/*
  Copyright (c) 2012-2014, Matthias Schiffer <mschiffer@universe-factory.net>
  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.
    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.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT HOLDER OR CONTRIBUTORS 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.
*/

/**
   \file

   Handling of command line options


   \def OPTION
   Defines a command line option without argument

   \def OPTION_ARG
   Defines a command line option with an argument

   \def OR
   Separates multiple alternative options with the same meaning

   \def SEPARATOR
   Separates groups of related options
*/


#include "fastd.h"
#include "config.h"
#include "peer.h"
#include <fastd_version.h>

#include <arpa/inet.h>


/** Prints the usage message for a single command line option */
static void print_usage(const char *options, const char *message) {
	/* 28 spaces */
	static const char spaces[] = {[0 ... 27] = ' ', [28] = 0};

	int len = strlen(options);

	printf("%s", options);

	if (len < 28)
		printf("%s", spaces+len);
	else
		printf("\n%s", spaces);

	puts(message);
}


/** Prints the usage message and exits */
static void usage(void) {
	puts("fastd (Fast and Secure Tunnelling Daemon) " FASTD_VERSION " usage:\n");

#define OR ", "
#define SEPARATOR puts("")
#define OPTION(func, options, message) print_usage("  " options, message)
#define OPTION_ARG(func, options, arg, message) print_usage("  " options " " arg, message)
#include "options.def.h"
#undef OR
#undef SEPARATOR
#undef OPTION
#undef OPTION_ARG

	exit(0);
}



/** Prints fastd's version and exits */
static void version(void) {
	puts("fastd " FASTD_VERSION);
	exit(0);
}

/** Handles the --daemon option */
static void option_daemon(void) {
	conf.daemon = true;
}

/** Handles the --pid-file option */
static void option_pid_file(const char *arg) {
	free(conf.pid_file);
	conf.pid_file = strdup(arg);
}


/** Handles the --config option */
static void option_config(const char *arg) {
	if (!strcmp(arg, "-"))
		arg = NULL;

	if (!fastd_config_read(arg, conf.peer_group, NULL, 0))
		exit(1);
}

/** Handles the --config-peer option */
static void option_config_peer(const char *arg) {
	fastd_peer_config_t *peer = fastd_peer_config_new(conf.peer_group);

	if(!fastd_config_read(arg, conf.peer_group, peer, 0))
		exit(1);

	peer->next = conf.peers;
	conf.peers = peer;

}

/** Handles the --config-peer-dir option */
static void option_config_peer_dir(const char *arg) {
	fastd_config_add_peer_dir(conf.peer_group, arg);
}


#ifdef WITH_CMDLINE_USER

/** Handles the --config-user option */
static void option_user(const char *arg) {
	free(conf.user);
	conf.user = strdup(arg);
}

/** Handles the --config-group option */
static void option_group(const char *arg) {
	free(conf.group);
	conf.group = strdup(arg);
}

#endif

#ifdef WITH_CMDLINE_LOGGING

/** Parses a log level argument */
static int parse_log_level(const char *arg) {
	if (!strcmp(arg, "fatal"))
		return LL_FATAL;
	else if (!strcmp(arg, "error"))
		return LL_ERROR;
	else if (!strcmp(arg, "warn"))
		return LL_WARN;
	else if (!strcmp(arg, "info"))
		return LL_INFO;
	else if (!strcmp(arg, "verbose"))
		return LL_VERBOSE;
	else if (!strcmp(arg, "debug"))
		return LL_DEBUG;
	else if (!strcmp(arg, "debug2"))
		return LL_DEBUG2;
	else
		exit_error("invalid log level `%s'", arg);
}

/** Handles the --log-level option */
static void option_log_level(const char *arg) {
	conf.log_stderr_level = parse_log_level(arg);
}

/** Handles the --syslog-level option */
static void option_syslog_level(const char *arg) {
	conf.log_syslog_level = parse_log_level(arg);
}

/** Handles the --syslog-ident option */
static void option_syslog_ident(const char *arg) {
	free(conf.log_syslog_ident);
	conf.log_syslog_ident = strdup(arg);
}

/** Handles the --hide-ip-addresses option */
static void option_hide_ip_addresses(void) {
	conf.hide_ip_addresses = true;
}

/** Handles the --hide-mac-addresses option */
static void option_hide_mac_addresses(void) {
	conf.hide_mac_addresses = true;
}

#endif

#ifdef WITH_CMDLINE_OPERATION

/** Handles the --mode option */
static void option_mode(const char *arg) {
	if (!strcmp(arg, "tap"))
		conf.mode = MODE_TAP;
	else if (!strcmp(arg, "tun"))
		conf.mode = MODE_TUN;
	else
		exit_error("invalid mode `%s'", arg);
}

/** Handles the --interface option */
static void option_interface(const char *arg) {
	free(conf.ifname);
	conf.ifname = strdup(arg);
}

/** Handles the --mtu option */
static void option_mtu(const char *arg) {
	char *endptr;
	long mtu = strtol(arg, &endptr, 10);

	if (*endptr || mtu < 576 || mtu > 65535)
		exit_error("invalid mtu `%s'", arg);

	conf.mtu = mtu;
}

/** Handles the --bind option */
static void option_bind(const char *arg) {
	long l;
	char *charptr;
	char *endptr;
	char *addrstr;
	char *ifname = NULL;

	if (arg[0] == '[') {
		charptr = strrchr(arg, ']');
		if (!charptr || (charptr[1] != ':' && charptr[1] != '\0'))
			exit_error("invalid bind address `%s'", arg);

		addrstr = strndup(arg+1, charptr-arg-1);

		if (charptr[1] == ':')
			charptr++;
		else
			charptr = NULL;
	}
	else {
		charptr = strrchr(arg, ':');
		if (charptr) {
			addrstr = strndup(arg, charptr-arg);
		}
		else {
			addrstr = strdup(arg);
		}
	}

	if (charptr) {
		l = strtol(charptr+1, &endptr, 10);
		if (*endptr || l < 1 || l > 65535)
			exit_error("invalid bind port `%s'", charptr+1);
	}
	else {
		l = 0;
	}

	fastd_peer_address_t addr = {};

	if (arg[0] == '[') {
		addr.in6.sin6_family = AF_INET6;
		addr.in6.sin6_port = htons(l);

		ifname = strchr(addrstr, '%');
		if (ifname) {
			*ifname = '\0';
			ifname++;
		}

		if (inet_pton(AF_INET6, addrstr, &addr.in6.sin6_addr) != 1)
			exit_error("invalid bind address `[%s]'", addrstr);
	}
	else if (strcmp(addrstr, "any") == 0) {
		addr.in.sin_family = AF_UNSPEC;
		addr.in.sin_port = htons(l);
	}
	else {
		addr.in.sin_family = AF_INET;
		addr.in.sin_port = htons(l);

		if (inet_pton(AF_INET, addrstr, &addr.in.sin_addr) != 1)
			exit_error("invalid bind address `%s'", addrstr);
	}

	free(addrstr);

	fastd_config_bind_address(&addr, ifname, false, false);
}

/** Handles the --protocol option */
static void option_protocol(const char *arg) {
	fastd_config_protocol(arg);
}

/** Handles the --method option */
static void option_method(const char *arg) {
	fastd_config_method(arg);
}

/** Handles the --forward option */
static void option_forward(void) {
	conf.forward = true;
}

#endif

#ifdef WITH_CMDLINE_COMMANDS

/** Handles the --on-pre-up option */
static void option_on_pre_up(const char *arg) {
	fastd_shell_command_set(&conf.on_pre_up, arg, true);
}

/** Handles the --on-up option */
static void option_on_up(const char *arg) {
	fastd_shell_command_set(&conf.on_up, arg, true);
}

/** Handles the --on-down option */
static void option_on_down(const char *arg) {
	fastd_shell_command_set(&conf.on_down, arg, true);
}

/** Handles the --on-post-down option */
static void option_on_post_down(const char *arg) {
	fastd_shell_command_set(&conf.on_post_down, arg, true);
}

/** Handles the --on-connect option */
static void option_on_connect(const char *arg) {
	fastd_shell_command_set(&conf.on_connect, arg, false);
}

/** Handles the --on-establish option */
static void option_on_establish(const char *arg) {
	fastd_shell_command_set(&conf.on_establish, arg, false);
}

/** Handles the --on-disestablish option */
static void option_on_disestablish(const char *arg) {
	fastd_shell_command_set(&conf.on_disestablish, arg, false);
}

#ifdef WITH_VERIFY

/** Handles the --on-verify option */
static void option_on_verify(const char *arg) {
	fastd_shell_command_set(&conf.on_verify, arg, false);
}

#endif

#endif

/** Handles the --verify-config option */
static void option_verify_config(void) {
	conf.verify_config = true;
}

/** Handles the --generate-key option */
static void option_generate_key(void) {
	conf.generate_key = true;
	conf.show_key = false;
}

/** Handles the --show-key option */
static void option_show_key(void) {
	conf.generate_key = false;
	conf.show_key = true;
}

/** Handles the --machine-readable option */
static void option_machine_readable(void) {
	conf.machine_readable = true;
}


/** Matches a command line options agains a NULL-terminated list of arguments */
static bool config_match(const char *opt, ...) {
	va_list ap;
	bool match = false;
	const char *str;

	va_start(ap, opt);

	while((str = va_arg(ap, const char*)) != NULL) {
		if (strcmp(opt, str) == 0) {
			match = true;
			break;
		}
	}

	va_end(ap);

	return match;
}

/** Parses and handles the supplied command line options */
void fastd_config_handle_options(int argc, char *const argv[]) {
	int i = 1;

	while (i < argc) {
#define OR ,
#define SEPARATOR do {} while (false)
#define OPTION(func, options, message)					\
		({							\
			if(config_match(argv[i], options, NULL)) {	\
				i++;					\
				func();			\
				continue;				\
			}						\
		})
#define OPTION_ARG(func, options, arg, message)				\
		({							\
			if(config_match(argv[i], options, NULL)) {	\
				i+=2;					\
				if (i > argc)				\
					exit_error("command line error: option `%s' needs an argument; see --help for usage", argv[i-2]); \
				func(argv[i-1]);		\
				continue;				\
			}						\
		})
#include "options.def.h"
#undef OR
#undef SEPARATOR
#undef OPTION
#undef OPTION_ARG

		exit_error("command line error: unknown option `%s'; see --help for usage", argv[i]);
	}
}