using System;
using Sandbox;

namespace SFXR;

[Title( "Vibrato" )]
[Category( "SFXR Effects" )]
[Icon( "waves" )]
public class SFXRVibrato : SFXREffect
{
    /// <summary>
    /// Amount by which the frequency is changed
    /// (Default: 0, Range: 0 - 1)
    /// </summary>
    [Property, Range( 0f, 1f, 0.01f )] public float Depth { get; set; } = 0.3f;

    /// <summary>
    /// Frequency of the vibrato in Hz
    /// (Default: 0, Range: 0 - 100)
    /// </summary>
    [Property, Range( 0f, 100f )]
    public float Speed { get; set; } = 40;

    public override short[] Apply( short[] samples, SFXRComponent sound )
    {
        if ( Depth == 0 || Speed == 0 )
        {
            return samples;
        }

        short[] outputSamples = new short[samples.Length];
        double oscillatorPosition = 0;
        double oscillatorIncrement = 2 * Math.PI * Speed / (double)sound.SampleRate;

        for ( int i = 0; i < samples.Length; i++ )
        {

            oscillatorPosition += oscillatorIncrement;
            if ( oscillatorPosition > 2 * Math.PI )
            {
                oscillatorPosition -= 2 * Math.PI;
            }

            double vibrato = Math.Sin( oscillatorPosition ) * Depth;

            outputSamples[i] = (short)(samples[i] * (1 + (float)vibrato));

        }

        return outputSamples;
    }
}