#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <arpa/inet.h>

#include "configfile.h"
#include "event.h"
#include "helper.h"
#include "list.h"
#include "logging.h"
#include "network.h"
#include "plugins.h"
#include "rrdtool.h"

#define BUFSIZE 8192

struct fwd_addr {
	struct list_head list;
	struct sockaddr_in addr;
};

static int fwd_sock;
static LIST_HEAD(fwd_list);

// todo: never freed..
static char *tx_buf, *rx_buf;
static int tx_pos;

int net_submit(const char *hostname, const char *pluginname, const char *filename, int ds_id, const char *data)
{
	if (list_empty(&fwd_list))
		return 0;

	int size = snprintf(tx_buf + tx_pos, BUFSIZE - tx_pos, "%s:%s:%s:%d %s\n",
				hostname, pluginname, filename, ds_id, data);

	if (size < 0 || size >= BUFSIZE - tx_pos) {
		log_print(LOG_ERROR, "net_submit(): arguments too long");
		// TODO: retry with flushed buffer?
		return -1;
	}

	tx_pos += size;
	return 0;
}

void net_submit_flush(void)
{
	if (tx_pos == 0)
		return;

	struct fwd_addr *entry;
	list_for_each_entry(entry, &fwd_list, list)
		sendto(fwd_sock, tx_buf, tx_pos, 0, (struct sockaddr *)&entry->addr, sizeof(entry->addr));

	tx_pos = 0;
}

static int net_receive(int socket, void *privdata)
{
	int size = recv(socket, rx_buf, BUFSIZE, 0);
	int rx_pos = 0;

	char *delim;
	while ((delim = memchr(rx_buf + rx_pos, '\n', size - rx_pos))) {
		*delim = '\0';

		char *data[2];
		int ret = strsplit(rx_buf + rx_pos, " ", data, 2);
		if (ret != 2) {
			log_print(LOG_ERROR, "net_receive(): abort data-split");
			continue;
		}

		char *part[4];
		ret = strsplit(data[0], ":", part, 4);
		if (ret != 4) {
			log_print(LOG_ERROR, "net_receive(): abort header-split");
			continue;
		}

		rrd_submit(part[0], part[1], part[2], atoi(part[3]), data[1]);

		rx_pos = (delim - rx_buf) +1;
	}
	return 0;
}

static int parse_saddr(const char *addr, struct sockaddr_in *sa)
{
	char *addr_cpy = strdup(addr);
	if (addr_cpy == NULL) {
		log_print(LOG_WARN, "parse_saddr(): out of memory");
		return -1;
	}

	char *tmp;
	char *ip = strtok_r(addr_cpy, ":", &tmp);
	if (ip == NULL) {
		free(addr_cpy);
		return -1;
	}

	char *port = strtok_r(NULL, ":", &tmp);
	if (port == NULL) {
		free(addr_cpy);
		return -1;
	}

	sa->sin_family = AF_INET;
	sa->sin_port = htons(atoi(port));
	int ret = inet_aton(ip, &sa->sin_addr);

	free(addr_cpy);
	return (ret != 0) ? 0 : -1;
}

static int net_init_srv_cb(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 = socket(PF_INET, SOCK_DGRAM, 0);
	if (sock < 0) {
		log_print(LOG_ERROR, "net_init_srv_cb(): socket()");
		return -1;
	}

	if (bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
		log_print(LOG_ERROR, "net_init_srv_cb(): bind()");
		close(sock);
		return -1;
	}

	event_add_readfd(NULL, sock, net_receive, NULL);
	log_print(LOG_INFO, "listen on %s:%d",
		inet_ntoa(addr.sin_addr),
		ntohs(addr.sin_port));

	return 0;
}

static int net_init_cli_cb(const char *value, void *privdata)
{
	struct fwd_addr *entry = malloc(sizeof(struct fwd_addr));
	if (entry == NULL) {
		log_print(LOG_ERROR, "net_init_cli_cb(): out of memory");
		return -1;
	}

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

	list_add(&entry->list, &fwd_list);
	log_print(LOG_INFO, "forwarding to %s:%d",
		inet_ntoa(entry->addr.sin_addr),
		ntohs(entry->addr.sin_port));

	return 0;
}

int net_init(void)
{
	int srv_cnt = config_get_strings("global", "listen", net_init_srv_cb, NULL);
	if (srv_cnt > 0) {
		rx_buf = malloc(BUFSIZE);
		if (rx_buf == NULL) {
			log_print(LOG_ERROR, "net_init(): out of memory");
			return -1;
		}
	}

	int cli_cnt = config_get_strings("global", "forward", net_init_cli_cb, NULL);
	if (cli_cnt > 0) {
		tx_buf = malloc(BUFSIZE);
		if (tx_buf == NULL) {
			log_print(LOG_ERROR, "net_init(): out of memory");
			return -1;
		}

		fwd_sock = socket(PF_INET, SOCK_DGRAM, 0);
		if (fwd_sock < 0) {
			log_print(LOG_ERROR, "net_init(): socket()");
			return -1;
		}
	}

	return 0;
}