/* GNU Mailutils -- a suite of utilities for electronic mail
   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2006, 2007, 2008, 2009,
   2010, 2011 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

#include <stdlib.h>
#include <errno.h>
#include <string.h>

#include <mailutils/debug.h>
#include <mailutils/errno.h>
#include <mailutils/error.h>
#include <mailutils/folder.h>
#include <mailutils/iterator.h>
#include <mailutils/list.h>
#include <mailutils/locker.h>
#include <mailutils/observer.h>
#include <mailutils/property.h>
#include <mailutils/registrar.h>
#include <mailutils/stream.h>
#include <mailutils/url.h>
#include <mailutils/attribute.h>
#include <mailutils/message.h>
#include <mailutils/util.h>

#include <mailutils/sys/mailbox.h>
#include <mailutils/sys/url.h>

/* Mailbox-specific flags */
#define _MU_MAILBOX_OPEN    0x10000000
#define _MU_MAILBOX_REMOVED 0x20000000
#define _MU_MAILBOX_MASK    0xF0000000

static int
mailbox_folder_create (mu_mailbox_t mbox, const char *name,
		       mu_record_t record)
{
  int rc;
  mu_url_t url;
  
  if ((rc = mu_url_uplevel (mbox->url, &url)))
    {
      if (rc == MU_ERR_NOENT)
	{
	  rc = mu_url_dup (mbox->url, &url);
	  if (rc)
	    return rc;
	}
      else
	return rc;
    }

  rc = mu_folder_create_from_record (&mbox->folder, url, record);
  if (rc)
    mu_url_destroy (&url);
  return rc;
}

int
_mailbox_create_from_record (mu_mailbox_t *pmbox,
			     mu_record_t record,
			     mu_url_t url, 
			     const char *name)
{
  int (*m_init) (mu_mailbox_t) = NULL;
      
  mu_record_get_mailbox (record, &m_init);
  if (m_init)
    {
      int status;
      int (*u_init) (mu_url_t) = NULL;
      mu_mailbox_t mbox;
      
      /* Allocate memory for mbox.  */
      mbox = calloc (1, sizeof (*mbox));
      if (mbox == NULL)
	return ENOMEM;
      
      /* Initialize the internal lock now, so the concrete mailbox
	 could use it. */
      status = mu_monitor_create (&mbox->monitor, 0, mbox);
      if (status != 0)
	{
	  mu_mailbox_destroy (&mbox);
	  return status;
	}
      
      /* Make sure scheme contains actual mailbox scheme */
      /* FIXME: It is appropriate not for all record types.  For now we
	 assume that if the record scheme ends with a plus sign, this
	 should not be done.  Probably it requires some flag in struct
	 _mu_record? */
      if (strcmp (url->scheme, record->scheme))
	{
	  char *p = strdup (record->scheme);
	  if (!p)
	    {
	      mu_mailbox_destroy (&mbox);
	      return errno;
	    }
	  free (url->scheme);
	  url->scheme = p;
	}
      
      mu_record_get_url (record, &u_init);
      if (u_init && (status = u_init (url)) != 0)
	{
	  mu_mailbox_destroy (&mbox);
	  return status;
	}
      
      mbox->url = url;
      
      /* Create the folder before initializing the concrete mailbox.
	 The mailbox needs it's back pointer. */
      status = mailbox_folder_create (mbox, name, record);
      
      if (status == 0)
	status = m_init (mbox);   /* Create the concrete mailbox type.  */
      
      if (status != 0)
	{
	  /* Take care not to destroy url.  Leave it to caller. */
	  mbox->url = NULL;
	  mu_mailbox_destroy (&mbox);
	}
      else
	*pmbox = mbox;
      return status;
    }
  return ENOSYS;
}

static int
_create_mailbox0 (mu_mailbox_t *pmbox, mu_url_t url, const char *name)
{
  mu_record_t record = NULL;

  if (mu_registrar_lookup_url (url, MU_FOLDER_ATTRIBUTE_FILE, &record, NULL)
      == 0)
    return _mailbox_create_from_record (pmbox, record, url, name);
  return ENOSYS;
}

static int
_create_mailbox (mu_mailbox_t *pmbox, const char *name)
{
  int status;
  mu_url_t url;

  status = mu_url_create (&url, name);
  if (status)
    return status;
  status = _create_mailbox0 (pmbox, url, name);
  if (status)
    mu_url_destroy (&url);
  return status;
}

/* The Mailbox Factory.
 */
int
mu_mailbox_create (mu_mailbox_t *pmbox, const char *name)
{
  if (pmbox == NULL)
    return MU_ERR_OUT_PTR_NULL;

  return _create_mailbox (pmbox, name);
}

int
mu_mailbox_create_from_url (mu_mailbox_t *pmbox, mu_url_t url)
{
  if (pmbox == NULL)
    return MU_ERR_OUT_PTR_NULL;
  return _create_mailbox0 (pmbox, url, mu_url_to_string (url));
}

int
mu_mailbox_create_from_record (mu_mailbox_t *pmbox, mu_record_t record,
			       const char *name)
{
  mu_url_t url;
  int rc;
  
  rc = mu_url_create (&url, name);
  if (rc)
    return rc;
  rc = _mailbox_create_from_record (pmbox, record, url, name);
  if (rc)
    mu_url_destroy (&url);
  return rc;
}

void
mu_mailbox_destroy (mu_mailbox_t *pmbox)
{
  if (pmbox && *pmbox)
    {
      mu_mailbox_t mbox = *pmbox;
      mu_monitor_t monitor = mbox->monitor;

      /* Notify the observers.  */
      if (mbox->observable)
	{
	  mu_observable_notify (mbox->observable, MU_EVT_MAILBOX_DESTROY,
				mbox);
	  mu_observable_destroy (&mbox->observable, mbox);
	}

      /* Call the concrete mailbox _destroy method. So it can clean itself.  */
      if (mbox->_destroy)
	mbox->_destroy (mbox);

      mu_monitor_wrlock (monitor);

      /* Close the stream and nuke it */
      if (mbox->stream)
	{
	  /* FIXME: Is this right, should the client be responsible
	     for closing the stream?  */
	  /* mu_stream_close (mbox->stream); */
	  mu_stream_destroy (&mbox->stream);
	}

      if (mbox->url)
        mu_url_destroy (&mbox->url);

      if (mbox->locker)
	mu_locker_destroy (&mbox->locker);

      if (mbox->folder)
	mu_folder_destroy (&mbox->folder);

      if (mbox->property)
	mu_property_destroy (&mbox->property);

      free (mbox);
      *pmbox = NULL;
      mu_monitor_unlock (monitor);
      mu_monitor_destroy (&monitor, mbox);
    }
}


/* -------------- stub functions ------------------- */

int
mu_mailbox_open (mu_mailbox_t mbox, int flag)
{
  int rc;
  
  if (!mbox)
    return EINVAL;
  if (mbox->_open == NULL)
    return MU_ERR_EMPTY_VFN;
  if (mbox->flags & _MU_MAILBOX_OPEN)
    return MU_ERR_OPEN;
  if (flag & MU_STREAM_QACCESS)
    {
      /* Quick access mailboxes are read-only */
      if (flag & (MU_STREAM_WRITE 
		  | MU_STREAM_APPEND | MU_STREAM_CREAT))
	return EACCES;
    }
  rc = mbox->_open (mbox, flag);
  if (rc == 0)
    mbox->flags |= _MU_MAILBOX_OPEN;
  return rc;
}

int
mu_mailbox_close (mu_mailbox_t mbox)
{
  int rc;

  if (!mbox)
    return EINVAL;
  if (!(mbox->flags & _MU_MAILBOX_OPEN))
    return MU_ERR_NOT_OPEN;
  if (mbox == NULL || mbox->_close == NULL)
    return MU_ERR_EMPTY_VFN;

  rc = mbox->_close (mbox);
  if (rc == 0)
    mbox->flags &= ~_MU_MAILBOX_OPEN;
  return rc;
}

int
mu_mailbox_remove (mu_mailbox_t mbox)
{
  if (!mbox)
    return EINVAL;
  if (mbox->flags & _MU_MAILBOX_OPEN)
    return MU_ERR_OPEN;
  if (mbox->flags & _MU_MAILBOX_REMOVED)
    return MU_ERR_MBX_REMOVED;
  if (!mbox->_remove)
    return MU_ERR_EMPTY_VFN;
  return mbox->_remove (mbox);
}

int
mu_mailbox_flush (mu_mailbox_t mbox, int expunge)
{
  size_t i, total = 0;
  int status = 0;
  
  if (!mbox)
    return EINVAL;
  if (mbox->flags & _MU_MAILBOX_REMOVED)
    return MU_ERR_MBX_REMOVED;
  if (!(mbox->flags & _MU_MAILBOX_OPEN))
    return _MU_MAILBOX_OPEN;
  if (!(mbox->flags & (MU_STREAM_WRITE|MU_STREAM_APPEND)))
    return 0;

  mu_mailbox_messages_count (mbox, &total);
  if (!(mbox->flags & MU_STREAM_APPEND))
    for (i = 1; i <= total; i++)
      {
	mu_message_t msg = NULL;
	mu_attribute_t attr = NULL;
	mu_mailbox_get_message (mbox, i, &msg);
	mu_message_get_attribute (msg, &attr);
	mu_attribute_set_seen (attr);
      }

  if (expunge)
    status = mu_mailbox_expunge (mbox);
  else
    status = mu_mailbox_sync (mbox);

  return status;
}

#define _MBOX_CHECK_FLAGS(mbox)			\
  if (mbox == NULL)				\
    return EINVAL;			        \
  if (mbox->flags & _MU_MAILBOX_REMOVED)	\
    return MU_ERR_MBX_REMOVED;			\
  if (!(mbox->flags & _MU_MAILBOX_OPEN))	\
    return _MU_MAILBOX_OPEN

#define _MBOX_CHECK(mbox,method)		\
  _MBOX_CHECK_FLAGS(mbox);			\
  if (mbox->method == NULL)			\
    return MU_ERR_EMPTY_VFN

#define _MBOX_CHECK_Q(mbox,method)		\
  _MBOX_CHECK(mbox,method);			\
  if (mbox->flags & MU_STREAM_QACCESS)		\
    return MU_ERR_BADOP

/* messages */
int
mu_mailbox_append_message (mu_mailbox_t mbox, mu_message_t msg)
{
  _MBOX_CHECK_Q (mbox, _append_message);
  if (!(mbox->flags & (MU_STREAM_WRITE|MU_STREAM_APPEND)))
    return EACCES;
  return mbox->_append_message (mbox, msg);
}

int
mu_mailbox_get_message (mu_mailbox_t mbox, size_t msgno,  mu_message_t *pmsg)
{
  _MBOX_CHECK_Q (mbox, _get_message);
  return mbox->_get_message (mbox, msgno, pmsg);
}

int
mu_mailbox_quick_get_message (mu_mailbox_t mbox, mu_message_qid_t qid,
			      mu_message_t *pmsg)
{
  _MBOX_CHECK (mbox, _quick_get_message);
  if (!(mbox->flags & MU_STREAM_QACCESS))
    return MU_ERR_BADOP;
  return mbox->_quick_get_message (mbox, qid, pmsg);
}

int
mu_mailbox_messages_count (mu_mailbox_t mbox, size_t *num)
{
  _MBOX_CHECK_Q (mbox, _messages_count);
  return mbox->_messages_count (mbox, num);
}

int
mu_mailbox_messages_recent (mu_mailbox_t mbox, size_t *num)
{
  _MBOX_CHECK_Q (mbox, _messages_recent);
  return mbox->_messages_recent (mbox, num);
}

int
mu_mailbox_message_unseen (mu_mailbox_t mbox, size_t *num)
{
  _MBOX_CHECK_Q (mbox, _message_unseen);
  return mbox->_message_unseen (mbox, num);
}

int
mu_mailbox_sync (mu_mailbox_t mbox)
{
  _MBOX_CHECK_Q (mbox, _sync);
  if (!(mbox->flags & (MU_STREAM_WRITE|MU_STREAM_APPEND)))
    return 0;
  return mbox->_sync (mbox);
}

/* Historic alias: */
int
mu_mailbox_save_attributes (mu_mailbox_t mbox)
{
  return mu_mailbox_sync (mbox);
}

int
mu_mailbox_expunge (mu_mailbox_t mbox)
{
  _MBOX_CHECK_Q (mbox, _expunge);
  if (!(mbox->flags & (MU_STREAM_WRITE|MU_STREAM_APPEND)))
    return EACCES;
  return mbox->_expunge (mbox);
}

int
mu_mailbox_is_updated (mu_mailbox_t mbox)
{
  if (mbox == NULL ||
      !(mbox->flags & _MU_MAILBOX_OPEN) ||
      (mbox->flags & _MU_MAILBOX_REMOVED) ||
      mbox->_is_updated == NULL)
    return 1;
  if (mbox->flags & MU_STREAM_QACCESS)
    return 1;
  return mbox->_is_updated (mbox);
}

int
mu_mailbox_scan (mu_mailbox_t mbox, size_t msgno, size_t *pcount)
{
  _MBOX_CHECK_Q (mbox, _scan);
  return mbox->_scan (mbox, msgno, pcount);
}

int
mu_mailbox_get_size (mu_mailbox_t mbox, mu_off_t *psize)
{
  int status;

  _MBOX_CHECK_FLAGS (mbox);
  if (mbox->flags & MU_STREAM_QACCESS)
    return MU_ERR_BADOP;
  if (mbox->_get_size == NULL
      || (status = mbox->_get_size (mbox, psize)) == ENOSYS)
    {
      /* Fall back to brute-force method */
      size_t i, total;
      mu_off_t size = 0;
      
      status = mu_mailbox_messages_count (mbox, &total);
      if (status)
	return status;
      for (i = 1; i <= total; i++)
	{
	  mu_message_t msg;
	  size_t msgsize;
	  status = mu_mailbox_get_message (mbox, i, &msg);
	  if (status)
	    return status;
	  status = mu_message_size (msg, &msgsize);
	  if (status)
	    return status;
	  size += msgsize;
	}
      *psize = size;
    }
  return status;
}

int
mu_mailbox_uidvalidity (mu_mailbox_t mbox, unsigned long *pvalid)
{
  _MBOX_CHECK_Q (mbox, _uidvalidity);
  return mbox->_uidvalidity (mbox, pvalid);
}

int
mu_mailbox_uidnext (mu_mailbox_t mbox, size_t *puidnext)
{
  _MBOX_CHECK_Q (mbox, _uidnext);
  return mbox->_uidnext (mbox, puidnext);
}

/* locking */
int
mu_mailbox_set_locker (mu_mailbox_t mbox, mu_locker_t locker)
{
  if (mbox == NULL)
    return EINVAL;
  if (mbox->locker)
    mu_locker_destroy (&mbox->locker);
  mbox->locker = locker;
  return 0;
}

int
mu_mailbox_get_locker (mu_mailbox_t mbox, mu_locker_t *plocker)
{
  if (mbox == NULL)
    return EINVAL;
  if (plocker == NULL)
    return MU_ERR_OUT_PTR_NULL;
  *plocker = mbox->locker;
  return 0;
}

int
mu_mailbox_get_flags (mu_mailbox_t mbox, int *flags)
{
  if (mbox == NULL)
    return EINVAL;
  if (!flags)
    return MU_ERR_OUT_PTR_NULL;
  *flags = mbox->flags & ~_MU_MAILBOX_MASK;
  return 0;
}

int
mu_mailbox_set_stream (mu_mailbox_t mbox, mu_stream_t stream)
{
  if (mbox == NULL)
    return EINVAL;
  if (mbox->flags & MU_STREAM_QACCESS)
    return MU_ERR_BADOP;
  if (mbox->stream)
    mu_stream_destroy (&mbox->stream);
  mbox->stream = stream;
  return 0;
}

/* FIXME: This is a problem.  We provide a mu_mailbox_get_stream ()
   and this stream is special: it should, in theory, represent
   a "view" of a flow of messages.  However, providing this perspective
   may make sense for local mailboxes, but downright impossible
   for remote mailboxes, short on downloading entire mailbox
   locally.

   This function will be removed in the short run.  It is no longer
   used by MU.  */
int
mu_mailbox_get_stream (mu_mailbox_t mbox, mu_stream_t *pstream)
{
  /* FIXME: Deprecation warning */
  if (mbox == NULL)
    return EINVAL;
  if (pstream == NULL)
    return MU_ERR_OUT_PTR_NULL;

  /* If null two cases:
     - it is no open yet.
     - it a remote stream and the socket stream is on the folder.  */
  if (mbox->stream == NULL)
    {
      if (mbox->folder)
	return mu_folder_get_stream (mbox->folder, pstream);
    }
  *pstream = mbox->stream;
  return 0;
}

int
mu_mailbox_get_streamref (mu_mailbox_t mbox, mu_stream_t *pstream)
{
  if (mbox == NULL)
    return EINVAL;
  if (pstream == NULL)
    return MU_ERR_OUT_PTR_NULL;

  /* If null two cases:
     - it is no open yet.
     - it a remote stream and the socket stream is on the folder.  */
  if (mbox->stream == NULL)
    {
      if (mbox->folder)
	return mu_folder_get_streamref (mbox->folder, pstream);
    }
  return mu_streamref_create (pstream, mbox->stream);
}

int
mu_mailbox_get_observable (mu_mailbox_t mbox, mu_observable_t *pobservable)
{
  if (mbox == NULL)
    return EINVAL;
  if (pobservable == NULL)
    return MU_ERR_OUT_PTR_NULL;

  if (mbox->observable == NULL)
    {
      int status = mu_observable_create (&mbox->observable, mbox);
      if (status != 0)
	return status;
    }
  *pobservable = mbox->observable;
  return 0;
}

int
mu_mailbox_set_property (mu_mailbox_t mbox, mu_property_t property)
{
  if (mbox == NULL)
    return EINVAL;
  if (mbox->property)
    mu_property_unref (mbox->property);
  mbox->property = property;
  mu_property_ref (property);
  return 0;
}

int
mu_mailbox_get_property (mu_mailbox_t mbox, mu_property_t *pproperty)
{
  if (mbox == NULL)
    return EINVAL;
  if (pproperty == NULL)
    return MU_ERR_OUT_PTR_NULL;
  
  if (mbox->property == NULL)
    {
      int status;

      if (mbox->_get_property)
	status = mbox->_get_property (mbox, &mbox->property);
      else
	status = mu_property_create_init (&mbox->property,
					  mu_assoc_property_init, NULL);
      if (status != 0)
	return status;
    }
  *pproperty = mbox->property;
  return 0;
}

int
mu_mailbox_get_url (mu_mailbox_t mbox, mu_url_t *purl)
{
  if (mbox == NULL)
    return EINVAL;
  if (purl == NULL)
    return MU_ERR_OUT_PTR_NULL;
  *purl = mbox->url;
  return 0;
}

int
mu_mailbox_get_folder (mu_mailbox_t mbox, mu_folder_t *pfolder)
{
  if (mbox == NULL)
    return EINVAL;
  if (pfolder == NULL)
    return MU_ERR_OUT_PTR_NULL;
  *pfolder = mbox->folder;
  return 0;
}

int
mu_mailbox_set_folder (mu_mailbox_t mbox, mu_folder_t folder)
{
  if (mbox == NULL)
    return EINVAL;
   mbox->folder = folder;
  return 0;
}

int
mu_mailbox_lock (mu_mailbox_t mbox)
{
  mu_locker_t lock = NULL;
  mu_mailbox_get_locker (mbox, &lock);
  return mu_locker_lock (lock);
}

int
mu_mailbox_unlock (mu_mailbox_t mbox)
{
  mu_locker_t lock = NULL;
  mu_mailbox_get_locker (mbox, &lock);
  return mu_locker_unlock (lock);
}

int
mu_mailbox_get_uidls (mu_mailbox_t mbox, mu_list_t *plist)
{
  mu_list_t list;
  int status;

  if (mbox == NULL)
    return EINVAL;
  if (plist == NULL)
    return MU_ERR_OUT_PTR_NULL;
  status = mu_list_create (&list);
  if (status)
    return status;
  mu_list_set_destroy_item (list, mu_list_free_item);
  if (mbox->_get_uidls)
    status = mbox->_get_uidls (mbox, list);
  else
    {
      size_t i, total;

      status = mu_mailbox_messages_count (mbox, &total);
      if (status)
	return status;
      for (i = 1; i <= total; i++)
	{
	  mu_message_t msg = NULL;
	  char buf[MU_UIDL_BUFFER_SIZE];
	  size_t n;
	  struct mu_uidl *uidl;
	  
	  status = mu_mailbox_get_message (mbox, i, &msg);
	  if (status)
	    break;
	  status = mu_message_get_uidl (msg, buf, sizeof (buf), &n);
	  if (status)
	    break;
	  uidl = malloc (sizeof (uidl[0]));
	  if (!uidl)
	    {
	      status = ENOMEM;
	      break;
	    }
	  uidl->msgno = i;
	  strncpy (uidl->uidl, strdup (buf), MU_UIDL_BUFFER_SIZE);
	  status = mu_list_append (list, uidl);
	  if (status)
	    {
	      free (uidl);
	      break;
	    }
	}
    }
  *plist = list;
  return status;
}


/* Auxiliary function. Performs binary search for a message with the
   given UID number */
static int
_uid_bsearch (mu_mailbox_t mbox, size_t start, size_t stop, size_t uid,
	      size_t *msgno)
{
  mu_message_t mid_msg = NULL;
  size_t num = 0, middle;
  int rc;
  
  middle = (start + stop) / 2;
  rc = mu_mailbox_get_message (mbox, middle, &mid_msg);
  if (rc)
    return rc;
  rc = mu_message_get_uid (mid_msg, &num);
  if (rc)
    return rc;

  if (num == uid)
    {
      *msgno = middle;
      return 0;
    }
      
  if (start >= stop)
    return MU_ERR_NOENT;

  if (num > uid)
    return _uid_bsearch (mbox, start, middle - 1, uid, msgno);
  else /*if (num < seqno)*/
    return _uid_bsearch (mbox, middle + 1, stop, uid, msgno);
}

static int
_search_message_uid (mu_mailbox_t mbox, size_t uid, size_t *result)
{
  int rc;
  size_t num, count;
  mu_message_t msg;

  rc = mu_mailbox_get_message (mbox, 1, &msg);
  if (rc)
    return rc;
  rc = mu_message_get_uid (msg, &num);
  if (rc)
    return rc;
  if (uid < num)
    return MU_ERR_NOENT;
  else if (uid == num)
    {
      *result = 1;
      return 0;
    }

  rc = mu_mailbox_messages_count (mbox, &count);
  if (rc)
    return rc;
  rc = mu_mailbox_get_message (mbox, count, &msg);
  if (rc)
    return rc;
  rc = mu_message_get_uid (msg, &num);
  if (rc)
    return rc;

  if (uid > num)
    return MU_ERR_NOENT;
  else if (uid == num)
    {
      *result = count;
      return 0;
    }
  return _uid_bsearch (mbox, 1, count, uid, result);
}

/* Translat message UIDs to message numbers and vice versa. */
int
mu_mailbox_translate (mu_mailbox_t mbox, int cmd, size_t from, size_t *to)
{
  int rc = ENOSYS;
  mu_message_t msg;
  
  if (mbox == NULL)
    return EINVAL;
  if (to == NULL)
    return MU_ERR_OUT_PTR_NULL;
  if (mbox->flags & MU_STREAM_QACCESS)
    return MU_ERR_BADOP;

  if (mbox->_translate)
    rc = mbox->_translate (mbox, cmd, from, to);
  if (rc == ENOSYS)
    {
      switch (cmd)
	{
	case MU_MAILBOX_UID_TO_MSGNO:
	  rc = _search_message_uid (mbox, from, to);
	  break;
	  
	case MU_MAILBOX_MSGNO_TO_UID:
	  rc = mu_mailbox_get_message (mbox, from, &msg);
	  if (rc)
	    return rc;
	  rc = mu_message_get_uid (msg, to);
	  break;
	  
	default:
	  break;
	}
    }
  return rc;
}