/* GTK - The GIMP Toolkit
 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
 * GtkStatusbar Copyright (C) 1998 Shawn T. Amundson
 *
 * 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/>.
 */

/*
 * Modified by the GTK+ Team and others 1997-2000.  See the AUTHORS
 * file for a list of people on the GTK+ Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GTK+ at ftp://ftp.gtk.org/pub/gtk/.
 */

#include "config.h"

#include "gtkstatusbar.h"
#include "gtkstatusbarprivate.h"

#include "gtkbinlayout.h"
#include "gtklabel.h"
#include "gtkmarshalers.h"
#include "gtkprivate.h"
#include "gtkintl.h"
#include "gtkorientable.h"
#include "gtktypebuiltins.h"
#include "gtkwidgetprivate.h"
#include "a11y/gtkstatusbaraccessible.h"

/**
 * SECTION:gtkstatusbar
 * @title: GtkStatusbar
 * @short_description: Report messages of minor importance to the user
 *
 * A #GtkStatusbar is usually placed along the bottom of an application's
 * main #GtkWindow. It may provide a regular commentary of the application's
 * status (as is usually the case in a web browser, for example), or may be
 * used to simply output a message when the status changes, (when an upload
 * is complete in an FTP client, for example).
 *
 * Status bars in GTK+ maintain a stack of messages. The message at
 * the top of the each bar’s stack is the one that will currently be displayed.
 *
 * Any messages added to a statusbar’s stack must specify a
 * context id that is used to uniquely identify
 * the source of a message. This context id can be generated by
 * gtk_statusbar_get_context_id(), given a message and the statusbar that
 * it will be added to. Note that messages are stored in a stack, and when
 * choosing which message to display, the stack structure is adhered to,
 * regardless of the context identifier of a message.
 *
 * One could say that a statusbar maintains one stack of messages for
 * display purposes, but allows multiple message producers to maintain
 * sub-stacks of the messages they produced (via context ids).
 *
 * Status bars are created using gtk_statusbar_new().
 *
 * Messages are added to the bar’s stack with gtk_statusbar_push().
 *
 * The message at the top of the stack can be removed using
 * gtk_statusbar_pop(). A message can be removed from anywhere in the
 * stack if its message id was recorded at the time it was added. This
 * is done using gtk_statusbar_remove().
 *
 * # CSS node
 *
 * GtkStatusbar has a single CSS node with name statusbar.
 */

typedef struct _GtkStatusbarMsg GtkStatusbarMsg;

typedef struct _GtkStatusbarClass         GtkStatusbarClass;

struct _GtkStatusbar
{
  GtkWidget parent_instance;

  GtkWidget     *label;
  GtkWidget     *message_area;

  GSList        *messages;
  GSList        *keys;

  guint          seq_context_id;
  guint          seq_message_id;
};

struct _GtkStatusbarClass
{
  GtkWidgetClass parent_class;

  void  (*text_pushed)  (GtkStatusbar   *statusbar,
                         guint           context_id,
                         const gchar    *text);
  void  (*text_popped)  (GtkStatusbar   *statusbar,
                         guint           context_id,
                         const gchar    *text);
};

struct _GtkStatusbarMsg
{
  gchar *text;
  guint context_id;
  guint message_id;
};

enum
{
  SIGNAL_TEXT_PUSHED,
  SIGNAL_TEXT_POPPED,
  SIGNAL_LAST
};

static void     gtk_statusbar_update            (GtkStatusbar      *statusbar,
						 guint              context_id,
						 const gchar       *text);

static void     gtk_statusbar_msg_free          (GtkStatusbarMsg *msg);

static guint              statusbar_signals[SIGNAL_LAST] = { 0 };

G_DEFINE_TYPE (GtkStatusbar, gtk_statusbar, GTK_TYPE_WIDGET)

static void
gtk_statusbar_dispose (GObject *object)
{
  GtkStatusbar *self = GTK_STATUSBAR (object);

  g_slist_free_full (self->messages, (GDestroyNotify) gtk_statusbar_msg_free);
  self->messages = NULL;

  g_slist_free_full (self->keys, g_free);
  self->keys = NULL;

  g_clear_pointer (&self->message_area, gtk_widget_unparent);

  G_OBJECT_CLASS (gtk_statusbar_parent_class)->dispose (object);
}

static void
gtk_statusbar_class_init (GtkStatusbarClass *class)
{
  GObjectClass *object_class = G_OBJECT_CLASS (class);
  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (class);

  object_class->dispose = gtk_statusbar_dispose;

  class->text_pushed = gtk_statusbar_update;
  class->text_popped = gtk_statusbar_update;

  /**
   * GtkStatusbar::text-pushed:
   * @statusbar: the object which received the signal
   * @context_id: the context id of the relevant message/statusbar
   * @text: the message that was pushed
   *
   * Is emitted whenever a new message gets pushed onto a statusbar's stack.
   */
  statusbar_signals[SIGNAL_TEXT_PUSHED] =
    g_signal_new (I_("text-pushed"),
		  G_OBJECT_CLASS_TYPE (class),
		  G_SIGNAL_RUN_LAST,
		  G_STRUCT_OFFSET (GtkStatusbarClass, text_pushed),
		  NULL, NULL,
		  _gtk_marshal_VOID__UINT_STRING,
		  G_TYPE_NONE, 2,
		  G_TYPE_UINT,
		  G_TYPE_STRING);

  /**
   * GtkStatusbar::text-popped:
   * @statusbar: the object which received the signal
   * @context_id: the context id of the relevant message/statusbar
   * @text: the message that was just popped
   *
   * Is emitted whenever a new message is popped off a statusbar's stack.
   */
  statusbar_signals[SIGNAL_TEXT_POPPED] =
    g_signal_new (I_("text-popped"),
		  G_OBJECT_CLASS_TYPE (class),
		  G_SIGNAL_RUN_LAST,
		  G_STRUCT_OFFSET (GtkStatusbarClass, text_popped),
		  NULL, NULL,
		  _gtk_marshal_VOID__UINT_STRING,
		  G_TYPE_NONE, 2,
		  G_TYPE_UINT,
		  G_TYPE_STRING);

  /* Bind class to template
   */
  gtk_widget_class_set_template_from_resource (widget_class, "/org/gtk/libgtk/ui/gtkstatusbar.ui");
  gtk_widget_class_bind_template_child_internal (widget_class, GtkStatusbar, message_area);
  gtk_widget_class_bind_template_child (widget_class, GtkStatusbar, label);

  gtk_widget_class_set_accessible_type (widget_class, GTK_TYPE_STATUSBAR_ACCESSIBLE);
  gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_BIN_LAYOUT);
  gtk_widget_class_set_css_name (widget_class, I_("statusbar"));
}

static void
gtk_statusbar_init (GtkStatusbar *statusbar)
{
  statusbar->seq_context_id = 1;
  statusbar->seq_message_id = 1;
  statusbar->messages = NULL;
  statusbar->keys = NULL;

  gtk_widget_init_template (GTK_WIDGET (statusbar));
}

/**
 * gtk_statusbar_new:
 *
 * Creates a new #GtkStatusbar ready for messages.
 *
 * Returns: the new #GtkStatusbar
 */
GtkWidget* 
gtk_statusbar_new (void)
{
  return g_object_new (GTK_TYPE_STATUSBAR, NULL);
}

static void
gtk_statusbar_update (GtkStatusbar *statusbar,
		      guint	    context_id,
		      const gchar  *text)
{
  g_return_if_fail (GTK_IS_STATUSBAR (statusbar));

  if (!text)
    text = "";

  gtk_label_set_text (GTK_LABEL (statusbar->label), text);
}

/**
 * gtk_statusbar_get_context_id:
 * @statusbar: a #GtkStatusbar
 * @context_description: textual description of what context 
 *                       the new message is being used in
 *
 * Returns a new context identifier, given a description 
 * of the actual context. Note that the description is 
 * not shown in the UI.
 *
 * Returns: an integer id
 */
guint
gtk_statusbar_get_context_id (GtkStatusbar *statusbar,
			      const gchar  *context_description)
{
  gchar *string;
  guint id;
  
  g_return_val_if_fail (GTK_IS_STATUSBAR (statusbar), 0);
  g_return_val_if_fail (context_description != NULL, 0);

  /* we need to preserve namespaces on object datas */
  string = g_strconcat ("gtk-status-bar-context:", context_description, NULL);

  id = GPOINTER_TO_UINT (g_object_get_data (G_OBJECT (statusbar), string));
  if (id == 0)
    {
      id = statusbar->seq_context_id++;
      g_object_set_data_full (G_OBJECT (statusbar), string, GUINT_TO_POINTER (id), NULL);
      statusbar->keys = g_slist_prepend (statusbar->keys, string);
    }
  else
    g_free (string);

  return id;
}

static GtkStatusbarMsg *
gtk_statusbar_msg_create (GtkStatusbar *statusbar,
		          guint         context_id,
		          const gchar  *text)
{
  GtkStatusbarMsg *msg;

  msg = g_slice_new (GtkStatusbarMsg);
  msg->text = g_strdup (text);
  msg->context_id = context_id;
  msg->message_id = statusbar->seq_message_id++;

  return msg;
}

static void
gtk_statusbar_msg_free (GtkStatusbarMsg *msg)
{
  g_free (msg->text);
  g_slice_free (GtkStatusbarMsg, msg);
}

/**
 * gtk_statusbar_push:
 * @statusbar: a #GtkStatusbar
 * @context_id: the message’s context id, as returned by
 *              gtk_statusbar_get_context_id()
 * @text: the message to add to the statusbar
 * 
 * Pushes a new message onto a statusbar’s stack.
 *
 * Returns: a message id that can be used with 
 *          gtk_statusbar_remove().
 */
guint
gtk_statusbar_push (GtkStatusbar *statusbar,
		    guint	  context_id,
		    const gchar  *text)
{
  GtkStatusbarMsg *msg;

  g_return_val_if_fail (GTK_IS_STATUSBAR (statusbar), 0);
  g_return_val_if_fail (text != NULL, 0);

  msg = gtk_statusbar_msg_create (statusbar, context_id, text);
  statusbar->messages = g_slist_prepend (statusbar->messages, msg);

  g_signal_emit (statusbar,
		 statusbar_signals[SIGNAL_TEXT_PUSHED],
		 0,
		 msg->context_id,
		 msg->text);

  return msg->message_id;
}

/**
 * gtk_statusbar_pop:
 * @statusbar: a #GtkStatusbar
 * @context_id: a context identifier
 * 
 * Removes the first message in the #GtkStatusbar’s stack
 * with the given context id. 
 *
 * Note that this may not change the displayed message, if 
 * the message at the top of the stack has a different 
 * context id.
 */
void
gtk_statusbar_pop (GtkStatusbar *statusbar,
		   guint	 context_id)
{
  GtkStatusbarMsg *msg;

  g_return_if_fail (GTK_IS_STATUSBAR (statusbar));

  if (statusbar->messages)
    {
      GSList *list;

      for (list = statusbar->messages; list; list = list->next)
	{
	  msg = list->data;

	  if (msg->context_id == context_id)
	    {
	      statusbar->messages = g_slist_remove_link (statusbar->messages, list);
	      gtk_statusbar_msg_free (msg);
	      g_slist_free_1 (list);
	      break;
	    }
	}
    }

  msg = statusbar->messages ? statusbar->messages->data : NULL;

  g_signal_emit (statusbar,
		 statusbar_signals[SIGNAL_TEXT_POPPED],
		 0,
		 (guint) (msg ? msg->context_id : 0),
		 msg ? msg->text : NULL);
}

/**
 * gtk_statusbar_remove:
 * @statusbar: a #GtkStatusbar
 * @context_id: a context identifier
 * @message_id: a message identifier, as returned by gtk_statusbar_push()
 *
 * Forces the removal of a message from a statusbar’s stack. 
 * The exact @context_id and @message_id must be specified.
 */
void
gtk_statusbar_remove (GtkStatusbar *statusbar,
		      guint	   context_id,
		      guint        message_id)
{
  GtkStatusbarMsg *msg;

  g_return_if_fail (GTK_IS_STATUSBAR (statusbar));
  g_return_if_fail (message_id > 0);

  msg = statusbar->messages ? statusbar->messages->data : NULL;
  if (msg)
    {
      GSList *list;

      /* care about signal emission if the topmost item is removed */
      if (msg->context_id == context_id &&
	  msg->message_id == message_id)
	{
	  gtk_statusbar_pop (statusbar, context_id);
	  return;
	}
      
      for (list = statusbar->messages; list; list = list->next)
	{
	  msg = list->data;
	  
	  if (msg->context_id == context_id &&
	      msg->message_id == message_id)
	    {
	      statusbar->messages = g_slist_remove_link (statusbar->messages, list);
	      gtk_statusbar_msg_free (msg);
	      g_slist_free_1 (list);
	      
	      break;
	    }
	}
    }
}

/**
 * gtk_statusbar_remove_all:
 * @statusbar: a #GtkStatusbar
 * @context_id: a context identifier
 *
 * Forces the removal of all messages from a statusbar's
 * stack with the exact @context_id.
 */
void
gtk_statusbar_remove_all (GtkStatusbar *statusbar,
                          guint         context_id)
{
  GtkStatusbarMsg *msg;
  GSList *prev, *list;

  g_return_if_fail (GTK_IS_STATUSBAR (statusbar));

  if (statusbar->messages == NULL)
    return;

  /* We special-case the topmost message at the bottom of this
   * function:
   * If we need to pop it, we have to update various state and we want
   * an up-to-date list of remaining messages in that case.
   */
  prev = statusbar->messages;
  list = prev->next;

  while (list != NULL)
    {
      msg = list->data;

      if (msg->context_id == context_id)
        {
          prev->next = list->next;

          gtk_statusbar_msg_free (msg);
          g_slist_free_1 (list);

          list = prev->next;
        }
      else
        {
          prev = list;
          list = prev->next;
        }
    }

  /* Treat topmost message here */
  msg = statusbar->messages->data;
  if (msg->context_id == context_id)
    {
      gtk_statusbar_pop (statusbar, context_id);
    }
}

/* < private >
 * gtk_statusbar_get_message_area:
 * @statusbar: a #GtkStatusbar
 *
 * Retrieves the box containing the label widget.
 *
 * Returns: (type Gtk.Box) (transfer none): a #GtkBox
 */
const char*
gtk_statusbar_get_message (GtkStatusbar *statusbar)
{
  g_return_val_if_fail (GTK_IS_STATUSBAR (statusbar), NULL);

  return gtk_label_get_label (GTK_LABEL (statusbar->label));
}