#include <arpa/inet.h>
#include <errno.h>
#include <netdb.h>
#include <netinet/in.h>
#include <signal.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/un.h>
#include <syslog.h>
#include <unistd.h>
#include "config.h"
#include "macros.h"

#define UNIX_PATH_MAX 108

pid_t fork_proc() {
	/* Fork off the parent. */
	pid_t pid = fork();

	/* The process id is non zero, so it must be the parent process. */
	if (pid) {
		/* Exit with EXIT_FAILURE if the parent's pid is
		 * negative, otherwise exit with EXIT_SUCCESS.
		 */
		exit((pid < 0) ? EXIT_FAILURE : EXIT_SUCCESS);
	}
	return pid;
}

void child_handler(int sig_num) {
	signal(SIGCHLD, child_handler);
}

void hangup_handler(int sig_num) {
	signal(SIGHUP, hangup_handler);
}

void init_daemon(int change_dir, char *path) {
	/* Fork the parent. */
	pid_t pid = fork_proc();

	/* Exit if the child process isn't the session leader. */
	if (setsid() < 0) {
		exit(EXIT_FAILURE);
	}

	/* Catch, ignore, and/or handle signals. */
	signal(SIGCHLD, child_handler);
	signal(SIGHUP, hangup_handler);

	/* Fork again. */
	pid = fork_proc();

	/* Set new file permissions. */
	umask(0);

	/* If change_dir is true, change the working directory to path, or
	 * the root directory if path isn't set.
	 */
	if (change_dir) {
		chdir((!path) ? "/" : path);
	}

	/* Close any open file descriptors. */
	for (int i = sysconf(_SC_OPEN_MAX); i >= 0; close(i--));

	/* Open the logfile. */
	openlog("pullreqd", LOG_PID, LOG_DAEMON);
}

int init_config(char *config_file, config **cfg) {
	log(LOG_INFO, "Reading config file %s.", config_file);

	*cfg = parse_config(config_file);

	/* Did the config file parser succeed? */
	if (*cfg != NULL) {
		log(LOG_INFO, "Successfully read %s.", config_file);
	} else {
		log(LOG_ERR, "Error reading %s.", config_file);
	}

	return (*cfg != NULL);
}

int init_socket(config *cfg) {
	union sock_addr {
		struct sockaddr sa;
		struct sockaddr_un sa_un;
		struct sockaddr_in sa_in;
	} sock_addr;
	/* Size of the socket address we're using. */
	size_t sockaddr_size = 0;
	/* Set socket type to unix socket, if socket-type was set to unix, otherwise set it to network socket. */
	const int sock_type = (strcasecmp(cfg->sock_type, "unix") == 0) ? AF_UNIX : AF_INET;

	if (sock_type == AF_UNIX) {
		size_t path_length = strlen(cfg->sock);
		/* Is the path too long? */
		if (path_length >= UNIX_PATH_MAX) {
			log(LOG_ERR, "The socket path is too long, and exceeded %i characters.", UNIX_PATH_MAX);
			return -1;
		}

		sockaddr_size = sizeof(sock_addr.sa_un);
		sock_addr.sa_un.sun_family = sock_type;
		memcpy(sock_addr.sa_un.sun_path, cfg->sock, path_length+1);
	} else {
		struct addrinfo hints, *ainfo_root, *ainfo;

		memset(&hints, 0, sizeof(hints));

		hints.ai_family = AF_UNSPEC;
		hints.ai_socktype = SOCK_SEQPACKET;
		/*hints.ai_protocol = IPPROTO_SCTP;*/
		hints.ai_flags = AI_PASSIVE;

		const int gai_ret = getaddrinfo(cfg->sock, cfg->port, &hints, &ainfo_root);
		/* Did getaddrinfo fail? */
		if (gai_ret) {
			log_reason(LOG_ERR, "getaddrinfo() failed for hostname %s.", cfg->sock, gai_strerror(gai_ret));
			return -1;
		}

		/* TODO: Create sockets for all resolved addresses, instead of just the first. */
		sockaddr_size = ainfo_root->ai_addrlen;
		sock_addr.sa = *ainfo_root->ai_addr;

		freeaddrinfo(ainfo_root);
	}

	/* Create a new listen socket. */
	const int fd = socket(sock_addr.sa.sa_family, SOCK_SEQPACKET, 0);

	/* Did we fail to create the listen socket? */
	if (fd < 0) {
		log_reason(LOG_ERR, "Failed to create listen socket.", strerror(errno));
		return -1;
	}


	/* Did we fail to bind the listen socket? */
	if (bind(fd, &sock_addr.sa, sockaddr_size) < 0) {
		log_reason(LOG_ERR, "Failed to bind listen socket.", strerror(errno));
		return -1;
	}

	int one = 1;

	/* Did we fail to enable SO_REUSEADDR? */
	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) < 0) {
		log_reason(LOG_ERR, "Failed to enable SO_REUSEADDR.", strerror(errno));
		return -1;
	}

	/* Did we fail to listen to the socket? */
	if (listen(fd, 20) < 0) {
		log_reason(LOG_ERR, "Failed to listen to socket.", strerror(errno));
		return -1;
	}

	log(LOG_INFO, "Successfully created socket descriptor %i for address %s.", fd, cfg->sock);
	return fd;
}

int main_loop(config *cfg, int listen_socket) {
	int done = 0;

	for (; !done;) {
		break;
	}

	return 0;
}

void cleanup(config *cfg, int listen_socket) {
	if (listen_socket > 0) {
		close(listen_socket);
		/* Is this a unix domain socket? */
		if (strcasecmp(cfg->sock_type, "unix") == 0) {
			unlink(cfg->sock);
		}
	}

	if (cfg) {
		cleanup_config(cfg);
	}
}

int main(int argc, char **argv) {
	config *cfg;
	char *config_file = "test.conf";
	int config_read = 0;
	int listen_socket = -1;
	int exit_status = EXIT_FAILURE;

	init_daemon(1, "/");
	log(LOG_NOTICE, "pullreqd started.");

	/* Read the config file. */
	config_read = init_config(config_file, &cfg);

	/* Did we successfully read the config file? */
	if (config_read) {
		/* Create the Listen socket. */
		listen_socket = init_socket(cfg);
	}

	/* Did we successfully read the config file, and create the listen socket? */
	if (config_read && listen_socket >= 0) {
		exit_status = main_loop(cfg, listen_socket);
	}

	cleanup(cfg, listen_socket);

	log(LOG_NOTICE, "pullreqd stopped.");

	closelog();

	return exit_status;
}