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

#include <platon/hash/md5.h>
#include <platon/str/strplus.h>
#include <platon/str/strctype.h>

/* Compilation against libplaton library:
   gcc -pedantic -L ../../platon/ -I ../../ -o md5scan md5scan.c -lplaton
*/

#define BUFSIZE			1000
#define MAX_PASSWORDS	 200

#define compute_and_check(__buf) \
			compute_md5(md5str, __buf); \
			check_passwords(md5str, __buf);

#define compute_md5(__md5, __buf) \
			MD5Init(&context); \
			MD5Update(&context, __buf, pw_len); \
			MD5Final(__md5, &context);

#define check_passwords(__md5, __plain) \
			for (j = 0; j < pw_cnt; j++) { \
				if (! memcmp(passwords[j], __md5, 16)) { \
					printf("Found: MD5('%s') = '", __plain); \
					for (k  = 0; k < 16; k++) { \
						printf("%02x", (unsigned char ) md5str[k]); \
					} \
					printf("', username: %s\n", usernames[j]); \
				} \
			}

int main(int argc, char **argv) /* {{{ */
{
	MD5_CTX context;
	char usernames[MAX_PASSWORDS][32];
	char passwords[MAX_PASSWORDS][16];
	char buf[BUFSIZE], buf2[BUFSIZE];
	char *ptr, md5str[16];

	FILE *f;
	int pw_len, buf_base;
	register int i, j, k, pw_cnt, line, feature;
	long int cnt;

	int feature_have_some_uppercase;

	if (argc <= 2) {
		printf("Usage: %s <password_file> <word-list-file_1> ... <word-list-file_N>\n", argv[0]);
		return 1;
	}

	if ((f = fopen(argv[1], "r")) == NULL) {
		printf("Cannot open password file '%s'.\n", argv[i]);
		return 2;
	}

	printf("[%02d/%02d] Loading passwords from '%s'...\n", 1, argc - 1, argv[1]);
	for (line = 0, pw_cnt = 0; fgets(buf, BUFSIZE - 1, f) != NULL; line++) {
		buf[BUFSIZE-1] = '\0';
		str_trim(buf);
		if (strlen(buf) <= 0) {
				printf("        Skipping empty line %d, continuing on next...\n", line + 1);
				continue;
		}
		for (ptr = buf; ptr - buf != 32; ptr += 2) {
			if (! isxdigit(ptr[0]) || !isxdigit(ptr[1])) {
				printf("Bad input on line %d: %s\n", line + 1, buf);
				return 4;
			}
			sscanf(ptr, "%2x", md5str + (ptr - buf) / 2);
		}
		if (i >= MAX_PASSWORDS) {
				printf("Sorry MAX_PASSWORDS reached, cannot continue. Recompilation required.\n");
				return 8;
		}
		str_trim(ptr);
		memcpy(passwords[pw_cnt], md5str, 16);
		memcpy(usernames[pw_cnt], ptr, 31);
		usernames[pw_cnt][31] = '\0';
		pw_cnt++;
	}
	printf("        Loading passwords finished, %d passwords loaded from %d lines.\n", pw_cnt, line);

	if (pw_cnt == 0) {
		printf("No passwords in password file.");
		return 16;
	}

	for (i = 2; i < argc; i++) {

		printf("[%02d/%02d] Processing word list '%s'...\n", i, argc - 1, argv[i]);

		if ((f = fopen(argv[i], "r")) == NULL) {
			printf("Cannot open word list file '%s'. File skipped.\n", argv[i]);
			continue;
		}

		for (cnt = 0; fgets(buf, BUFSIZE - 1, f) != NULL; ) {
			pw_len = strlen(buf);
			if (pw_len >= BUFSIZE) {
				printf("WARNING: too long password on the input (%d)\n", pw_len);
				continue;
			}
			str_trim(buf);
			pw_len = strlen(buf);
			if (! pw_len) {
				continue;
			}
			cnt++;

			/* Features:
			 * - plain
			 * - reverse string
			 * - lowercase
			 * - lowercase capitalize first
			 * - capitalize first
			 * - append 1 digit
			 * - append 1 digits
			 */

			for (feature_have_some_uppercase = 0, j = 0; j < pw_len; j++) {
				if (isupper(buf[j])) {
					feature_have_some_uppercase = 1;
					break;
				}
			}

			/* Feature: plain */
			compute_and_check(buf);

			if (islower(buf[0])) { /* Feature: ucfirst */
				k = buf[0];
				buf[0] = toupper(buf[0]);
				compute_and_check(buf);
				buf[0] = k;
			}

			if (feature_have_some_uppercase) { /* Feature: lowercase */
				strncpy(buf2, buf, BUFSIZE);
				strtolower(buf2);
				compute_and_check(buf2);
				if (islower(buf2[0])) { /* Feature: lowercase & ucfirst */
					buf2[0] = toupper(buf2[0]);
					compute_and_check(buf2);
				}
			}

			/* Feature: reverse */
			strncpy(buf2, buf, BUFSIZE);
			strrev(buf2);
			compute_and_check(buf2);

			if (islower(buf2[0])) { /* Feature: reverse & ucfirst */
				k = buf2[0];
				buf2[0] = toupper(buf2[0]);
				compute_and_check(buf2);
				buf2[0] = k;
			}

			if (feature_have_some_uppercase) { /* Feature: reverse & lowercase */
				strtolower(buf2);
				compute_and_check(buf2);
				if (islower(buf2[0])) { /* Feature: reverse & lowercase & ucfirst */
					buf2[0] = toupper(buf2[0]);
					compute_and_check(buf2);
				}
			}

		}

		printf("        %ld passwords checked.\n", cnt);
		fclose(f);
	}

	return 0;
} /* }}} */

/* Modeline for ViM {{{
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 * }}} */