import reverbGen from './reverbGen.mjs';

import { clamp } from './util.mjs';

if (typeof AudioContext !== 'undefined') {

  AudioContext.prototype.adjustLength = function (duration, buffer, speed = 1, offsetAmount = 0) {

    const sampleOffset = Math.floor(clamp(offsetAmount, 0, 1) * buffer.length);

    const newLength = buffer.sampleRate * duration;

    const newBuffer = this.createBuffer(buffer.numberOfChannels, buffer.length, buffer.sampleRate);

    for (let channel = 0; channel < buffer.numberOfChannels; channel++) {

      let oldData = buffer.getChannelData(channel);

      let newData = newBuffer.getChannelData(channel);

      for (let i = 0; i < newLength; i++) {

        // loop the buffer around to prevent

        let position = (sampleOffset + i * Math.abs(speed)) % oldData.length;

        if (speed < 1) {

          position = position * -1;

        }

        newData[i] = oldData.at(position) || 0;

      }

    }

    return newBuffer;

  };

  AudioContext.prototype.createReverb = function (duration, fade, lp, dim, ir, irspeed, irbegin) {

    const convolver = this.createConvolver();

    convolver.generate = (d = 2, fade = 0.1, lp = 15000, dim = 1000, ir, irspeed, irbegin) => {

      convolver.duration = d;

      convolver.fade = fade;

      convolver.lp = lp;

      convolver.dim = dim;

      convolver.ir = ir;

      convolver.irspeed = irspeed;

      convolver.irbegin = irbegin;

      if (ir) {

        convolver.buffer = this.adjustLength(d, ir, irspeed, irbegin);

      } else {

        reverbGen.generateReverb(

          {

            audioContext: this,

            numChannels: 2,

            decayTime: d,

            fadeInTime: fade,

            lpFreqStart: lp,

            lpFreqEnd: dim,

          },

          (buffer) => {

            convolver.buffer = buffer;

          },

        );

      }

    };

    convolver.generate(duration, fade, lp, dim, ir, irspeed, irbegin);

    return convolver;

  };

}