//
//  PdAudioUnit.h
//  libpd
//
//  Created on 29/09/11.
//
//  For information on usage and redistribution, and for a DISCLAIMER OF ALL
//  WARRANTIES, see the file, "LICENSE.txt," in this distribution.
//
//  Updated 2018 Dan Wilcox <danomatika@gmail.com>
//

#import <Foundation/Foundation.h>
#import "AudioUnit/AudioUnit.h"

/// PdAudioUnit: object that operates pd's audio input and
/// output through an Audio Unit. The parameters can be changed
/// after it has been instatiated with its configure method,
/// which will cause the underlying audio unit to be reconstructed.
///
/// For debugging, AU_DEBUG_VERBOSE can be defined to print extra information.
@interface PdAudioUnit : NSObject {
@protected
	AudioUnit _audioUnit; ///< the underlying audio unit instance
	BOOL _inputEnabled;   ///< is audio input enabled?
	BOOL _initialized;    ///< has the audio unit been successfully inited?
	int _blockSizeAsLog;  ///< log(blockSize) for fast bitshift division
}

/// A reference to the audio unit which can be used to query or set other
/// properties.
@property (nonatomic, readonly) AudioUnit audioUnit;

/// A reference to the audio unit callback function. Override the getter method
/// if you want to subclass PdAudioUnit and implement your own custom sample
/// rendering.
///
/// In your custom PdAudioUnit subclass .m:
///
/// // your custom render callback
/// static OSStatus MyRenderCallback(void *inRefCon,
///                                  AudioUnitRenderActionFlags *ioActionFlags,
///                                  const AudioTimeStamp *inTimeStamp,
///                                  UInt32 inBusNumber,
///                                  UInt32 inNumberFrames,
///                                  AudioBufferList *ioData) {
///     // do something with the samples, see PdAudioUnit.m AudioRenderCallback
///     return noErr;
/// }
///
/// // return method
/// - (AURenderCallback)renderCallback {
///		return MyRenderCallback;
/// }
///
@property (nonatomic, readonly) AURenderCallback renderCallback;

/// Check or set the active status of the audio unit.
@property (nonatomic, getter=isActive) BOOL active;

/// The configure method sets all parameters of the audio unit that may require
/// it to be recreated at the same time. This is an expensive process and will
/// stop the audio unit before any reconstruction, causing a momentary pause in
/// audio and UI if run from the main thread.
/// Returns zero on success.
- (int)configureWithSampleRate:(Float64)sampleRate
                numberChannels:(int)numChannels
                  inputEnabled:(BOOL)inputEnabled;

/// Print info on the audio unit settings to the console
- (void)print;

/// Called by configureWithSampleRate when setting up the internal audio unit.
/// Default format: 32 bit, floating point, linear PCM, interleaved
- (AudioStreamBasicDescription)ASBDForSampleRate:(Float64)sampleRate
                                  numberChannels:(UInt32)numChannels;

@end