/* PCM capture/playback processors for the optional low-latency voice path. */
'use strict';

class AtlasPcmCaptureProcessor extends AudioWorkletProcessor {
  constructor(){
    super();
    this.pending=[];
    this.pendingLength=0;
    this.port.onmessage=(event)=>{
      if((event.data||{}).type!=='flush') return;
      this.flush();
      this.port.postMessage({type:'flushed'});
    };
  }

  flush(){
    if(!this.pendingLength) return;
    const samples=new Float32Array(this.pendingLength);
    let offset=0;
    this.pending.forEach(function(chunk){samples.set(chunk,offset);offset+=chunk.length;});
    this.pending=[];
    this.pendingLength=0;
    this.port.postMessage({type:'pcm',samples:samples.buffer},[samples.buffer]);
  }

  process(inputs){
    const input=inputs[0]&&inputs[0][0];
    if(!input||!input.length) return true;
    this.pending.push(new Float32Array(input));
    this.pendingLength+=input.length;
    if(this.pendingLength>=1024){
      this.flush();
    }
    return true;
  }
}

class AtlasPcmPlaybackProcessor extends AudioWorkletProcessor {
  constructor(){
    super();
    this.queue=[];
    this.queueOffset=0;
    this.phase=0;
    this.sourceRate=22050;
    this.ended=false;
    this.cancelled=false;
    this.queuedFrames=0;
    this.reportCountdown=0;
    this.drainedSent=false;
    this.port.onmessage=(event)=>{
      const data=event.data||{};
      if(data.type==='push'&&data.samples){
        const pcm=new Int16Array(data.samples);
        const samples=new Float32Array(pcm.length);
        for(let index=0;index<pcm.length;index+=1) samples[index]=pcm[index]/32768;
        this.sourceRate=Number(data.sampleRate)||this.sourceRate;
        this.queue.push(samples);
        this.queuedFrames+=samples.length;
        this.drainedSent=false;
      }else if(data.type==='end'){
        this.ended=true;
      }else if(data.type==='cancel'){
        this.cancelled=true;
        this.queue=[];
        this.queuedFrames=0;
      }
    };
  }

  currentSample(){
    while(this.queue.length&&this.queueOffset>=this.queue[0].length){
      this.queue.shift();
      this.queueOffset=0;
    }
    return this.queue.length?this.queue[0][this.queueOffset]:null;
  }

  nextSample(){
    if(!this.queue.length) return null;
    if(this.queueOffset+1<this.queue[0].length) return this.queue[0][this.queueOffset+1];
    return this.queue.length>1&&this.queue[1].length?this.queue[1][0]:this.queue[0][this.queueOffset];
  }

  advance(){
    if(!this.queue.length) return;
    this.queueOffset+=1;
    this.queuedFrames=Math.max(0,this.queuedFrames-1);
    if(this.queueOffset>=this.queue[0].length){this.queue.shift();this.queueOffset=0;}
  }

  process(_inputs,outputs){
    const output=outputs[0]&&outputs[0][0];
    if(!output) return !this.cancelled;
    output.fill(0);
    if(this.cancelled) return false;
    const ratio=this.sourceRate/sampleRate;
    for(let index=0;index<output.length;index+=1){
      const left=this.currentSample();
      if(left===null) break;
      const right=this.nextSample();
      output[index]=right===null?left:left+((right-left)*this.phase);
      this.phase+=ratio;
      while(this.phase>=1){this.advance();this.phase-=1;}
    }
    this.reportCountdown-=1;
    if(this.reportCountdown<=0){
      this.reportCountdown=20;
      this.port.postMessage({type:'buffer',frames:this.queuedFrames});
    }
    if(this.ended&&!this.queue.length&&!this.drainedSent){
      this.drainedSent=true;
      this.port.postMessage({type:'drained'});
    }
    return true;
  }
}

registerProcessor('atlas-pcm-capture',AtlasPcmCaptureProcessor);
registerProcessor('atlas-pcm-playback',AtlasPcmPlaybackProcessor);