#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;

/* pilnuje zakresu 0-255 */
int clamp(double value) {
    if (value < 0) {
        return 0;
    }

    if (value > 255) {
        return 255;
    }

    return (int)value;
}

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;

    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] = clamp(ptr[0] + (percent / 100.0) * ptr[0]);
            ptr[1] = clamp(ptr[1] + (percent / 100.0) * ptr[1]);
            ptr[2] = clamp(ptr[2] + (percent / 100.0) * ptr[2]);
        }
    }
}

void contrast() {
    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] = clamp(times * (ptr[0] - 127) + 127);
            ptr[1] = clamp(times * (ptr[1] - 127) + 127);
            ptr[2] = clamp(times * (ptr[2] - 127) + 127);
        }
    }
}

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

            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();
    }
    else {
        printf("Nieznany filtr: %s\n", filter);
    }
}

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

void read_jpeg_file(const char *filename)
{
    struct jpeg_decompress_struct cinfo;
    struct jpeg_error_mgr jerr;
    int y;

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

    if (!infile)
    {
        abort_("Error opening input jpeg file %s!\n", filename);
    }

    cinfo.err = jpeg_std_error(&jerr);
    jpeg_create_decompress(&cinfo);

    jpeg_stdio_src(&cinfo, infile);

    jpeg_read_header(&cinfo, TRUE);

    jpeg_start_decompress(&cinfo);

    width = cinfo.output_width;
    height = cinfo.output_height;
    num_components = cinfo.out_color_components;
    color_space = cinfo.out_color_space;

    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);
    }

    y = 0;
    JSAMPARRAY tmp = row_pointers;

    while (cinfo.output_scanline < cinfo.image_height)
    {
        y = jpeg_read_scanlines(&cinfo, tmp, 1);
        tmp += y;
    }

    jpeg_finish_decompress(&cinfo);
    jpeg_destroy_decompress(&cinfo);

    fclose(infile);
}

void write_jpeg_file(const char *filename)
{
    struct jpeg_compress_struct cinfo;
    struct jpeg_error_mgr jerr;
    int y;
    JSAMPARRAY tmp;

    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);

    cinfo.image_width = width;
    cinfo.image_height = height;
    cinfo.input_components = num_components;
    cinfo.in_color_space = color_space;

    jpeg_set_defaults(&cinfo);
    jpeg_set_quality(&cinfo, quality, TRUE);

    jpeg_start_compress(&cinfo, TRUE);

    tmp = row_pointers;

    while (cinfo.next_scanline < cinfo.image_height)
    {
        y = jpeg_write_scanlines(&cinfo, tmp, 1);
        tmp += y;
    }

    jpeg_finish_compress(&cinfo);
    jpeg_destroy_compress(&cinfo);

    fclose(outfile);

    for (y = 0; y < height; y++) {
        free(row_pointers[y]);
    }

    free(row_pointers);
}

int main(int argc, char **argv)
{
    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>", "Multiplier for contrast");
    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");
        return 1;
    }

    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;
}