/////////////////////////////////////////////////////////////////////////////
// Name:        src/generic/panelg.cpp
// Purpose:     wxPanel and the keyboard handling code
// Author:      Julian Smart, Robert Roebling, Vadim Zeitlin
// Modified by:
// Created:     04/01/98
// RCS-ID:      $Id$
// Copyright:   (c) Julian Smart and Markus Holzem
// Licence:     wxWindows license
/////////////////////////////////////////////////////////////////////////////

// ============================================================================
// declarations
// ============================================================================

// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------

#ifdef __GNUG__
    #pragma implementation "panelg.h"
#endif

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
    #pragma hdrstop
#endif

#ifndef WX_PRECOMP
    #include "wx/object.h"
    #include "wx/font.h"
    #include "wx/colour.h"
    #include "wx/settings.h"
    #include "wx/log.h"
#endif

#include "wx/toolbar.h"
#include "wx/statusbr.h"

#include "wx/generic/panelg.h"

// ----------------------------------------------------------------------------
// wxWin macros
// ----------------------------------------------------------------------------

IMPLEMENT_DYNAMIC_CLASS(wxPanel, wxWindow)

BEGIN_EVENT_TABLE(wxPanel, wxWindow)
  EVT_SYS_COLOUR_CHANGED(wxPanel::OnSysColourChanged)
  EVT_SET_FOCUS(wxPanel::OnFocus)
  EVT_NAVIGATION_KEY(wxPanel::OnNavigationKey)
  EVT_SIZE(wxPanel::OnSize)
END_EVENT_TABLE()

// ============================================================================
// implementation
// ============================================================================

// ----------------------------------------------------------------------------
// wxPanel creation
// ----------------------------------------------------------------------------

void wxPanel::Init()
{
    m_winLastFocused = (wxWindow *)NULL;
    m_btnDefault = (wxButton *)NULL;
}

bool wxPanel::Create(wxWindow *parent, wxWindowID id,
                     const wxPoint& pos,
                     const wxSize& size,
                     long style,
                     const wxString& name)
{
    bool ret = wxWindow::Create(parent, id, pos, size, style, name);

    if ( ret )
    {
        SetBackgroundColour(wxSystemSettings::GetSystemColour(wxSYS_COLOUR_3DFACE));
        SetFont(wxSystemSettings::GetSystemFont(wxSYS_DEFAULT_GUI_FONT));
    }

    return ret;
}

// ----------------------------------------------------------------------------
// misc
// ----------------------------------------------------------------------------

void wxPanel::InitDialog()
{
    wxInitDialogEvent event(GetId());
    event.SetEventObject(this);
    GetEventHandler()->ProcessEvent(event);
}

// Responds to colour changes, and passes event on to children.
void wxPanel::OnSysColourChanged(wxSysColourChangedEvent& event)
{
    SetBackgroundColour(wxSystemSettings::GetSystemColour(wxSYS_COLOUR_3DFACE));
    Refresh();

    // Propagate the event to the non-top-level children
    wxWindow::OnSysColourChanged(event);
}

void wxPanel::OnSize(wxSizeEvent& WXUNUSED(event))
{
#if wxUSE_CONSTRAINTS
    if (GetAutoLayout())
        Layout();
#endif
}

// ----------------------------------------------------------------------------
// Keyboard handling - this is the place where the TAB traversal logic is
// implemented. As this code is common to all ports, this ensures consistent
// behaviour even if we don't specify how exactly the wxNavigationKeyEvent are
// generated and this is done in platform specific code which also ensures that
// we can follow the given platform standards.
// ----------------------------------------------------------------------------

void wxPanel::OnNavigationKey( wxNavigationKeyEvent& event )
{
    // the event is propagated downwards if the event emitter was our parent
    bool goingDown = event.GetEventObject() == GetParent();

    const wxWindowList& children = GetChildren();

    // there is not much to do if we don't have children and we're not
    // interested in "notebook page change" events here
    if ( !children.GetCount() || event.IsWindowChange() )
    {
        // let the parent process it unless it already comes from our parent
        // of we don't have any
        wxWindow *parent = GetParent();
        if ( goingDown ||
             !parent || !parent->GetEventHandler()->ProcessEvent(event) )
        {
            event.Skip();
        }

        return;
    }

    // where are we going?
    bool forward = event.GetDirection();

    // the node of the children list from which we should start looking for the
    // next acceptable child
    wxWindowList::Node *node, *start_node;

    // we should start from the first/last control and not from the one which
    // had focus the last time if we're propagating the event downwards because
    // for our parent we look like a single control
    if ( goingDown )
    {
        // just to be sure it's not used (normally this is not necessary, but
        // doesn't hurt neither)
        m_winLastFocused = (wxWindow *)NULL;

        // start from first or last depending on where we're going
        node = forward ? children.GetFirst() : children.GetLast();

        // we want to cycle over all nodes
        start_node = (wxWindowList::Node *)NULL;
    }
    else
    {
        // try to find the child which has the focus currently

        // the event emitter might have done this for us
        wxWindow *winFocus = event.GetCurrentFocus();

        // but if not, we might know where the focus was ourselves
        if (!winFocus)
            winFocus = m_winLastFocused;

        // if still no luck, do it the hard way
        if (!winFocus)
            winFocus = wxWindow::FindFocus();

        if ( winFocus )
        {
            // ok, we found the focus - now is it our child?
            start_node = children.Find( winFocus );
        }
        else
        {
            start_node = (wxWindowList::Node *)NULL;
        }

        if ( !start_node && m_winLastFocused )
        {
            // window which has focus isn't our child, fall back to the one
            // which had the focus the last time
            start_node = children.Find( m_winLastFocused );
        }

        // if we still didn't find anything, we should start with the first one
        if ( !start_node )
        {
            start_node = children.GetFirst();
        }

        // and the first child which we can try setting focus to is the next or
        // the previous one
        node = forward ? start_node->GetNext() : start_node->GetPrevious();
    }

    // we want to cycle over all elements passing by NULL
    while ( node != start_node )
    {
        // Have we come to the last or first item on the panel?
        if ( !node )
        {
            if ( !goingDown )
            {
                // Check if our (may be grand) parent is another panel: if this
                // is the case, they will know what to do with this navigation
                // key and so give them the chance to process it instead of
                // looping inside this panel (normally, the focus will go to
                // the next/previous item after this panel in the parent
                // panel).
                wxWindow *focussed_child_of_parent = this;
                for ( wxWindow *parent = GetParent();
                      parent;
                      parent = parent->GetParent() )
                {
                    // we don't want to tab into a different dialog or frame
                    if ( focussed_child_of_parent->IsTopLevel() )
                        break;

                    event.SetCurrentFocus( focussed_child_of_parent );
                    if (parent->GetEventHandler()->ProcessEvent( event ))
                        return;

                    focussed_child_of_parent = parent;
                }
            }
            //else: as the focus came from our parent, we definitely don't want
            //      to send it back to it!

            // no, we are not inside another panel so process this ourself
            node = forward ? children.GetFirst() : children.GetLast();

            continue;
        }

        wxWindow *child = node->GetData();

        if ( child->AcceptsFocus() )
        {
            m_winLastFocused = child;  // should be redundant, but it is not

            // if we're setting the focus to a child panel we should prevent it
            // from giving it to the child which had the focus the last time
            // and instead give it to the first/last child depending from which
            // direction we're coming
            wxPanel *subpanel = wxDynamicCast(child, wxPanel);
            if ( subpanel )
            {
                // trick the panel into thinking that it got the navigation
                // event - instead of duplicating all the code here
                //
                // make sure that we do trick it by setting all the parameters
                // correctly (consistently with the code in this very function
                // above) and that it starts from the very beginning/end by
                // using SetLastFocus(NULL)
                subpanel->SetLastFocus((wxWindow *)NULL);
            }

            event.SetEventObject(this);
            if ( !child->GetEventHandler()->ProcessEvent(event) )
            {
                // everything is simple: just give focus to it
                child->SetFocus();
            }
            //else: the child manages its focus itself

            event.Skip( FALSE );
            return;
        }

        node = forward ? node->GetNext() : node->GetPrevious();
    }

    // we cycled through all of our children and none of them wanted to accept
    // focus
    event.Skip();
}

void wxPanel::SetFocus()
{
    wxLogTrace(_T("focus"), _T("SetFocus on wxPanel 0x%08x."), GetHandle());

    // If the panel gets the focus *by way of getting it set directly*
    // we move the focus to the first window that can get it.

    // VZ: no, we set the focus to the last window too. I don't understand why
    //     should we make this distinction: if an app wants to set focus to
    //     some precise control, it may always do it directly, but if we don't
    //     use m_winLastFocused here, the focus won't be set correctly after a
    //     notebook page change nor after frame activation under MSW (it calls
    //     SetFocus too)
    //
    // RR: yes, when I the tab key to navigate in a panel with some controls and
    //     a notebook and the focus jumps to the notebook (typically coming from
    //     a button at the top) the notebook should focus the first child in the
    //     current notebook page, not the last one which would otherwise get the
    //     focus if you used the tab key to navigate from the current notebook
    //     page to button at the bottom. See every page in the controls sample.
    //
    // VZ: ok, but this still doesn't (at least I don't see how it can) take
    //     care of first/last child problem: i.e. if Shift-TAB is pressed in a
    //     situation like above, the focus should be given to the last child,
    //     not the first one (and not to the last focused one neither) - I
    //     think my addition to OnNavigationKey() above takes care of it.
    //     Keeping #ifdef __WXGTK__ for now, but please try removing it and see
    //     what happens.
    //
    // RR: Removed for now. Let's see what happens..

    if ( !SetFocusToChild() )
    {
        wxWindow::SetFocus();
    }
}

void wxPanel::OnFocus(wxFocusEvent& event)
{
    wxLogTrace(_T("focus"), _T("OnFocus on wxPanel 0x%08x, name: %s"), GetHandle(), GetName().c_str() );

    // If the panel gets the focus *by way of getting clicked on*
    // we move the focus to either the last window that had the
    // focus or the first one that can get it.
    (void)SetFocusToChild();

    event.Skip();
}

bool wxPanel::SetFocusToChild()
{
    return wxSetFocusToChild(this, &m_winLastFocused);
}

// ----------------------------------------------------------------------------
// SetFocusToChild(): this function is used by wxPanel but also by wxFrame in
// wxMSW, this is why it is outside of wxPanel class
// ----------------------------------------------------------------------------

bool wxSetFocusToChild(wxWindow *win, wxWindow **childLastFocused)
{
    wxCHECK_MSG( win, FALSE, _T("wxSetFocusToChild(): invalid window") );

    if ( *childLastFocused )
    {
        // It might happen that the window got reparented or no longer accepts
        // the focus.
        if ( (*childLastFocused)->GetParent() == win &&
             (*childLastFocused)->AcceptsFocus() )
        {
            wxLogTrace(_T("focus"),
                       _T("SetFocusToChild() => last child (0x%08x)."),
                       (*childLastFocused)->GetHandle());

            (*childLastFocused)->SetFocus();
            return TRUE;
        }
        else
        {
            // it doesn't count as such any more
            *childLastFocused = (wxWindow *)NULL;
        }
    }

    // set the focus to the first child who wants it
    wxWindowList::Node *node = win->GetChildren().GetFirst();
    while ( node )
    {
        wxWindow *child = node->GetData();

        if ( child->AcceptsFocus()
             && !child->IsTopLevel()
#if wxUSE_TOOLBAR
             && !wxDynamicCast(child, wxToolBar)
#endif // wxUSE_TOOLBAR
#if wxUSE_STATUSBAR
             && !wxDynamicCast(child, wxStatusBar)
#endif // wxUSE_STATUSBAR
           )
        {
            wxLogTrace(_T("focus"),
                       _T("SetFocusToChild() => first child (0x%08x)."),
                       child->GetHandle());

            *childLastFocused = child;  // should be redundant, but it is not
            child->SetFocus();
            return TRUE;
        }

        node = node->GetNext();
    }

    return FALSE;
}