using System.Collections.Concurrent;
using TeamsISO.Engine.Interop;
using TeamsISO.Engine.Pipeline;

namespace TeamsISO.Engine.Tests.Fakes;

/// <summary>
/// In-memory test double for <see cref="INdiInterop"/>. Tests configure source lists and frame
/// queues; the fake feeds those into engine code as if a real NDI runtime were present.
/// </summary>
public sealed class FakeNdiInterop : INdiInterop
{
    public List<string> Sources { get; } = new();
    public ConcurrentDictionary<string, ConcurrentQueue<RawFrame>> ReceiverFrames { get; } = new();
    public ConcurrentDictionary<string, List<ProcessedFrame>> SentFrames { get; } = new();
    public string RuntimeVersion { get; set; } = "6.0.0";
    public Dictionary<string, int> ReceiverCreatedCount { get; } = new();
    public Dictionary<string, int> SenderCreatedCount { get; } = new();

    /// <summary>Last <c>groups</c> string seen by <see cref="CreateFinder"/>; null = default Public.</summary>
    public string? LastFinderGroups { get; private set; }
    /// <summary>Per-output <c>groups</c> string seen by <see cref="CreateSender"/>; null = default Public.</summary>
    public Dictionary<string, string?> SenderGroups { get; } = new();

    public NdiFindHandle CreateFinder(string? groups = null)
    {
        LastFinderGroups = groups;
        return new FakeFindHandle();
    }
    public IReadOnlyList<string> GetCurrentSources(NdiFindHandle finder) => Sources.ToArray();

    public NdiReceiverHandle CreateReceiver(string sourceFullName)
    {
        ReceiverCreatedCount[sourceFullName] = ReceiverCreatedCount.GetValueOrDefault(sourceFullName) + 1;
        ReceiverFrames.GetOrAdd(sourceFullName, _ => new ConcurrentQueue<RawFrame>());
        return new FakeReceiverHandle(sourceFullName);
    }

    public RawFrame? CaptureFrame(NdiReceiverHandle receiver, int timeoutMs)
    {
        var key = ((FakeReceiverHandle)receiver).Source;
        if (ReceiverFrames.TryGetValue(key, out var q) && q.TryDequeue(out var frame))
            return frame;
        return null; // simulate timeout
    }

    public NdiSenderHandle CreateSender(string outputName, string? groups = null)
    {
        SenderCreatedCount[outputName] = SenderCreatedCount.GetValueOrDefault(outputName) + 1;
        SenderGroups[outputName] = groups;
        SentFrames.GetOrAdd(outputName, _ => new List<ProcessedFrame>());
        return new FakeSenderHandle(outputName);
    }

    public void SendFrame(NdiSenderHandle sender, ProcessedFrame frame)
    {
        var key = ((FakeSenderHandle)sender).Output;
        SentFrames[key].Add(frame);
    }

    public string GetRuntimeVersion() => RuntimeVersion;

    private sealed class FakeFindHandle : NdiFindHandle
    {
        public override void Dispose() { }
    }

    private sealed class FakeReceiverHandle : NdiReceiverHandle
    {
        public string Source { get; }
        public FakeReceiverHandle(string source) => Source = source;
        public override void Dispose() { }
    }

    private sealed class FakeSenderHandle : NdiSenderHandle
    {
        public string Output { get; }
        public FakeSenderHandle(string output) => Output = output;
        public override void Dispose() { }
    }
}