/*
 * Copyright (c) 2001 George C A Reid <greid@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer
 *    in this position and unchanged.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <gd/gd.h>
#include <gd/gdfontt.h>
#include <gd/gdfonts.h>
#include <gd/gdfontmb.h>
#include <gd/gdfontl.h>
#include <gd/gdfontg.h>

#define CENTREY(a,b)	((((b)->sy)-((a)->sy))/2)

#ifdef CGI
char	x2c(char *);
void	unescape_url(char *);
char **	getcgivars(void);
#endif
int	merge_images(FILE *, FILE *, unsigned char *s);

int main(int argc, char *argv[])
{
#ifdef CGI
	char **cgivars = getcgivars();
	int i;
#endif
	char *sptr = NULL;
	FILE *a, *b;

#ifdef CGI
	for (i=0; cgivars[i]; i+=2) {
		if (!strncmp(cgivars[i], "a", 1))
			a = fopen(cgivars[i+1], "r");
		if (!strncmp(cgivars[i], "b", 1))
			b = fopen(cgivars[i+1], "r");
		if (!strncmp(cgivars[i], "s", 1))
			sptr = cgivars[i+1];
	}
	printf("Content-type: image/png\n\n");
#else
	fprintf(stderr, "mergeimg: Copyright (C) 2001 George C A Reid <greid@FreeBSD.org>\n");
	if (argc < 4) {
		fprintf(stderr, "\nusage: %s file1.png file2.png text\n",
			argv[0]);
		exit(1);
	}
	a = fopen(argv[1], "r");
	b = fopen(argv[2], "r");
	sptr = argv[3];
#endif
	merge_images(a, b, sptr);		
	return 0;
}

int merge_images(FILE *q, FILE *p, unsigned char *s)
{
	int black;
	gdImagePtr input, output;
	input = gdImageCreateFromPng(q);
	output = gdImageCreateFromPng(p);
	gdImageCopyMerge(output, input, 325, CENTREY(input, output), 0, 0,
		input->sx, input->sy, 20);
	black = gdImageColorClosest(output, 0, 0, 0);
	gdImageString(output, gdFontLarge,
	        325+(input->sx/2) - (strlen(s) * gdFontLarge->w / 2),
	        0, s, black);
	gdImagePng(output, stdout);
	gdImageDestroy(output);
	gdImageDestroy(input);
	return 0;
}

#ifdef CGI
char x2c(char *what)
{
	char digit;

	digit = (what[0] >= 'A' ?
		 ((what[0] & 0xdf) - 'A') + 10 : (what[0] - '0'));
	digit *= 16;
	digit += (what[1] >= 'A' ?
		((what[1] & 0xdf) - 'A') + 10 : (what[1] - '0'));
	return digit;
}

void unescape_url(char *url)
{
	register int i, j;

	for (i = 0, j = 0; url[j]; ++i, ++j) {
		if ((url[i] = url[j]) == '%') {
			url[i] = x2c(&url[j + 1]);
			j += 2;
		}
	}
	url[i] = '\0';
}

char **getcgivars()
{
	register int i;
	char *request_method;
	int content_length;
	char *cgiinput;
	char **cgivars;
	char **pairlist;
	int paircount;
	char *nvpair;
	char *eqpos;

	request_method = getenv("REQUEST_METHOD");
	if (!strcmp(request_method, "GET")
	    || !strcmp(request_method, "HEAD")) {
		cgiinput = strdup(getenv("QUERY_STRING"));
	} else if (!strcmp(request_method, "POST")) {
		if (strcasecmp(getenv("CONTENT_TYPE"),
			"application/x-www-form-urlencoded")) {
			printf("getcgivars(): Unsupported Content-Type.\n");
			exit(1);
		}
		if (!(content_length = atoi(getenv("CONTENT_LENGTH")))) {
			printf
			    ("getcgivars(): No Content-Length was sent with the POST request.\n");
			exit(1);
		}
		if (!(cgiinput = (char *) malloc(content_length + 1))) {
			printf
			    ("getcgivars(): Could not malloc for cgiinput.\n");
			exit(1);
		}
		if (!fread(cgiinput, content_length, 1, stdin)) {
			printf("Couldn't read CGI input from STDIN.\n");
			exit(1);
		}
		cgiinput[content_length] = '\0';
	} else {
		printf("getcgivars(): unsupported REQUEST_METHOD\n");
		exit(1);
	}

	for (i = 0; cgiinput[i]; i++)
		if (cgiinput[i] == '+')
			cgiinput[i] = ' ';

	pairlist = (char **) malloc(256 * sizeof(char **));
	paircount = 0;
	nvpair = strtok(cgiinput, "&");
	while (nvpair) {
		pairlist[paircount++] = strdup(nvpair);
		if (!(paircount % 256))
			pairlist =
			    (char **) realloc(pairlist,
					      (paircount +
					       256) * sizeof(char **));
		nvpair = strtok(NULL, "&");
	}
	pairlist[paircount] = 0;	/* terminate the list with NULL */

	cgivars = (char **) malloc((paircount * 2 + 1) * sizeof(char **));
	for (i = 0; i < paircount; i++) {
		if ((eqpos = strchr(pairlist[i], '='))) {
			*eqpos = '\0';
			unescape_url(cgivars[i * 2 + 1] =
				     strdup(eqpos + 1));
		} else {
			unescape_url(cgivars[i * 2 + 1] = strdup(""));
		}
		unescape_url(cgivars[i * 2] = strdup(pairlist[i]));
	}
	cgivars[paircount * 2] = 0;	/* terminate the list with NULL */

	free(cgiinput);
	for (i = 0; pairlist[i]; i++)
		free(pairlist[i]);
	free(pairlist);

	return cgivars;

}
#endif /* CGI */