#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.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"
#include "sockaddr.h"

#define PKTSIZE 1400

struct net_entry {
	struct list_head list;
	struct event_fd *event;
	struct sockaddr_in addr;
	int socket;
};

static LIST_HEAD(srv_list);
static LIST_HEAD(cli_list);

static char *fwd_buf;
static int fwd_buf_len;

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

	struct net_entry *entry;
	list_for_each_entry(entry, &cli_list, list)
		sendto(entry->socket, fwd_buf, fwd_buf_len, 0, (struct sockaddr *)&entry->addr, sizeof(entry->addr));

	fwd_buf_len = 0;
}

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

	int size = snprintf(fwd_buf + fwd_buf_len, PKTSIZE - fwd_buf_len, "%s:%s:%s:%d %s\n",
				hostname, pluginname, filename, ds_id, data);

	if (size < 0 || size >= PKTSIZE - fwd_buf_len) {
		/* the complete buffer is already full */
		if (fwd_buf_len == 0) {
			log_print(LOG_ERROR, "net_submit(): arguments too long");
			return -1;
		}

		/* flush & retry */
		net_submit_flush();
		return net_submit(hostname, pluginname, filename, ds_id, data);
	}

	fwd_buf_len += size;
	return 0;
}

static int net_receive(int socket, void *privdata)
{
	int recvsize;
	if (ioctl(socket, FIONREAD, &recvsize) == -1) {
		log_print(LOG_WARN, "net_receive(): ioctl(FIONREAD)");
		return 0;
	}

	char *buf = malloc(recvsize);
	if (buf == NULL) {
		log_print(LOG_WARN, "net_receive(): out of memory");
		return 0;
	}

	int size = recv(socket, buf, recvsize, 0);
	if (size <= 0) {
		log_print(LOG_WARN, "net_receive(): recv()");
		free(buf);
		return 0;
	}

	char *delim;
	int pos = 0;
	while ((delim = memchr(buf + pos, '\n', size - pos)) != NULL) {
		*delim = '\0';

		char *data[2];
		int ret = strsplit(buf + pos, " ", data, 2);
		pos = (delim - buf) +1;
		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]);
	}

	free(buf);
	return 0;
}

static struct net_entry * create_net_entry(const char *value)
{
	struct net_entry *entry = malloc(sizeof(struct net_entry));
	if (entry == NULL)
		return NULL;

	if (parse_sockaddr(value, &entry->addr) < 0) {
		free(entry);
		return NULL;
	}

	entry->socket = socket(PF_INET, SOCK_DGRAM, 0);
	if (entry->socket < 0) {
		free(entry);
		return NULL;
	}

	return entry;
}

static int net_init_srv_cb(const char *value, void *privdata)
{
	struct net_entry *entry = create_net_entry(value);
	if (entry == NULL) {
		log_print(LOG_ERROR, "net_init_srv_cb(): can not create net_entry");
		return -1;
	}

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

	entry->event = event_add_readfd(NULL, entry->socket, net_receive, NULL);
	list_add(&entry->list, &srv_list);
	log_print(LOG_INFO, "listen on %s", get_sockaddr_buf(&entry->addr));
	return 0;
}

static int net_init_cli_cb(const char *value, void *privdata)
{
	struct net_entry *entry = create_net_entry(value);
	if (entry == NULL) {
		log_print(LOG_ERROR, "net_init_cli_cb(): can not create net_entry");
		return -1;
	}

	list_add(&entry->list, &cli_list);
	log_print(LOG_INFO, "forwarding to %s", get_sockaddr_buf(&entry->addr));
	return 0;
}

int net_init(void)
{
	config_get_strings("global", "listen", net_init_srv_cb, NULL);
	config_get_strings("global", "forward", net_init_cli_cb, NULL);

	fwd_buf = malloc(PKTSIZE);
	if (fwd_buf == NULL) {
		log_print(LOG_ERROR, "net_submit(): out of memory");
		return -1;
	}

	return 0;
}

void net_close(void) {
	struct net_entry *entry, *tmp;
	list_for_each_entry_safe(entry, tmp, &cli_list, list) {
		list_del(&entry->list);
		close(entry->socket);
		free(entry);
	}

	list_for_each_entry_safe(entry, tmp, &srv_list, list) {
		list_del(&entry->list);
		event_remove_fd(entry->event);
		close(entry->socket);
		free(entry);
	}

	fwd_buf_len = 0;
	if (fwd_buf != NULL)
		free(fwd_buf);
}