#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 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 merge input.png output-r.png output-g.png output-b.png\n", argv[0]);

    exit(1);
}

int cammy_merge(int argc, char **argv) {
    cammy_image *image_in_r,
                *image_in_g,
                *image_in_b,
                *image_out;

    if (argc < 3) {
        usage(argc, argv, "No red input file provided");
    } else if (argc < 4) {
        usage(argc, argv, "No green input file provided");
    } else if (argc < 5) {
        usage(argc, argv, "No blue input file provided");
    } else if (argc < 6) {
        usage(argc, argv, "No output PNG filename provided");
    }

    if ((image_in_r = cammy_image_open(argv[2])) == NULL) {
        goto error_image_open_r;
    }

    if ((image_in_g = cammy_image_open(argv[3])) == NULL) {
        goto error_image_open_g;
    }

    if ((image_in_b = cammy_image_open(argv[4])) == NULL) {
        goto error_image_open_b;
    }

    if ((image_out = cammy_image_merge(image_in_r,
                                       image_in_g,
                                       image_in_b)) == NULL) {
        goto error_image_merge;
    }

    if (cammy_image_save(image_out, argv[5]) < 0) {
        goto error_image_save;
    }

    cammy_image_destroy(image_out);
    cammy_image_destroy(image_in_b);
    cammy_image_destroy(image_in_g);
    cammy_image_destroy(image_in_r);

    return 0;

error_image_save:
    cammy_image_destroy(image_out);

error_image_merge:
    cammy_image_destroy(image_in_b);

error_image_open_b:
    cammy_image_destroy(image_in_g);

error_image_open_g:
    cammy_image_destroy(image_in_r);

error_image_open_r:
    return 1;
}