/* GNU Mailutils -- a suite of utilities for electronic mail
   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2006, 2007, 2009, 2010
   Free Software Foundation, Inc.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 3 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General
   Public License along with this library.  If not, see
   <http://www.gnu.org/licenses/>. */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#ifdef ENABLE_SMTP

#include <errno.h>
#include <netdb.h>
#include <pwd.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <mailutils/address.h>
#include <mailutils/argcv.h>
#include <mailutils/debug.h>
#include <mailutils/errno.h>
#include <mailutils/header.h>
#include <mailutils/body.h>
#include <mailutils/iterator.h>
#include <mailutils/message.h>
#include <mailutils/mime.h>
#include <mailutils/util.h>
#include <mailutils/observer.h>
#include <mailutils/property.h>
#include <mailutils/stream.h>
#include <mailutils/smtp.h>
#include <mailutils/tls.h>
#include <mailutils/cstr.h>
#include <mailutils/sys/mailer.h>
#include <mailutils/sys/url.h>
#include <mailutils/sys/registrar.h>

static int      _mailer_smtp_init (mu_mailer_t);

static int
_url_smtp_init (mu_url_t url)
{
  /* host isn't optional */
  if (!url->host)
    return EINVAL;

  /* accept url->user, pass, and auth
     for the ESMTP authentication */

  /* all other fields must be NULL */
  if (url->path || url->qargc)
    return EINVAL;

  if (url->port == 0)
    url->port = MU_SMTP_PORT;

  return 0;
}

static struct _mu_record _smtp_record = {
  MU_SMTP_PRIO,
  MU_SMTP_SCHEME,
  _url_smtp_init,		/* url init.  */
  _mu_mailer_mailbox_init,	/* Mailbox init.  */
  _mailer_smtp_init,		/* Mailer init.  */
  _mu_mailer_folder_init,	/* Folder init.  */
  NULL,				/* No need for a back pointer.  */
  NULL,				/* _is_scheme method.  */
  NULL,				/* _get_url method.  */
  NULL,				/* _get_mailbox method.  */
  NULL,				/* _get_mailer method.  */
  NULL				/* _get_folder method.  */
};

/* We export : url parsing and the initialisation of
   the mailbox, via the register entry/record.  */
mu_record_t     mu_smtp_record = &_smtp_record;

struct _smtp_mailer
{
  mu_mailer_t     mailer;
  mu_smtp_t       smtp;

  mu_address_t    rcpt_to;
  mu_address_t    rcpt_bcc;
};

static int
smtp_open (mu_mailer_t mailer, int flags)
{
  const char *host;
  long port;
  struct _smtp_mailer *smtp_mailer = mailer->data;
  int rc;
  size_t parmc = 0;
  char **parmv = NULL;
  int notls = 0;
  int noauth = 0;
  
  rc = mu_smtp_create (&smtp_mailer->smtp);
  if (rc)
    return rc;
  if (mu_debug_check_level (mailer->debug, MU_DEBUG_PROT))
    mu_smtp_trace (smtp_mailer->smtp, MU_SMTP_TRACE_SET);
  if (mu_debug_check_level (mailer->debug, MU_DEBUG_TRACE6))
    mu_smtp_trace_mask (smtp_mailer->smtp, MU_SMTP_TRACE_SET,
			MU_XSCRIPT_SECURE);
  if (mu_debug_check_level (mailer->debug, MU_DEBUG_TRACE7))
    mu_smtp_trace_mask (smtp_mailer->smtp, MU_SMTP_TRACE_SET,
			MU_XSCRIPT_PAYLOAD);
  
  mu_smtp_set_param (smtp_mailer->smtp, MU_SMTP_PARAM_URL,
		     mu_url_to_string (mailer->url));

  rc = mu_url_sget_host (mailer->url, &host);
  if (rc)
    return rc;
  if (mu_url_get_port (mailer->url, &port))
    port = 25;

  /* Additional information is supplied in the arguments */
  if (mu_url_sget_fvpairs (mailer->url, &parmc, &parmv) == 0)
    {
      size_t i;
      
      for (i = 0; i < parmc; i++)
	{
	  if (strcmp (parmv[i], "notls") == 0)
	    notls = 1;
	  else if (strcmp (parmv[i], "noauth") == 0)
	    noauth = 1;
	  else if (strncmp (parmv[i], "auth=", 5) == 0)
	    {
	      int mc, j;
	      char **mv;
	  
	      rc = mu_argcv_get_np (parmv[i] + 5, strlen (parmv[i] + 5),
				    ",", NULL,
				    0,
				    &mc, &mv, NULL);
	      if (rc == 0)
		for (j = 0; j < mc; j++)
		  mu_smtp_add_auth_mech (smtp_mailer->smtp, mv[j]);
	      
	      free (mv);
	    }
	  /* unrecognized arguments silently ignored */
	}
    }
  
  if (mailer->stream == NULL)
    {
      rc = mu_tcp_stream_create (&mailer->stream, host, port, mailer->flags);
      if (rc)
	return rc;
      mu_stream_set_buffer (mailer->stream, mu_buffer_line, 0);
    }
  mu_smtp_set_carrier (smtp_mailer->smtp, mailer->stream);
  /* FIXME: Unref the stream */

  rc = mu_smtp_open (smtp_mailer->smtp);
  if (rc)
    return rc;

  rc = mu_smtp_ehlo (smtp_mailer->smtp);
  if (rc)
    return rc;

  if (!notls && mu_tls_enable &&
      mu_smtp_capa_test (smtp_mailer->smtp, "STARTTLS", NULL) == 0)
    {
      rc = mu_smtp_starttls (smtp_mailer->smtp);
      if (rc == 0)
	{
	  rc = mu_smtp_ehlo (smtp_mailer->smtp);
	  if (rc)
	    return rc;
	}
    }

  if (!noauth && mu_smtp_capa_test (smtp_mailer->smtp, "AUTH", NULL) == 0)
    {
      rc = mu_smtp_auth (smtp_mailer->smtp);
      switch (rc)
	{
	case 0:
	  rc = mu_smtp_ehlo (smtp_mailer->smtp);
	  break;
	  
	case ENOSYS:
	case MU_ERR_AUTH_NO_CRED:
	  mu_diag_output (MU_DIAG_NOTICE, "authentication disabled: %s",
			  mu_strerror (rc));
	  rc = 0; /* Continue anyway */
	  break;
	}
      if (rc)
	return rc;
    }
  
  return 0;
}

static void
smtp_destroy (mu_mailer_t mailer)
{
  struct _smtp_mailer *smp = mailer->data;
  
  mu_address_destroy (&smp->rcpt_to);
  mu_address_destroy (&smp->rcpt_bcc);
  mu_smtp_destroy (&smp->smtp);

  free (smp);

  mailer->data = NULL;
}

static int
smtp_close (mu_mailer_t mailer)
{
  struct _smtp_mailer *smp = mailer->data;
  return mu_smtp_quit (smp->smtp);
}


int
smtp_address_add (mu_address_t *paddr, const char *value)
{
  mu_address_t addr = NULL;
  int status;

  status = mu_address_create (&addr, value);
  if (status)
    return status;
  status = mu_address_union (paddr, addr);
  mu_address_destroy (&addr);
  return status;
}

static int
_smtp_property_is_set (struct _smtp_mailer *smp, const char *name)
{
  mu_property_t property = NULL;

  mu_mailer_get_property (smp->mailer, &property);
  return mu_property_is_set (property, name);
}


static int
_smtp_set_rcpt (struct _smtp_mailer *smp, mu_message_t msg, mu_address_t to)
{
  int             status = 0;

  /* Get RCPT_TO from TO, or the message. */

  if (to)
    {
      /* Use the specified mu_address_t. */
      if ((status = mu_mailer_check_to (to)) != 0)
	{
	  MU_DEBUG (smp->mailer->debug, MU_DEBUG_ERROR,
		    "mu_mailer_send_message(): explicit to not valid\n");
	  return status;
	}
      smp->rcpt_to = to;

      if (status)
	return status;
    }

  if (!to || _smtp_property_is_set (smp, "READ_RECIPIENTS"))
    {
      mu_header_t     header;
      
      if ((status = mu_message_get_header (msg, &header)))
	return status;

      do
	{
	  const char      *value;
	  
	  status = mu_header_sget_value (header, MU_HEADER_TO, &value);
	  if (status == 0)
	    smtp_address_add (&smp->rcpt_to, value);
	  else if (status != MU_ERR_NOENT)
	    break;

	  status = mu_header_sget_value (header, MU_HEADER_CC, &value);
	  if (status == 0)
	    smtp_address_add (&smp->rcpt_to, value);
	  else if (status != MU_ERR_NOENT)
	    break;

	  status = mu_header_sget_value (header, MU_HEADER_BCC, &value);
	  if (status == 0)
	    smtp_address_add (&smp->rcpt_bcc, value);
	  else if (status != MU_ERR_NOENT)
	    break;

	  if (smp->rcpt_to && (status = mu_mailer_check_to (smp->rcpt_to)))
	    break;

	  if (smp->rcpt_bcc && (status = mu_mailer_check_to (smp->rcpt_bcc)))
	    break;
	}
      while (0);
    }

  if (status)
    {
      mu_address_destroy (&smp->rcpt_to);
      mu_address_destroy (&smp->rcpt_bcc);
    }
  else
    {
      size_t rcpt_cnt, bcc_cnt;
      
      if (smp->rcpt_to)
	mu_address_get_count (smp->rcpt_to, &rcpt_cnt);
      
      if (smp->rcpt_bcc)
	mu_address_get_count (smp->rcpt_bcc, &bcc_cnt);

      if (rcpt_cnt + bcc_cnt == 0)
	status = MU_ERR_MAILER_NO_RCPT_TO;
    }

  return status;
}

static int
_rcpt_to_addr (mu_smtp_t smtp, mu_address_t addr, size_t *pcount)
{
  size_t i, count, rcpt_cnt = 0;
  int status;
  
  status = mu_address_get_count (addr, &count);
  if (status)
    return status;

  for (i = 1; i <= count; i++)
    {
      const char *to = NULL;

      status = mu_address_sget_email (addr, i, &to);
      if (status == 0)
	{
	  status = mu_smtp_rcpt_basic (smtp, to, NULL);
	  if (status == 0)
	    rcpt_cnt++;
	  else if (status != MU_ERR_REPLY)
	    break;
	}
    }
  *pcount = rcpt_cnt;
  return status;
}

static int
smtp_send_message (mu_mailer_t mailer, mu_message_t msg,
		   mu_address_t argfrom, mu_address_t argto)
{
  struct _smtp_mailer *smp = mailer->data;
  mu_smtp_t smtp = smp->smtp;
  int status;
  size_t size, lines, count;
  const char *mail_from, *size_str;
  mu_header_t     header;
      
  if (mailer == NULL)
    return EINVAL;
  
  smp = mailer->data;
  if (!smp)
    return EINVAL;

  if ((status = mu_message_get_header (msg, &header)))
    return status;
  
  status = _smtp_set_rcpt (smp, msg, argto);
  if (status)
    return status;

  status = mu_address_sget_email (argfrom, 1, &mail_from);
  if (status)
    return status;
  
  if (mu_smtp_capa_test (smp->smtp, "SIZE", &size_str) == 0 &&
      mu_message_size (msg, &size) == 0 &&
      mu_message_lines (msg, &lines) == 0)
    {
      size_t msgsize = size + lines;
      size_t maxsize = strtoul (size_str + 5, NULL, 10);

      if (msgsize && msgsize > maxsize)
	return EFBIG;
      status = mu_smtp_mail_basic (smp->smtp, mail_from,
				   "SIZE=%lu",
				   (unsigned long) msgsize);
    }
  else
    status = mu_smtp_mail_basic (smp->smtp, mail_from, NULL);
  if (status)
    return status;

  status = _rcpt_to_addr (smtp, smp->rcpt_to, &count);
  if (status && count == 0)
    return status;
  status = _rcpt_to_addr (smtp, smp->rcpt_bcc, &count);
  if (status && count == 0)
    return status;

  if (mu_header_sget_value (header, MU_HEADER_BCC, NULL))
    {
      mu_iterator_t itr;
      mu_body_t body;
      mu_stream_t ostr, bstr;

      status = mu_smtp_data (smtp, &ostr);
      if (status)
	return status;
      mu_header_get_iterator (header, &itr);
      for (mu_iterator_first (itr); !mu_iterator_is_done (itr);
	   mu_iterator_next (itr))
	{
	  const char *name;
	  void *value;

	  mu_iterator_current_kv (itr, (void*) &name, &value);
	  if (mu_c_strcasecmp (name, MU_HEADER_BCC) == 0)
	    continue;
	  mu_stream_printf (ostr, "%s: %s\n", name, (char*)value);
	}
      mu_iterator_destroy (&itr);
      mu_stream_write (ostr, "\n", 1, NULL);
      
      mu_message_get_body (msg, &body);
      mu_body_get_streamref (body, &bstr);
      mu_stream_copy (ostr, bstr, 0, NULL);
      mu_stream_destroy (&bstr);
      mu_stream_close (ostr);
      mu_stream_destroy (&ostr);
    }
  else
    {
      mu_stream_t str;
      mu_message_get_streamref (msg, &str);
      status = mu_smtp_send_stream (smtp, str);
      mu_stream_destroy (&str);
    }
  mu_smtp_quit (smtp);
  mu_address_destroy (&smp->rcpt_to);
  mu_address_destroy (&smp->rcpt_bcc);
  return status;
}


static int
_mailer_smtp_init (mu_mailer_t mailer)
{
  struct _smtp_mailer *smp;

  /* Allocate memory specific to smtp mailer.  */
  smp = mailer->data = calloc (1, sizeof (*smp));
  if (mailer->data == NULL)
    return ENOMEM;

  smp->mailer = mailer;	/* Back pointer.  */

  mailer->_destroy = smtp_destroy;
  mailer->_open = smtp_open;
  mailer->_close = smtp_close;
  mailer->_send_message = smtp_send_message;

  /* Set our properties.  */
  {
    mu_property_t   property = NULL;

    mu_mailer_get_property (mailer, &property);
    mu_property_set_value (property, "TYPE", "SMTP", 1);
  }

  return 0;
}

#else
#include <stdio.h>
#include <mailutils/sys/registrar.h>
mu_record_t     mu_smtp_record = NULL;
mu_record_t     mu_remote_smtp_record = NULL;
#endif