/*
  header-container.cpp  -  Implementation of the header container widget
 
  Copyright (C)         Lumiera.org
    2008,               Joel Holdsworth <joel@airwebreathe.org.uk>
 
  This program 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 program 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 General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
* *****************************************************/

#include <boost/foreach.hpp>

#include "header-container.hpp"
#include "track.hpp"
#include "../timeline-widget.hpp"

using namespace Gtk;
using namespace std;

namespace gui {
namespace widgets {
namespace timeline {

HeaderContainer::HeaderContainer(gui::widgets::TimelineWidget
    *timeline_widget) :
    Glib::ObjectBase("HeaderContainer"),
    timelineWidget(timeline_widget),
    margin(-1)
{
  REQUIRE(timeline_widget != NULL);

  // This widget will not have a window at first
  set_flags(Gtk::NO_WINDOW);
  
  set_redraw_on_allocate(false);
  
  // Connect to the timeline widget's vertical scroll event,
  // so that we get notified when the view shifts
  timelineWidget->verticalAdjustment.signal_value_changed().connect(
    sigc::mem_fun(this, &HeaderContainer::on_scroll) );
    
  // Install style properties
  register_styles();
}
  
void
HeaderContainer::update_headers()
{
  REQUIRE(timelineWidget != NULL);
  
  // Remove any pre-exisitng headers
  BOOST_FOREACH( RootHeader header, rootHeaders )
    {
      header.widget->unparent();
    }
    
  rootHeaders.clear();
  
  // Add fresh headers  
  BOOST_FOREACH( Track* track, timelineWidget->tracks )
    {
      ASSERT(track != NULL);
           
      const RootHeader header = { &track->get_header_widget(), track };
      header.widget->set_parent(*this);

      rootHeaders.push_back(header);
    }
    
  layout_headers();
}
  
void
HeaderContainer::on_realize()
{
  set_flags(Gtk::NO_WINDOW);
  
  // Call base class:
  Gtk::Container::on_realize();
  
  // Create the GdkWindow:
  GdkWindowAttr attributes;
  memset(&attributes, 0, sizeof(attributes));

  Allocation allocation = get_allocation();

  // Set initial position and size of the Gdk::Window:
  attributes.x = allocation.get_x();
  attributes.y = allocation.get_y();
  attributes.width = allocation.get_width();
  attributes.height = allocation.get_height();

  attributes.event_mask = get_events () | Gdk::EXPOSURE_MASK; 
  attributes.window_type = GDK_WINDOW_CHILD;
  attributes.wclass = GDK_INPUT_OUTPUT;

  gdkWindow = Gdk::Window::create(get_window(), &attributes,
          GDK_WA_X | GDK_WA_Y);
  unset_flags(Gtk::NO_WINDOW);
  set_window(gdkWindow);
  
  // Unset the background so as to make the colour match the parent window
  unset_bg(STATE_NORMAL);

  // Make the widget receive expose events
  gdkWindow->set_user_data(gobj());
}
  
void
HeaderContainer::on_unrealize()
{
  // Unreference any window we may have created
  gdkWindow.clear();

  // Call base class:
  Gtk::Widget::on_unrealize();
}

void
HeaderContainer::on_size_request (Requisition* requisition)
{ 
  // Initialize the output parameter:
  *requisition = Gtk::Requisition();
  
  // We don't care about the size of all the child widgets, but if we
  // don't send the size request down the tree, some widgets fail to
  // calculate their text layout correctly.  
  BOOST_FOREACH( RootHeader header, rootHeaders )
    {
      if(header.widget != NULL && header.widget->is_visible())
        header.widget->size_request();
    }

  requisition->width = TimelineWidget::HeaderWidth; 
  requisition->height = 0;
}
  
void
HeaderContainer::on_size_allocate (Allocation& allocation)
{ 
  // Use the offered allocation for this container:
  set_allocation(allocation);
  
  // Resize the widget's window
  if(gdkWindow)
    gdkWindow->resize(allocation.get_width(), allocation.get_height());
  
  // Relayout the child widgets of the headers
  layout_headers();
}
  
void
HeaderContainer::forall_vfunc(gboolean /* include_internals */,
        GtkCallback callback, gpointer callback_data)
{ 
  BOOST_FOREACH( RootHeader &header, rootHeaders )
    {
      ASSERT(header.widget);
      callback(header.widget->gobj(), callback_data);
    }
}

bool
HeaderContainer::on_expose_event(GdkEventExpose *event)
{
  if(gdkWindow)
    {
      int offset = 0;
      const int y_scroll_offset = timelineWidget->get_y_scroll_offset();
      
      Glib::RefPtr<Style> style = get_style();
      const Allocation container_allocation = get_allocation();
      
      read_styles();
       
      // Paint a border underneath all the root headers
      BOOST_FOREACH( RootHeader &header, rootHeaders )
        {
          ASSERT(header.widget);
          ASSERT(header.track != NULL);
          
          const int height = header.track->get_height();
          ASSERT(height >= 0);
               
          style->paint_box(
            gdkWindow, STATE_NORMAL, SHADOW_OUT,
            Gdk::Rectangle(
              0, 0,
              container_allocation.get_width(),
              container_allocation.get_height()),
            *this, "", 0, offset - y_scroll_offset,
            container_allocation.get_width(), height);
          
          offset += height + TimelineWidget::TrackPadding;
        }
    }

  return Container::on_expose_event(event);
}
  
void
HeaderContainer::on_scroll()
{
  // If the scroll has changed, we will have to shift all the
  // header widgets
  layout_headers();
}
  
void
HeaderContainer::layout_headers()
{
  ASSERT(timelineWidget != NULL);
  
  // We can't layout before the widget has been set up
  if(!gdkWindow)
    return;

  int offset = 0;
  const int y_scroll_offset = timelineWidget->get_y_scroll_offset();
  
  read_styles();
  
  const Allocation container_allocation = get_allocation();
  const int header_width = container_allocation.get_width ()
     - margin * 2;
  
  BOOST_FOREACH( RootHeader &header, rootHeaders )
    {
      ASSERT(header.widget);
      ASSERT(header.track != NULL);
      
      const int height = header.track->get_height();
      ASSERT(height >= 0);
           
      Gtk::Allocation header_allocation;
      header_allocation.set_x (margin);
      header_allocation.set_y (offset - y_scroll_offset + margin);
      header_allocation.set_width (header_width);
      header_allocation.set_height (height - margin * 2);
      
      if(header.widget->is_visible())
        header.widget->size_allocate (header_allocation);
      
      offset += height + TimelineWidget::TrackPadding;
    }
    
  // Repaint the background of our parenting
  queue_draw ();
}

void
HeaderContainer::register_styles() const
{
  GtkWidgetClass *klass = GTK_WIDGET_CLASS(G_OBJECT_GET_CLASS(gobj()));

  gtk_widget_class_install_style_property(klass, 
    g_param_spec_int("heading_margin",
    "Heading Margin",
    "The amount of padding around each header pixels.",
    0, G_MAXINT, 4, G_PARAM_READABLE));
}

void
HeaderContainer::read_styles()
{
  if(margin <= 0)
    get_style_property("heading_margin", margin);
}

}   // namespace timeline
}   // namespace widgets
}   // namespace gui