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

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

/* Makro zapobiegające przekroczeniu zakresu 0-255 przez wartości kolorów */
#define CLAMP(x) ((x) < 0 ? 0 : ((x) > 255 ? 255 : (x)))

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_filter() {
    int x, y, c;
    for (y = 0; y < height; y++) {
        JSAMPROW row = row_pointers[y];
        for (x = 0; x < width; x++) {
            JSAMPROW ptr = &(row[x * num_components]);
            for (c = 0; c < num_components; c++) {
                ptr[c] = CLAMP(255 - ptr[c]);
            }
        }
    }
}

void brightness_filter() {
    int x, y, c;
    double factor = 1.0 + (percent / 100.0);
    
    for (y = 0; y < height; y++) {
        JSAMPROW row = row_pointers[y];
        for (x = 0; x < width; x++) {
            JSAMPROW ptr = &(row[x * num_components]);
            for (c = 0; c < num_components; c++) {
                int val = (int)(ptr[c] * factor);
                ptr[c] = CLAMP(val);
            }
        }
    }
}

void contrast_filter() {
    int x, y, c;
    for (y = 0; y < height; y++) {
        JSAMPROW row = row_pointers[y];
        for (x = 0; x < width; x++) {
            JSAMPROW ptr = &(row[x * num_components]);
            for (c = 0; c < num_components; c++) {
                int val = (int)(times * (ptr[c] - 127) + 127);
                ptr[c] = CLAMP(val);
            }
        }
    }
}

void sepia_filter() {
    int x, y;
    
    /* Filtr sepia ma sens głównie dla obrazów RGB */
    if (color_space != JCS_RGB || num_components != 3) {
        printf("Warning: Sepia filter requires an RGB image.\n");
        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 tr = (int)(0.393 * r + 0.769 * g + 0.189 * b);
            int tg = (int)(0.349 * r + 0.686 * g + 0.168 * b);
            int tb = (int)(0.272 * r + 0.534 * g + 0.131 * b);

            ptr[0] = CLAMP(tr);
            ptr[1] = CLAMP(tg);
            ptr[2] = CLAMP(tb);
        }
    }
}

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

/**
 * read_jpeg_file Reads from a jpeg file on disk specified by filename and saves into the 
 * raw_image buffer in an uncompressed format.
 */
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);
}

/**
 * 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.
 */
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);
    
    /* 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 (negate, brightness, contrast, sepia)");
    struct arg_dbl  *times_arg       = arg_dbl0("t", "times", "<times>", "Multiplier for contrast");
    struct arg_dbl  *percent_arg     = arg_dbl0("p", "percent", "<percent>", "Percentage for brightness");
    struct arg_lit  *help            = arg_lit0("h", "help", "print this help and exit");
    struct arg_end  *end             = arg_end(10); 
    
    int nerrors;
    
    // Zmienna 'end' musi znajdować się na końcu
    void *argtable[] = {input_file_arg, output_file_arg, filter_arg, times_arg, percent_arg, help, end};
    
    if (arg_nullcheck(argtable) != 0) {
        printf("error: insufficient memory\n");
        return 1;
    }
    
    // Ustawienie wartości domyślnych dla parametrów opcjonalnych
    times_arg->dval[0] = 1.0;
    percent_arg->dval[0] = 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]; // Odczytanie nowego parametru
    }
    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;
}