/* GIO - GLib Input, Output and Streaming Library
 * 
 * Copyright (C) 2006-2007 Red Hat, 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 2 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/>.
 *
 * Authors: Alexander Larsson <alexl@redhat.com>
 *          John McCutchan <john@johnmccutchan.com> 
 *          Sebastian Dröge <slomo@circular-chaos.org>
 */

#include "config.h"
#include <fam.h>
#include <gio/gfilemonitor.h>
#include <gio/gfile.h>

#include "fam-helper.h"

static FAMConnection* fam_connection = NULL;
static gint fam_watch_id = 0;
G_LOCK_DEFINE_STATIC(fam_connection);

struct _fam_sub
{
  gchar *pathname;
  gboolean directory;
  gpointer user_data;
  gboolean cancelled;
  FAMRequest request;
};

/* This uses int as the argument type because the
   real type differs between implementations:
   gamin has "typedef enum FAMCodes {....} FAMCodes;"
   fam has "enum FAMCodes { ... }".
*/
static GFileMonitorEvent  
fam_event_to_file_monitor_event (int code)
{
  switch (code)
    {
    case FAMChanged:
      return G_FILE_MONITOR_EVENT_CHANGED;
      break;
    case FAMDeleted:
      return G_FILE_MONITOR_EVENT_DELETED;
      break;
    case FAMCreated:
      return G_FILE_MONITOR_EVENT_CREATED;
      break;
    default:
      return -1;
      break;
    }
}

static gboolean
fam_do_iter_unlocked (void)
{
  while (fam_connection != NULL && FAMPending (fam_connection)) 
    {
      FAMEvent ev;
      fam_sub* sub = NULL;
      gboolean cancelled;
    
      if (FAMNextEvent (fam_connection, &ev) != 1) 
        {
          FAMClose (fam_connection);
          g_free (fam_connection);
          g_source_remove (fam_watch_id);
          fam_watch_id = 0;
          fam_connection = NULL;
          return FALSE;
        }
    
      sub = (fam_sub*)ev.userdata;
      cancelled = sub->cancelled;
      if (ev.code == FAMAcknowledge && cancelled)
        {
	  _fam_sub_free (sub);
	  continue;
        }
    
      if (cancelled)
        continue;
    
      if (sub->directory)
        {
	  GFileMonitor* monitor = G_FILE_MONITOR (sub->user_data);
	  GFileMonitorEvent eflags = fam_event_to_file_monitor_event (ev.code);
	  gchar* path = NULL;
	  GFile *child, *parent;
	
	  /* unsupported event */
	  if (eflags == -1)
	    continue;
	
	  if (ev.filename[0] == '/')
	    path = g_strdup (ev.filename);
	  else
	    path = g_strdup_printf ("%s/%s", sub->pathname, ev.filename);

	  child = g_file_new_for_path (path);
	  parent = g_file_get_parent (child);
	  g_file_monitor_emit_event (monitor, child, NULL, eflags);
	  g_free (path);
	  g_object_unref (child);
	  g_object_unref (parent);
        } 
      else 
        {
	  GFile *child;
	  GFileMonitor* monitor = G_FILE_MONITOR (sub->user_data);
	  GFileMonitorEvent eflags = fam_event_to_file_monitor_event (ev.code);
	  gchar* path = NULL;
      
	  if (eflags == -1)
	    continue;
	  path = g_strdup (ev.filename);
	  child = g_file_new_for_path (path);
	  g_file_monitor_emit_event (monitor, child, NULL, eflags);
	  g_free (path);
	  g_object_unref (child);
        }
    }
  
  return TRUE;
}

static gboolean
fam_callback (GIOChannel   *source,
              GIOCondition  condition,
              gpointer      data)
{
  gboolean res;
  G_LOCK (fam_connection);
  
  res = fam_do_iter_unlocked ();
  
  G_UNLOCK (fam_connection);
  return res;
}

gboolean
_fam_sub_startup (void)
{
  GIOChannel *ioc;
  
  G_LOCK (fam_connection);
  
  if (fam_connection == NULL) 
    {
      fam_connection = g_new0 (FAMConnection, 1);
      if (FAMOpen2 (fam_connection, "gvfs user") != 0) 
        {
          g_warning ("FAMOpen failed, FAMErrno=%d\n", FAMErrno);
          g_free (fam_connection);
          fam_connection = NULL;
          G_UNLOCK (fam_connection);
          return FALSE;
        }
#ifdef HAVE_FAM_NO_EXISTS
    /* This is a gamin extension that avoids sending all the Exists event for dir monitors */
      FAMNoExists (fam_connection);
#endif
      ioc = g_io_channel_unix_new (FAMCONNECTION_GETFD(fam_connection));
      fam_watch_id = g_io_add_watch (ioc,
  				     G_IO_IN | G_IO_HUP | G_IO_ERR,
				     fam_callback, fam_connection);
      g_io_channel_unref (ioc);
    }
  
  G_UNLOCK (fam_connection);
  
  return TRUE;
}

void
_fam_sub_shutdown (void)
{
  G_LOCK (fam_connection);

  if (fam_connection != NULL) 
    {
      FAMClose (fam_connection);
      g_free (fam_connection);
      g_source_remove (fam_watch_id);
      fam_watch_id = 0;
      fam_connection = NULL;
    }

  G_UNLOCK (fam_connection);
}

fam_sub*
_fam_sub_add (const gchar *pathname,
	      gboolean     directory,
	      gpointer     user_data)
{
  fam_sub *sub;

  if (!_fam_sub_startup ())
    return NULL;
  
  G_LOCK (fam_connection);
  /* We need to queue up incoming messages to avoid blocking on write
   *  if there are many monitors being canceled */
  fam_do_iter_unlocked ();
  
  if (fam_connection == NULL) 
    {
      G_UNLOCK (fam_connection);
      return NULL;
    }

  sub = g_new0 (fam_sub, 1);
  sub->pathname = g_strdup (pathname);
  sub->directory = directory;
  sub->user_data = user_data;
  
  if (directory)
    FAMMonitorDirectory (fam_connection, pathname, &sub->request, sub);
  else
    FAMMonitorFile (fam_connection, pathname, &sub->request, sub);
  
  G_UNLOCK (fam_connection);

  return sub;
}

gboolean
_fam_sub_cancel (fam_sub* sub)
{
  if (sub->cancelled)
    return TRUE;
  
  sub->cancelled = TRUE;
  
  G_LOCK (fam_connection);
  /* We need to queue up incoming messages to avoid blocking on write
   *  if there are many monitors being canceled */
  fam_do_iter_unlocked ();
  
  if (fam_connection == NULL) 
    {
      G_UNLOCK (fam_connection);
      return FALSE;
    }
  
  FAMCancelMonitor (fam_connection, &sub->request);
  
  G_UNLOCK (fam_connection);
  
  return TRUE;
}

void
_fam_sub_free (fam_sub* sub)
{
  g_free (sub->pathname);
  g_free (sub);
}

