FromResult(resp);
        }
    }

    private sealed class FakeMediaMuxer : IMediaMuxer
    {
        public Task RemuxAsync(string ffmpeg, string input, string output, CancellationToken ct)
        {
            File.Copy(input, output, overwrite: true);
            return Task.CompletedTask;
        }

        public Task DownloadDashAsync(string ffmpeg, Uri mpdUrl, string output, double durationSec, HttpClient http, IProgress<DownloadProgress>? progress, CancellationToken ct) => Task.CompletedTask;

        public string? ResolveFfmpeg(AppConfig config) => "fake-ffmpeg";
    }
}