/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Execute arbitrary authenticate commands
 *
 * \author Mark Spencer <markster@digium.com>
 * 
 * \ingroup applications
 */

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision$")

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

#include "asterisk/lock.h"
#include "asterisk/file.h"
#include "asterisk/logger.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/module.h"
#include "asterisk/app.h"
#include "asterisk/astdb.h"
#include "asterisk/utils.h"
#include "asterisk/options.h"

enum {
	OPT_ACCOUNT = (1 << 0),
	OPT_DATABASE = (1 << 1),
	OPT_MULTIPLE = (1 << 3),
	OPT_REMOVE = (1 << 4),
} auth_option_flags;

AST_APP_OPTIONS(auth_app_options, {
	AST_APP_OPTION('a', OPT_ACCOUNT),
	AST_APP_OPTION('d', OPT_DATABASE),
	AST_APP_OPTION('m', OPT_MULTIPLE),
	AST_APP_OPTION('r', OPT_REMOVE),
});


static char *app = "Authenticate";

static char *synopsis = "Authenticate a user";

static char *descrip =
"  Authenticate(password[|options[|maxdigits]]): This application asks the caller\n"
"to enter a given password in order to continue dialplan execution. If the password\n"
"begins with the '/' character, it is interpreted as a file which contains a list of\n"
"valid passwords, listed 1 password per line in the file.\n"
"  When using a database key, the value associated with the key can be anything.\n"
"Users have three attempts to authenticate before the channel is hung up.\n"
"  Options:\n"
"     a - Set the channels' account code to the password that is entered\n"
"     d - Interpret the given path as database key, not a literal file\n"
"     m - Interpret the given path as a file which contains a list of account\n"
"         codes and password hashes delimited with ':', listed one per line in\n"
"         the file. When one of the passwords is matched, the channel will have\n"
"         its account code set to the corresponding account code in the file.\n"
"     r - Remove the database key upon successful entry (valid with 'd' only)\n"
"     maxdigits  - maximum acceptable number of digits. Stops reading after\n"
"         maxdigits have been entered (without requiring the user to\n"
"         press the '#' key).\n"
"         Defaults to 0 - no limit - wait for the user press the '#' key.\n"
;

static int auth_exec(struct ast_channel *chan, void *data)
{
	int res=0;
	int retries;
	struct ast_module_user *u;
	char passwd[256];
	char *prompt;
	int maxdigits;
	char *argcopy =NULL;
	struct ast_flags flags = {0};

	AST_DECLARE_APP_ARGS(arglist,
		AST_APP_ARG(password);
		AST_APP_ARG(options);
		AST_APP_ARG(maxdigits);
	);
	
	if (ast_strlen_zero(data)) {
		ast_log(LOG_WARNING, "Authenticate requires an argument(password)\n");
		return -1;
	}
	
	u = ast_module_user_add(chan);

	if (chan->_state != AST_STATE_UP) {
		res = ast_answer(chan);
		if (res) {
			ast_module_user_remove(u);
			return -1;
		}
	}
	
	argcopy = ast_strdupa(data);

	AST_STANDARD_APP_ARGS(arglist,argcopy);
	
	if (!ast_strlen_zero(arglist.options)) {
		ast_app_parse_options(auth_app_options, &flags, NULL, arglist.options);
	}

	if (!ast_strlen_zero(arglist.maxdigits)) {
		maxdigits = atoi(arglist.maxdigits);
		if ((maxdigits<1) || (maxdigits>sizeof(passwd)-2))
			maxdigits = sizeof(passwd) - 2;
	} else {
		maxdigits = sizeof(passwd) - 2;
	}

	/* Start asking for password */
	prompt = "agent-pass";
	for (retries = 0; retries < 3; retries++) {
		res = ast_app_getdata(chan, prompt, passwd, maxdigits, 0);
		if (res < 0)
			break;
		res = 0;
		if (arglist.password[0] == '/') {
			if (ast_test_flag(&flags,OPT_DATABASE)) {
				char tmp[256];
				/* Compare against a database key */
				if (!ast_db_get(arglist.password + 1, passwd, tmp, sizeof(tmp))) {
					/* It's a good password */
					if (ast_test_flag(&flags,OPT_REMOVE)) {
						ast_db_del(arglist.password + 1, passwd);
					}
					break;
				}
			} else {
				/* Compare against a file */
				FILE *f;
				f = fopen(arglist.password, "r");
				if (f) {
					char buf[256] = "";
					char md5passwd[33] = "";
					char *md5secret = NULL;

					while (!feof(f)) {
						fgets(buf, sizeof(buf), f);
						if (!feof(f) && !ast_strlen_zero(buf)) {
							buf[strlen(buf) - 1] = '\0';
							if (ast_test_flag(&flags,OPT_MULTIPLE)) {
								md5secret = strchr(buf, ':');
								if (md5secret == NULL)
									continue;
								*md5secret = '\0';
								md5secret++;
								ast_md5_hash(md5passwd, passwd);
								if (!strcmp(md5passwd, md5secret)) {
									if (ast_test_flag(&flags,OPT_ACCOUNT))
										ast_cdr_setaccount(chan, buf);
									break;
								}
							} else {
								if (!strcmp(passwd, buf)) {
									if (ast_test_flag(&flags,OPT_ACCOUNT))
										ast_cdr_setaccount(chan, buf);
									break;
								}
							}
						}
					}
					fclose(f);
					if (!ast_strlen_zero(buf)) {
						if (ast_test_flag(&flags,OPT_MULTIPLE)) {
							if (md5secret && !strcmp(md5passwd, md5secret))
								break;
						} else {
							if (!strcmp(passwd, buf))
								break;
						}
					}
				} else 
					ast_log(LOG_WARNING, "Unable to open file '%s' for authentication: %s\n", arglist.password, strerror(errno));
			}
		} else {
			/* Compare against a fixed password */
			if (!strcmp(passwd, arglist.password)) 
				break;
		}
		prompt="auth-incorrect";
	}
	if ((retries < 3) && !res) {
		if (ast_test_flag(&flags,OPT_ACCOUNT) && !ast_test_flag(&flags,OPT_MULTIPLE)) 
			ast_cdr_setaccount(chan, passwd);
		res = ast_streamfile(chan, "auth-thankyou", chan->language);
		if (!res)
			res = ast_waitstream(chan, "");
	} else {
		if (!ast_streamfile(chan, "vm-goodbye", chan->language))
			res = ast_waitstream(chan, "");
		res = -1;
	}
	ast_module_user_remove(u);
	return res;
}

static int unload_module(void)
{
	int res;

	ast_module_user_hangup_all();

	res = ast_unregister_application(app);

	
	return res;
}

static int load_module(void)
{
	return ast_register_application(app, auth_exec, synopsis, descrip);
}

AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Authentication Application");