#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <math.h>

#include <vorbis/vorbisenc.h>

#define READ_SZ 1024
signed char readbuffer[READ_SZ*4+44];

int main(int argc, char **argv)
{
	ogg_stream_state	os; /* take physical pages, weld into a logical
                          stream of packets */
	ogg_page		og; /* one Ogg bitstream page.  Vorbis packets are inside */
	ogg_packet		op; /* one raw packet of data for decode */

	vorbis_info		vi; /* struct that stores all the static vorbis bitstream
	                          settings */
	vorbis_comment		vc; /* struct that stores all the user comments */

	vorbis_dsp_state	vd; /* central working state for the packet->PCM decoder */
	vorbis_block		vb; /* local working space for packet->PCM decode */

	int eos=0,ret;
	int i, founddata;
	FILE *fin=NULL,*fout=NULL;

	/* get input/output files from input */
	if (argc != 3)
	{
		printf("%s [input] [output]\n",argv[0]);
		exit(1);
	}

	fin = fopen(argv[1],"r");
	if (fin == NULL)
	{
		printf("Cant open file %s\n", argv[1]);
		exit(1);
	}

	fout = fopen(argv[2],"w");
	if (fout == NULL)
	{
		printf("Cant open file %s\n", argv[2]);
		exit(1);
	}

	/* encoding setup */
	vorbis_info_init(&vi);

	ret=vorbis_encode_init_vbr(&vi,2,44100,-.1);
	if (ret)
	{
		printf("Cant setup encode mode\n");
		exit(1);
	}

	/* add comment */
	vorbis_comment_init(&vc);
	vorbis_comment_add_tag(&vc, "ENCODER", "encoder_example.c");

	/* set up the analysis state and auxiliary encoding storage */
	vorbis_analysis_init(&vd, &vi);
	vorbis_block_init(&vd, &vb);

	/* set up our packet->stream encoder */
	/* pick a random serial number; that way we can more likely build
	     chained streams just by concatenation */
	srand(time(NULL));
	ogg_stream_init(&os, rand());

	/* Vorbis streams begin with three headers; the initial header (with
	   most of the codec setup parameters) which is mandated by the Ogg
	   bitstream spec.  The second header holds any comment fields.  The
	   third header holds the bitstream codebook.  We merely need to
	   make the headers, then pass them to libvorbis one at a time;
	   libvorbis handles the additional Ogg bitstream constraints */

	{
		ogg_packet header;
		ogg_packet header_comm;
		ogg_packet header_code;

		vorbis_analysis_headerout(&vd, &vc, &header, &header_comm, &header_code);
		ogg_stream_packetin(&os, &header); /* automatically placed in its own
	                                         page */
		ogg_stream_packetin(&os, &header_comm);
		ogg_stream_packetin(&os, &header_code);

		/* This ensures the actual
		 * audio data will start on a new page, as per spec
		 */
		while(!eos)
		{
			int result=ogg_stream_flush(&os, &og);
			if(result==0)
				break;
			fwrite(og.header, 1, og.header_len, fout);
			fwrite(og.body,   1, og.body_len,   fout);
		}
	}

	while (!eos)
	{
		long i;
		long bytes = fread(readbuffer, 1, READ_SZ*4, fin);

		if (bytes == 0)
		{
			vorbis_analysis_wrote(&vd, 0);
		} else
		{
			float **buffer = vorbis_analysis_buffer(&vd, READ_SZ);
			/*do i need interleaver samples*/
			for (i=0; i<bytes/4; i++)
			{
				buffer[0][i] = ((readbuffer[i*4+1]<<8)|
					(0x00ff&(int)readbuffer[i*4]))/32768.f;
				buffer[1][i] = ((readbuffer[i*4+3]<<8)|
					(0x00ff&(int)readbuffer[i*4+2]))/32768.f;
			}
			vorbis_analysis_wrote(&vd, bytes/4);
		}

		/* vorbis does some data preanalysis, then divvies up blocks for
		   more involved (potentially parallel) processing.  Get a single
		   block for encoding now */

		while (vorbis_analysis_blockout(&vd, &vb)==1)
		{
			/* analysis, assume we want to use bitrate management */
			vorbis_analysis(&vb, NULL);
			vorbis_bitrate_addblock(&vb);

			while(vorbis_bitrate_flushpacket(&vd,&op))
			{
				/* weld the packet into the bitstream */
				ogg_stream_packetin(&os, &op);

				/* write out pages (if any) */
				while (!eos)
				{
					int result = ogg_stream_pageout(&os, &og);
					if (result == 0)
						break;
					fwrite(og.header, 1, og.header_len, fout);
					fwrite(og.body, 1, og.body_len, fout);
					
					/* this could be set above, but for illustrative purposes, I do
					   it here (to show that vorbis does know where the stream ends) */

					if (ogg_page_eos(&og))
						eos=1;
				}
			}

		}
	}
	
	ogg_stream_clear(&os);
	vorbis_block_clear(&vb);
	vorbis_dsp_clear(&vd);
	vorbis_comment_clear(&vc);
	vorbis_info_clear(&vi);

	fclose(fout);
	fclose(fin);

	printf("Done\n");

	return 0;
}