/*

 * Copyright (C) 2005, 2006 Apple Computer, 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

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 * (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 "InsertLineBreakCommand.h"

#include "CSSMutableStyleDeclaration.h"

#include "Document.h"

#include "Frame.h"

#include "HTMLElement.h"

#include "HTMLNames.h"

#include "Range.h"

#include "RenderObject.h"

#include "Text.h"

#include "VisiblePosition.h"

#include "htmlediting.h"

#include "visible_units.h"

namespace WebCore {

using namespace HTMLNames;

InsertLineBreakCommand::InsertLineBreakCommand(Document* document) 

    : CompositeEditCommand(document)

{

}

bool InsertLineBreakCommand::preservesTypingStyle() const

{

    return true;

}

void InsertLineBreakCommand::insertNodeAfterPosition(Node* node, const Position& pos)

{

    // Insert the BR after the caret position. In the case the

    // position is a block, do an append. We don't want to insert

    // the BR *after* the block.

    Element* cb = pos.node()->enclosingBlockFlowElement();

    if (cb == pos.node())

        appendNode(node, cb);

    else

        insertNodeAfter(node, pos.node());

}

void InsertLineBreakCommand::insertNodeBeforePosition(Node* node, const Position& pos)

{

    // Insert the BR after the caret position. In the case the

    // position is a block, do an append. We don't want to insert

    // the BR *before* the block.

    Element* cb = pos.node()->enclosingBlockFlowElement();

    if (cb == pos.node())

        appendNode(node, cb);

    else

        insertNodeBefore(node, pos.node());

}

// Whether we should insert a break element or a '\n'.

bool InsertLineBreakCommand::shouldUseBreakElement(const Position& insertionPos)

{

    // An editing position like [input, 0] actually refers to the position before

    // the input element, and in that case we need to check the input element's

    // parent's renderer.

    Position p(rangeCompliantEquivalent(insertionPos));

    return p.node()->renderer() && !p.node()->renderer()->style()->preserveNewline();

}

void InsertLineBreakCommand::doApply()

{

    deleteSelection();

    VisibleSelection selection = endingSelection();

    if (selection.isNone())

        return;

    VisiblePosition caret(selection.visibleStart());

    // FIXME: If the node is hidden, we should still be able to insert text. 

    // For now, we return to avoid a crash.  https://bugs.webkit.org/show_bug.cgi?id=40342

    if (caret.isNull())

        return;

    Position pos(caret.deepEquivalent());

    pos = positionAvoidingSpecialElementBoundary(pos);

    pos = positionOutsideTabSpan(pos);

    RefPtr<Node> nodeToInsert;

    if (shouldUseBreakElement(pos))

        nodeToInsert = createBreakElement(document());

    else

        nodeToInsert = document()->createTextNode("\n");

    // FIXME: Need to merge text nodes when inserting just after or before text.

    if (isEndOfParagraph(caret) && !lineBreakExistsAtVisiblePosition(caret)) {

        bool needExtraLineBreak = !pos.node()->hasTagName(hrTag) && !pos.node()->hasTagName(tableTag);

        insertNodeAt(nodeToInsert.get(), pos);

        if (needExtraLineBreak)

            insertNodeBefore(nodeToInsert->cloneNode(false), nodeToInsert);

        VisiblePosition endingPosition(Position(nodeToInsert.get(), 0));

        setEndingSelection(VisibleSelection(endingPosition));

    } else if (pos.deprecatedEditingOffset() <= caretMinOffset(pos.node())) {

        insertNodeAt(nodeToInsert.get(), pos);

        // Insert an extra br or '\n' if the just inserted one collapsed.

        if (!isStartOfParagraph(VisiblePosition(Position(nodeToInsert.get(), 0))))

            insertNodeBefore(nodeToInsert->cloneNode(false).get(), nodeToInsert.get());

        setEndingSelection(VisibleSelection(positionInParentAfterNode(nodeToInsert.get()), DOWNSTREAM));

    // If we're inserting after all of the rendered text in a text node, or into a non-text node,

    // a simple insertion is sufficient.

    } else if (pos.deprecatedEditingOffset() >= caretMaxOffset(pos.node()) || !pos.node()->isTextNode()) {

        insertNodeAt(nodeToInsert.get(), pos);

        setEndingSelection(VisibleSelection(positionInParentAfterNode(nodeToInsert.get()), DOWNSTREAM));

    } else if (pos.node()->isTextNode()) {

        // Split a text node

        Text* textNode = static_cast<Text*>(pos.node());

        splitTextNode(textNode, pos.deprecatedEditingOffset());

        insertNodeBefore(nodeToInsert, textNode);

        Position endingPosition = Position(textNode, 0);

        // Handle whitespace that occurs after the split

        updateLayout();

        if (!endingPosition.isRenderedCharacter()) {

            Position positionBeforeTextNode(positionInParentBeforeNode(textNode));

            // Clear out all whitespace and insert one non-breaking space

            deleteInsignificantTextDownstream(endingPosition);

            ASSERT(!textNode->renderer() || textNode->renderer()->style()->collapseWhiteSpace());

            // Deleting insignificant whitespace will remove textNode if it contains nothing but insignificant whitespace.

            if (textNode->inDocument())

                insertTextIntoNode(textNode, 0, nonBreakingSpaceString());

            else {

                RefPtr<Text> nbspNode = document()->createTextNode(nonBreakingSpaceString());

                insertNodeAt(nbspNode.get(), positionBeforeTextNode);

                endingPosition = Position(nbspNode.get(), 0);

            }

        }

        setEndingSelection(VisibleSelection(endingPosition, DOWNSTREAM));

    }

    // Handle the case where there is a typing style.

    CSSMutableStyleDeclaration* typingStyle = document()->frame()->typingStyle();

    if (typingStyle && typingStyle->length() > 0) {

        // Apply the typing style to the inserted line break, so that if the selection

        // leaves and then comes back, new input will have the right style.

        // FIXME: We shouldn't always apply the typing style to the line break here,

        // see <rdar://problem/5794462>.

        applyStyle(typingStyle, firstDeepEditingPositionForNode(nodeToInsert.get()), lastDeepEditingPositionForNode(nodeToInsert.get()));

        // Even though this applyStyle operates on a Range, it still sets an endingSelection().

        // It tries to set a VisibleSelection around the content it operated on. So, that VisibleSelection

        // will either (a) select the line break we inserted, or it will (b) be a caret just 

        // before the line break (if the line break is at the end of a block it isn't selectable).

        // So, this next call sets the endingSelection() to a caret just after the line break 

        // that we inserted, or just before it if it's at the end of a block.

        setEndingSelection(endingSelection().visibleEnd());

    }

    rebalanceWhitespace();

}

}