using System.Diagnostics;
using System.Text.Json;
using Explorer.Application;
using Explorer.Contracts;
using Explorer.Domain;
using Explorer.Hosting.Ipc;
using Explorer.Plugin.Abstractions;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging.Abstractions;

namespace Explorer.Hosting.Tests;

public class WorkbenchPipeTests
{
    [Fact]
    public void Handle_forwards_indexing_and_transfer_calls()
    {
        var indexing = new FakeIndexing();
        var transfers = new FakeTransfers();
        var server = CreateServer(indexing, transfers);

        var ping = server.Handle(new IpcEnvelope { V = WorkbenchIpc.ProtocolVersion, Op = "Ping" });
        Assert.True(ping.Ok);

        var scan = server.Handle(new IpcEnvelope { V = WorkbenchIpc.ProtocolVersion, Op = "Indexing.EnqueueFullScan", N = 42 });
        Assert.True(scan.Ok);
        Assert.Equal(42, indexing.FullScanId);

        var pause = server.Handle(new IpcEnvelope { V = WorkbenchIpc.ProtocolVersion, Op = "Transfers.PauseAll" });
        Assert.True(pause.Ok);
        Assert.True(transfers.PausedAll);

        var paused = server.Handle(new IpcEnvelope { V = WorkbenchIpc.ProtocolVersion, Op = "Transfers.IsPaused" });
        Assert.True(paused.Paused);

        var copy = server.Handle(new IpcEnvelope
        {
            V = WorkbenchIpc.ProtocolVersion,
            Op = "Transfers.EnqueueCopy",
            Paths = ["C:\\a.txt"],
            Dest = "D:\\"
        });
        Assert.True(copy.Ok);
        Assert.Equal(@"D:\", transfers.CopiedDest);
    }

    [Fact]
    public void Handle_rejects_other_protocol_versions()
    {
        var server = CreateServer(new FakeIndexing(), new FakeTransfers());
        var reply = server.Handle(new IpcEnvelope { V = 99, Op = "Ping" });
        Assert.False(reply.Ok);
        Assert.Contains("99", reply.Error);
    }

    [Fact]
    public async Task Connect_to_a_missing_pipe_fails_quickly()
    {
        var options = new WorkbenchIpcOptions { PipeName = "ew-missing-" + Guid.NewGuid().ToString("N") };
        var started = Stopwatch.GetTimestamp();
        await Assert.ThrowsAsync<TimeoutException>(() =>
            WorkbenchPipeClient.ConnectAsync(options, TimeSpan.FromMilliseconds(400)));
        Assert.True(
            Stopwatch.GetElapsedTime(started) < TimeSpan.FromSeconds(3),
            "Named-pipe connect hung instead of timing out.");
    }

    [Fact]
    public void Handle_cloud_places_does_not_need_a_workbench()
    {
        var services = new ServiceCollection();
        services.AddSingleton<ICloudOverlay>(NullCloudOverlay.Instance);
        using var sp = services.BuildServiceProvider();
        var server = new WorkbenchPipeServer(
            sp,
            new WorkbenchIpcOptions(),
            NullLogger<WorkbenchPipeServer>.Instance);
        var reply = server.Handle(new IpcEnvelope { V = WorkbenchIpc.ProtocolVersion, Op = "Cloud.Places" });
        Assert.True(reply.Ok);
        var places = JsonSerializer.Deserialize<ProviderPlace[]>(reply.Payload ?? "null", WorkbenchIpc.Json);
        Assert.NotNull(places);
        Assert.Empty(places);
    }

    [Fact]
    public async Task IsListening_does_not_consume_the_server_instance()
    {
        var options = new WorkbenchIpcOptions { PipeName = "ew-probe-" + Guid.NewGuid().ToString("N") };
        using var sp = new ServiceCollection().BuildServiceProvider();
        var server = new WorkbenchPipeServer(
            sp,
            options,
            NullLogger<WorkbenchPipeServer>.Instance);
        await server.StartAsync(CancellationToken.None);
        try
        {
            await server.Listening.WaitAsync(TimeSpan.FromSeconds(3));
            Assert.True(WorkbenchIpc.IsListening(options.PipeName, 200));
            await using var client = await WorkbenchPipeClient.ConnectAsync(options, TimeSpan.FromSeconds(3));
        }
        finally
        {
            await server.StopAsync(CancellationToken.None);
        }
    }

    [Fact]
    public void Handle_host_shutdown_does_not_need_a_workbench()
    {
        using var sp = new ServiceCollection().BuildServiceProvider();
        var server = new WorkbenchPipeServer(
            sp,
            new WorkbenchIpcOptions(),
            NullLogger<WorkbenchPipeServer>.Instance);
        var stopped = false;
        server.ShutdownRequested = () => stopped = true;
        var reply = server.Handle(new IpcEnvelope { V = WorkbenchIpc.ProtocolVersion, Op = "Host.Shutdown" });
        Assert.True(reply.Ok);
        Assert.True(stopped);
    }

    [Fact]
    public void Ping_does_not_need_a_workbench()
    {
        using var sp = new ServiceCollection().BuildServiceProvider();
        var server = new WorkbenchPipeServer(
            sp,
            new WorkbenchIpcOptions(),
            NullLogger<WorkbenchPipeServer>.Instance);
        var ping = server.Handle(new IpcEnvelope { V = WorkbenchIpc.ProtocolVersion, Op = "Ping" });
        Assert.True(ping.Ok);
    }

    [Fact]
    public async Task Ping_roundtrip_over_a_live_named_pipe()
    {
        var options = new WorkbenchIpcOptions { PipeName = "ew-live-" + Guid.NewGuid().ToString("N") };
        using var sp = new ServiceCollection().BuildServiceProvider();
        var server = new WorkbenchPipeServer(
            sp,
            options,
            NullLogger<WorkbenchPipeServer>.Instance);
        await server.StartAsync(CancellationToken.None);
        try
        {
            await server.Listening.WaitAsync(TimeSpan.FromSeconds(3));
            await using var client = await WorkbenchPipeClient.ConnectAsync(options, TimeSpan.FromSeconds(3));
        }
        finally
        {
            await server.StopAsync(CancellationToken.None);
        }
    }

    private static WorkbenchPipeServer CreateServer(FakeIndexing indexing, FakeTransfers transfers)
    {
        var services = new ServiceCollection();
        services.AddSingleton<IWorkbenchHost>(
            new WorkbenchHost(indexing, transfers, new StubSources(), new StubMutations()));
        return new WorkbenchPipeServer(
            services.BuildServiceProvider(),
            new WorkbenchIpcOptions { PipeName = "ew-test" },
            NullLogger<WorkbenchPipeServer>.Instance);
    }

    private sealed class FakeIndexing : IIndexingHost
    {
        public long FullScanId { get; private set; }
        public event EventHandler<ScanProgress>? ProgressChanged = delegate { };
        public void EnqueueFullScan(long sourceId) => FullScanId = sourceId;
        public void EnqueueFolderScan(long sourceId, string pathRel) { }
        public void EnqueueReconcile(long sourceId, string pathRel) { }
        public void Cancel(long sourceId) { }
    }

    private sealed class FakeTransfers : ITransferHost
    {
        public bool PausedAll { get; private set; }
        public event EventHandler? Changed = delegate { };
        public event EventHandler<TransferJob>? JobFinished = delegate { };
        public bool IsPaused => PausedAll;
        public IReadOnlyList<TransferJob> Snapshot() => [];
        public void PauseAll() => PausedAll = true;
        public void ResumeAll() => PausedAll = false;
        public void Pause(long jobId) { }
        public void Resume(long jobId) { }
        public void Retry(long jobId) { }
        public void Cancel(long jobId) { }
        public void Dismiss(long jobId) { }
        public void ClearFinished() { }
        public bool MoveUp(long jobId) => false;
        public bool MoveDown(long jobId) => false;
        public string? CopiedDest { get; private set; }
        public Task EnqueueCopyAsync(IReadOnlyList<string> sources, string destinationDirectory, CancellationToken cancellationToken = default)
        {
            CopiedDest = destinationDirectory;
            return Task.CompletedTask;
        }
    }

    private sealed class StubSources : ISourceHost
    {
        public Task RefreshAsync(CancellationToken cancellationToken = default) => Task.CompletedTask;
        public Task<Source> AddUncAsync(string path, CancellationToken cancellationToken = default)
            => Task.FromResult(new Source { StableKey = "x", DisplayName = path });
        public Task<Source?> EnsureForPathAsync(string path, CancellationToken cancellationToken = default)
            => Task.FromResult<Source?>(null);
        public Task<bool> ForgetAsync(string path, CancellationToken cancellationToken = default)
            => Task.FromResult(false);
    }

    private sealed class StubMutations : IIndexMutations
    {
        public Task<long> UpsertSyncProfileAsync(SyncProfile profile, CancellationToken cancellationToken = default)
            => Task.FromResult(1L);
        public Task DeleteSyncProfileAsync(long id, CancellationToken cancellationToken = default) => Task.CompletedTask;
        public Task<long> UpsertOperationProfileAsync(OperationProfile profile, CancellationToken cancellationToken = default)
            => Task.FromResult(1L);
        public Task DeleteOperationProfileAsync(long id, CancellationToken cancellationToken = default) => Task.CompletedTask;
        public Task<long> CreateRenameBatchAsync(IReadOnlyList<RenameBatchItem> items, CancellationToken cancellationToken = default)
            => Task.FromResult(1L);
        public Task MarkRenameBatchUndoneAsync(long id, CancellationToken cancellationToken = default) => Task.CompletedTask;
        public Task EnqueueHashCollisionsAsync(long? sourceId, CancellationToken cancellationToken = default) => Task.CompletedTask;
        public Task UpsertRelationAsync(FileRelation relation, CancellationToken cancellationToken = default) => Task.CompletedTask;
    }
}