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

#include "configfile.h"
#include "connection.h"
#include "event.h"
#include "list.h"
#include "logging.h"
#include "network.h"

static LIST_HEAD(connection_list);

static int server_handler(int fd, void *privdata)
{
	struct connection *con = (struct connection *)privdata;
	char buf[256];

	int len = read(fd, buf, sizeof(buf));
	if (len <= 0) {
		list_del(&con->list);
		destroy_connection(con);
		return -1;
	}

	write(con->src_fd, buf, len);
	return 0;
}

static int client_handler(int fd, void *privdata)
{
	struct connection *con = (struct connection *)privdata;
	char buf[256];

	int len = read(fd, buf, sizeof(buf));
	if (len <= 0) {
		list_del(&con->list);
		destroy_connection(con);
		return -1;
	}

	if (con->dst_fd != -1) {
		write(con->dst_fd, buf, len);
		return 0;
	}

	// check destination
	int sock = tcp_connect_socket(&con->dst_addr);
	if (sock < 0) {
		list_del(&con->list);
		destroy_connection(con);
		return -1;
	}

	event_add_readfd(sock, server_handler, con);
	log_print(LOG_INFO, "forwarding to %s", get_sockaddr_buf(&con->dst_addr));
	return 0;
}

static int listen_handler(int fd, void *privdata)
{
	struct connection *con = malloc(sizeof(struct connection));
	if (con == NULL) {
		log_print(LOG_WARN, "listen_handler(): out of memory");
		return 0;
	}

	int i = sizeof(con->src_addr);
	con->src_fd = accept(fd, (struct sockaddr *)&con->src_addr, &i);
	if (con->src_fd < 0) {
		free(con);
		return 0;
	}

	con->dst_fd = -1;
	con->login_time = con->idle_time = time(NULL);

	log_print(LOG_INFO, "accepted connection from %s", get_sockaddr_buf(&con->src_addr));

	list_add_tail(&con->list, &connection_list);
	event_add_readfd(con->src_fd, client_handler, con);
	return 0;
}

static int listen_init(const char *value, void *privdata)
{
	struct sockaddr_in addr;

	if (parse_saddr(value, &addr) == -1) {
		log_print(LOG_WARN, "invalid listen addr: '%s'", value);
		return -1;
	}

	int sock = tcp_listen_socket(&addr, 10);
	if (sock < 0)
		return -1;

	event_add_readfd(sock, listen_handler, NULL);
	log_print(LOG_INFO, "listen on %s", get_sockaddr_buf(&addr));
	return 0;
}

int main(int argc, char *argv[])
{
	if (config_parse("telnetproxy.conf") == -1)
		return -1;

	int cnt = config_get_strings("global", "listen", listen_init, NULL);
	if (cnt <= 0) {
		log_print(LOG_ERROR, "no listen sockets defined!");
		return -1;
	}

	event_loop();

	return 0;
}