// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.

using System;
using System.IO;
using System.Text;
using System.Threading.Tasks;
using NUnit.Framework;
using osu.Framework.Extensions;
using osu.Framework.Platform;
using osu.Framework.Testing;
using osu.Game.Tests.Resources;

namespace osu.Game.Tests.Collections.IO
{
    [TestFixture]
    public class ImportCollectionsTest : ImportTest
    {
        [Test]
        public async Task TestImportEmptyDatabase()
        {
            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
            {
                try
                {
                    var osu = LoadOsuIntoHost(host);

                    await importCollectionsFromStream(osu, new MemoryStream());

                    Assert.That(osu.CollectionManager.Collections.Count, Is.Zero);
                }
                finally
                {
                    host.Exit();
                }
            }
        }

        [Test]
        public async Task TestImportWithNoBeatmaps()
        {
            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
            {
                try
                {
                    var osu = LoadOsuIntoHost(host);

                    await importCollectionsFromStream(osu, TestResources.OpenResource("Collections/collections.db"));

                    Assert.That(osu.CollectionManager.Collections.Count, Is.EqualTo(2));

                    // Even with no beatmaps imported, collections are tracking the hashes and will continue to.
                    // In the future this whole mechanism will be replaced with having the collections in realm,
                    // but until that happens it makes rough sense that we want to track not-yet-imported beatmaps
                    // and have them associate with collections if/when they become available.

                    Assert.That(osu.CollectionManager.Collections[0].Name.Value, Is.EqualTo("First"));
                    Assert.That(osu.CollectionManager.Collections[0].Beatmaps.Count, Is.EqualTo(1));

                    Assert.That(osu.CollectionManager.Collections[1].Name.Value, Is.EqualTo("Second"));
                    Assert.That(osu.CollectionManager.Collections[1].Beatmaps.Count, Is.EqualTo(12));
                }
                finally
                {
                    host.Exit();
                }
            }
        }

        [Test]
        public async Task TestImportWithBeatmaps()
        {
            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
            {
                try
                {
                    var osu = LoadOsuIntoHost(host, true);

                    await importCollectionsFromStream(osu, TestResources.OpenResource("Collections/collections.db"));

                    Assert.That(osu.CollectionManager.Collections.Count, Is.EqualTo(2));

                    Assert.That(osu.CollectionManager.Collections[0].Name.Value, Is.EqualTo("First"));
                    Assert.That(osu.CollectionManager.Collections[0].Beatmaps.Count, Is.EqualTo(1));

                    Assert.That(osu.CollectionManager.Collections[1].Name.Value, Is.EqualTo("Second"));
                    Assert.That(osu.CollectionManager.Collections[1].Beatmaps.Count, Is.EqualTo(12));
                }
                finally
                {
                    host.Exit();
                }
            }
        }

        [Test]
        public async Task TestImportMalformedDatabase()
        {
            bool exceptionThrown = false;
            UnhandledExceptionEventHandler setException = (_, __) => exceptionThrown = true;

            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
            {
                try
                {
                    AppDomain.CurrentDomain.UnhandledException += setException;

                    var osu = LoadOsuIntoHost(host, true);

                    using (var ms = new MemoryStream())
                    {
                        using (var bw = new BinaryWriter(ms, Encoding.UTF8, true))
                        {
                            for (int i = 0; i < 10000; i++)
                                bw.Write((byte)i);
                        }

                        ms.Seek(0, SeekOrigin.Begin);

                        await importCollectionsFromStream(osu, ms);
                    }

                    Assert.That(exceptionThrown, Is.False);
                    Assert.That(osu.CollectionManager.Collections.Count, Is.EqualTo(0));
                }
                finally
                {
                    host.Exit();
                    AppDomain.CurrentDomain.UnhandledException -= setException;
                }
            }
        }

        [Test]
        public async Task TestSaveAndReload()
        {
            string firstRunName;

            using (var host = new CleanRunHeadlessGameHost(bypassCleanup: true))
            {
                firstRunName = host.Name;

                try
                {
                    var osu = LoadOsuIntoHost(host, true);

                    await importCollectionsFromStream(osu, TestResources.OpenResource("Collections/collections.db"));

                    // Move first beatmap from second collection into the first.
                    osu.CollectionManager.Collections[0].Beatmaps.Add(osu.CollectionManager.Collections[1].Beatmaps[0]);
                    osu.CollectionManager.Collections[1].Beatmaps.RemoveAt(0);

                    // Rename the second collecction.
                    osu.CollectionManager.Collections[1].Name.Value = "Another";
                }
                finally
                {
                    host.Exit();
                }
            }

            // Name matches the automatically chosen name from `CleanRunHeadlessGameHost` above, so we end up using the same storage location.
            using (HeadlessGameHost host = new TestRunHeadlessGameHost(firstRunName, null))
            {
                try
                {
                    var osu = LoadOsuIntoHost(host, true);

                    Assert.That(osu.CollectionManager.Collections.Count, Is.EqualTo(2));

                    Assert.That(osu.CollectionManager.Collections[0].Name.Value, Is.EqualTo("First"));
                    Assert.That(osu.CollectionManager.Collections[0].Beatmaps.Count, Is.EqualTo(2));

                    Assert.That(osu.CollectionManager.Collections[1].Name.Value, Is.EqualTo("Another"));
                    Assert.That(osu.CollectionManager.Collections[1].Beatmaps.Count, Is.EqualTo(11));
                }
                finally
                {
                    host.Exit();
                }
            }
        }

        private static async Task importCollectionsFromStream(TestOsuGameBase osu, Stream stream)
        {
            // intentionally spin this up on a separate task to avoid disposal deadlocks.
            // see https://github.com/EventStore/EventStore/issues/1179
            await Task.Factory.StartNew(() => osu.CollectionManager.Import(stream).WaitSafely(), TaskCreationOptions.LongRunning);
        }
    }
}