using System;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Paca.Core.Media;
using Xunit;

namespace Paca.Tests.Media;

public class HardwareTranscoderAndCastingExtremeRedTests
{
    [Fact]
    public void BuildFfmpegTranscodeCommand_NullSpec_ThrowsArgumentNullException()
    {
        Assert.Throws<ArgumentNullException>(() =>
            HardwareTranscoderStudio.BuildFfmpegTranscodeCommand("input.mp4", "output.mp4", null!));
    }

    [Theory]
    [InlineData(null)]
    [InlineData("")]
    [InlineData("   ")]
    public void BuildFfmpegTranscodeCommand_NullOrWhitespaceInput_ThrowsArgumentException(string? invalidInput)
    {
        var spec = new TranscodePresetSpec();
        Assert.Throws<ArgumentException>(() =>
            HardwareTranscoderStudio.BuildFfmpegTranscodeCommand(invalidInput!, "output.mp4", spec));
    }

    [Theory]
    [InlineData(null)]
    [InlineData("")]
    [InlineData("   ")]
    public void BuildFfmpegTranscodeCommand_NullOrWhitespaceOutput_ThrowsArgumentException(string? invalidOutput)
    {
        var spec = new TranscodePresetSpec();
        Assert.Throws<ArgumentException>(() =>
            HardwareTranscoderStudio.BuildFfmpegTranscodeCommand("input.mp4", invalidOutput!, spec));
    }

    [Fact]
    public void BuildFfmpegTranscodeCommand_SameInputAndOutput_ThrowsInvalidOperationException()
    {
        var tempFile = Path.GetTempFileName();
        try
        {
            var spec = new TranscodePresetSpec();
            Assert.Throws<InvalidOperationException>(() =>
                HardwareTranscoderStudio.BuildFfmpegTranscodeCommand(tempFile, tempFile, spec));
        }
        finally
        {
            if (File.Exists(tempFile)) File.Delete(tempFile);
        }
    }

    [Fact]
    public void BuildFfmpegTranscodeCommand_QuotedPaths_StripsQuotesAndProducesValidArgs()
    {
        var spec = new TranscodePresetSpec { Backend = HardwareEncoderBackend.SoftwareCpu, Codec = VideoCodecTarget.H264 };
        var args = HardwareTranscoderStudio.BuildFfmpegTranscodeCommand("\"C:\\input video.mp4\"", "\"C:\\out.mp4\"", spec);

        Assert.Equal("C:\\input video.mp4", args[1]);
        Assert.Equal("C:\\out.mp4", args.Last());
    }

    [Fact]
    public void BuildFfmpegTranscodeCommand_NullOrEmptyAudioCodec_DefaultsToAac()
    {
        var spec = new TranscodePresetSpec { AudioCodec = "   " };
        var args = HardwareTranscoderStudio.BuildFfmpegTranscodeCommand("in.mkv", "out.mp4", spec);

        var aIndex = args.IndexOf("-c:a");
        Assert.True(aIndex >= 0);
        Assert.Equal("aac", args[aIndex + 1]);
    }

    [Theory]
    [InlineData(HardwareEncoderBackend.NvidiaNvenc, VideoCodecTarget.AV1, "av1_nvenc")]
    [InlineData(HardwareEncoderBackend.NvidiaNvenc, VideoCodecTarget.HEVC_H265, "hevc_nvenc")]
    [InlineData(HardwareEncoderBackend.NvidiaNvenc, VideoCodecTarget.H264, "h264_nvenc")]
    [InlineData(HardwareEncoderBackend.IntelQsv, VideoCodecTarget.AV1, "av1_qsv")]
    [InlineData(HardwareEncoderBackend.IntelQsv, VideoCodecTarget.HEVC_H265, "hevc_qsv")]
    [InlineData(HardwareEncoderBackend.AmdAmf, VideoCodecTarget.AV1, "av1_amf")]
    [InlineData(HardwareEncoderBackend.AmdAmf, VideoCodecTarget.HEVC_H265, "hevc_amf")]
    [InlineData(HardwareEncoderBackend.SoftwareCpu, VideoCodecTarget.AV1, "libsvtav1")]
    [InlineData(HardwareEncoderBackend.SoftwareCpu, VideoCodecTarget.HEVC_H265, "libx265")]
    public void BuildFfmpegTranscodeCommand_Backends_ProducesCorrectVideoCodec(
        HardwareEncoderBackend backend, VideoCodecTarget codec, string expectedCodec)
    {
        var spec = new TranscodePresetSpec { Backend = backend, Codec = codec };
        var args = HardwareTranscoderStudio.BuildFfmpegTranscodeCommand("in.mp4", "out.mp4", spec);

        var vIndex = args.IndexOf("-c:v");
        Assert.True(vIndex >= 0);
        Assert.Equal(expectedCodec, args[vIndex + 1]);
    }

    [Fact]
    public void BuildFfmpegTranscodeCommand_NegativeBitrate_DoesNotEmitBitrateFlag()
    {
        var spec = new TranscodePresetSpec { TargetBitrateKbps = -100 };
        var args = HardwareTranscoderStudio.BuildFfmpegTranscodeCommand("in.mp4", "out.mp4", spec);

        Assert.DoesNotContain("-b:v", args);
    }

    [Fact]
    public void WebRtcCastingEngine_TerminateSession_NullSessionId_ReturnsFalseWithoutThrowing()
    {
        var engine = new WebRtcCastingEngine();
        var result = engine.TerminateSession(null!);
        Assert.False(result);
    }

    [Fact]
    public void WebRtcCastingEngine_TerminateSession_UnknownSessionId_ReturnsFalse()
    {
        var engine = new WebRtcCastingEngine();
        var result = engine.TerminateSession("non-existent-uuid");
        Assert.False(result);
    }

    [Theory]
    [InlineData(null)]
    [InlineData("")]
    [InlineData("   ")]
    public void WebRtcCastingEngine_CreateCastSession_NullOrWhitespaceDevice_DefaultsToDefaultDisplay(string? deviceName)
    {
        var engine = new WebRtcCastingEngine();
        var session = engine.CreateCastSession(deviceName!);
        Assert.Equal("Default Display", session.TargetDeviceName);
    }

    [Fact]
    public void WebRtcCastingEngine_GetSession_WorksCorrectly()
    {
        var engine = new WebRtcCastingEngine();
        Assert.Null(engine.GetSession(null!));
        Assert.Null(engine.GetSession("unknown-id"));

        var created = engine.CreateCastSession("Living Room TV");
        var found = engine.GetSession(created.SessionId);
        Assert.NotNull(found);
        Assert.Equal("Living Room TV", found.TargetDeviceName);
    }

    [Fact]
    public void WebRtcCastingEngine_GenerateOffer_InvalidDimensions_NormalizesDimensions()
    {
        var engine = new WebRtcCastingEngine();
        var desc = engine.GenerateOffer(null!, width: -50, height: 0, fps: -1);
        Assert.Equal("offer", desc.Type);
        Assert.Contains("v=0", desc.Sdp);
        Assert.Contains("H264", desc.Sdp);
    }

    [Fact]
    public void WebRtcCastingEngine_ThreadSafety_ConcurrentCreateAndTerminate()
    {
        var engine = new WebRtcCastingEngine();
        Parallel.For(0, 50, i =>
        {
            var session = engine.CreateCastSession($"Device {i}");
            Assert.NotNull(engine.GetSession(session.SessionId));
            var terminated = engine.TerminateSession(session.SessionId);
            Assert.True(terminated);
            Assert.Null(engine.GetSession(session.SessionId));
        });
        Assert.Equal(0, engine.ActiveSessionsCount);
    }
}