#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include "colourspace.h"
#include "pngoutput.h"

static void read_image( int infd, double *luma, double *cb, double *cr,
                        int width, int height )
{
    int i;

    for( i = 0; i < width * height; i++ ) {
        unsigned char cur;
        read( infd, &cur, 1 );
        *luma++ = ( (double) ( cur - 16 ) ) / 219.0;
    }

    for( i = 0; i < ((width/2) * (height/2)); i++ ) {
        unsigned char cur;
        read( infd, &cur, 1 );
        *cb++ = ( (double) ( cur - 128 ) ) / 224.0;
    }

    for( i = 0; i < ((width/2) * (height/2)); i++ ) {
        unsigned char cur;
        read( infd, &cur, 1 );
        *cr++ = ( (double) ( cur - 128 ) ) / 224.0;
    }
}

int main( int argc, char **argv )
{
    double *luma;
    double *cbin;
    double *crin;
    double *cb444;
    double *cr444;
    unsigned char *scanline;
    matrix_t *fcc_to_xyz;
    pngoutput_t *pngout;
    int infd, width, height, i, j;

    fcc_to_xyz = build_rgb_xyz_matrix_from_chromaticities(
/*
                     0.67, 0.33,
                     0.21, 0.71,
                     0.14, 0.08,
                     0.310, 0.316 );
*/
/*
                     0.630, 0.340,
                     0.310, 0.595,
                     0.155, 0.070,
                     0.3127, 0.3290 );
*/
                     0.64, 0.33,
                     0.30, 0.60,
                     0.15, 0.06,
                     0.3127, 0.3290 );

    infd = open( argv[ 1 ], O_RDONLY );
    if( infd < 0 ) {
        fprintf( stderr, "Can't open %s.\n", argv[ 1 ] );
        return 1;
    }

    read( infd, &width, sizeof( int ) );
    read( infd, &height, sizeof( int ) );
    fprintf( stderr, "ycbcrtorgb: Input is %dx%d resolution.\n",
             width, height );

    pngout = pngoutput_new( argv[ 2 ], width, height, 0.45 );
    if( !pngout ) {
        fprintf( stderr, "ycbcrtorgb: Can't open output file %s.\n",
                 argv[ 2 ] );
        close( infd );
        return 1;
    }

    luma  = (double *) malloc( width * height * sizeof( double ) );
    cbin  = (double *) malloc( (width/2) * (height/2) * sizeof( double ) );
    crin  = (double *) malloc( (width/2) * (height/2) * sizeof( double ) );
    cb444 = (double *) malloc( width * height * sizeof( double ) );
    cr444 = (double *) malloc( width * height * sizeof( double ) );
    scanline = (unsigned char *) malloc( width * 3 );
    if( !luma || !cbin || !crin || !cb444 || !cr444 || !scanline ) {
        fprintf( stderr, "ycbcrtorgb: Can't allocate memory.\n" );
        pngoutput_delete( pngout );
        close( infd );
        return 1;
    }
    read_image( infd, luma, cbin, crin, width, height );
    resample_chroma_420_to_444( cbin, cb444, width/2, height/2 );
    resample_chroma_420_to_444( crin, cr444, width/2, height/2 );

    for( i = 0; i < height; i++ ) {
        unsigned char *s = scanline;
        for( j = 0; j < width; j++ ) {
            double yp = luma[ (i * width) + j ];
            double pb = cb444[ (i * width) + j ];
            double pr = cr444[ (i * width) + j ];
            double rfcc, gfcc, bfcc;
            double rfccl, gfccl, bfccl;
            double x, y, z;
            double r, g, b;
            double rp, gp, bp;


            mpeg2_ypbpr_to_rgb_fcc( yp, pb, pr, &rfcc, &gfcc, &bfcc );
            nonlinear_to_linear_rec709( rfcc, gfcc, bfcc, &rfccl, &gfccl, &bfccl );
            matrix_rgb_to_xyz( fcc_to_xyz, rfccl, gfccl, bfccl, &x, &y, &z );
            xyz_to_srgb( x, y, z, &r, &g, &b );
            if( r < 0.0 || r > 1.0 || g < 0.0 || g > 1.0 || b < 0.0 || b > 1.0 ) {
                r = g = b = 0.0;
            }
            linear_to_nonlinear_srgb( r, g, b, &rp, &gp, &bp );


/*
            //mpeg2_ypbpr_to_rgb_fcc( yp, pb, pr, &rp, &gp, &bp );
            mpeg2_ypbpr_to_rgb_rec709( yp, pb, pr, &rp, &gp, &bp );
            if( rp < 0.0 || rp > 1.0 || gp < 0.0 || gp > 1.0 || bp < 0.0 || bp > 1.0 ) {
                rp = gp = bp = 0.0;
            }
*/
            *s++ = (unsigned char) ( ( rp * 255.0 ) + 0.5 );
            *s++ = (unsigned char) ( ( gp * 255.0 ) + 0.5 );
            *s++ = (unsigned char) ( ( bp * 255.0 ) + 0.5 );
        }
        pngoutput_scanline( pngout, scanline );
    }

    pngoutput_delete( pngout );
    close( infd );
    return 0;
}