using ManagedBass;

namespace T3.Core.Audio;

/// <summary>
/// Configuration settings for the audio system.
/// Compile-time constants are used for buffer sizes that require static initialization.
/// Runtime settings can be configured through UserSettings in the Editor.
/// </summary>
public static class AudioConfig
{

    #region Mixer Configuration
    // Note: MixerFrequency is determined at runtime from the device's sample rate.
    // Other values are const because they are used for static array initialization.

    /// <summary>
    /// Sample rate for all mixer streams (Hz).
    /// This is set at runtime to match the device's current sample rate.
    /// Default value is 48000Hz until Bass is initialized.
    /// </summary>
    public static int MixerFrequency { get; internal set; } = 48000;

    /// <summary>
    /// BASS update period in milliseconds for low-latency playback.
    /// </summary>
    internal const int UpdatePeriodMs = 10;

    /// <summary>
    /// Number of BASS update threads.
    /// </summary>
    internal const int UpdateThreads = 2;

    /// <summary>
    /// Playback buffer length in milliseconds.
    /// </summary>
    internal const int PlaybackBufferLengthMs = 100;

    /// <summary>
    /// Device buffer length in milliseconds for low-latency output.
    /// </summary>
    internal const int DeviceBufferLengthMs = 20;
    #endregion

    #region 3D Audio Configuration
    /// <summary>
    /// Distance factor for 3D audio. This is the number of units per meter.
    /// Default is 1.0 (1 unit = 1 meter). Set to 100 if your world uses centimeters.
    /// </summary>
    internal static float DistanceFactor { get; set; } = 1.0f;

    /// <summary>
    /// Rolloff factor for 3D audio distance attenuation.
    /// 0 = no rolloff, 1 = real-world rolloff, higher = faster rolloff.
    /// </summary>
    internal static float RolloffFactor { get; set; } = 1.0f;

    /// <summary>
    /// Doppler factor for 3D audio velocity effects.
    /// 0 = no Doppler, 1 = real-world Doppler, higher = exaggerated Doppler.
    /// </summary>
    internal static float DopplerFactor { get; set; } = 1.0f;
    #endregion

    #region FFT and Analysis Configuration (Compile-time Constants)
    // Note: These are const because AudioAnalysis uses them to allocate static arrays.

    /// <summary>
    /// FFT buffer size for frequency analysis.
    /// </summary>
    internal const int FftBufferSize = 1024;

    /// <summary>
    /// BASS data flag corresponding to the FFT buffer size.
    /// </summary>
    public const DataFlags BassFftDataFlag = DataFlags.FFT2048;

    /// <summary>
    /// Number of frequency bands for audio analysis.
    /// </summary>
    internal const int FrequencyBandCount = 32;

    /// <summary>
    /// Waveform sample buffer size.
    /// </summary>
    internal const int WaveformSampleCount = 1024;

    /// <summary>
    /// Low-pass filter cutoff frequency (Hz) for low frequency separation.
    /// </summary>
    internal const float LowPassCutoffFrequency = 250f;

    /// <summary>
    /// High-pass filter cutoff frequency (Hz) for high frequency separation.
    /// </summary>
    internal const float HighPassCutoffFrequency = 2000f;
    #endregion

    #region Metering Configuration
    /// <summary>
    /// Time window in seconds for level metering via Bass.ChannelGetLevel (level-ex variant).
    /// Shorter values = more responsive but noisier, longer values = smoother but more latency.
    /// 0.05s (50ms) provides a good balance for visual metering.
    /// </summary>
    internal const float LevelMeteringWindowSeconds = 0.05f;
    #endregion
}