//  -*-objc-*-
//  Calando - Volume Fading for OS X
//  Copyright (C) 2007  Greg Heartsfield

#import "VolumeFader.h"

@implementation VolumeFader

+ (void)fadeSystemVolumeThreaded:(id)anObject {
  NSLog(@"Starting fade volume thread...");
  // Create new autorelease pool for the thread, which will
  // automatically release itself at thread termination.
  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
  // Do thread work here
  [anObject fadeSystemVolume:[anObject getFinalVolume]
	    withSecondsDuration:[anObject getSecondsDuration]];
  NSLog(@"fadeSystemVolumeThreaded method finished");
}

- (void)setFinalVolume:(Float32)volume {
  finalVolume = volume;
}

- (void)setSecondsDuration:(int)duration {
  fadeDuration = duration;
}

- (Float32)getFinalVolume {
  return finalVolume;
}

- (int)getSecondsDuration {
  return fadeDuration;
}

- (bool)isFadeRunning {
  return !finished;
}

- (void)stopFade {
  fadeShouldStop = YES;
}

- (void)setNotifyFinished:(id)object {
  notifyFinishedObject = object;
}

- (void)fadeSystemVolume:(Float32)volume withSecondsDuration:(int)duration {
  finished = NO;
  fadeShouldStop = NO;
  // Get Default Output Device
  OSStatus theStatus;
  UInt32 theSize;
  AudioDeviceID theID;
  theSize = sizeof(AudioDeviceID);
  MTCoreAudioVolumeInfo rv;
  rv.theVolume = 0.0;
  Float32 currVolume;
  int i;
  Float32 startingVolume;
  Float32 prevVolume;
  Float32 endVolume;
  Float32 volumeDiff;
  
  theStatus = AudioHardwareGetProperty
    (kAudioHardwarePropertyDefaultOutputDevice,
     &theSize,
     &theID);
  if (theStatus != 0)
    NSLog(@"Problem with output device!");

  // Every second from now until duration ends, decrease the volume 
  // First, get current system volume, for our starting point
  theStatus = AudioDeviceGetProperty(theID,
				     1,
				     0,
				     kAudioDevicePropertyVolumeScalar,
				     &theSize,
				     &rv.theVolume);

  if (theStatus != 0)
    NSLog(@"Error getting audio device volume");

  currVolume = rv.theVolume;
  startingVolume = rv.theVolume;

  // calculate what the ending volume should be
  endVolume = currVolume * volume;
  for (i=0; i < duration; i++) {
    // get current volume
    theStatus = AudioDeviceGetProperty(theID,
				       1,
				       0,
				       kAudioDevicePropertyVolumeScalar,
				       &theSize,
				       &rv.theVolume);
    if (theStatus != 0)
      NSLog(@"Error getting audio device volume");
    volumeDiff = rv.theVolume - currVolume;
    if (fabs(volumeDiff) > 0.05) {
      NSLog (@"Volume changed from external source, stopping fade.");
      //TODO: make finished action a private method
      fadeShouldStop = YES;
    }
    currVolume = startingVolume -
      ((startingVolume - endVolume) / duration) * i;
    prevVolume = currVolume;
    // set volume of channel 1
    theStatus = AudioDeviceSetProperty (theID,
					NULL,
					1,
					0,
					kAudioDevicePropertyVolumeScalar,
					sizeof(Float32),
					&currVolume);
    // set volume of channel 2
    theStatus = AudioDeviceSetProperty (theID,
					NULL,
					2,
					0,
					kAudioDevicePropertyVolumeScalar,
					sizeof(Float32),
					&currVolume);

    // Log current volume every 10 seconds to console
    if (i%10 == 0) {
      NSLog(@"Setting the volume to %f", currVolume);
    }
    // sleep for one second
    id sleepUntil = [NSDate dateWithTimeIntervalSinceNow:1];
    [NSThread sleepUntilDate:sleepUntil];
    if (fadeShouldStop) {
      // skip to end of duration loop
      i = duration;
    }
  }
  [notifyFinishedObject volumeFadeFinished];
  finished=YES;
}

@end