/*
 * Copyright (C) 2019 Weber Yann
 * 
 * This file is part of PyFCGI.
 * 
 * PyFCGI is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 * 
 * PyFCGI is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with PyFCGI.  If not, see <http://www.gnu.org/licenses/>.
 */

/**@defgroup monitor_proc Monitoring process
 * @brief Collect informations and run a monitoring server providing statistics
 * @ingroup main_proc
 */
/**@defgroup monitoring Monitoring server
 * @brief A small UDP server for monitoring
 *
 * PyFCGI have the ability to listen on a UDP socket, replying to simple
 * queries (or simple stats).
 * @ingroup monitor_proc
 */
/**@file monitor.h
 * @brief Monitoring server headers
 * @ingroup monitoring
 */
#ifndef _MONITOR__H___
#define _MONITOR__H___
#include "config.h"

#include <fcgiapp.h> /* fcgi library; put it first*/

#include <netdb.h>
#include <strings.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define UNIX_SOCKPATH_MAX 108
#define PYFCGI_MONITOR_STREAM_BACKLOG 5

typedef struct pyfcgi_monitor_s pyfcgi_monitor_t;
typedef union pyfcgi_monitor_addr_u pyfcgi_monitor_addr_t;

#include "conf.h"
#include "logger.h"
#include "stats.h"

union pyfcgi_monitor_addr_u
{
	struct sockaddr_in in;
	struct sockaddr_in6 in6;
	struct sockaddr_un un;
};

struct pyfcgi_monitor_s
{
	int sockserv;
	int sockcli;
	int sockargs[3];
	pyfcgi_monitor_addr_t addr;

};

/**@brief Attempt to init unitialized IPC component
 *
 * If an error occured it will be logged, and the init should be retry latter.
 *
 * @note the monitor process uses IPC_WREQS to count requests IPC_SEMST for
 * SHM syn and IPC_SHMST for SHM initalization
 */
int pyfcgi_monitor_IPC_init();

/**@brief Start the stats server monitoring server 
 * @return PID of the child process and -1 on error
 * @note When called the configuration has to be parsed */
pid_t pyfcgi_spawn_monitor();

/**@brief Main function for socket stats server
 *
 * Create the socket & bind to indicated address. If bind fails, sleep 30s, then
 * exit, in order to retry the whole process
 */
void pyfcgi_monitor_loop();

void pyfcgi_monitor_stream_loop();
void pyfcgi_monitor_dgram_loop();

/**@brief Check socket URL validity
 * @param sockurl the URL to check
 * @return -1 if error else 0
 * @note Logs error using dprintf(2, ...) because this function will
 * be called when checking configuration
 */
int pyfcgi_monitor_check_sock(const char* sockurl);

/**@brief Parse stored socket URL
 * @param sockurl the URL to parse
 * @param sockargs socket creation arguments
 * @param listen_addr the addr to bind to
 * @return 0 if no error else -1
 * @todo add support for xxx://[IPV6]:port
 */
int pyfcgi_monitor_parse_sock(const char* sockurl, int sockargs[3],
	pyfcgi_monitor_addr_t* listen_addr);

/**@brief Parse an addres:port string in a sockaddr_in
 * @param addr_str the hostname:port string
 * @param socktype socket family
 * @param listen_addr the addr pointer
 * @param domain if not NULL will be set to choosen domain
 * @return 0 if no erro else -1
 * @todo add support for xxx://[IPV6]:port
 */
int pyfcgi_monitor_parse_inet_addr(const char* addr_str, int socktype,
	pyfcgi_monitor_addr_t* listen_addr, int* domain);

/**@brief Monitor process sighandler */
void pyfcgi_monitor_sighandler(int signum);
/**@brief Monitor timeout sighandler */
void pyfcgi_monitor_timeout(int signum);

#endif