#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <err.h>
#include <errno.h>
#include <netinet/in.h>
#include <event.h>

#include "libglouglou.h"

/* Server - private */
struct gg_user *user_add(struct gg_server *, struct sockaddr_in *);
struct gg_user *user_find(struct gg_server *, struct sockaddr_in *);
void cb_srv_receive(evutil_socket_t, short, void *);
void cb_cli_receive(evutil_socket_t, short, void *);

/*
 * Server
 */

/*
 * start a server
 */
struct gg_server *
gg_server_start(struct event_base *ev_base, char *ip, int port,
                int (*handle_conn)(struct gg_server *, struct gg_user *),
                int (*handle_packet)(struct gg_server *, struct gg_user *, struct gg_packet *))
{
  struct gg_server *srv;
  struct sockaddr_in sock_addr;
  struct event *ev;
  int s;
  int sock_on = 1;

  srv = xcalloc(1, sizeof(struct gg_server));
  srv->ip = ip;
  srv->port = port;
  srv->handle_conn = handle_conn;
  srv->handle_packet = handle_packet;
  s = socket(AF_INET, SOCK_DGRAM, 0);
  if (s < 0)
    goto err;
  srv->sock = s;
	setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
		&sock_on, sizeof(sock_on));
	fd_nonblock(s);

	bzero(&sock_addr, sizeof(sock_addr));
	sock_addr.sin_family = AF_INET;
	sock_addr.sin_addr.s_addr = inet_addr(ip);
	sock_addr.sin_port = htons(port);

	if (bind(s, (struct sockaddr *)&sock_addr,
			sizeof(sock_addr)) != 0)
		goto err;

	ev = event_new(ev_base, s, EV_READ|EV_PERSIST, cb_srv_receive, srv);
	event_add(ev, NULL);
	srv->ev = ev;

  return srv;

err:
  printf("libglouglou: gg_server_start: Error ! %s",
        strerror(errno));
  gg_server_stop(srv);
  return NULL;
}

int
gg_server_send(struct gg_server *s, int client_id, struct gg_packet *p)
{
  return -1;
}

void
gg_server_stop(struct gg_server *srv)
{
  if (srv->ev)
    event_del(srv->ev);
  if (srv->sock)
    close(srv->sock);
  free(srv);
}

/*
 * Server - private
 */

struct gg_user *
user_find(struct gg_server *srv, struct sockaddr_in *remote)
{
	struct gg_user *usr;
	struct sockaddr_in *u;

	LIST_FOREACH(usr, &srv->user_list, entry) {
		u = &usr->addr;
		if (u->sin_addr.s_addr == remote->sin_addr.s_addr &&
			u->sin_port == remote->sin_port)
			return usr;
	}
	return NULL;
}

struct gg_user *
user_add(struct gg_server *srv, struct sockaddr_in *remote)
{
  struct gg_user *usr;

  usr = xcalloc(1, sizeof(struct gg_user));
  usr->id = srv->user_id_count;
  srv->user_id_count++;
  addrcpy(&usr->addr, remote);
  LIST_INSERT_HEAD(&srv->user_list, usr, entry);

  return usr;
}

struct gg_packet *
pkt_decode(char **buf, int *buf_len)
{
  char *p;
  int len;

  p = *buf;
  len = *buf_len;

  // XXX IN PROGRESS

  *buf = p;
  *buf_len = len;
  return NULL;
}

void cb_srv_receive(evutil_socket_t fd, short what, void *arg)
{
  struct gg_server *srv;
  struct gg_user *usr;
  struct gg_packet *pkt;
	struct sockaddr_in remote;
  socklen_t remote_len;
  char buf[16384];
  char *buf_p;
	int buf_len;
	int len;

  srv = arg;
  remote_len = sizeof(struct sockaddr_in);
	len = recvfrom(fd, buf, sizeof(buf), 0,
		(struct sockaddr *)&remote, &remote_len);
	if (len < 0) {
		printf("libglouglou: cb_srv_receive: recvfrom failed\n");
		return;
	}
	usr = user_find(srv, &remote);
	if (!usr) {
	  usr = user_add(srv, &remote);
    if (srv->handle_conn)
      srv->handle_conn(srv, usr);
    printf("srv: New user %d !\n", usr->id);
    if (sendto(srv->sock, "", strlen(""), 0,
           (struct sockaddr *)&remote, remote_len) == -1)
      printf("srv: send failed: %s\n", strerror(errno));
  } else {
    printf("srv: Incoming data from existing user !\n");
    buf_p = buf;
    buf_len = len;
    while ((pkt = pkt_decode(&buf_p, &buf_len)))
      if (srv->handle_packet)
        srv->handle_packet(srv, usr, pkt);
    if (buf_len > 0) {
      /* XXX store incomplete packet for next recv */
      printf("srv: incomplete packet, dropped %d bytes !\n", buf_len);
    }
  }
}

/* 
 * Client
 */

/*
 * connect to a server
 */
struct gg_client *
gg_client_connect(struct event_base *ev_base, char *ip, int port,
                  int (*handle_conn)(struct gg_client *),
                  int (*handle_packet)(struct gg_client *, struct gg_packet *))
{
  struct gg_client *cli;
  struct sockaddr_in sock_addr;
  struct event *ev;
  int s;
  int sock_on = 1;

  cli = xcalloc(1, sizeof(struct gg_client));
  cli->ip = ip;
  cli->port = port;
  cli->handle_conn = handle_conn;
  cli->handle_packet = handle_packet;
  s = socket(AF_INET, SOCK_DGRAM, 0);
  if (s < 0)
    goto err;
  cli->sock = s;
	setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
		&sock_on, sizeof(sock_on));
	fd_nonblock(s);

	bzero(&sock_addr, sizeof(sock_addr));
  sock_addr.sin_family = AF_INET;
  sock_addr.sin_addr.s_addr=inet_addr(ip);
  sock_addr.sin_port=htons(port);

	ev = event_new(ev_base, s, EV_READ|EV_PERSIST, cb_cli_receive, cli);
	event_add(ev, NULL);
	cli->ev = ev;

  if (sendto(s, "", strlen(""), 0,
         (struct sockaddr *)&sock_addr, sizeof(struct sockaddr_in)) == -1)
    printf("cli: send failed: %s\n", strerror(errno));

  return cli;

err:
  printf("libglouglou: gg_client_connect: Error ! %s",
        strerror(errno));
  gg_client_disconnect(cli);
  return NULL;
}

int
gg_client_send(struct gg_client *c, struct gg_packet *p)
{
  return -1;
}

void
gg_client_disconnect(struct gg_client *cli)
{
  if (cli->ev)
    event_del(cli->ev);
  if (cli->sock)
    close(cli->sock);
  free(cli);
}

/*
 * Client - private
 */

void cb_cli_receive(evutil_socket_t fd, short what, void *arg)
{
  struct gg_client *cli;
  struct gg_packet *pkt;
  struct sockaddr_in remote;
	socklen_t	remote_len;
  char buf[16384];
  char *buf_p;
  int buf_len;
  int len;

  cli = arg;
	len = recvfrom(fd, buf, sizeof(buf), 0,
		(struct sockaddr *)&remote, &remote_len);
	if (len < 0) {
		printf("libglouglou: cb_cli_receive: recvfrom failed\n");
		return;
	}

  switch (cli->status) {
  case GG_CLIENT_STATUS_DISCONNECTED:
    printf("cli: Connected !\n");
    cli->status = GG_CLIENT_STATUS_CONNECTED;
    if (cli->handle_conn)
      cli->handle_conn(cli);
    break;
  case GG_CLIENT_STATUS_CONNECTED:
    printf("cli: Incoming data !\n");
    buf_p = buf;
    buf_len = len;
    while ((pkt = pkt_decode(&buf_p, &buf_len)))
      if (cli->handle_packet)
        cli->handle_packet(cli, pkt);
    if (buf_len > 0) {
      /* XXX store incomplete packet for next recv */
      printf("cli: incomplete packet, dropped %d bytes !\n", buf_len);
    }
    break;
  }
}

/*
 * Utils
 */

void *
xmalloc(size_t size)
{
  void *data;

  data = malloc(size);
  if (!data)
    err(1, "could not malloc %d", (int)size);
  return data;
}

void *
xcalloc(size_t nmemb, size_t size)
{
  void *data;

  data = calloc(nmemb, size);
  if (!data)
    err(1, "could not calloc %d", (int)size);
  return data;
}

void
fd_nonblock(int fd)
{
	int flags = fcntl(fd, F_GETFL, 0);
	int rc = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
	if (rc == -1)
		printf("failed to set fd %i non-blocking", fd);
}

void
addrcpy(struct sockaddr_in *dst, struct sockaddr_in *src)
{
  dst->sin_addr.s_addr = src->sin_addr.s_addr;
  dst->sin_port = src->sin_port;
  dst->sin_family = src->sin_family;
}