/* GTK - The GIMP Toolkit
 * gtkprintbackend.h: Abstract printer backend interfaces
 * Copyright (C) 2003, 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, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include "config.h"
#include <string.h>

#include <gmodule.h>

#include "gtkintl.h"
#include "gtkmodules.h"
#include "gtkprivate.h"
#include "gtkprintbackend.h"
#include "gtkalias.h"

#define GTK_PRINT_BACKEND_GET_PRIVATE(o)  \
   (G_TYPE_INSTANCE_GET_PRIVATE ((o), GTK_TYPE_PRINT_BACKEND, GtkPrintBackendPrivate))

static void gtk_print_backend_dispose (GObject *object);

struct _GtkPrintBackendPrivate
{
  GHashTable *printers;
  guint printer_list_requested : 1;
  guint printer_list_done : 1;
};

enum {
  PRINTER_LIST_CHANGED,
  PRINTER_LIST_DONE,
  PRINTER_ADDED,
  PRINTER_REMOVED,
  PRINTER_STATUS_CHANGED,
  LAST_SIGNAL
};

static guint signals[LAST_SIGNAL] = { 0 };

static GObjectClass *backend_parent_class;

GQuark
gtk_print_backend_error_quark (void)
{
  static GQuark quark = 0;
  if (quark == 0)
    quark = g_quark_from_static_string ("gtk-print-backend-error-quark");
  return quark;
}

/*****************************************
 *     GtkPrintBackendModule modules     *
 *****************************************/

typedef struct _GtkPrintBackendModule GtkPrintBackendModule;
typedef struct _GtkPrintBackendModuleClass GtkPrintBackendModuleClass;

struct _GtkPrintBackendModule
{
  GTypeModule parent_instance;
  
  GModule *library;

  void             (*init)     (GTypeModule    *module);
  void             (*exit)     (void);
  GtkPrintBackend* (*create)   (void);

  gchar *path;
};

struct _GtkPrintBackendModuleClass
{
  GTypeModuleClass parent_class;
};

G_DEFINE_TYPE (GtkPrintBackendModule, _gtk_print_backend_module, G_TYPE_TYPE_MODULE);
#define GTK_TYPE_PRINT_BACKEND_MODULE      (_gtk_print_backend_module_get_type ())
#define GTK_PRINT_BACKEND_MODULE(module)   (G_TYPE_CHECK_INSTANCE_CAST ((module), GTK_TYPE_PRINT_BACKEND_MODULE, GtkPrintBackendModule))

static GSList *loaded_backends;

static gboolean
gtk_print_backend_module_load (GTypeModule *module)
{
  GtkPrintBackendModule *pb_module = GTK_PRINT_BACKEND_MODULE (module); 
  gpointer initp, exitp, createp;
 
  pb_module->library = g_module_open (pb_module->path, G_MODULE_BIND_LAZY | G_MODULE_BIND_LOCAL);
  if (!pb_module->library)
    {
      g_warning (g_module_error());
      return FALSE;
    }
  
  /* extract symbols from the lib */
  if (!g_module_symbol (pb_module->library, "pb_module_init",
			&initp) ||
      !g_module_symbol (pb_module->library, "pb_module_exit", 
			&exitp) ||
      !g_module_symbol (pb_module->library, "pb_module_create", 
			&createp))
    {
      g_warning (g_module_error());
      g_module_close (pb_module->library);
      
      return FALSE;
    }

  pb_module->init = initp;
  pb_module->exit = exitp;
  pb_module->create = createp;

  /* call the filesystems's init function to let it */
  /* setup anything it needs to set up. */
  pb_module->init (module);

  return TRUE;
}

static void
gtk_print_backend_module_unload (GTypeModule *module)
{
  GtkPrintBackendModule *pb_module = GTK_PRINT_BACKEND_MODULE (module);
  
  pb_module->exit();

  g_module_close (pb_module->library);
  pb_module->library = NULL;

  pb_module->init = NULL;
  pb_module->exit = NULL;
  pb_module->create = NULL;
}

/* This only will ever be called if an error occurs during
 * initialization
 */
static void
gtk_print_backend_module_finalize (GObject *object)
{
  GtkPrintBackendModule *module = GTK_PRINT_BACKEND_MODULE (object);

  g_free (module->path);

  G_OBJECT_CLASS (_gtk_print_backend_module_parent_class)->finalize (object);
}

static void
_gtk_print_backend_module_class_init (GtkPrintBackendModuleClass *class)
{
  GTypeModuleClass *module_class = G_TYPE_MODULE_CLASS (class);
  GObjectClass *gobject_class = G_OBJECT_CLASS (class);

  module_class->load = gtk_print_backend_module_load;
  module_class->unload = gtk_print_backend_module_unload;

  gobject_class->finalize = gtk_print_backend_module_finalize;
}

static void
_gtk_print_backend_module_init (GtkPrintBackendModule *pb_module)
{
}

static GtkPrintBackend *
_gtk_print_backend_module_create (GtkPrintBackendModule *pb_module)
{
  GtkPrintBackend *pb;
  
  if (g_type_module_use (G_TYPE_MODULE (pb_module)))
    {
      pb = pb_module->create ();
      g_type_module_unuse (G_TYPE_MODULE (pb_module));
      return pb;
    }
  return NULL;
}

GtkPrintBackend *
_gtk_print_backend_create (const char *backend_name)
{
  GSList *l;
  char *module_path;
  char *full_name;
  GtkPrintBackendModule *pb_module;
  GtkPrintBackend *pb;

  /* TODO: make module loading code work */
  for (l = loaded_backends; l != NULL; l = l->next)
    {
      pb_module = l->data;
      
      if (strcmp (G_TYPE_MODULE (pb_module)->name, backend_name) == 0)
	return _gtk_print_backend_module_create (pb_module);
    }

  pb = NULL;
  if (g_module_supported ())
    {
      full_name = g_strconcat ("printbackend-", backend_name, NULL);
      module_path = _gtk_find_module (full_name, "printbackends");
      g_free (full_name);

      if (module_path)
	{
	  pb_module = g_object_new (GTK_TYPE_PRINT_BACKEND_MODULE, NULL);

	  g_type_module_set_name (G_TYPE_MODULE (pb_module), backend_name);
	  pb_module->path = g_strdup (module_path);

	  loaded_backends = g_slist_prepend (loaded_backends,
		   		             pb_module);

	  pb = _gtk_print_backend_module_create (pb_module);
	}
      
      g_free (module_path);
    }

  return pb;

  return NULL;
}

static void
gtk_print_backend_initialize (void)
{
  static gboolean initialized = FALSE;

  if (!initialized)
    {
      gtk_settings_install_property (g_param_spec_string ("gtk-print-backends",
							  P_("Default print backend"),
							  P_("List of the GtkPrintBackend backends to use by default"),
							  GTK_PRINT_BACKENDS,
							  GTK_PARAM_READWRITE));

      initialized = TRUE;
    }
}



GList *
gtk_print_backend_load_modules ()
{
  GList *result;
  GtkPrintBackend *backend;
  gchar *setting;
  gchar **backends;
  gint i;
  GtkSettings *settings;

  result = NULL;

  gtk_print_backend_initialize ();
  
  settings = gtk_settings_get_default ();

  g_object_get (settings, "gtk-print-backends", &setting, NULL);

  backends = g_strsplit (setting, ",", -1);

  for (i = 0; backends[i]; i++)
    {
      g_strchug (backends[i]);
      g_strchomp (backends[i]);
      backend = _gtk_print_backend_create (backends[i]);
      
      if (backend)
        result = g_list_append (result, backend);
    }

  g_strfreev (backends);
  g_free (setting);

  return result;
}

/*****************************************
 *             GtkPrintBackend           *
 *****************************************/

G_DEFINE_TYPE (GtkPrintBackend, gtk_print_backend, G_TYPE_OBJECT);

static void
gtk_print_backend_class_init (GtkPrintBackendClass *class)
{
  GObjectClass *object_class;
  object_class = (GObjectClass *) class;

  backend_parent_class = g_type_class_peek_parent (class);
  
  object_class->dispose = gtk_print_backend_dispose;

  g_type_class_add_private (class, sizeof (GtkPrintBackendPrivate));

  
  signals[PRINTER_LIST_CHANGED] =
    g_signal_new ("printer-list-changed",
		  G_TYPE_FROM_CLASS (class),
		  G_SIGNAL_RUN_LAST,
		  G_STRUCT_OFFSET (GtkPrintBackendClass, printer_list_changed),
		  NULL, NULL,
		  g_cclosure_marshal_VOID__VOID,
		  G_TYPE_NONE, 0);
  signals[PRINTER_LIST_DONE] =
      g_signal_new ("printer-list-done",
		    G_TYPE_FROM_CLASS (class),
		    G_SIGNAL_RUN_LAST,
		    G_STRUCT_OFFSET (GtkPrintBackendClass, printer_list_done),
		    NULL, NULL,
		    g_cclosure_marshal_VOID__VOID,
		    G_TYPE_NONE, 0);
  signals[PRINTER_ADDED] =
    g_signal_new ("printer-added",
		  G_TYPE_FROM_CLASS (class),
		  G_SIGNAL_RUN_LAST,
		  G_STRUCT_OFFSET (GtkPrintBackendClass, printer_added),
		  NULL, NULL,
		  g_cclosure_marshal_VOID__OBJECT,
		  G_TYPE_NONE, 1, GTK_TYPE_PRINTER);
  signals[PRINTER_REMOVED] =
    g_signal_new ("printer-removed",
		  G_TYPE_FROM_CLASS (class),
		  G_SIGNAL_RUN_LAST,
		  G_STRUCT_OFFSET (GtkPrintBackendClass, printer_removed),
		  NULL, NULL,
		  g_cclosure_marshal_VOID__OBJECT,
		  G_TYPE_NONE, 1, GTK_TYPE_PRINTER);
  signals[PRINTER_STATUS_CHANGED] =
    g_signal_new ("printer-status-changed",
		  G_TYPE_FROM_CLASS (class),
		  G_SIGNAL_RUN_LAST,
		  G_STRUCT_OFFSET (GtkPrintBackendClass, printer_status_changed),
		  NULL, NULL,
		  g_cclosure_marshal_VOID__OBJECT,
		  G_TYPE_NONE, 1, GTK_TYPE_PRINTER);
}

static void
gtk_print_backend_init (GtkPrintBackend *backend)
{
  GtkPrintBackendPrivate *priv;

  priv = backend->priv = GTK_PRINT_BACKEND_GET_PRIVATE (backend); 

  priv->printers = g_hash_table_new_full (g_str_hash, g_str_equal, 
					  (GDestroyNotify) g_free,
					  (GDestroyNotify) g_object_unref);
}

static void
gtk_print_backend_dispose (GObject *object)
{
  GtkPrintBackend *backend;
  GtkPrintBackendPrivate *priv;

  backend = GTK_PRINT_BACKEND (object);
  priv = backend->priv;

  /* We unref the printers in dispose, not in finalize so that
     we can break refcount cycles with gtk_print_backend_destroy */
  if (priv->printers)
    {
      g_hash_table_destroy (priv->printers);
      priv->printers = NULL;
    }

  backend_parent_class->dispose (object);
}


static void
printer_hash_to_sorted_active_list (const gchar *key,
                                    gpointer value,
                                    GList **out_list)
{
  GtkPrinter *printer;

  printer = GTK_PRINTER (value);

  if (gtk_printer_get_name (printer) == NULL)
    return;

  if (!gtk_printer_is_active (printer))
    return;

  *out_list = g_list_insert_sorted (*out_list, value, (GCompareFunc) gtk_printer_compare);
}


void
gtk_print_backend_add_printer (GtkPrintBackend *backend,
			       GtkPrinter *printer)
{
  GtkPrintBackendPrivate *priv;
  
  g_return_if_fail (GTK_IS_PRINT_BACKEND (backend));

  priv = backend->priv;

  if (!priv->printers)
    return;
  
  g_hash_table_insert (priv->printers,
		       g_strdup (gtk_printer_get_name (printer)), 
		       g_object_ref (printer));
}

void
gtk_print_backend_remove_printer (GtkPrintBackend *backend,
				  GtkPrinter *printer)
{
  GtkPrintBackendPrivate *priv;
  
  g_return_if_fail (GTK_IS_PRINT_BACKEND (backend));
  priv = backend->priv;

  if (!priv->printers)
    return;
  
  g_hash_table_remove (priv->printers,
		       gtk_printer_get_name (printer));
}

void
gtk_print_backend_set_list_done (GtkPrintBackend *backend)
{
  if (!backend->priv->printer_list_done)
    {
      backend->priv->printer_list_done = TRUE;
      g_signal_emit (backend, signals[PRINTER_LIST_DONE], 0);
    }
}


GList *
gtk_print_backend_get_printer_list (GtkPrintBackend *backend)
{
  GtkPrintBackendPrivate *priv;
  GList *result;
  
  g_return_val_if_fail (GTK_IS_PRINT_BACKEND (backend), NULL);

  priv = backend->priv;

  result = NULL;
  if (priv->printers != NULL)
    g_hash_table_foreach (priv->printers,
                          (GHFunc) printer_hash_to_sorted_active_list,
                          &result);

  if (!priv->printer_list_requested && priv->printers != NULL)
    {
      if (GTK_PRINT_BACKEND_GET_CLASS (backend)->request_printer_list)
	GTK_PRINT_BACKEND_GET_CLASS (backend)->request_printer_list (backend);
      priv->printer_list_requested = TRUE;
    }
  
  return result;;
}

gboolean
gtk_print_backend_printer_list_is_done (GtkPrintBackend *print_backend)
{
  g_return_val_if_fail (GTK_IS_PRINT_BACKEND (print_backend), TRUE);

  return print_backend->priv->printer_list_done;
}

GtkPrinter *
gtk_print_backend_find_printer (GtkPrintBackend *backend,
                                const gchar *printer_name)
{
  GtkPrintBackendPrivate *priv;
  GtkPrinter *printer;
  
  g_return_val_if_fail (GTK_IS_PRINT_BACKEND (backend), NULL);

  priv = backend->priv;

  if (priv->printers)
    printer = g_hash_table_lookup (priv->printers, printer_name);
  else
    printer = NULL;

  return printer;  
}

void
gtk_print_backend_print_stream (GtkPrintBackend *backend,
                                GtkPrintJob *job,
                                gint data_fd,
                                GtkPrintJobCompleteFunc callback,
                                gpointer user_data,
				GDestroyNotify dnotify)
{
  g_return_if_fail (GTK_IS_PRINT_BACKEND (backend));

  GTK_PRINT_BACKEND_GET_CLASS (backend)->print_stream (backend,
						       job,
						       data_fd,
						       callback,
						       user_data,
						       dnotify);
}

static gboolean
unref_at_idle_cb (gpointer data)
{
  g_object_unref (data);
  return FALSE;
}

void
gtk_print_backend_unref_at_idle (GtkPrintBackend *print_backend)
{
  g_idle_add (unref_at_idle_cb, print_backend);
}

void
gtk_print_backend_destroy (GtkPrintBackend *print_backend)
{
  /* The lifecycle of print backends and printers are tied, such that
     the backend owns the printers, but the printers also ref the backend.
     This is so that if the app has a reference to a printer its backend
     will be around. However, this results in a cycle, which we break
     with this call, which causes the print backend to release its printers.
  */
  g_object_run_dispose (G_OBJECT (print_backend));
}

#define __GTK_PRINT_BACKEND_C__
#include "gtkaliasdef.c"