#region license
// This file is part of Vocaluxe.
//
// Vocaluxe is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Vocaluxe is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Vocaluxe. If not, see <http://www.gnu.org/licenses/>.
#endregion

extern alias songserver;

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Text;
using System.Text.Json;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc.Testing;
using Microsoft.Extensions.Logging.Abstractions;
using NUnit.Framework;
using Vocaluxe.Base.SongServer;
using VocaluxeSongServer.Contracts;
using CLibraryScanner = songserver::VocaluxeSongServer.Library.CLibraryScanner;
using ServerProgram = songserver::Program;

namespace Tests.SongServer
{
    [TestFixture]
    public class CSongServerTest
    {
        private string _Root;
        private string _Library;
        private string _Cache;

        [SetUp]
        public void SetUp()
        {
            _Root = Path.Combine(Path.GetTempPath(), "vlx-songserver-test-" + Guid.NewGuid().ToString("N"));
            _Library = Path.Combine(_Root, "library");
            _Cache = Path.Combine(_Root, "cache");
            Directory.CreateDirectory(Path.Combine(_Library, "A - One"));
            Directory.CreateDirectory(Path.Combine(_Library, "Sub", "Künstler - Lied"));
            Directory.CreateDirectory(Path.Combine(_Library, "NoSong"));
            File.WriteAllText(Path.Combine(_Library, "A - One", "A - One.txt"), "#TITLE:One\n#ARTIST:A\n#MP3:One.mp3\n#COVER:cover.jpg\n#BPM:300\n: 0 4 5 La\nE\n");
            File.WriteAllBytes(Path.Combine(_Library, "A - One", "One.mp3"), _RandomBytes(300000, 1));
            File.WriteAllBytes(Path.Combine(_Library, "A - One", "cover.jpg"), _RandomBytes(2000, 2));
            // Latin-1 encoded, like many old song files
            File.WriteAllBytes(Path.Combine(_Library, "Sub", "Künstler - Lied", "lied.txt"),
                Encoding.Latin1.GetBytes("#TITLE:Lied über\n#ARTIST:Künstler\n#AUDIO:a.ogg\n#BPM:200\n: 0 4 5 La\nE\n"));
            File.WriteAllBytes(Path.Combine(_Library, "Sub", "Künstler - Lied", "a.ogg"), _RandomBytes(1000, 3));
            File.WriteAllText(Path.Combine(_Library, "NoSong", "readme.txt"), "not a song");
        }

        [TearDown]
        public void TearDown()
        {
            try
            {
                Directory.Delete(_Root, true);
            }
            catch (IOException) { }
        }

        private static byte[] _RandomBytes(int count, int seed)
        {
            var bytes = new byte[count];
            new Random(seed).NextBytes(bytes);
            return bytes;
        }

        [Test]
        public void TestParseHeader()
        {
            var header = CLibraryScanner.ParseHeader("#TITLE:Song\r\n#ARTIST:Artist\r\n#MP3:x.mp3\r\n: 0 1 1 a\r\n#TITLE:ignored\n");
            Assert.That(header, Is.Not.Null);
            Assert.That(header.Title, Is.EqualTo("Song"));
            Assert.That(header.Artist, Is.EqualTo("Artist"));
            Assert.That(CLibraryScanner.ParseHeader("#TITLE:Song\n#ARTIST:Artist\n"), Is.Null, "no audio");
            Assert.That(CLibraryScanner.ParseHeader("just text"), Is.Null);
        }

        [Test]
        public void TestDecodeText()
        {
            Assert.That(CLibraryScanner.DecodeText(Encoding.UTF8.GetPreamble().Concat(Encoding.UTF8.GetBytes("über")).ToArray()), Is.EqualTo("über"));
            Assert.That(CLibraryScanner.DecodeText(Encoding.UTF8.GetBytes("über")), Is.EqualTo("über"));
            Assert.That(CLibraryScanner.DecodeText(Encoding.Latin1.GetBytes("über")), Is.EqualTo("über"));
        }

        [Test]
        public void TestScan()
        {
            var scanner = new CLibraryScanner(NullLogger<CLibraryScanner>.Instance);
            var snapshot = scanner.Scan(_Library);
            Assert.That(snapshot.Dto.Songs.Select(s => s.Path), Is.EqualTo(new[] { "A - One/A - One.txt", "Sub/Künstler - Lied/lied.txt" }));
            Assert.That(snapshot.Dto.Songs[1].Title, Is.EqualTo("Lied über"));
            Assert.That(snapshot.Dto.Files.Select(f => f.Path), Does.Not.Contain("NoSong/readme.txt"), "only files in song folders are served");
            Assert.That(snapshot.Dto.Files.Count, Is.EqualTo(5));

            var version = snapshot.Dto.Version;
            Assert.That(scanner.Scan(_Library).Dto.Version, Is.EqualTo(version), "unchanged library, same version");
            File.WriteAllBytes(Path.Combine(_Library, "A - One", "One.mp3"), _RandomBytes(300001, 1));
            Assert.That(scanner.Scan(_Library).Dto.Version, Is.Not.EqualTo(version), "changed file, new version");
        }

        private WebApplicationFactory<ServerProgram> _CreateServer(string apiKey = "")
        {
            return new WebApplicationFactory<ServerProgram>().WithWebHostBuilder(b =>
            {
                b.UseSetting("Library:Path", _Library);
                b.UseSetting("Library:ApiKey", apiKey);
            });
        }

        private static async Task<LibraryDto> _GetLibrary(HttpClient client)
        {
            for (var i = 0; i < 50; i++)
            {
                var response = await client.GetAsync("/api/v1/library");
                if (response.StatusCode != HttpStatusCode.ServiceUnavailable)
                {
                    response.EnsureSuccessStatusCode();
                    return JsonSerializer.Deserialize<LibraryDto>(await response.Content.ReadAsStringAsync(), new JsonSerializerOptions(JsonSerializerDefaults.Web));
                }

                await Task.Delay(100); // first scan still running
            }

            throw new TimeoutException("library scan did not finish");
        }

        [Test]
        public async Task TestApiKey()
        {
            using (var server = _CreateServer("secret"))
            {
                var client = server.CreateClient();
                Assert.That((await client.GetAsync("/api/v1/library")).StatusCode, Is.EqualTo(HttpStatusCode.Unauthorized));
                client.DefaultRequestHeaders.Add("X-Api-Key", "secret");
                Assert.That((await _GetLibrary(client)).Songs.Count, Is.EqualTo(2));
            }
        }

        [Test]
        public async Task TestDownloadOnDemand()
        {
            using (var server = _CreateServer())
            {
                var client = server.CreateClient();
                var library = await _GetLibrary(client);
                var provider = new CRemoteSongFileProvider(client, _Cache, library.Files);

                var mp3 = CRemoteSongFileProvider.GetLocalPath(_Cache, "A - One/One.mp3");
                // Case differs from the server file, as often in song files
                var cover = CRemoteSongFileProvider.GetLocalPath(_Cache, "A - One/COVER.jpg");
                var ogg = CRemoteSongFileProvider.GetLocalPath(_Cache, "Sub/Künstler - Lied/a.ogg");

                Assert.That(provider.Exists(mp3), Is.True);
                Assert.That(provider.IsLocal(mp3), Is.False);
                Assert.That(provider.Exists(Path.Combine(_Cache, "nothing.mp3")), Is.False);
                Assert.That(provider.GetProgress(new[] { mp3 }), Is.EqualTo(0f));

                // Interrupted earlier download: the rest is fetched with a Range request
                Directory.CreateDirectory(Path.GetDirectoryName(mp3));
                File.WriteAllBytes(mp3 + ".part", _RandomBytes(300000, 1).Take(1000).ToArray());

                await provider.RequestAsync(new[] { mp3, cover, ogg, mp3 });

                Assert.That(provider.IsLocal(mp3) && provider.IsLocal(cover) && provider.IsLocal(ogg), Is.True);
                Assert.That(File.ReadAllBytes(mp3), Is.EqualTo(File.ReadAllBytes(Path.Combine(_Library, "A - One", "One.mp3"))));
                Assert.That(File.ReadAllBytes(ogg), Is.EqualTo(File.ReadAllBytes(Path.Combine(_Library, "Sub", "Künstler - Lied", "a.ogg"))));
                Assert.That(File.Exists(mp3 + ".part"), Is.False);
                Assert.That(provider.GetProgress(new[] { mp3, cover, ogg }), Is.EqualTo(1f));

                // A changed file on the server makes the local copy outdated
                var changed = library.Files.Select(f => f.Path == "A - One/One.mp3" ? new FileDto { Path = f.Path, Size = f.Size, Modified = f.Modified + 60000 } : f);
                Assert.That(new CRemoteSongFileProvider(client, _Cache, changed).IsLocal(mp3), Is.False);
            }
        }

        [Test]
        public async Task TestBundleAndFileSecurity()
        {
            using (var server = _CreateServer())
            {
                var client = server.CreateClient();
                await _GetLibrary(client);
                var body = new StringContent(JsonSerializer.Serialize(new BundleRequest { Paths = new List<string> { "Sub/Künstler - Lied/lied.txt", "NoSong/readme.txt" } },
                    new JsonSerializerOptions(JsonSerializerDefaults.Web)), Encoding.UTF8, "application/json");
                var response = await client.PostAsync("/api/v1/files/bundle", body);
                response.EnsureSuccessStatusCode();
                using (var zip = new System.IO.Compression.ZipArchive(await response.Content.ReadAsStreamAsync()))
                {
                    Assert.That(zip.Entries.Select(e => e.FullName), Is.EqualTo(new[] { "Sub/Künstler - Lied/lied.txt" }));
                }

                Assert.That((await client.GetAsync("/api/v1/files/NoSong/readme.txt")).StatusCode, Is.EqualTo(HttpStatusCode.NotFound));
                Assert.That((await client.GetAsync("/api/v1/files/..%2F..%2Fsecret.txt")).StatusCode, Is.EqualTo(HttpStatusCode.NotFound));
            }
        }
    }
}