#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>

#include <jpeglib.h>
#include <argtable2.h>
#include <string.h>

const char * input_file;
const char * output_file;
const char * filter;
double times;
double percent;

/* we will be using this uninitialized pointer later to store raw, uncompressd image */
JSAMPARRAY row_pointers = NULL;

/* dimensions of the image we want to write */
JDIMENSION width;
JDIMENSION height;
int num_components;
int quality = 75;
J_COLOR_SPACE color_space;

void negate(){
    int x, y;
    if (color_space != JCS_RGB) return;

    for (y=0; y<height; y++) {
        JSAMPROW row = row_pointers[y];
        for (x=0; x<width; x++) {
            JSAMPROW ptr = &(row[x*3]);

            ptr[0] = 255-ptr[0];
            ptr[1] = 255-ptr[1];
            ptr[2] = 255-ptr[2];
        }
    }
}

void brightness(){
    int x, y, c;
    if (color_space != JCS_RGB) return;

    for (y=0; y<height; y++) {
        JSAMPROW row = row_pointers[y];
        for (x=0; x<width; x++) {
            JSAMPROW ptr = &(row[x*3]);

            for(c = 0; c < 3; c++) {
                int new_val = ptr[c] + (int)(ptr[c] * (percent / 100.0));

                if (new_val > 255) new_val = 255;
                if (new_val < 0) new_val = 0;

                ptr[c] = new_val;
            }
        }
    }
}

void contrast(){
    int x, y, c;
    if (color_space != JCS_RGB) return;

    for (y=0; y<height; y++) {
        JSAMPROW row = row_pointers[y];
        for (x=0; x<width; x++) {
            JSAMPROW ptr = &(row[x*3]);

            for(c = 0; c < 3; c++) {
                int new_val = (int)(times * (ptr[c] - 127) + 127);

                if (new_val > 255) new_val = 255;
                if (new_val < 0) new_val = 0;

                ptr[c] = new_val;
            }
        }
    }
}

void sepia(){
    int x, y;
    if (color_space != JCS_RGB) return;

    for (y=0; y<height; y++) {
        JSAMPROW row = row_pointers[y];
        for (x=0; x<width; x++) {
            JSAMPROW ptr = &(row[x*3]);

            int r = ptr[0];
            int g = ptr[1];
            int b = ptr[2];

            int new_r = (int)(0.393 * r + 0.769 * g + 0.189 * b);
            int new_g = (int)(0.349 * r + 0.686 * g + 0.168 * b);
            int new_b = (int)(0.272 * r + 0.534 * g + 0.131 * b);

            if (new_r > 255) new_r = 255;
            if (new_g > 255) new_g = 255;
            if (new_b > 255) new_b = 255;

            ptr[0] = new_r;
            ptr[1] = new_g;
            ptr[2] = new_b;
        }
    }
}

void process_file(){
    if(strcmp(filter, "negate") == 0 ){
        negate();
    }
    else if(strcmp(filter, "brightness") == 0 ){
        brightness();
    }
     else if(strcmp(filter, "contrast") == 0 ){
        contrast();
    }
    else if(strcmp(filter, "sepia") == 0 ){
        sepia();
    }
}

void abort_(const char * s, ...)
{
    va_list args;
    va_start(args, s);
    vfprintf(stderr, s, args);
    fprintf(stderr, "\n");
    va_end(args);
    abort();
}

/**
* read_jpeg_file Reads from a jpeg file on disk specified by filename and saves into the
* raw_image buffer in an uncompressed format.
* * \returns positive integer if successful, -1 otherwise
* \param *filename char string specifying the file name to read from
*
*/

void read_jpeg_file( const char *filename )
{
    /* these are standard libjpeg structures for reading(decompression) */
    struct jpeg_decompress_struct cinfo;
    struct jpeg_error_mgr jerr;
    /* libjpeg data structure for storing one row, that is, scanline of an image */
    int y;

    FILE *infile = fopen( filename, "rb" );

    if ( !infile )
    {
        abort_("Error opening input jpeg file %s!\n", filename);
    }
    /* here we set up the standard libjpeg error handler */
    cinfo.err = jpeg_std_error( &jerr );
    jpeg_create_decompress( &cinfo );
    /* this makes the library read from infile */
    jpeg_stdio_src( &cinfo, infile );
    /* reading the image header which contains image information */
    jpeg_read_header( &cinfo, TRUE );

    /* Start decompression jpeg here */
    jpeg_start_decompress( &cinfo );
    width = cinfo.output_width;
    height = cinfo.output_height;
    num_components = cinfo.out_color_components;
    color_space = cinfo.out_color_space;

    /* allocate memory to hold the uncompressed image */
    size_t rowbytes = width * num_components;
    row_pointers = (JSAMPARRAY) malloc(sizeof(j_common_ptr) * height);
    for (y=0; y<height; y++){
        row_pointers[y] = (JSAMPROW) malloc(rowbytes);
    }

    /* read one scan line at a time */
    y=0;
    JSAMPARRAY tmp = row_pointers;
    while( cinfo.output_scanline < cinfo.image_height )
    {
        y = jpeg_read_scanlines( &cinfo, tmp, 1 );
        tmp +=y;
    }
    /* wrap up decompression, destroy objects, free pointers and close open files */
    jpeg_finish_decompress( &cinfo );
    jpeg_destroy_decompress( &cinfo );
//     free( row_pointer[0] );
    fclose( infile );
    /* yup, we succeeded! */
}

/**
* write_jpeg_file Writes the raw image data stored in the raw_image buffer
* to a jpeg image with default compression and smoothing options in the file
* specified by *filename.
*
* \returns positive integer if successful, -1 otherwise
* \param *filename char string specifying the file name to save to
*
*/
void write_jpeg_file( const char *filename )
{
    struct jpeg_compress_struct cinfo;
    struct jpeg_error_mgr jerr;
    int y;
    JSAMPARRAY tmp;

    /* this is a pointer to one row of image data */
    FILE *outfile = fopen( filename, "wb" );

    if ( !outfile )    {
        abort_("Error opening output jpeg file %s!\n", filename );
    }
    cinfo.err = jpeg_std_error( &jerr );
    jpeg_create_compress(&cinfo);
    jpeg_stdio_dest(&cinfo, outfile);

    /* Setting the parameters of the output file here */
    cinfo.image_width = width;    
    cinfo.image_height = height;
    cinfo.input_components = num_components;
    cinfo.in_color_space = color_space;
/* default compression parameters, we shouldn't be worried about these */
    jpeg_set_defaults( &cinfo );
    jpeg_set_quality (&cinfo, quality, TRUE);
    /* Now do the compression .. */
    jpeg_start_compress( &cinfo, TRUE );
    /* like reading a file, this time write one row at a time */
    tmp = row_pointers;
    while( cinfo.next_scanline < cinfo.image_height )
    {
        y = jpeg_write_scanlines( &cinfo, tmp, 1 );
        tmp +=y;
    }
    /* similar to read file, clean up after we're done compressing */
    jpeg_finish_compress( &cinfo );
    jpeg_destroy_compress( &cinfo );
    fclose( outfile );

/* cleanup heap allocation */
    for (y=0; y<height; y++){
        free(row_pointers[y]);
    }
    free(row_pointers);
}

int main(int argc, char **argv){
    // Options
    struct arg_file *input_file_arg = arg_file1("i", "in-file", "<input>", "Input JPEG File");
    struct arg_file *output_file_arg = arg_file1("o", "out-file" , "<output>", "Output JPEG File");
    struct arg_str *filter_arg = arg_str1("f", "filter" , "<filter>", "Filter");
    struct arg_dbl *times_arg = arg_dbl0("t", "times" , "<times>", "Multiplyer");
    struct arg_dbl *percent_arg = arg_dbl0("p", "percent" , "<percent>", "Percent for brightness");
    struct arg_lit *help = arg_lit0("h","help", "print this help and exit");
    struct arg_end *end = arg_end(10);

    int nerrors;

    void *argtable[] = {input_file_arg, output_file_arg, filter_arg,percent_arg, times_arg, help, end};

    if (arg_nullcheck(argtable) != 0) printf("error: insufficient memory\n");

    times_arg->dval[0] = 1;
    percent_arg->dval[0]=0;

    nerrors = arg_parse(argc, argv, argtable);

    if (help->count > 0){
        printf("Usage: point");
        arg_print_syntax(stdout, argtable,"\n");
        arg_print_glossary(stdout, argtable," %-25s %s\n");
        arg_freetable(argtable, sizeof(argtable)/sizeof(argtable[0]));
        return 0;
    }

    if (nerrors==0){
        input_file = input_file_arg->filename[0];
        output_file = output_file_arg->filename[0];
        filter = filter_arg->sval[0];
        times = times_arg->dval[0];
        percent = percent_arg->dval[0];
    }
    else{
        arg_print_errors(stderr, end, "point");
        arg_print_glossary(stderr, argtable, " %-25s %s\n");
        arg_freetable(argtable, sizeof(argtable)/sizeof(argtable[0]));
        return 1;
    }

    read_jpeg_file(input_file);
    process_file();
    write_jpeg_file(output_file);
    arg_freetable(argtable, sizeof(argtable)/sizeof(argtable[0]));
    return 0;
}