/*
 * Copyright notice from original mutt:
 * Copyright (C) 1998 Michael R. Elkins <me@mutt.org>
 * Copyright (C) 1999-2005 Brendan Cully <brendan@kublai.com>
 * Copyright (C) 1999-2000 Tommi Komulainen <Tommi.Komulainen@iki.fi>
 *
 * This file is part of mutt-ng, see http://www.muttng.org/.
 * It's licensed under the GNU General Public License,
 * please see the file GPL in the top level source directory.
 */

#if HAVE_CONFIG_H
# include "config.h"
#endif

#include "mutt.h"
#include "globals.h"
#include "mutt_socket.h"
#include "mutt_tunnel.h"
#if defined(USE_SSL) || defined(USE_GNUTLS)
# include "mutt_ssl.h"
#endif

#include "mutt_idna.h"

#include "lib/mem.h"
#include "lib/intl.h"
#include "lib/str.h"
#include "lib/debug.h"

#include <unistd.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#include <errno.h>

/* support for multiple socket connections */
static CONNECTION *Connections = NULL;

/* forward declarations */
static int socket_preconnect (void);
static int socket_connect (int fd, struct sockaddr *sa);
static CONNECTION *socket_new_conn (void);

/* Wrappers */
int mutt_socket_open (CONNECTION * conn)
{
  if (socket_preconnect ())
    return -1;

  return conn->conn_open (conn);
}

int mutt_socket_close (CONNECTION * conn)
{
  int rc = -1;

  if (conn->fd < 0)
    debug_print (1, ("Attempt to close closed connection.\n"));
  else
    rc = conn->conn_close (conn);

  conn->fd = -1;
  conn->ssf = 0;

  return rc;
}

int mutt_socket_read (CONNECTION * conn, char *buf, size_t len)
{
  int rc;

  if (conn->fd < 0) {
    debug_print (1, ("attempt to read from closed connection\n"));
    return -1;
  }

  rc = conn->conn_read (conn, buf, len);
  /* EOF */
  if (rc == 0) {
    mutt_error (_("Connection to %s closed"), conn->account.host);
    mutt_sleep (2);
  }
  if (rc <= 0)
    mutt_socket_close (conn);

  return rc;
}

int mutt_socket_write_d (CONNECTION * conn, const char *buf, int dbg)
{
  int rc;
  int len;

  debug_print (dbg, ("> %s", buf));

  if (conn->fd < 0) {
    debug_print (1, ("attempt to write to closed connection\n"));
    return -1;
  }

  len = str_len (buf);
  if ((rc = conn->conn_write (conn, buf, len)) < 0) {
    debug_print (1, ("error writing, closing socket\n"));
    mutt_socket_close (conn);

    return -1;
  }

  if (rc < len) {
    debug_print (1, ("ERROR: wrote %d of %d bytes!\n", rc, len));
  }

  return rc;
}

/* simple read buffering to speed things up. */
int mutt_socket_readchar (CONNECTION * conn, char *c)
{
  if (conn->bufpos >= conn->available) {
    if (conn->fd >= 0)
      conn->available =
        conn->conn_read (conn, conn->inbuf, sizeof (conn->inbuf));
    else {
      debug_print (1, ("attempt to read from closed connection.\n"));
      return -1;
    }
    conn->bufpos = 0;
    if (conn->available == 0) {
      mutt_error (_("Connection to %s closed"), conn->account.host);
      mutt_sleep (2);
    }
    if (conn->available <= 0) {
      mutt_socket_close (conn);
      return -1;
    }
  }
  *c = conn->inbuf[conn->bufpos];
  conn->bufpos++;
  return 1;
}

int mutt_socket_readln_d (char *buf, size_t buflen, CONNECTION * conn,
                          int dbg)
{
  char ch;
  int i;

  for (i = 0; i < buflen - 1; i++) {
    if (mutt_socket_readchar (conn, &ch) != 1) {
      buf[i] = '\0';
      return -1;
    }

    if (ch == '\n')
      break;
    buf[i] = ch;
  }

  /* strip \r from \r\n termination */
  if (i && buf[i - 1] == '\r')
    buf[--i] = '\0';
  else
    buf[i] = '\0';

  debug_print (dbg, ("< %s\n", buf));

  /* number of bytes read, not str_len */
  return i + 1;
}

CONNECTION *mutt_socket_head (void)
{
  return Connections;
}

/* mutt_socket_free: remove connection from connection list and free it */
void mutt_socket_free (CONNECTION * conn)
{
  CONNECTION *iter;
  CONNECTION *tmp;

  iter = Connections;

  /* head is special case, doesn't need prev updated */
  if (iter == conn) {
    Connections = iter->next;
    mem_free (&iter);
    return;
  }

  while (iter->next) {
    if (iter->next == conn) {
      tmp = iter->next;
      iter->next = tmp->next;
      mem_free (&tmp);
      return;
    }
    iter = iter->next;
  }
}

/* mutt_conn_find: find a connection off the list of connections whose
 *   account matches account. If start is not null, only search for
 *   connections after the given connection (allows higher level socket code
 *   to make more fine-grained searches than account info - eg in IMAP we may
 *   wish to find a connection which is not in IMAP_SELECTED state) */
CONNECTION *mutt_conn_find (const CONNECTION * start, const ACCOUNT * account)
{
  CONNECTION *conn;
  ciss_url_t url;
  char hook[LONG_STRING];

  /* account isn't actually modified, since url isn't either */
  mutt_account_tourl ((ACCOUNT *) account, &url);
  url.path = NULL;
  url_ciss_tostring (&url, hook, sizeof (hook), 0);
  mutt_account_hook (hook);

  conn = start ? start->next : Connections;
  while (conn) {
    if (mutt_account_match (account, &(conn->account)))
      return conn;
    conn = conn->next;
  }

  conn = socket_new_conn ();
  memcpy (&conn->account, account, sizeof (ACCOUNT));

  conn->next = Connections;
  Connections = conn;

  if (Tunnel && *Tunnel)
    mutt_tunnel_socket_setup (conn);
  else if (account->flags & M_ACCT_SSL) {
#if defined (USE_SSL) || defined (USE_GNUTLS)
    if (mutt_ssl_socket_setup (conn) < 0) {
      mutt_socket_free (conn);
      return NULL;
    }
#else
    mutt_error _("SSL is unavailable.");

    mutt_sleep (2);
    mutt_socket_free (conn);

    return NULL;
#endif
  }
  else {
    conn->conn_read = raw_socket_read;
    conn->conn_write = raw_socket_write;
    conn->conn_open = raw_socket_open;
    conn->conn_close = raw_socket_close;
  }

  return conn;
}

static int socket_preconnect (void)
{
  int rc;
  int save_errno;

  if (str_len (Preconnect)) {
    debug_print (2, ("Executing preconnect: %s\n", Preconnect));
    rc = mutt_system (Preconnect);
    debug_print (2, ("Preconnect result: %d\n", rc));
    if (rc) {
      save_errno = errno;
      mutt_perror (_("Preconnect command failed."));
      mutt_sleep (1);

      return save_errno;
    }
  }

  return 0;
}

/* socket_connect: set up to connect to a socket fd. */
static int socket_connect (int fd, struct sockaddr *sa)
{
  int sa_size;
  int save_errno;

  if (sa->sa_family == AF_INET)
    sa_size = sizeof (struct sockaddr_in);
#ifdef HAVE_GETADDRINFO
  else if (sa->sa_family == AF_INET6)
    sa_size = sizeof (struct sockaddr_in6);
#endif
  else {
    debug_print (1, ("Unknown address family!\n"));
    return -1;
  }

  if (ConnectTimeout > 0)
    alarm (ConnectTimeout);

  mutt_allow_interrupt (1);

  save_errno = 0;

  if (connect (fd, sa, sa_size) < 0) {
    save_errno = errno;
    debug_print (2, ("Connection failed. errno: %d...\n", errno));
    SigInt = 0;                 /* reset in case we caught SIGINTR while in connect() */
  }

  if (ConnectTimeout > 0)
    alarm (0);
  mutt_allow_interrupt (0);

  return save_errno;
}

/* socket_new_conn: allocate and initialise a new connection. */
static CONNECTION *socket_new_conn (void)
{
  CONNECTION *conn;

  conn = (CONNECTION *) mem_calloc (1, sizeof (CONNECTION));
  conn->fd = -1;

  return conn;
}

int raw_socket_close (CONNECTION * conn)
{
  return close (conn->fd);
}

int raw_socket_read (CONNECTION * conn, char *buf, size_t len)
{
  int rc;

  if ((rc = read (conn->fd, buf, len)) == -1) {
    mutt_error (_("Error talking to %s (%s)"), conn->account.host,
                strerror (errno));
    mutt_sleep (2);
  }

  return rc;
}

int raw_socket_write (CONNECTION * conn, const char *buf, size_t count)
{
  int rc;

  if ((rc = write (conn->fd, buf, count)) == -1) {
    mutt_error (_("Error talking to %s (%s)"), conn->account.host,
                strerror (errno));
    mutt_sleep (2);
  }

  return rc;
}

int raw_socket_open (CONNECTION * conn)
{
  int rc;
  int fd;

  char *host_idna = NULL;

#ifdef HAVE_GETADDRINFO
/* --- IPv4/6 --- */

  /* "65536\0" */
  char port[6];
  struct addrinfo hints;
  struct addrinfo *res;
  struct addrinfo *cur;

  /* we accept v4 or v6 STREAM sockets */
  memset (&hints, 0, sizeof (hints));

  if (option (OPTUSEIPV6))
    hints.ai_family = AF_UNSPEC;
  else
    hints.ai_family = AF_INET;

  hints.ai_socktype = SOCK_STREAM;

  snprintf (port, sizeof (port), "%d", conn->account.port);

# ifdef HAVE_LIBIDN
  if (idna_to_ascii_lz (conn->account.host, &host_idna, 1) != IDNA_SUCCESS) {
    mutt_error (_("Bad IDN \"%s\"."), conn->account.host);
    return -1;
  }
# else
  host_idna = conn->account.host;
# endif

  mutt_message (_("Looking up %s..."), conn->account.host);


  rc = getaddrinfo (host_idna, port, &hints, &res);

# ifdef HAVE_LIBIDN
  mem_free (&host_idna);
# endif

  if (rc) {
    mutt_error (_("Could not find the host \"%s\""), conn->account.host);
    mutt_sleep (2);
    return -1;
  }

  mutt_message (_("Connecting to %s..."), conn->account.host);

  rc = -1;
  for (cur = res; cur != NULL; cur = cur->ai_next) {
    fd = socket (cur->ai_family, cur->ai_socktype, cur->ai_protocol);
    if (fd >= 0) {
      if ((rc = socket_connect (fd, cur->ai_addr)) == 0) {
        fcntl (fd, F_SETFD, FD_CLOEXEC);
        conn->fd = fd;
        break;
      }
      else
        close (fd);
    }
  }

  freeaddrinfo (res);

#else
  /* --- IPv4 only --- */

  struct sockaddr_in sin;
  struct hostent *he;
  int i;

  memset (&sin, 0, sizeof (sin));
  sin.sin_port = htons (conn->account.port);
  sin.sin_family = AF_INET;

# ifdef HAVE_LIBIDN
  if (idna_to_ascii_lz (conn->account.host, &host_idna, 1) != IDNA_SUCCESS) {
    mutt_error (_("Bad IDN \"%s\"."), conn->account.host);
    return -1;
  }
# else
  host_idna = conn->account.host;
# endif

  mutt_message (_("Looking up %s..."), conn->account.host);

  if ((he = gethostbyname (host_idna)) == NULL) {
# ifdef HAVE_LIBIDN
    mem_free (&host_idna);
# endif
    mutt_error (_("Could not find the host \"%s\""), conn->account.host);

    return -1;
  }

# ifdef HAVE_LIBIDN
  mem_free (&host_idna);
# endif

  mutt_message (_("Connecting to %s..."), conn->account.host);

  rc = -1;
  for (i = 0; he->h_addr_list[i] != NULL; i++) {
    memcpy (&sin.sin_addr, he->h_addr_list[i], he->h_length);
    fd = socket (PF_INET, SOCK_STREAM, IPPROTO_IP);

    if (fd >= 0) {
      if ((rc = socket_connect (fd, (struct sockaddr *) &sin)) == 0) {
        fcntl (fd, F_SETFD, FD_CLOEXEC);
        conn->fd = fd;
        break;
      }
      else
        close (fd);
    }
  }

#endif
  if (rc) {
    mutt_error (_("Could not connect to %s (%s)."), conn->account.host,
                (rc > 0) ? strerror (rc) : _("unknown error"));
    mutt_sleep (2);
    return -1;
  }

  return 0;
}