/* $Id$ */
/*
 * Copyright (C) 2008-2009 Nick Schermer <nick@xfce.org>
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU 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 General Public License for
 * more details.
 *
 * You should have received a copy of the GNU Library 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
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef HAVE_MATH_H
#include <math.h>
#endif

#include <gtk/gtk.h>

#include <common/panel-private.h>
#include <libxfce4panel/libxfce4panel.h>


/* design limit for the panel, to reduce the uncached pixbuf size */
#define MAX_PIXBUF_SIZE (128)

#define XFCE_PANEL_IMAGE_GET_PRIVATE(obj) (G_TYPE_INSTANCE_GET_PRIVATE ((obj), \
                                           XFCE_TYPE_PANEL_IMAGE, \
                                           XfcePanelImagePrivate))



struct _XfcePanelImagePrivate
{
  /* pixbuf set by the user */
  GdkPixbuf *pixbuf;

  /* internal cached pixbuf (resized) */
  GdkPixbuf *cache;

  /* source name */
  gchar     *source;

  /* fixed size */
  gint       size;

  /* whether we round to fixed icon sizes */
  guint      force_icon_sizes : 1;

  /* cached width and height */
  gint       width;
  gint       height;
};

enum
{
  PROP_0,
  PROP_SOURCE,
  PROP_PIXBUF,
  PROP_SIZE
};



static void       xfce_panel_image_get_property  (GObject         *object,
                                                  guint            prop_id,
                                                  GValue          *value,
                                                  GParamSpec      *pspec);
static void       xfce_panel_image_set_property  (GObject         *object,
                                                  guint            prop_id,
                                                  const GValue    *value,
                                                  GParamSpec      *pspec);
static void       xfce_panel_image_finalize      (GObject         *object);
static void       xfce_panel_image_size_request  (GtkWidget       *widget,
                                                  GtkRequisition  *requisition);
static void       xfce_panel_image_size_allocate (GtkWidget       *widget,
                                                  GtkAllocation   *allocation);
static gboolean   xfce_panel_image_expose_event  (GtkWidget       *widget,
                                                  GdkEventExpose  *event);
static void       xfce_panel_image_style_set     (GtkWidget       *widget,
                                                  GtkStyle        *previous_style);
static GdkPixbuf *xfce_panel_image_scale_pixbuf  (GdkPixbuf       *source,
                                                  gint             dest_width,
                                                  gint             dest_height);



G_DEFINE_TYPE (XfcePanelImage, xfce_panel_image, GTK_TYPE_WIDGET)



static void
xfce_panel_image_class_init (XfcePanelImageClass *klass)
{
  GObjectClass   *gobject_class;
  GtkWidgetClass *gtkwidget_class;

  /* add private data */
  g_type_class_add_private (klass, sizeof (XfcePanelImagePrivate));

  gobject_class = G_OBJECT_CLASS (klass);
  gobject_class->get_property = xfce_panel_image_get_property;
  gobject_class->set_property = xfce_panel_image_set_property;
  gobject_class->finalize = xfce_panel_image_finalize;

  gtkwidget_class = GTK_WIDGET_CLASS (klass);
  gtkwidget_class->size_request = xfce_panel_image_size_request;
  gtkwidget_class->size_allocate = xfce_panel_image_size_allocate;
  gtkwidget_class->expose_event = xfce_panel_image_expose_event;
  gtkwidget_class->style_set = xfce_panel_image_style_set;

  g_object_class_install_property (gobject_class,
                                   PROP_SOURCE,
                                   g_param_spec_string ("source",
                                                        "Source",
                                                        "Icon or filename",
                                                        NULL,
                                                        G_PARAM_READWRITE
                                                        | G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (gobject_class,
                                   PROP_PIXBUF,
                                   g_param_spec_object ("pixbuf",
                                                        "Pixbuf",
                                                        "Pixbuf image",
                                                        GDK_TYPE_PIXBUF,
                                                        G_PARAM_READWRITE
                                                        | G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (gobject_class,
                                   PROP_SIZE,
                                   g_param_spec_int ("size",
                                                     "Size",
                                                     "Pixel size of the image",
                                                     -1, MAX_PIXBUF_SIZE, -1,
                                                     G_PARAM_READWRITE
                                                     | G_PARAM_STATIC_STRINGS));

  gtk_widget_class_install_style_property (gtkwidget_class,
                                           g_param_spec_boolean ("force-gtk-icon-sizes",
                                                                 NULL,
                                                                 "Force the image to fix to GtkIconSizes",
                                                                 FALSE,
                                                                 G_PARAM_READWRITE
                                                                 | G_PARAM_STATIC_STRINGS));
}



static void
xfce_panel_image_init (XfcePanelImage *image)
{
  GTK_WIDGET_SET_FLAGS (image, GTK_NO_WINDOW);

  /* set private pointer */
  image->priv = XFCE_PANEL_IMAGE_GET_PRIVATE (image);

  /* initialize */
  image->priv->pixbuf = NULL;
  image->priv->cache = NULL;
  image->priv->source = NULL;
  image->priv->size = -1;
  image->priv->width = -1;
  image->priv->height = -1;
  image->priv->force_icon_sizes = FALSE;
}



static void
xfce_panel_image_get_property (GObject    *object,
                               guint       prop_id,
                               GValue     *value,
                               GParamSpec *pspec)
{
  XfcePanelImagePrivate *priv = XFCE_PANEL_IMAGE (object)->priv;

  switch (prop_id)
    {
      case PROP_SOURCE:
        g_value_set_string (value, priv->source);
        break;

      case PROP_PIXBUF:
        g_value_set_object (value, priv->pixbuf);
        break;

      case PROP_SIZE:
        g_value_set_int (value, priv->size);
        break;

      default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
        break;
    }
}



static void
xfce_panel_image_set_property (GObject      *object,
                               guint         prop_id,
                               const GValue *value,
                               GParamSpec   *pspec)
{
  XfcePanelImagePrivate *priv;
  gint                   size;

  switch (prop_id)
    {
      case PROP_SOURCE:
        xfce_panel_image_set_from_source (XFCE_PANEL_IMAGE (object),
                                          g_value_get_string (value));
        break;

      case PROP_PIXBUF:
        xfce_panel_image_set_from_pixbuf (XFCE_PANEL_IMAGE (object),
                                          g_value_get_object (value));
        break;

      case PROP_SIZE:
        priv = XFCE_PANEL_IMAGE (object)->priv;
        size = g_value_get_int (value);
        if (G_LIKELY (priv->size != size))
          {
            priv->size = size;
            gtk_widget_queue_resize (GTK_WIDGET (object));
          }
        break;

      default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
        break;
    }
}



static void
xfce_panel_image_finalize (GObject *object)
{
  /* cleanup */
  xfce_panel_image_clear (XFCE_PANEL_IMAGE (object));

  (*G_OBJECT_CLASS (xfce_panel_image_parent_class)->finalize) (object);
}



static void
xfce_panel_image_size_request (GtkWidget      *widget,
                               GtkRequisition *requisition)
{
  XfcePanelImagePrivate *priv = XFCE_PANEL_IMAGE (widget)->priv;

  if (priv->size > 0)
    {
      requisition->width = priv->size;
      requisition->height = priv->size;
    }
  else if (priv->pixbuf != NULL)
    {
      requisition->width = gdk_pixbuf_get_width (priv->pixbuf);
      requisition->height = gdk_pixbuf_get_height (priv->pixbuf);
    }
  else
    {
      requisition->width = widget->allocation.width;
      requisition->height = widget->allocation.height;
    }
}



static void
xfce_panel_image_size_allocate (GtkWidget     *widget,
                                GtkAllocation *allocation)
{
  XfcePanelImagePrivate *priv = XFCE_PANEL_IMAGE (widget)->priv;
  GdkPixbuf             *pixbuf = NULL;
  GdkScreen             *screen;
  GError                *error = NULL;
  gint                   size;

  widget->allocation = *allocation;

  /* check if the available size changed */
  if ((priv->pixbuf != NULL || priv->source != NULL)
      && allocation->width > 0
      && allocation->height > 0
      && (allocation->width != priv->width
      || allocation->height != priv->height))
    {
      /* store the new size */
      priv->width = allocation->width;
      priv->height = allocation->height;

      /* free cache */
      if (G_LIKELY (priv->cache != NULL))
        g_object_unref (G_OBJECT (priv->cache));
      priv->cache = NULL;

      if (priv->pixbuf != NULL)
        {
          /* use the pixbuf set by the user */
          pixbuf = g_object_ref (G_OBJECT (priv->pixbuf));
        }
      else if (g_path_is_absolute (priv->source))
        {
          pixbuf = gdk_pixbuf_new_from_file (priv->source, &error);
          if (G_UNLIKELY (pixbuf == NULL))
            {
              g_critical ("Failed to loading image \"%s\": %s",
                          priv->source, error->message);
              g_error_free (error);
              return;
            }
        }
      else
        {
          screen = gtk_widget_get_screen (widget);

          size = MIN (priv->width, priv->height);
          if (G_UNLIKELY (priv->force_icon_sizes && size < 32))
            {
              /* we use some hardcoded values here for convienence,
               * above 32 pixels svg icons will kick in */
              if (size > 16 && size < 22)
                size = 16;
              else if (size > 22 && size < 24)
                size = 22;
              else if (size > 24 && size < 32)
                size = 24;
            }

          /* get a pixbuf from the icon name */
          pixbuf = gtk_icon_theme_load_icon (gtk_icon_theme_get_for_screen (screen),
                                             priv->source, size, 0, NULL);

          /* TODO more loading modes: try without extension and lower case */
        }

      if (G_LIKELY (pixbuf != NULL))
        {
          /* scale the icon to the correct size */
          priv->cache = xfce_panel_image_scale_pixbuf (pixbuf, priv->width,
                                                       priv->height);

          /* release the pixbuf */
          g_object_unref (G_OBJECT (pixbuf));
        }
    }
}



static gboolean
xfce_panel_image_expose_event (GtkWidget      *widget,
                               GdkEventExpose *event)
{
  XfcePanelImagePrivate *priv = XFCE_PANEL_IMAGE (widget)->priv;
  gint                   source_width, source_height;
  gint                   dest_x, dest_y;

  if (G_LIKELY (priv->cache != NULL))
    {
      /* get the size of the cache pixbuf */
      source_width = gdk_pixbuf_get_width (priv->cache);
      source_height = gdk_pixbuf_get_height (priv->cache);

      /* position */
      dest_x = widget->allocation.x + (priv->width - source_width) / 2;
      dest_y = widget->allocation.y + (priv->height - source_height) / 2;

      /* draw the pixbuf */
      gdk_draw_pixbuf (widget->window,
                       widget->style->black_gc,
                       priv->cache,
                       0, 0,
                       dest_x, dest_y,
                       source_width, source_height,
                       GDK_RGB_DITHER_NORMAL, 0, 0);
    }

  return FALSE;
}



static void
xfce_panel_image_style_set (GtkWidget *widget,
                            GtkStyle  *previous_style)
{
  XfcePanelImagePrivate *priv = XFCE_PANEL_IMAGE (widget)->priv;
  gboolean               force;

  /* let gtk update the widget style */
  (*GTK_WIDGET_CLASS (xfce_panel_image_parent_class)->style_set) (widget, previous_style);

  /* get style property */
  gtk_widget_style_get (widget, "force-gtk-icon-sizes", &force, NULL);

  /* update if needed */
  if (priv->force_icon_sizes != force)
    {
      priv->force_icon_sizes = force;
      if (priv->size > 0)
        gtk_widget_queue_resize (widget);
    }
}



static GdkPixbuf *
xfce_panel_image_scale_pixbuf (GdkPixbuf *source,
                               gint       dest_width,
                               gint       dest_height)
{
  gdouble wratio;
  gdouble hratio;
  gint    source_width;
  gint    source_height;

  panel_return_val_if_fail (GDK_IS_PIXBUF (source), NULL);
  panel_return_val_if_fail (dest_width > 0, NULL);
  panel_return_val_if_fail (dest_height > 0, NULL);

  source_width = gdk_pixbuf_get_width (source);
  source_height = gdk_pixbuf_get_height (source);

  /* check if we need to scale */
  if (source_width <= dest_width && source_height <= dest_height)
    return g_object_ref (G_OBJECT (source));

  /* calculate the new dimensions */
  wratio = (gdouble) source_width  / (gdouble) dest_width;
  hratio = (gdouble) source_height / (gdouble) dest_height;

  if (hratio > wratio)
    dest_width  = rint (source_width / hratio);
  else
    dest_height = rint (source_height / wratio);

  return gdk_pixbuf_scale_simple (source, MAX (dest_width, 1),
                                  MAX (dest_height, 1),
                                  GDK_INTERP_BILINEAR);
}



GtkWidget *
xfce_panel_image_new (void)
{
  return g_object_new (XFCE_TYPE_PANEL_IMAGE, NULL);
}



GtkWidget *
xfce_panel_image_new_from_pixbuf (GdkPixbuf *pixbuf)
{
  g_return_val_if_fail (GDK_IS_PIXBUF (pixbuf), NULL);

  return g_object_new (XFCE_TYPE_PANEL_IMAGE,
                       "pixbuf", pixbuf, NULL);
}



GtkWidget *
xfce_panel_image_new_from_source (const gchar *source)
{
  g_return_val_if_fail (IS_STRING (source), NULL);

  return g_object_new (XFCE_TYPE_PANEL_IMAGE,
                       "source", source, NULL);
}



void
xfce_panel_image_set_from_pixbuf (XfcePanelImage *image,
                                  GdkPixbuf      *pixbuf)
{
  g_return_if_fail (XFCE_IS_PANEL_IMAGE (image));
  g_return_if_fail (GDK_IS_PIXBUF (pixbuf));

  /* cleanup */
  xfce_panel_image_clear (image);

  /* set the new pixbuf, scale it to the maximum size if needed */
  image->priv->pixbuf = xfce_panel_image_scale_pixbuf (pixbuf,
      MAX_PIXBUF_SIZE, MAX_PIXBUF_SIZE);

  /* queue a resize */
  gtk_widget_queue_resize (GTK_WIDGET (image));
}



void
xfce_panel_image_set_from_source (XfcePanelImage *image,
                                  const gchar    *source)
{
  g_return_if_fail (XFCE_IS_PANEL_IMAGE (image));
  g_return_if_fail (IS_STRING (source));

  /* cleanup */
  xfce_panel_image_clear (image);

  /* set new value */
  image->priv->source = g_strdup (source);

  /* queue a resize */
  gtk_widget_queue_resize (GTK_WIDGET (image));
}



void
xfce_panel_image_clear (XfcePanelImage *image)
{
  XfcePanelImagePrivate *priv = XFCE_PANEL_IMAGE (image)->priv;

  g_return_if_fail (XFCE_IS_PANEL_IMAGE (image));

  if (priv->source != NULL)
    {
     g_free (priv->source);
     priv->source = NULL;
    }

  if (priv->pixbuf != NULL)
    {
     g_object_unref (G_OBJECT (priv->pixbuf));
     priv->pixbuf = NULL;
    }

  if (priv->cache != NULL)
    {
     g_object_unref (G_OBJECT (priv->cache));
     priv->cache = NULL;
    }

  /* reset values */
  priv->width = -1;
  priv->height = -1;
}