// Assignment 1 Part 3
// William Chien
// This program will generate repetition of beep tone.
// Each repetition, the tone's amplitude is increased.
// User will hear that the program is beeping louder and louder.
// 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"

//constants for producing sine wave tone
#define NUM_SECONDS 3
#define SAMPLE_RATE 44100
#define BUFFER_SIZE 256
#define F 6.283185307179586 //F = 2pi
#define FREQUENCY 1000

struct paSoundData
{
    float amplitude;
    float frequency;
	float phase;
	unsigned long samples;
};



//******************************************************************************
// 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;

    //Produce sinewave tone
	//Same ideas from Professor Dobrian's Pa_cosine example
	float A = data->amplitude;
	float phase = data->phase;
	float y;  //Temporary output constant
    float G = F*data->frequency/SAMPLE_RATE;

    for( i=0; i<framesPerBuffer; i++ )
    {
	  y = A*sin(G*(data->samples++)+phase); //Sine wave equation
		*out++ = y;	 // left channel
        *out++ = y;  // right channel
    }
    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)
{
    float n=1;
	int times;

    cout << "How many beeps do you want to genearate?.\n";
	cout << "Each beep will become louder and louder.\n";
	cin  >> times;
	

	//Loops that increases the amplitude.
	for (n=1; n<=times ; n++)
	{
	PortAudioStream *stream;
    // Initialize our data for use by callback.
    	data.amplitude = 0.5*n;
		data.frequency = FREQUENCY;
        data.phase = 0.;

    
	// Initialize library before making any other calls.
    PaError err = Pa_Initialize();
    if( err != paNoError ) return error(err);
   

		// 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);
				err = Pa_StopStream( stream );
			
				if( err != paNoError ) return error(err);
    
				err = Pa_CloseStream( stream );
				if( err != paNoError ) return error(err);

	}
		Pa_Terminate();
		cout << "Finished.\n";

		return 0;
		
}