/*

 * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

 */

#include "config.h"

#include "FocusController.h"

#include "AXObjectCache.h"

#include "Chrome.h"

#include "Document.h"

#include "Editor.h"

#include "EditorClient.h"

#include "Element.h"

#include "Event.h"

#include "EventHandler.h"

#include "EventNames.h"

#include "Frame.h"

#include "FrameView.h"

#include "FrameTree.h"

#include "HTMLFrameOwnerElement.h"

#include "HTMLNames.h"

#include "KeyboardEvent.h"

#include "Page.h"

#include "Range.h"

#include "RenderObject.h"

#include "RenderWidget.h"

#include "SelectionController.h"

#include "Widget.h"

#include <wtf/Platform.h>

namespace WebCore {

using namespace EventNames;

using namespace HTMLNames;

FocusController::FocusController(Page* page)

    : m_page(page)

{

}

void FocusController::setFocusedFrame(PassRefPtr<Frame> frame)

{

    if (m_focusedFrame == frame)

        return;

    if (m_focusedFrame) {

        m_focusedFrame->setWindowHasFocus(false);

        m_focusedFrame->setIsActive(false);

    }

    m_focusedFrame = frame;

    if (m_focusedFrame) {

        m_focusedFrame->setWindowHasFocus(true);

        m_focusedFrame->setIsActive(true);

    }

}

Frame* FocusController::focusedOrMainFrame()

{

    if (Frame* frame = focusedFrame())

        return frame;

    return m_page->mainFrame();

}

static Node* deepFocusableNode(FocusDirection direction, Node* node, KeyboardEvent* event)

{

    // The node we found might be a HTMLFrameOwnerElement, so descend down the frame tree until we find either:

    // 1) a focusable node, or

    // 2) the deepest-nested HTMLFrameOwnerElement

    while (node && node->isFrameOwnerElement()) {

        HTMLFrameOwnerElement* owner = static_cast<HTMLFrameOwnerElement*>(node);

        if (!owner->contentFrame())

            break;

        Document* document = owner->contentFrame()->document();

        if (!document)

            break;

        node = (direction == FocusDirectionForward)

            ? document->nextFocusableNode(0, event)

            : document->previousFocusableNode(0, event);

        if (!node) {

            node = owner;

            break;

        }

    }

    return node;

}

bool FocusController::setInitialFocus(FocusDirection direction, KeyboardEvent* event)

{

    return advanceFocus(direction, event, true);

}

bool FocusController::advanceFocus(KeyboardEvent* event)

{

    return advanceFocus((event && event->shiftKey()) ? FocusDirectionBackward : FocusDirectionForward, event);

}

bool FocusController::advanceFocus(FocusDirection direction, KeyboardEvent* event, bool initialFocus)

{

    Frame* frame = focusedOrMainFrame();

    ASSERT(frame);

    Document* document = frame->document();

    if (!document)

        return false;

    Node* node = (direction == FocusDirectionForward)

        ? document->nextFocusableNode(document->focusedNode(), event)

        : document->previousFocusableNode(document->focusedNode(), event);

    // If there's no focusable node to advance to, move up the frame tree until we find one.

    while (!node && frame) {

        Frame* parentFrame = frame->tree()->parent();

        if (!parentFrame)

            break;

        Document* parentDocument = parentFrame->document();

        if (!parentDocument)

            break;

        HTMLFrameOwnerElement* owner = frame->ownerElement();

        if (!owner)

            break;

        node = (direction == FocusDirectionForward)

            ? parentDocument->nextFocusableNode(owner, event)

            : parentDocument->previousFocusableNode(owner, event);

        frame = parentFrame;

    }

    node = deepFocusableNode(direction, node, event);

    if (!node) {

        // We didn't find a node to focus, so we should try to pass focus to Chrome.

        if (!initialFocus && m_page->chrome()->canTakeFocus(direction)) {

            document->setFocusedNode(0);

            setFocusedFrame(0);

            m_page->chrome()->takeFocus(direction);

            return true;

        }

        // Chrome doesn't want focus, so we should wrap focus.

        if (Document* d = m_page->mainFrame()->document())

            node = (direction == FocusDirectionForward)

                ? d->nextFocusableNode(0, event)

                : d->previousFocusableNode(0, event);

        node = deepFocusableNode(direction, node, event);

        if (!node)

            return false;

    }

    ASSERT(node);

    if (node == document->focusedNode())

        // Focus wrapped around to the same node.

        return true;

    if (!node->isElementNode())

        // FIXME: May need a way to focus a document here.

        return false;

    if (node->isFrameOwnerElement()) {

        // We focus frames rather than frame owners.

        // FIXME: We should not focus frames that have no scrollbars, as focusing them isn't useful to the user.

        HTMLFrameOwnerElement* owner = static_cast<HTMLFrameOwnerElement*>(node);

        if (!owner->contentFrame())

            return false;

        document->setFocusedNode(0);

        setFocusedFrame(owner->contentFrame());

        return true;

    }

    // FIXME: It would be nice to just be able to call setFocusedNode(node) here, but we can't do

    // that because some elements (e.g. HTMLInputElement and HTMLTextAreaElement) do extra work in

    // their focus() methods.

    Document* newDocument = node->document();

    if (newDocument != document)

        // Focus is going away from this document, so clear the focused node.

        document->setFocusedNode(0);

    if (newDocument)

        setFocusedFrame(newDocument->frame());

    static_cast<Element*>(node)->focus(false);

    return true;

}

static bool relinquishesEditingFocus(Node *node)

{

    ASSERT(node);

    ASSERT(node->isContentEditable());

    Node* root = node->rootEditableElement();

    Frame* frame = node->document()->frame();

    if (!frame || !root)

        return false;

    return frame->editor()->shouldEndEditing(rangeOfContents(root).get());

}

static void clearSelectionIfNeeded(Frame* oldFocusedFrame, Frame* newFocusedFrame, Node* newFocusedNode)

{

    if (!oldFocusedFrame || !newFocusedFrame)

        return;

    if (oldFocusedFrame->document() != newFocusedFrame->document())

        return;

    SelectionController* s = oldFocusedFrame->selectionController();

    if (s->isNone())

        return;

    Node* selectionStartNode = s->selection().start().node();

    if (selectionStartNode == newFocusedNode || selectionStartNode->isDescendantOf(newFocusedNode) || selectionStartNode->shadowAncestorNode() == newFocusedNode)

        return;

    if (Node* mousePressNode = newFocusedFrame->eventHandler()->mousePressNode())

        if (mousePressNode->renderer() && !mousePressNode->canStartSelection())

            if (Node* root = s->rootEditableElement())

                if (Node* shadowAncestorNode = root->shadowAncestorNode())

                    // Don't do this for textareas and text fields, when they lose focus their selections should be cleared

                    // and then restored when they regain focus, to match other browsers.

                    if (!shadowAncestorNode->hasTagName(inputTag) && !shadowAncestorNode->hasTagName(textareaTag))

                        return;

    s->clear();

}

bool FocusController::setFocusedNode(Node* node, PassRefPtr<Frame> newFocusedFrame)

{

    RefPtr<Frame> oldFocusedFrame = focusedFrame();

    RefPtr<Document> oldDocument = oldFocusedFrame ? oldFocusedFrame->document() : 0;

    Node* oldFocusedNode = oldDocument ? oldDocument->focusedNode() : 0;

    if (oldFocusedNode == node)

        return true;

    if (oldFocusedNode && oldFocusedNode->rootEditableElement() == oldFocusedNode && !relinquishesEditingFocus(oldFocusedNode))

        return false;

    clearSelectionIfNeeded(oldFocusedFrame.get(), newFocusedFrame.get(), node);

    if (!node) {

        if (oldDocument)

            oldDocument->setFocusedNode(0);

        m_page->editorClient()->setInputMethodState(false);

        return true;

    }

    RefPtr<Document> newDocument = node ? node->document() : 0;

    if (newDocument && newDocument->focusedNode() == node) {

        m_page->editorClient()->setInputMethodState(node->shouldUseInputMethod());

        return true;

    }

    if (oldDocument && oldDocument != newDocument)

        oldDocument->setFocusedNode(0);

    setFocusedFrame(newFocusedFrame);

    if (newDocument)

        newDocument->setFocusedNode(node);

    m_page->editorClient()->setInputMethodState(node->shouldUseInputMethod());

    return true;

}

} // namespace WebCore