ZZZES3 : ZZZ{

  var out,
  clocks,
  vcos;

  *new{
    arg channels;
    ^super.newCopyArgs(channels).init;
  }

  init{
    out = Dictionary();
    clocks = Dictionary();
    vcos = Dictionary();
    "Interfacing ZZZ ES-3, using the following channels:".postln;
    (1..8).do({
      arg item, i;
      out.add(item -> super.channels[i]);
      postln(item.asString ++ " -> " ++ super.channels[i].asString);
    });
  }

  /**
   * Returns the number of the hardware output on the system for a provided
   * ES-3 output number
   * @return system hardware output number
   */
  out{
    arg output;
    if((output > 0) && (output <= 8), {
      ^out.at(output);
    },{
      ^nil;
    });
  }

  addClock{
    arg output, freq;
    if(vcos.at(output).isNil, {
      if(clocks.at(output).isNil, {
        clocks.add(output -> Synth(\ZZZClock, [\out, this.out(output), \freq, freq]));
      },{
        ("Cannot add clock on output "++ output ++". There is a clock playing.").error;
      });
    },{
      ("Cannot add clock on output "++ output ++". There is a VCO playing.").error;
    });
  }

  removeClock{
    arg output;
    if(clocks.at(output).notNil, {
      clocks.at(output).free;
      clocks.removeAt(output);
    });
  }

  setClock{
    arg output, freq, delta;
    var currentFreq, diff, env;
    if(clocks.at(output).notNil, {
      if(delta.notNil, {
        clocks.at(output).get(\freq, {
          arg value;
          currentFreq = value;
          diff = (currentFreq-freq).abs;
          if(currentFreq > freq, {
            diff = diff*(-1);
          });
          env = Env.sine((delta*2), diff).asStream;
          {
            (delta*10).do({
              clocks.at(output).set(\freq, (currentFreq+env.next));
              0.1.wait;
            });
            clocks.at(output).set(\freq, freq);
          }.fork;
        });
      },{
        clocks.at(output).set(\freq, freq);
      });
    });
  }

  clock{
    arg output;
    ^clocks.at(output);
  }

  addVCO{
    arg output, mul;
    if(clocks.at(output).isNil, {
      if(vcos.at(output).isNil, {
        vcos.add(output -> Synth(\ZZZConstant, [\out, this.out(output), \mul, mul]));
      },{
        ("Cannot add VCO on output "++ output ++". There is a VCO playing.").error;
      });
    },{
      ("Cannot add VCO on output "++ output ++". There is a clock playing.").error;
    });
  }

  setVCO{
    arg output, mul;
    if(vcos.at(output).notNil, {
      vcos.at(output).set(\mul, mul);
    });
  }

  removeVCO{
    arg output;
    vcos.removeAt(output);
  }

  vco{
    arg output;
    ^vcos.at(output);
  }

}