// Assignment 1
// William Chien
/* This is a program that is trying to play sound several times.  Each time, the program will
   increase the sleeping time, so the sound will become longer and longer.
*/
// Basically, this program is mainly using C++ language.
// C++ Modified version is provided by Eric Johnson

#include <iostream.h>
#include <stdio.h>
#include <math.h>
#include "portaudio.h"

const int NUM_SECONDS = 3;

struct paSoundData
{
    float left_phase;
    float right_phase;
};



//******************************************************************************
// Callback Function (From PortAudio Website).
// This routine is for Callback Funciton.
static int paSoundCallback( void *inputBuffer, void *outputBuffer,
                           unsigned long framesPerBuffer,
                           PaTimestamp outTime, void *userData )
{
    // Cast data passed through stream to our structure.
    paSoundData *data = (paSoundData*)userData;
    float *out = (float*)outputBuffer;
    unsigned int i;
    (void) outTime; // Prevent unused variable warnings.
    (void) inputBuffer;

    for( i=0; i<framesPerBuffer; i++ )
    {
        *out++ = data->left_phase;  /* left */
        *out++ = data->right_phase;  /* right */
        // Generate simple sawtooth phaser that ranges between -1.0 and 1.0.
        data->left_phase += 0.01f;
        // When signal reaches top, drop back down.
        if( data->left_phase >= 1.0f ) data->left_phase -= 2.0f;
        // higher pitch so we can distinguish left and right.
        data->right_phase += 0.02f;
        if( data->right_phase >= 1.0f ) data->right_phase -= 2.0f;
    }
    return 0;
}
//****************************************************************************
// Error handling function
// replaces the goto label used in some of the examples
int error (const int err)
{
	
    Pa_Terminate();
    cerr << "An error occured while using the portaudio stream\n";
    cerr << "Error number: " << err << "\n";
    cerr << "Error message: " << Pa_GetErrorText( err ) << endl;

	return err;

}
//*******************************************************************
static paSoundData data;

int main(void)
{
    int n=1;
	int times;

    cout << "This program will repeat a sound.\n";
	cout << "Each repetition, the sound will be played with longer sleep time.\n";
	cout << "How many times you want to play?\n";
	cin  >> times;
	
	PortAudioStream *stream;
    // Initialize our data for use by callback.
    data.left_phase = data.right_phase = 0.0;
    
	// Initialize library before making any other calls.
    PaError err = Pa_Initialize();
    if( err != paNoError ) return error(err);
    
	//loop for repetiting the tone
	//Each time, it will increase the sleeping time.
	for (n=1; n<=times ; n++)
	{
		// Open an audio I/O stream.
		err = Pa_OpenDefaultStream(
				&stream,
			    0,                // no input channels
				2,                // stereo output
				paFloat32,        // 32 bit floating point output
				44100,            // Sampling Rate
				256,              // frames per buffer
				0,                // number of buffers, if zero then use default minimum
				paSoundCallback,  // specific callback
				&data );          // Pass data through Call back
    
				if( err != paNoError ) 
					return error(err);
		
				err = Pa_StartStream( stream );
				if( err != paNoError ) return error(err);
			
				// Sleep for several seconds.
				Pa_Sleep(NUM_SECONDS*100*n);
				err = Pa_StopStream( stream );
			
				if( err != paNoError ) return error(err);
    
				err = Pa_CloseStream( stream );
				if( err != paNoError ) return error(err);
				
				//Instead of just reopening the stream again,
				//add another sleep function to create silence between each tone.
				Pa_Sleep(NUM_SECONDS*100);
	}
		Pa_Terminate();
		cout << "Finished.\n";

		return err;
		
}