#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>

#include <cammy/image.h>
#include <cammy/photo.h>

#include "commands.h"

static cammy_image_color palette[4] = {
    {   0,   0,   0, 255 },
    {  85,  85,  85, 255 },
    { 171, 171, 171, 255 },
    { 255, 255, 255, 255 }
};

static void usage(int argc, char **argv, const char *message, ...) {
    if (message) {
        va_list args;

        va_start(args, message);
        vfprintf(stderr, message, args);
        va_end(args);
         fprintf(stderr, "\n");
    }

    fprintf(stderr, "usage: %1$s dither input.png output.png\n", argv[0]);

    exit(1);
}

static cammy_image *image_dither(cammy_image *image) {
    cammy_image *image_tile,
                *dest;

    cammy_image_region from = {
        0, 0, image->width, image->height
    };

    cammy_image_point to = {
        0, 0
    };

    if ((image_tile = cammy_image_new(CAMMY_IMAGE_TILE,
                                      CAMMY_IMAGE_2BPP,
                                      palette,
                                      image->width,
                                      image->height)) == NULL) {
        goto error_image_new_2bpp;
    }

    cammy_image_copy(image_tile, image, &to, &from);

    if ((dest = cammy_image_new(CAMMY_IMAGE_BITMAP,
                                CAMMY_IMAGE_24BPP_RGB,
                                palette,
                                image->width,
                                image->height)) == NULL) {
        goto error_image_new_dest;
    }

    cammy_image_copy(dest, image_tile, &to, &from);

    cammy_image_destroy(image_tile);

    return dest;

error_image_new_dest:
    cammy_image_destroy(image_tile);

error_image_new_2bpp:
    return NULL;
}

int cammy_dither(int argc, char **argv) {
    cammy_image *image_in,
                *image_out;

    if (argc < 3) {
        usage(argc, argv, "No PNG input file provided");
    } else if (argc < 4) {
        usage(argc, argv, "No PNG output filename provided");
    }

    if ((image_in = cammy_image_open(argv[2])) == NULL) {
        goto error_image_open;
    }

    if ((image_out = image_dither(image_in)) == NULL) {
        goto error_image_dither;
    }

    if (cammy_image_save(image_out, argv[3]) < 0) {
        goto error_image_save;
    }

    cammy_image_destroy(image_out);
    cammy_image_destroy(image_in);

    return 0;

error_image_save:
    cammy_image_destroy(image_out);

error_image_dither:
    cammy_image_destroy(image_in);

error_image_open:
    return 1;
}