namespace VoiceCat.Codec;

public enum OpusApplication { Voip = 2048, Audio = 2049, LowDelay = 2051 }

public sealed record OpusOptions
{
    public int SampleRate { get; init; } = 48000;
    public int Channels { get; init; } = 1;
    public int FrameDurationMilliseconds { get; init; } = 20;
    public int Bitrate { get; init; } = 24000;
    public int MaximumBandwidthHz { get; init; }
    public int Complexity { get; init; } = 10;
    public int ExpectedPacketLossPercent { get; init; }
    public bool ForwardErrorCorrection { get; init; } = true;
    public bool DiscontinuousTransmission { get; init; }
    public bool DeepRedundancy { get; init; }
    public OpusApplication Application { get; init; } = OpusApplication.Voip;
    public int SamplesPerChannel => SampleRate / 1000 * FrameDurationMilliseconds;

    internal void Validate()
    {
        if (SampleRate is not (8000 or 12000 or 16000 or 24000 or 48000)) throw new ArgumentOutOfRangeException(nameof(SampleRate));
        if (Channels is not (1 or 2)) throw new ArgumentOutOfRangeException(nameof(Channels));
        if (FrameDurationMilliseconds is not (10 or 20 or 40 or 60)) throw new ArgumentOutOfRangeException(nameof(FrameDurationMilliseconds));
        if (Application == OpusApplication.LowDelay && FrameDurationMilliseconds > 20) throw new ArgumentException("Low-delay Opus requires frames of at most 20 ms.");
        if (!Enum.IsDefined(Application)) throw new ArgumentOutOfRangeException(nameof(Application));
        if (Bitrate is < 500 or > 512000) throw new ArgumentOutOfRangeException(nameof(Bitrate));
        if (Complexity is < 0 or > 10) throw new ArgumentOutOfRangeException(nameof(Complexity));
        if (ExpectedPacketLossPercent is < 0 or > 100) throw new ArgumentOutOfRangeException(nameof(ExpectedPacketLossPercent));
        ArgumentOutOfRangeException.ThrowIfNegative(MaximumBandwidthHz);
    }
}