#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 "png.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 slice x-pad y-pad input.png\n", argv[0]);

    exit(1);
}

int cammy_slice(int argc, char **argv) {
    uint8_t *buf;

    size_t width, height,
           x_pad, y_pad;

    int depth;

    if (argc < 3) {
        usage(argc, argv, "No X padding provided");
    } else if (argc < 4) {
        usage(argc, argv, "No Y padding provided");
    } else if (argc < 5) {
        usage(argc, argv, "No input PNG image provided");
    }

    x_pad = atoi(argv[2]);
    y_pad = atoi(argv[3]);

    if ((buf = cammy_png_load(argv[4], &width, &height, &depth)) == NULL) {
        goto error_read_png_file;
    }

    if (cammy_image_slice(buf, width, height, x_pad, y_pad, depth) < 0) {
        goto error_image_slice;
    }

    free(buf);

    return 0;

error_image_slice:
    free(buf);

error_read_png_file:
    return 1;
}