/**
 * This script will reduce the volume on a music track whenever there are clips
 * on a narrative track.
 * Written By: Edward Troxel - Vegas Tips, Tricks, & Scripts
 * Modified By: David Arendt - multiple successive tracks now working
 **/

import System;
import System.IO;
import System.Object;
import System.Windows.Forms;
import SonicFoundry.Vegas;


try {
  // Set the defaults
  var FadeWhen = 2; // 1 = all before/after, 2 = Centered on start/end
  var FadeMS : Double = 2000; //500 = 1/2 second - Time is MilliSeconds
  var LoudVol = 1; //1 = 0db, 2 = 6db, 1.5 = 3.5db, 1.75 = 4.8db
  var SoftVol = 0.25; //0 = -inf, .5 = -6db, .25 = -12db


  if (FadeWhen == 2) {
      FadeMS = FadeMS / 2;
  }

  var FadeTime = new Timecode(FadeMS);



  // Find the two audio tracks by name
  var VoiceTrack = FindTrack("Narrative");
  if (null == VoiceTrack)
      throw "no selected track";

  var MusicTrack = FindTrack("Music");
  if (null == MusicTrack)
      throw "no selected track";

  // Find the volume envelope on the music track - add if needed
  var VolEnv = FindEnvelope(MusicTrack, EnvelopeType.Volume);
  if (null == VolEnv) {
      VolEnv = new Envelope(EnvelopeType.Volume);
      MusicTrack.Envelopes.Add(VolEnv);
  }

  // Go thru the events on the narrative track finding in/out points
  var eventEnum = new Enumerator(VoiceTrack.Events);
  while (!eventEnum.atEnd()) {
    var evnt : TrackEvent = TrackEvent(eventEnum.item());
    var evntStart : Timecode = evnt.Start;
    var evntLen : Timecode = evnt.Length;
    
    // begin modification by David Arendt
    eventEnum.moveNext();
    var nextEvnt : TrackEvent;
    var nextEvntStart : Timecode;
    var nextEvntLen : Timecode;
    while (!eventEnum.atEnd())
    {
      nextEvnt = TrackEvent(eventEnum.item());
      nextEvntStart = nextEvnt.Start;
      nextEvntLen = nextEvnt.Length;
      if (nextEvntStart > evntStart + evntLen + FadeTime + FadeTime)
        break;
      evntLen = nextEvntStart - evntStart + nextEvntLen;          
      eventEnum.moveNext();
    }
    // end modification by David Arendt

    VolEnv.Points.Add(new EnvelopePoint(evntStart - FadeTime, LoudVol));
    if (FadeWhen == 2) {
        VolEnv.Points.Add(new EnvelopePoint(evntStart + FadeTime, SoftVol));
    } else {
        VolEnv.Points.Add(new EnvelopePoint(evntStart, SoftVol));
    }

    if (FadeWhen == 2) {
        VolEnv.Points.Add(new EnvelopePoint(evntStart + evntLen - FadeTime, SoftVol));
    } else {
        VolEnv.Points.Add(new EnvelopePoint(evntStart + evntLen, SoftVol));
    }
    VolEnv.Points.Add(new EnvelopePoint(evntStart + evntLen + FadeTime, LoudVol));


  }


} catch (e) {
    MessageBox.Show(e);
}


function FindTrack(WhichTrack) : Track {
  var trackEnum = new Enumerator(Vegas.Project.Tracks);
  var PrevTrack : Track = Track(trackEnum.item());
  while (!trackEnum.atEnd()) {
    var track : Track = Track(trackEnum.item());
    if (WhichTrack == "Current") {
        if (track.Selected) {
            return track;
        }
    }
    if (WhichTrack == "Previous") {
        if (track.Selected) {
            return PrevTrack;
        }
    }
    if (track.Name == WhichTrack) {
        return track;
    }
    trackEnum.moveNext();
  }
  return null;
}

function FindEnvelope(track : Track, etype : EnvelopeType) : Envelope {
  var envEnum : Enumerator = new Enumerator(track.Envelopes);
  while (!envEnum.atEnd()) {
    var env : Envelope = envEnum.item();
    if (env.Type == etype) {
        return env;
    }
    envEnum.moveNext();
  }
  return null;
}