#include <stdio.h>
#include <stdlib.h>
#include <math.h>//need to link with -lm switch 
#include <time.h>
//ensures machine independent use of PI
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif


//function prototypes
//single tone
unsigned long int tone(unsigned long int SampleRate,double frequency,unsigned long int tenth_seconds,FILE *fp);


//main line of program
int main(int argc, char *argv[])
{

//variables
FILE *fp;
FILE *fp2;

unsigned long int file_position_ChunkSize;
unsigned long int file_position_SubChunk2Size;


//wave header, format and data sections

//header block
char ChunkID[4]={'R','I','F','F'};//very start of file RIFF header block group id
unsigned long int ChunkSize=0;//set this to the total file size minus 8 to ignore RIFF and WAVE
char Format[4]={'W','A','V','E'};

unsigned long int header_size = sizeof(ChunkSize);//ignore sGroupID and sRiffType
//printf("header size -> %d\n",(int)header_size);

//format block
char SubChunk1ID[4]={'f','m','t',' '};//format block group id
unsigned long int SubChunk1Size=0;//length of rest of chunk in bytes excludes FsGroupID and dwChunkSize
unsigned short int AudioFormat =1;//always 1 to indicate PCM format
unsigned short int NumChannels =2;//stereo so 2 channels
unsigned long int SampleRate = 44100;//the audio sampling rate
unsigned short int BitsPerSample=16;//16 bits per sample
//when writing to file do wBlockAlign BEFORE dwBitsPerSample
unsigned short int BlockAlign = NumChannels * (BitsPerSample/8);
//when writing to file do dwAvgBytesPerSec BEFORE wBlockAlign 
unsigned long int ByteRate = SampleRate * NumChannels * (BitsPerSample/8);

SubChunk1Size = sizeof(AudioFormat)+sizeof(NumChannels)+sizeof(SampleRate)
		+sizeof(BitsPerSample)+sizeof(BlockAlign)+sizeof(ByteRate);

//printf("dwChunkSize minus FsGroupID & dwChunkSize -> %d\n",(unsigned short int)dwChunkSize);

//data block
unsigned long int NumSamples=0;//the number of data samples written to the file
char SubChunk2ID[4]={'d','a','t','a'};
unsigned long int SubChunk2Size=NumSamples * NumChannels * (BitsPerSample/8);

//data is held in array in functions in as -> short int data[2]={0,0};


ChunkSize =4 + (8+SubChunk1Size) + (8+SubChunk2Size);//should total out at 36
//printf("%li\n",ChunkSize);

/* see if file name is specified */

if (argc!=3) {

printf("Need input and output filenames\n");

exit(1);

}

if ((fp= fopen(argv[2], "wb")) == NULL) //wb means open for writing of binary file - file need not exist
{

printf("cannot open output file\n");

exit(1);

}
//the input file 
if ((fp2= fopen(argv[1], "rb")) == NULL) //wb means open for writing of binary file - file need not exist
{

printf("cannot open input file\n");

exit(1);

}


printf("Fitness WAV writer -> Started\n");

//to allow time taken calculation
clock_t start_clock = clock();


//chunk 1
fwrite(ChunkID, sizeof(ChunkID[0]) ,4 ,fp );
file_position_ChunkSize=ftell(fp);
fwrite(&ChunkSize,sizeof(ChunkSize),1,fp);
fwrite(Format, sizeof(Format[0]) ,4 ,fp );

//chunk 2
fwrite(&SubChunk1ID, sizeof(SubChunk1ID[0]) ,4 ,fp );
fwrite(&SubChunk1Size,sizeof(SubChunk1Size),1,fp);
fwrite(&AudioFormat,sizeof(AudioFormat),1,fp);
fwrite(&NumChannels,sizeof(NumChannels),1,fp);
fwrite(&SampleRate,sizeof(SampleRate),1,fp);
fwrite(&ByteRate,sizeof(ByteRate),1,fp);
fwrite(&BlockAlign,sizeof(BlockAlign),1,fp);
fwrite(&BitsPerSample,sizeof(BitsPerSample),1,fp);

//chunk 3
//sound data header
fwrite(SubChunk2ID,sizeof(SubChunk2ID[0]),4,fp);
file_position_SubChunk2Size=ftell(fp);
fwrite(&SubChunk2Size,sizeof(SubChunk2Size),1,fp);


//file format repeats,frequency,tone time (hundredths seconds),space time (hundredths seconds)
int repeats=2;
double frequency=440.0;
int tone_time=10;
int space_time=10;
int i=0;
int value=0;

//value =fscanf(fp2,"%i,%lf,%i,%i",&repeats,&frequency,&tone_time,&space_time);
//printf("%i\n",value);
//printf("%i,%lf,%i,%i",repeats,frequency,tone_time,space_time);


printf("Repeats\tFrequency\tTone_time\tSpace_time (both in 10th of seconds)\n");
//read from text file
while ((fscanf(fp2,"%i,%lf,%i,%i,",&repeats,&frequency,&tone_time,&space_time))==4)
{

printf("%i\t%lf\t%i\t\t%i\n",repeats,frequency,tone_time,space_time);

for (i=0;i<repeats;i++)
{
//deal with tone
NumSamples+=tone(SampleRate,frequency,tone_time,fp);
//deal with space
NumSamples+=tone(SampleRate,0,space_time,fp);
}

}

//printf("NumSamples written %i\n",(int)NumSamples);

//calculate number of data samples
SubChunk2Size=NumSamples * NumChannels * (BitsPerSample/8);
ChunkSize+=SubChunk2Size;
//printf("sub chunk 2 size %li\n",SubChunk2Size);
//printf("chunk size %li\n",ChunkSize);
//finish up writing correct sizes to file
fseek(fp,file_position_SubChunk2Size,SEEK_SET);
fwrite(&SubChunk2Size,sizeof(SubChunk2Size),1,fp);
fseek(fp,file_position_ChunkSize,SEEK_SET);
fwrite(&ChunkSize,sizeof(ChunkSize),1,fp);


//print out time taken
printf("Processor time used -> %g seconds\n",(clock()-start_clock)/(double)CLOCKS_PER_SEC);


//the end so close file
fclose(fp);

//the end so close file
fclose(fp2);



printf("Fitness WAV writer -> Finished\n");

return 0;

}

//generate tone
unsigned long int tone(unsigned long int SampleRate,double frequency,unsigned long int tenth_seconds,FILE *fp)
{

//function variables
unsigned long int i=0;
unsigned long int j=0;
double t=(M_PI*2*frequency)/(SampleRate);

//not same formula as c# version which was
//double t=(M_PI*2*frequency)/(SampleRate*NumChannels);
//that gave 500hz when 1khz was specified
short int amplitude =32760;
unsigned long int elements=0;//used to write out number of elements recorded
//array for the data
short int data[2]={0,0};


//write sound data to file

for(i=0;i<(SampleRate/10)*tenth_seconds;i++)
{
	data[0]= (amplitude * sin(t*i) );
	data[1]= data[0];
	elements=elements+ fwrite(data, sizeof(data[0]) ,2 ,fp );
}
//printf("%i elements written -> %d bytes each\n",(int)elements ,sizeof(data[0]) );


return ((SampleRate/10)*tenth_seconds);//test return
}