/* GNU Mailutils -- a suite of utilities for electronic mail
   Copyright (C) 1999-2025 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_POP

#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <netdb.h>
#include <netinet/in.h>

#include <mailutils/pop3.h>
#include <mailutils/attribute.h>
#include <mailutils/auth.h>
#include <mailutils/body.h>
#include <mailutils/debug.h>
#include <mailutils/errno.h>
#include <mailutils/error.h>
#include <mailutils/header.h>
#include <mailutils/message.h>
#include <mailutils/observer.h>
#include <mailutils/property.h>
#include <mailutils/stream.h>
#include <mailutils/filter.h>
#include <mailutils/url.h>
#include <mailutils/secret.h>
#include <mailutils/tls.h>
#include <mailutils/md5.h>
#include <mailutils/io.h>
#include <mailutils/util.h>
#include <mailutils/cstr.h>
#include <mailutils/cctype.h>
#include <mailutils/opool.h>
#include <mailutils/sockaddr.h>

#include <mailutils/sys/folder.h>
#include <mailutils/sys/mailbox.h>
#include <mailutils/sys/message.h>
#include <mailutils/sys/registrar.h>
#include <mailutils/sys/url.h>

#define _POP3_MSG_CACHED  0x01      /* Message is already cached */
#define _POP3_MSG_SIZE    0x02      /* Message size obtained */
#define _POP3_MSG_SCANNED 0x04      /* Message has been scanned */
#define _POP3_MSG_ATTRSET 0x08      /* Attributes has been set */
#define _POP3_MSG_LINES   0x10      /* Number of lines was obtained */

struct _pop3_message
{
  int flags;
  mu_off_t offset;          /* Offset in the message cache stream */
  mu_off_t body_start;      /* Start of message, relative to offset */
  mu_off_t body_end;        /* End of message, relative to offset */
  size_t header_lines;      /* Number of lines in the header */
  size_t body_lines;        /* Number of lines in the body */
  int attr_flags;           /* Message attributes */
  size_t message_size;      /* Message size */
  size_t message_lines;     /* Number of lines in the message */
  size_t num;               /* Message number */
  char *uidl;               /* Cached uidl string.  */
  mu_message_t message;     /* Pointer to the message structure */
  struct _pop3_mailbox *mpd; /* Back pointer.  */
};

struct _pop3_mailbox
{
  mu_pop3_t pop3;             /* mu_pop3_t is the working horse */
  int pops;                   /* true if pop3 over SSL is being used */
  int is_updated;             /* true if the mailbox info is up to date */

  size_t msg_count;           /* Number of messages in the mailbox */
  mu_off_t total_size;        /* Total mailbox size. */
  struct _pop3_message **msg; /* Array of messages */
  size_t msg_max;             /* Actual size of the array */
  mu_mailbox_t mbox;          /* MU mailbox corresponding to this one. */

  mu_stream_t cache;          /* Message cache stream */
   /* Temporary holders for user and passwd: */
  char *user;
  mu_secret_t secret;
};

static int pop_create_pop3_message (struct _pop3_mailbox *mpd, size_t msgno,
				    struct _pop3_message **mptr);


/* ------------------------------------------------------------------------- */
/* Basic operations */

static int
pop_open (mu_mailbox_t mbox, int flags)
{
  struct _pop3_mailbox *mpd = mbox->data;
  int status;
  mu_stream_t stream;
  struct mu_sockaddr *sa;
  struct mu_sockaddr_hints hints;

  /* Sanity checks. */
  if (mpd == NULL)
    return EINVAL;

  mbox->flags = flags;

  memset (&hints, 0, sizeof (hints));
  hints.flags = MU_AH_DETECT_FAMILY;
  hints.port = mpd->pops ? MU_POPS_PORT : MU_POP_PORT;
  hints.protocol = IPPROTO_TCP;
  hints.socktype = SOCK_STREAM;
  status = mu_sockaddr_from_url (&sa, mbox->url, &hints);
  if (status)
    return status;

  status = mu_tcp_stream_create_from_sa (&stream, sa, NULL, mbox->flags);
  if (status)
    {
      mu_sockaddr_free (sa);
      return status;
    }
#ifdef WITH_TLS
  if (mpd->pops)
    {
      mu_stream_t tlsstream;

      status = mu_tlsfd_stream_convert (&tlsstream, stream, NULL,
					MU_TLS_CLIENT);
      mu_stream_unref (stream);
      if (status)
	{
	  if (status == MU_ERR_TRANSPORT_SET)
	    mu_stream_destroy (&tlsstream);
	  mu_debug (MU_DEBCAT_FOLDER, MU_DEBUG_ERROR,
		    ("cannot create TLS stream: %s", mu_strerror (status)));
	  return status;
	}
      stream = tlsstream;
    }
#endif /* WITH_TLS */

  /* FIXME: How to configure buffer size? */
  mu_stream_set_buffer (stream, mu_buffer_line, 0);

  status = mu_pop3_create (&mpd->pop3);
  if (status)
    {
      mu_stream_destroy (&stream);
      return status;
    }
  mu_pop3_set_carrier (mpd->pop3, stream);
  mu_stream_unref (stream);

  if (mu_debug_level_p (MU_DEBCAT_MAILBOX, MU_DEBUG_PROT))
    mu_pop3_trace (mpd->pop3, MU_POP3_TRACE_SET);
  if (mu_debug_level_p (MU_DEBCAT_MAILBOX, MU_DEBUG_TRACE6))
    mu_pop3_trace_mask (mpd->pop3, MU_POP3_TRACE_SET, MU_XSCRIPT_SECURE);
  if (mu_debug_level_p (MU_DEBCAT_MAILBOX, MU_DEBUG_TRACE7))
    mu_pop3_trace_mask (mpd->pop3, MU_POP3_TRACE_SET, MU_XSCRIPT_PAYLOAD);

  do
    {
      status = mu_pop3_connect (mpd->pop3);
      if (status)
	break;

      status = mu_pop3_capa (mpd->pop3, 1, NULL);
      if (status == MU_ERR_REPLY)
	{
	  mu_debug (MU_DEBCAT_MAILBOX, MU_DEBUG_ERROR,
		    ("server rejected the CAPA command: %s",
		     mu_pop3_strresp (mpd->pop3)));
	  /* try to continue anyway */
	}
      else if (status)
	return status;

#ifdef WITH_TLS
      if (!mpd->pops &&
	  mu_url_sget_param (mbox->url, "notls", NULL) == MU_ERR_NOENT &&
	  mu_pop3_capa_test (mpd->pop3, "STLS", NULL) == 0)
	{
	  status = mu_pop3_stls (mpd->pop3);
	  if (status)
	    break;
	}
#endif
      status = mu_authority_authenticate (mbox->folder->authority);
    }
  while (0);

  if (status)
    mu_pop3_destroy (&mpd->pop3);
  return status;
}

static int
pop_close (mu_mailbox_t mbox)
{
  struct _pop3_mailbox *mpd = mbox->data;
  int status;

  status = mu_pop3_quit (mpd->pop3);
  if (status)
    mu_error ("mu_pop3_quit failed: %s", mu_strerror (status));
  status = mu_pop3_disconnect (mpd->pop3);
  if (status)
    mu_error ("mu_pop3_disconnect failed: %s", mu_strerror (status));
  if (mpd->msg)
    {
      size_t i;

      mu_monitor_wrlock (mbox->monitor);
      /* Destroy the pop messages and resources associated to them.  */
      for (i = 0; i < mpd->msg_count; i++)
	{
	  if (mpd->msg[i])
	    {
	      mu_message_destroy (&mpd->msg[i]->message, mpd->msg[i]);
	      if (mpd->msg[i]->uidl)
		free (mpd->msg[i]->uidl);
	      free (mpd->msg[i]);
	    }
	}
      mu_monitor_unlock (mbox->monitor);
    }
  mu_stream_destroy (&mpd->cache);
  return 0;
}

static void
pop_destroy (mu_mailbox_t mbox)
{
  struct _pop3_mailbox *mpd = mbox->data;
  if (mpd)
    {
      mu_pop3_destroy (&mpd->pop3);
      if (mpd->user)
	free (mpd->user);
      if (mpd->secret)
	mu_secret_unref (mpd->secret);
   }
}

/* Update and scanning.  */
static int
pop_is_updated (mu_mailbox_t mbox)
{
  struct _pop3_mailbox *mpd = mbox->data;
  if (mpd == NULL)
    return 0;
  return mpd->is_updated;
}

/* Return the number of messages in the mailbox */
static int
pop_messages_count (mu_mailbox_t mbox, size_t *pcount)
{
  struct _pop3_mailbox *mpd = mbox->data;
  int status;

  if (mpd == NULL)
    return EINVAL;

  if (pop_is_updated (mbox))
    {
      if (pcount)
	*pcount = mpd->msg_count;
      return 0;
    }

  status = mu_pop3_stat (mpd->pop3, &mpd->msg_count, &mpd->total_size);
  if (status == 0)
    {
      if (pcount)
	*pcount = mpd->msg_count;
      mpd->is_updated = 1;
    }
  return status;
}

static int
pop_scan (mu_mailbox_t mbox, size_t msgno, size_t *pcount)
{
  int status;
  size_t i;
  size_t count = 0;
  struct _pop3_mailbox *mpd = mbox->data;
  int flags;
  mu_iterator_t itr;

  status = pop_messages_count (mbox, &count);
  if (status != 0)
    return status;
  if (pcount)
    *pcount = count;

  flags = _POP3_MSG_SIZE;
  if (!mu_pop3_capa_test (mpd->pop3, "XLINES", NULL))
    flags |= _POP3_MSG_LINES;

  status = mu_pop3_list_all (mpd->pop3, &itr);
  if (status)
    return status;

  for (i = 0, mu_iterator_first (itr);
       i <= count && !mu_iterator_is_done (itr);
       i++, mu_iterator_next (itr))
    {
      const char *str;
      char *p;
      size_t num;

      mu_iterator_current (itr, (void**) &str);
      num = strtoul (str, &p, 10);

      if (*p != ' ')
	{
	  mu_debug (MU_DEBCAT_MAILBOX, MU_DEBUG_ERROR,
		    ("invalid reply to LIST command: %s", str));
	  status = MU_ERR_BADREPLY;
	  break;
	}
      if (num >= msgno)
	{
	  size_t size, lines;
	  struct _pop3_message *mpm;

	  size = strtoul (p + 1, &p, 10);
	  if (flags & _POP3_MSG_LINES)
	    {
	      if (*p != ' ')
		{
		  mu_debug (MU_DEBCAT_MAILBOX, MU_DEBUG_ERROR,
			    ("invalid reply to LIST command: %s", str));
		  status = MU_ERR_BADREPLY;
		  break;
		}
	      lines = strtoul (p + 1, &p, 10);
	    }

	  status = pop_create_pop3_message (mpd, num, &mpm);
	  if (status)
	    break;
	  mpm->message_size = size;
	  if (flags & _POP3_MSG_LINES)
	    mpm->message_lines = lines;
	  mpm->flags |= flags;

	  if (mbox->observable)
	    {
	      if (((i + 1) % 10) == 0)
		mu_observable_notify (mbox->observable,
				      MU_EVT_MAILBOX_PROGRESS,
				      NULL);
	    }
	}
    }

  mu_iterator_destroy (&itr);

  if (mbox->observable)
    {
      /* MU_EVT_MESSAGE_ADD must be delivered only when it is already possible
	 to retrieve the message in question.  It could not be done in the
	 main loop because no other pop3d function can be called while LIST
	 is being handled.  Hence the extra loop. */
      for (i = 0; i <= count; i++)
	{
	  if (mu_observable_notify (mbox->observable, MU_EVT_MESSAGE_ADD,
				    &i) != 0)
	    break;
	}
    }

  return status;
}

/* There's no way to retrieve this info via POP3 */
static int
pop_message_unseen (mu_mailbox_t mbox, size_t *punseen)
{
  size_t count = 0;
  int status = pop_messages_count (mbox, &count);
  if (status != 0)
    return status;
  if (punseen)
    *punseen = (count > 0) ? 1 : 0;
  return 0;
}

static int
pop_get_size (mu_mailbox_t mbox, mu_off_t *psize)
{
  struct _pop3_mailbox *mpd = mbox->data;
  int status = 0;

  if (mpd == NULL)
    return EINVAL;

  if (!pop_is_updated (mbox))
    status = pop_messages_count (mbox, NULL);
  if (psize)
    *psize = mpd->total_size;
  return status;
}

static int
pop_get_uidls (mu_mailbox_t mbox, mu_list_t list)
{
  struct _pop3_mailbox *mpd = mbox->data;
  mu_iterator_t itr;
  int status = mu_pop3_uidl_all (mpd->pop3, &itr);
  if (status)
    return status;

  for (mu_iterator_first (itr); !mu_iterator_is_done (itr);
       mu_iterator_next (itr))
    {
      const char *str;
      char *p;
      size_t num;
      struct mu_uidl *uidl;

      mu_iterator_current (itr, (void**) &str);

      num = strtoul (str, &p, 10);
      if (*p != ' ')
	{
	  mu_debug (MU_DEBCAT_MAILBOX, MU_DEBUG_ERROR,
		    ("invalid reply to UIDL command: %s", str));
	  status = MU_ERR_BADREPLY;
	  break;
	}
      p++;

      uidl = malloc (sizeof (*uidl));
      if (!uidl)
	{
	  status = ENOMEM;
	  mu_debug (MU_DEBCAT_MAILBOX, MU_DEBUG_ERROR,
		    ("out of memory when processing the UIDL response"));
	  break;
	}

      uidl->msgno = num;
      strncpy (uidl->uidl, p, sizeof (uidl->uidl));

      if ((status = mu_list_append (list, uidl)) != 0)
	{
	  mu_debug (MU_DEBCAT_MAILBOX, MU_DEBUG_ERROR,
		    ("error appending to list when processing the UIDL"
		     " response: %s", mu_strerror (status)));
	  free (uidl);
	  break;
	}
    }
  mu_iterator_destroy (&itr);
  if (status)
    mu_list_clear (list);
  return status;
}

/* ------------------------------------------------------------------------- */
/* POP3 message streams */

static void
pop_stream_drain (mu_stream_t str)
{
  char buf[2048];
  size_t size;

  while (mu_stream_read (str, buf, sizeof buf, &size) == 0 && size)
    ;
}

static int
_pop_message_get_stream (struct _pop3_message *mpm, mu_stream_t *pstr)
{
  int status;
  struct _pop3_mailbox *mpd = mpm->mpd;

  if (!(mpm->flags & _POP3_MSG_CACHED))
    {
      mu_stream_t stream;
      mu_off_t size;

      status = mu_pop3_retr (mpd->pop3, mpm->num, &stream);
      if (status)
	return status;

      do
	{
	  mu_stream_t flt;

	  if (!mpd->cache)
	    {
	      status = mu_temp_stream_create (&mpd->cache, 0);
	      if (status)
		/* FIXME: Try to recover first */
		break;

	      mu_stream_set_buffer (mpd->cache, mu_buffer_full, 8192);
	    }

	  status = mu_stream_size (mpd->cache, &mpm->offset);
	  if (status)
	    break;

	  status = mu_filter_create (&flt, stream, "CRLF", MU_FILTER_DECODE,
				     MU_STREAM_READ);
	  if (status)
	    break;

	  status = mu_stream_copy (mpd->cache, flt, 0, &size);

	  mu_stream_destroy (&flt);
	}
      while (0);

      if (status)
	{
	  pop_stream_drain (stream);
	  mu_stream_unref (stream);
	  return status;
	}

      mu_stream_unref (stream);

      mpm->message_size = size; /* FIXME: Possible overflow. */

      mpm->flags |= _POP3_MSG_CACHED | _POP3_MSG_SIZE;
    }
  return mu_streamref_create_abridged (pstr, mpd->cache,
				       mpm->offset,
				       mpm->offset + mpm->message_size - 1);
}

static int
pop_message_get_stream (mu_message_t msg, mu_stream_t *pstr)
{
  struct _pop3_message *mpm = mu_message_get_owner (msg);
  return _pop_message_get_stream (mpm, pstr);
}

static int
pop_scan_message (struct _pop3_message *mpm)
{
  int status;
  mu_stream_t stream;
  struct mu_message_scan scan;

  if (mpm->flags & _POP3_MSG_SCANNED)
    return 0;

  status = _pop_message_get_stream (mpm, &stream);
  if (status)
    return status;

  scan.flags = MU_SCAN_SEEK | MU_SCAN_SIZE;
  scan.message_start = 0;
  scan.message_size = mpm->message_size;
  status = mu_stream_scan_message (stream, &scan);
  mu_stream_unref (stream);

  if (status == 0)
    {
      mpm->body_start = scan.body_start;
      mpm->body_end = scan.body_end;
      mpm->header_lines = scan.header_lines;
      mpm->body_lines = scan.body_lines;
      if (!(mpm->flags & _POP3_MSG_ATTRSET))
	{
	  mpm->attr_flags = scan.attr_flags;
	  mpm->flags |= _POP3_MSG_ATTRSET;
	}

      mpm->flags |= _POP3_MSG_SCANNED;
    }

  return status;
}


static int
pop_message_size (mu_message_t msg, size_t *psize)
{
  struct _pop3_message *mpm = mu_message_get_owner (msg);
  struct _pop3_mailbox *mpd = mpm->mpd;

  if (mpm == NULL)
    return EINVAL;

  if (!(mpm->flags & _POP3_MSG_SIZE))
    {
      /* FIXME: The size obtained this way may differ from the actual one
	 by the number of lines in the message. */
      int status = mu_pop3_list (mpd->pop3, mpm->num, &mpm->message_size);
      if (status)
	return status;
      mpm->flags |= _POP3_MSG_SIZE;
    }
  if (psize)
    *psize = mpm->message_size;
  return 0;
}

static int
pop_message_lines (mu_message_t msg, size_t *plines, int quick)
{
  int rc;
  struct _pop3_message *mpm = mu_message_get_owner (msg);

  if (!(mpm->flags & _POP3_MSG_LINES))
    {
      if (quick && !(mpm->flags & _POP3_MSG_CACHED))
	return MU_ERR_INFO_UNAVAILABLE;
      if (!pop_is_updated (mpm->mpd->mbox))
	pop_scan (mpm->mpd->mbox, 1, NULL);
      rc = pop_scan_message (mpm);
      if (rc)
	return rc;
      mpm->message_lines = mpm->header_lines + mpm->body_lines + 1;
      mpm->flags |= _POP3_MSG_LINES;
    }

  *plines = mpm->message_lines;
  return 0;
}

static void
pop_message_detach (mu_message_t msg)
{
  struct _pop3_message *mpm = mu_message_get_owner (msg);
  mpm->message = NULL;
}

static int
pop_create_message (struct _pop3_message *mpm, struct _pop3_mailbox *mpd)
{
  int status;
  mu_message_t msg;

  status = mu_message_create (&msg, mpm);
  if (status)
    return status;
  msg->_detach = pop_message_detach;
  mu_message_set_get_stream (msg, pop_message_get_stream, mpm);
  mu_message_set_size (msg, pop_message_size, mpm);
  mu_message_set_lines (msg, pop_message_lines, mpm);
  mpm->message = msg;
  return 0;
}

static int
pop_create_pop3_message (struct _pop3_mailbox *mpd, size_t msgno,
			 struct _pop3_message **mptr)
{
  struct _pop3_message *mpm;

  if (msgno > mpd->msg_count)
    return MU_ERR_NOENT;

  if (!mpd->msg)
    {
      mpd->msg = calloc (mpd->msg_count, sizeof (mpd->msg[0]));
      if (!mpd->msg)
	return ENOMEM;
    }
  if (mpd->msg[msgno - 1])
    {
      *mptr = mpd->msg[msgno - 1];
      return 0;
    }

  mpm = calloc (1, sizeof (*mpm));
  if (mpm == NULL)
    return ENOMEM;

  /* Back pointer.  */
  mpm->mpd = mpd;
  mpm->num = msgno;

  mpd->msg[msgno - 1] = mpm;
  *mptr = mpm;
  return 0;
}



/* ------------------------------------------------------------------------- */
/* Header */

int
pop_header_blurb (mu_stream_t stream, size_t maxlines,
		  char **pbuf, size_t *plen)
{
  int status;
  mu_opool_t opool;
  size_t size = 0;
  char *buf = NULL;
  size_t n;
  size_t nlines = 0;

  status = mu_opool_create (&opool, MU_OPOOL_DEFAULT);
  if (status)
    return status;

  while ((status = mu_stream_getline (stream, &buf, &size, &n)) == 0 && n > 0)
    {
      size_t len = mu_rtrim_class (buf, MU_CTYPE_ENDLN);
      if (len == 0)
	break;
      mu_opool_append (opool, buf, len);
      mu_opool_append_char (opool, '\n');
      if (maxlines && ++nlines >= maxlines)
	break;
    }

  if (status == 0)
    {
      n = mu_opool_size (opool);
      if (n > size)
	{
	  char *p = realloc (buf, n);
	  if (!p)
	    {
	      free (buf);
	      status = ENOMEM;
	    }
	  else
	    buf = p;
	}
    }

  if (status == 0)
    {
      mu_opool_copy (opool, buf, n);
      *pbuf = buf;
      *plen = n;
    }
  else
    free (buf);
  mu_opool_destroy (&opool);

  return 0;
}

static int
pop_header_fill (void *data, char **pbuf, size_t *plen)
{
  struct _pop3_message *mpm = data;
  struct _pop3_mailbox *mpd = mpm->mpd;
  mu_stream_t stream;
  int status;

  if (mpm->flags & _POP3_MSG_SCANNED)
    {
      status = _pop_message_get_stream (mpm, &stream);
      if (status == 0)
	{
	  status = pop_header_blurb (stream, mpm->header_lines, pbuf, plen);
	  mu_stream_destroy (&stream);
	}
    }
  else
    {
      status = mu_pop3_top (mpd->pop3, mpm->num, 0, &stream);
      if (status)
	status = _pop_message_get_stream (mpm, &stream);

      if (status == 0)
	{
	  status = pop_header_blurb (stream, 0, pbuf, plen);
	  if (!mu_stream_eof (stream))
	    pop_stream_drain (stream);
	  mu_stream_destroy (&stream);
	}
      return status;
    }

  return status;
}

static int
pop_create_header (struct _pop3_message *mpm)
{
  int status;
  mu_header_t header = NULL;

  status = mu_header_create (&header, NULL, 0);
  if (status)
    return status;
  mu_header_set_fill (header, pop_header_fill, mpm);
  mu_message_set_header (mpm->message, header, mpm);
  return 0;
}


/* ------------------------------------------------------------------------- */
/* Attributes */

/* There is no POP3 command to return message attributes, therefore we
   have to recourse to reading the "Status:" header.  Unfortunately, some
   servers remove it when you download a message, and in this case a message
   will always look like new even if you already read it.  There is also
   no way to set an attribute on remote mailbox via the POP server and
   many server once you do a RETR (and in some cases a TOP) will mark the
   message as read (Status: RO).  Even worse, some servers may be configured
   to delete after the RETR, and some go as much as deleting after the TOP,
   since technically you can download a message via TOP without RETR'eiving
   it.  */
static int
pop_get_attribute (mu_attribute_t attr, int *pflags)
{
  struct _pop3_message *mpm = mu_attribute_get_owner (attr);
  char hdr_status[64];
  mu_header_t header = NULL;

  if (mpm == NULL || pflags == NULL)
    return EINVAL;
  if (!(mpm->flags & _POP3_MSG_ATTRSET))
    {
      hdr_status[0] = '\0';

      mu_message_get_header (mpm->message, &header);
      mu_header_get_value (header, MU_HEADER_STATUS,
			   hdr_status, sizeof hdr_status, NULL);
      mu_attribute_string_to_flags (hdr_status, &mpm->attr_flags);
    }
  *pflags = mpm->attr_flags;
  return 0;
}

static int
pop_set_attribute (mu_attribute_t attr, int flags)
{
  struct _pop3_message *mpm = mu_attribute_get_owner (attr);

  if (mpm == NULL)
    return EINVAL;
  mpm->attr_flags |= flags;
  mpm->flags |= _POP3_MSG_ATTRSET;
  return 0;
}

static int
pop_unset_attribute (mu_attribute_t attr, int flags)
{
  struct _pop3_message *mpm = mu_attribute_get_owner (attr);

  if (mpm == NULL)
    return EINVAL;
  mpm->attr_flags &= ~flags;
  mpm->flags |= _POP3_MSG_ATTRSET;
  return 0;
}

static int
pop_create_attribute (struct _pop3_message *mpm)
{
  int status;
  mu_attribute_t attribute;

  status = mu_attribute_create (&attribute, mpm);
  if (status)
    return status;

  mu_attribute_set_get_flags (attribute, pop_get_attribute, mpm);
  mu_attribute_set_set_flags (attribute, pop_set_attribute, mpm);
  mu_attribute_set_unset_flags (attribute, pop_unset_attribute, mpm);
  mu_message_set_attribute (mpm->message, attribute, mpm);
  return 0;
}

/* ------------------------------------------------------------------------- */
/* Body */

int
pop_body_get_stream (mu_body_t body, mu_stream_t *pstr)
{
  mu_message_t msg = mu_body_get_owner (body);
  struct _pop3_message *mpm = mu_message_get_owner (msg);
  struct _pop3_mailbox *mpd = mpm->mpd;
  int status = pop_scan_message (mpm);
  if (status)
    return status;
  return mu_streamref_create_abridged (pstr, mpd->cache,
				       mpm->offset + mpm->body_start,
				       mpm->offset + mpm->body_end - 1);
}

static int
pop_body_size (mu_body_t body, size_t *psize)
{
  mu_message_t msg = mu_body_get_owner (body);
  struct _pop3_message *mpm = mu_message_get_owner (msg);
  int status = pop_scan_message (mpm);
  if (status)
    return status;
  *psize = mpm->body_end - mpm->body_start;
  return 0;
}

static int
pop_body_lines (mu_body_t body, size_t *plines)
{
  mu_message_t msg = mu_body_get_owner (body);
  struct _pop3_message *mpm = mu_message_get_owner (msg);
  int status = pop_scan_message (mpm);
  if (status)
    return status;
  *plines = mpm->body_lines;
  return 0;
}

static int
pop_create_body (struct _pop3_message *mpm)
{
  int status;
  mu_body_t body = NULL;
  mu_message_t msg = mpm->message;

  /* FIXME: The owner of the body *must* be the message it belongs to. */
  status = mu_body_create (&body, msg);
  if (status)
    return status;

  mu_body_set_get_stream (body, pop_body_get_stream, msg);
  mu_body_set_size (body, pop_body_size, msg);
  mu_body_set_lines (body, pop_body_lines, msg);

  mu_message_set_body (mpm->message, body, mpm);

  return 0;
}


/* FIXME: change prototype to avoid fixed size buffer */
static int
pop_uidl (mu_message_t msg, char *buffer, size_t buflen, size_t *pnwriten)
{
  struct _pop3_message *mpm = mu_message_get_owner (msg);
  struct _pop3_mailbox *mpd = mpm->mpd;
  size_t len;

  if (!mpm->uidl)
    {
      if (mu_pop3_capa_test (mpd->pop3, "UIDL", NULL) == 0)
	{
	  int status = mu_pop3_uidl (mpd->pop3, mpm->num, &mpm->uidl);
	  if (status)
	    return status;
	}
      else
	return ENOSYS;
    }

  len = strlen (mpm->uidl);
  if (buffer)
    {
      buflen--; /* Leave space for the null.  */
      buflen = (len > buflen) ? buflen : len;
      memcpy (buffer, mpm->uidl, buflen);
      buffer[buflen] = 0;
    }
  else
    buflen = len;
  if (pnwriten)
    *pnwriten = buflen;
  return 0;
}

static int
pop_uid (mu_message_t msg,  size_t *puid)
{
  struct _pop3_message *mpm = mu_message_get_owner (msg);
  if (puid)
    *puid = mpm->num;
  return 0;
}

static int
pop_get_message (mu_mailbox_t mbox, size_t msgno, mu_message_t *pmsg)
{
  struct _pop3_mailbox *mpd = mbox->data;
  struct _pop3_message *mpm;
  int status;

  /* Sanity checks. */
  if (pmsg == NULL || mpd == NULL)
    return EINVAL;

  /* If we did not start a scanning yet do it now.  */
  if (!pop_is_updated (mbox))
    pop_scan (mbox, 1, NULL);

  status = pop_create_pop3_message (mpd, msgno, &mpm);
  if (status)
    return status;
  if (mpm->message)
    {
      *pmsg = mpm->message;
      return 0;
    }

  status = pop_create_message (mpm, mpd);
  if (status)
    return status;

  do
    {
      status = pop_create_header (mpm);
      if (status)
	break;
      status = pop_create_attribute (mpm);
      if (status)
	break;
      status = pop_create_body (mpm);
    }
  while (0);

  if (status)
    {
      mu_message_destroy (&mpm->message, mpm);
      free (mpm);
      return status;
    }

  if (mu_pop3_capa_test (mpd->pop3, "UIDL", NULL) == 0)
    mu_message_set_uidl (mpm->message, pop_uidl, mpm);

  mu_message_set_uid (mpm->message, pop_uid, mpm);

  mu_message_set_mailbox (mpm->message, mbox, mpm);
  *pmsg = mpm->message;
  return 0;
}

static int
pop_expunge (mu_mailbox_t mbox)
{
  struct _pop3_mailbox *mpd = mbox->data;
  int status = 0;
  size_t i;
  size_t expcount = 0;

  if (mpd == NULL)
    return EINVAL;

  if (!mpd->msg)
    return 0;

  for (i = 0; i < mpd->msg_count; i++)
    {
      struct _pop3_message *mpm = mpd->msg[i];

      if (mpm &&
	  (mpm->flags & _POP3_MSG_ATTRSET) &&
	  (mpm->attr_flags & MU_ATTRIBUTE_DELETED))
	{
	  size_t expevt[2] = { i + 1, expcount };
	  status = mu_pop3_dele (mpd->pop3, mpm->num);
	  if (status)
	    break;
	  mu_observable_notify (mbox->observable,
				MU_EVT_MAILBOX_MESSAGE_EXPUNGE,
				&expevt);
	  ++expcount;
	}
    }
  return 0;
}

/* ------------------------------------------------------------------------- */
/* Initialization */

static int
_pop3_mailbox_init (mu_mailbox_t mbox, int pops)
{
  struct _pop3_mailbox *mpd;
  int status = 0;

  /* Allocate specifics for pop data.  */
  mpd = mbox->data = calloc (1, sizeof (*mpd));
  if (mbox->data == NULL)
    return ENOMEM;

  mpd->pop3 = NULL;

  mpd->mbox = mbox;		/* Back pointer.  */
  mpd->pops = pops;

  /* Initialize the structure.  */
  mbox->_destroy = pop_destroy;

  mbox->_open = pop_open;
  mbox->_close = pop_close;
  mbox->_messages_count = pop_messages_count;
  /* FIXME: There is no way to retrieve the number of recent messages via
     POP3 protocol, so we consider all messages recent. */
  mbox->_messages_recent = pop_messages_count;
  mbox->_is_updated = pop_is_updated;
  mbox->_scan = pop_scan;
  mbox->_message_unseen = pop_message_unseen;
  mbox->_get_size = pop_get_size;
  mbox->_get_uidls = pop_get_uidls;

  /* Messages.  */
  mbox->_get_message = pop_get_message;
  mbox->_expunge = pop_expunge;

  /* Set our properties.  */
  {
    mu_property_t property = NULL;
    mu_mailbox_get_property (mbox, &property);
    mu_property_set_value (property, "TYPE", "POP3", 1);
  }

  /* Hack! POP does not really have a folder.  */
  mbox->folder->data = mbox;
  return status;
}

int
_mailbox_pop_init (mu_mailbox_t mbox)
{
  return _pop3_mailbox_init (mbox, 0);
}

int
_mailbox_pops_init (mu_mailbox_t mbox)
{
  return _pop3_mailbox_init (mbox, 1);
}


/* ------------------------------------------------------------------------- */
/* Authentication */

/* Extract the User from the URL or the ticket.  */
static int
pop_get_user (mu_authority_t auth)
{
  mu_folder_t folder = mu_authority_get_owner (auth);
  mu_mailbox_t mbox = folder->data;
  struct _pop3_mailbox *mpd = mbox->data;
  mu_ticket_t ticket = NULL;
  int status;
  /*  Fetch the user from them.  */

  mu_authority_get_ticket (auth, &ticket);
  if (mpd->user)
    {
      free (mpd->user);
      mpd->user = NULL;
    }
  /* Was it in the URL? */
  status = mu_url_aget_user (mbox->url, &mpd->user);
  if (status == MU_ERR_NOENT)
    status = mu_ticket_get_cred (ticket, mbox->url, "Pop User: ",
				 &mpd->user, NULL);
  if (status == MU_ERR_NOENT || mpd->user == NULL)
    return MU_ERR_NOUSERNAME;
  return status;
}

/* Extract the User from the URL or the ticket.  */
static int
pop_get_passwd (mu_authority_t auth)
{
  mu_folder_t folder = mu_authority_get_owner (auth);
  mu_mailbox_t mbox = folder->data;
  struct _pop3_mailbox *mpd = mbox->data;
  mu_ticket_t ticket = NULL;
  int status;

  mu_authority_get_ticket (auth, &ticket);
  /* Was it in the URL? */
  status = mu_url_get_secret (mbox->url, &mpd->secret);
  if (status == MU_ERR_NOENT)
    status = mu_ticket_get_cred (ticket, mbox->url, "Pop Passwd: ",
				 NULL, &mpd->secret);
  if (status == MU_ERR_NOENT || !mpd->secret)
    /* FIXME: Is this always right? The user might legitimately have
       no password */
    return MU_ERR_NOPASSWORD;
  return 0;
}

int
_pop_apop (mu_authority_t auth)
{
  mu_folder_t folder = mu_authority_get_owner (auth);
  mu_mailbox_t mbox = folder->data;
  struct _pop3_mailbox *mpd = mbox->data;
  int status;

  status = pop_get_user (auth);
  if (status)
    return status;

  /* Fetch the secret from them.  */
  status = pop_get_passwd (auth);
  if (status)
    return status;
  status = mu_pop3_apop (mpd->pop3, mpd->user,
			 mu_secret_password (mpd->secret));
  mu_secret_password_unref (mpd->secret);
  mu_secret_unref (mpd->secret);
  mpd->secret = NULL;
  free (mpd->user);
  mpd->user = NULL;
  return status;
}

int
_pop_user (mu_authority_t auth)
{
  mu_folder_t folder = mu_authority_get_owner (auth);
  mu_mailbox_t mbox = folder->data;
  struct _pop3_mailbox *mpd = mbox->data;
  int status;

  status = pop_get_user (auth);
  if (status)
    return status;
  status = mu_pop3_user (mpd->pop3, mpd->user);
  if (status == 0)
    {
      /* Fetch the secret from them.  */
      status = pop_get_passwd (auth);
      if (status == 0)
	{
	  status = mu_pop3_pass (mpd->pop3, mu_secret_password (mpd->secret));
	  mu_secret_password_unref (mpd->secret);
	  mu_secret_unref (mpd->secret);
	  mpd->secret = NULL;
	}
    }
  free (mpd->user);
  mpd->user = NULL;
  return status;
}


#endif /* ENABLE_POP */
