/*

 * 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

 * 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 "InsertParagraphSeparatorCommand.h"

#include "CSSComputedStyleDeclaration.h"

#include "CSSMutableStyleDeclaration.h"

#include "CSSPropertyNames.h"

#include "Document.h"

#include "HTMLElement.h"

#include "HTMLNames.h"

#include "InsertLineBreakCommand.h"

#include "Logging.h"

#include "RenderObject.h"

#include "Text.h"

#include "htmlediting.h"

#include "visible_units.h"

#include "ApplyStyleCommand.h"

namespace WebCore {

using namespace HTMLNames;

// When inserting a new line, we want to avoid nesting empty divs if we can.  Otherwise, when

// pasting, it's easy to have each new line be a div deeper than the previous.  E.g., in the case

// below, we want to insert at ^ instead of |.

// <div>foo<div>bar</div>|</div>^

static Element* highestVisuallyEquivalentDivBelowRoot(Element* startBlock)

{

    Element* curBlock = startBlock;

    // We don't want to return a root node (if it happens to be a div, e.g., in a document fragment) because there are no

    // siblings for us to append to.

    while (!curBlock->nextSibling() && curBlock->parentElement()->hasTagName(divTag) && curBlock->parentElement()->parentElement()) {

        NamedNodeMap* attributes = curBlock->parentElement()->attributes(true);

        if (attributes && !attributes->isEmpty())

            break;

        curBlock = curBlock->parentElement();

    }

    return curBlock;

}

InsertParagraphSeparatorCommand::InsertParagraphSeparatorCommand(Document *document, bool mustUseDefaultParagraphElement) 

    : CompositeEditCommand(document)

    , m_mustUseDefaultParagraphElement(mustUseDefaultParagraphElement)

{

}

bool InsertParagraphSeparatorCommand::preservesTypingStyle() const

{

    return true;

}

void InsertParagraphSeparatorCommand::calculateStyleBeforeInsertion(const Position &pos)

{

    // It is only important to set a style to apply later if we're at the boundaries of

    // a paragraph. Otherwise, content that is moved as part of the work of the command

    // will lend their styles to the new paragraph without any extra work needed.

    VisiblePosition visiblePos(pos, VP_DEFAULT_AFFINITY);

    if (!isStartOfParagraph(visiblePos) && !isEndOfParagraph(visiblePos))

        return;

    m_style = ApplyStyleCommand::editingStyleAtPosition(pos, IncludeTypingStyle);

}

void InsertParagraphSeparatorCommand::applyStyleAfterInsertion(Node* originalEnclosingBlock)

{

    // Not only do we break out of header tags, but we also do not preserve the typing style,

    // in order to match other browsers.

    if (originalEnclosingBlock->hasTagName(h1Tag) ||

        originalEnclosingBlock->hasTagName(h2Tag) ||

        originalEnclosingBlock->hasTagName(h3Tag) ||

        originalEnclosingBlock->hasTagName(h4Tag) ||

        originalEnclosingBlock->hasTagName(h5Tag))

        return;

    if (!m_style)

        return;

    prepareEditingStyleToApplyAt(m_style.get(), endingSelection().start());

    if (m_style->length() > 0)

        applyStyle(m_style.get());

}

bool InsertParagraphSeparatorCommand::shouldUseDefaultParagraphElement(Node* enclosingBlock) const

{

    if (m_mustUseDefaultParagraphElement)

        return true;

    // Assumes that if there was a range selection, it was already deleted.

    if (!isEndOfBlock(endingSelection().visibleStart()))

        return false;

    return enclosingBlock->hasTagName(h1Tag) ||

           enclosingBlock->hasTagName(h2Tag) ||

           enclosingBlock->hasTagName(h3Tag) ||

           enclosingBlock->hasTagName(h4Tag) ||

           enclosingBlock->hasTagName(h5Tag);

}

void InsertParagraphSeparatorCommand::getAncestorsInsideBlock(const Node* insertionNode, Element* outerBlock, Vector<Element*>& ancestors)

{

    ancestors.clear();

    // Build up list of ancestors elements between the insertion node and the outer block.

    if (insertionNode != outerBlock) {

        for (Element* n = insertionNode->parentElement(); n && n != outerBlock; n = n->parentElement())

            ancestors.append(n);

    }

}

PassRefPtr<Element> InsertParagraphSeparatorCommand::cloneHierarchyUnderNewBlock(const Vector<Element*>& ancestors, PassRefPtr<Element> blockToInsert)

{

    // Make clones of ancestors in between the start node and the start block.

    RefPtr<Element> parent = blockToInsert;

    for (size_t i = ancestors.size(); i != 0; --i) {

        RefPtr<Element> child = ancestors[i - 1]->cloneElementWithoutChildren();

        appendNode(child, parent);

        parent = child.release();

    }

    return parent.release();

}

void InsertParagraphSeparatorCommand::doApply()

{

    bool splitText = false;

    if (endingSelection().isNone())

        return;

    Position insertionPosition = endingSelection().start();

    EAffinity affinity = endingSelection().affinity();

    // Delete the current selection.

    if (endingSelection().isRange()) {

        calculateStyleBeforeInsertion(insertionPosition);

        deleteSelection(false, true);

        insertionPosition = endingSelection().start();

        affinity = endingSelection().affinity();

    }

    // FIXME: The rangeCompliantEquivalent conversion needs to be moved into enclosingBlock.

    Node* startBlockNode = enclosingBlock(rangeCompliantEquivalent(insertionPosition).node());

    Position canonicalPos = VisiblePosition(insertionPosition).deepEquivalent();

    Element* startBlock = static_cast<Element*>(startBlockNode);

    if (!startBlockNode

            || !startBlockNode->isElementNode()

            || !startBlock->parentNode()

            || isTableCell(startBlock)

            || startBlock->hasTagName(formTag)

            // FIXME: If the node is hidden, we don't have a canonical position so we will do the wrong thing for tables and <hr>. https://bugs.webkit.org/show_bug.cgi?id=40342

            || (!canonicalPos.isNull() && canonicalPos.node()->renderer() && canonicalPos.node()->renderer()->isTable())

            || (!canonicalPos.isNull() && canonicalPos.node()->hasTagName(hrTag))) {

        applyCommandToComposite(InsertLineBreakCommand::create(document()));

        return;

    }

    // Use the leftmost candidate.

    insertionPosition = insertionPosition.upstream();

    if (!insertionPosition.isCandidate())

        insertionPosition = insertionPosition.downstream();

    // Adjust the insertion position after the delete

    insertionPosition = positionAvoidingSpecialElementBoundary(insertionPosition);

    VisiblePosition visiblePos(insertionPosition, affinity);

    calculateStyleBeforeInsertion(insertionPosition);

    //---------------------------------------------------------------------

    // Handle special case of typing return on an empty list item

    if (breakOutOfEmptyListItem())

        return;

    //---------------------------------------------------------------------

    // Prepare for more general cases.

    bool isFirstInBlock = isStartOfBlock(visiblePos);

    bool isLastInBlock = isEndOfBlock(visiblePos);

    bool nestNewBlock = false;

    // Create block to be inserted.

    RefPtr<Element> blockToInsert;

    if (startBlock == startBlock->rootEditableElement()) {

        blockToInsert = createDefaultParagraphElement(document());

        nestNewBlock = true;

    } else if (shouldUseDefaultParagraphElement(startBlock)) 

        blockToInsert = createDefaultParagraphElement(document());

    else

        blockToInsert = startBlock->cloneElementWithoutChildren();

    //---------------------------------------------------------------------

    // Handle case when position is in the last visible position in its block,

    // including when the block is empty. 

    if (isLastInBlock) {

        if (nestNewBlock) {

            if (isFirstInBlock && !lineBreakExistsAtVisiblePosition(visiblePos)) {

                // The block is empty.  Create an empty block to

                // represent the paragraph that we're leaving.

                RefPtr<Element> extraBlock = createDefaultParagraphElement(document());

                appendNode(extraBlock, startBlock);

                appendBlockPlaceholder(extraBlock);

            }

            appendNode(blockToInsert, startBlock);

        } else {

            // We can get here if we pasted a copied portion of a blockquote with a newline at the end and are trying to paste it

            // into an unquoted area. We then don't want the newline within the blockquote or else it will also be quoted.

            if (Node* highestBlockquote = highestEnclosingNodeOfType(canonicalPos, &isMailBlockquote))

                startBlock = static_cast<Element*>(highestBlockquote);

            // Most of the time we want to stay at the nesting level of the startBlock (e.g., when nesting within lists).  However,

            // for div nodes, this can result in nested div tags that are hard to break out of.

            Element* siblingNode = startBlock;

            if (blockToInsert->hasTagName(divTag))

                siblingNode = highestVisuallyEquivalentDivBelowRoot(startBlock);

            insertNodeAfter(blockToInsert, siblingNode);

        }

        // Recreate the same structure in the new paragraph.

        Vector<Element*> ancestors;

        getAncestorsInsideBlock(insertionPosition.node(), startBlock, ancestors);      

        RefPtr<Element> parent = cloneHierarchyUnderNewBlock(ancestors, blockToInsert);

        appendBlockPlaceholder(parent);

        setEndingSelection(VisibleSelection(Position(parent.get(), 0), DOWNSTREAM));

        return;

    }

    //---------------------------------------------------------------------

    // Handle case when position is in the first visible position in its block, and

    // similar case where previous position is in another, presumeably nested, block.

    if (isFirstInBlock || !inSameBlock(visiblePos, visiblePos.previous())) {

        Node *refNode;

        if (isFirstInBlock && !nestNewBlock)

            refNode = startBlock;

        else if (insertionPosition.node() == startBlock && nestNewBlock) {

            refNode = startBlock->childNode(insertionPosition.deprecatedEditingOffset());

            ASSERT(refNode); // must be true or we'd be in the end of block case

        } else

            refNode = insertionPosition.node();

        // find ending selection position easily before inserting the paragraph

        insertionPosition = insertionPosition.downstream();

        insertNodeBefore(blockToInsert, refNode);

        // Recreate the same structure in the new paragraph.

        Vector<Element*> ancestors;

        getAncestorsInsideBlock(positionAvoidingSpecialElementBoundary(insertionPosition).node(), startBlock, ancestors);

        appendBlockPlaceholder(cloneHierarchyUnderNewBlock(ancestors, blockToInsert));

        // In this case, we need to set the new ending selection.

        setEndingSelection(VisibleSelection(insertionPosition, DOWNSTREAM));

        return;

    }

    //---------------------------------------------------------------------

    // Handle the (more complicated) general case,

    // All of the content in the current block after visiblePos is

    // about to be wrapped in a new paragraph element.  Add a br before 

    // it if visiblePos is at the start of a paragraph so that the 

    // content will move down a line.

    if (isStartOfParagraph(visiblePos)) {

        RefPtr<Element> br = createBreakElement(document());

        insertNodeAt(br.get(), insertionPosition);

        insertionPosition = positionInParentAfterNode(br.get());

    }

    // Move downstream. Typing style code will take care of carrying along the 

    // style of the upstream position.

    insertionPosition = insertionPosition.downstream();

    // At this point, the insertionPosition's node could be a container, and we want to make sure we include

    // all of the correct nodes when building the ancestor list.  So this needs to be the deepest representation of the position

    // before we walk the DOM tree.

    insertionPosition = VisiblePosition(insertionPosition).deepEquivalent();

    // Build up list of ancestors in between the start node and the start block.

    Vector<Element*> ancestors;

    getAncestorsInsideBlock(insertionPosition.node(), startBlock, ancestors);

    // Make sure we do not cause a rendered space to become unrendered.

    // FIXME: We need the affinity for pos, but pos.downstream() does not give it

    Position leadingWhitespace = insertionPosition.leadingWhitespacePosition(VP_DEFAULT_AFFINITY);

    // FIXME: leadingWhitespacePosition is returning the position before preserved newlines for positions

    // after the preserved newline, causing the newline to be turned into a nbsp.

    if (leadingWhitespace.isNotNull() && leadingWhitespace.node()->isTextNode()) {

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

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

        replaceTextInNode(textNode, leadingWhitespace.deprecatedEditingOffset(), 1, nonBreakingSpaceString());

    }

    // Split at pos if in the middle of a text node.

    if (insertionPosition.node()->isTextNode()) {

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

        bool atEnd = (unsigned)insertionPosition.deprecatedEditingOffset() >= textNode->length();

        if (insertionPosition.deprecatedEditingOffset() > 0 && !atEnd) {

            splitTextNode(textNode, insertionPosition.deprecatedEditingOffset());

            insertionPosition.moveToOffset(0);

            visiblePos = VisiblePosition(insertionPosition);

            splitText = true;

        }

    }

    // Put the added block in the tree.

    if (nestNewBlock)

        appendNode(blockToInsert.get(), startBlock);

    else

        insertNodeAfter(blockToInsert.get(), startBlock);

    updateLayout();

    // Make clones of ancestors in between the start node and the outer block.

    RefPtr<Element> parent = cloneHierarchyUnderNewBlock(ancestors, blockToInsert);

    // If the paragraph separator was inserted at the end of a paragraph, an empty line must be

    // created.  All of the nodes, starting at visiblePos, are about to be added to the new paragraph 

    // element.  If the first node to be inserted won't be one that will hold an empty line open, add a br.

    if (isEndOfParagraph(visiblePos) && !lineBreakExistsAtVisiblePosition(visiblePos))

        appendNode(createBreakElement(document()).get(), blockToInsert.get());

    // Move the start node and the siblings of the start node.

    if (insertionPosition.node() != startBlock) {

        Node* n = insertionPosition.node();

        if (insertionPosition.deprecatedEditingOffset() >= caretMaxOffset(n))

            n = n->nextSibling();

        while (n && n != blockToInsert) {

            Node *next = n->nextSibling();

            removeNode(n);

            appendNode(n, parent.get());

            n = next;

        }

    }            

    // Move everything after the start node.

    if (!ancestors.isEmpty()) {

        Element* leftParent = ancestors.first();

        while (leftParent && leftParent != startBlock) {

            parent = parent->parentElement();

            if (!parent)

                break;

            Node* n = leftParent->nextSibling();

            while (n && n != blockToInsert) {

                Node* next = n->nextSibling();

                removeNode(n);

                appendNode(n, parent.get());

                n = next;

            }

            leftParent = leftParent->parentElement();

        }

    }

    // Handle whitespace that occurs after the split

    if (splitText) {

        updateLayout();

        insertionPosition = Position(insertionPosition.node(), 0);

        if (!insertionPosition.isRenderedCharacter()) {

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

            ASSERT(!insertionPosition.node()->renderer() || insertionPosition.node()->renderer()->style()->collapseWhiteSpace());

            deleteInsignificantTextDownstream(insertionPosition);

            if (insertionPosition.node()->isTextNode())

                insertTextIntoNode(static_cast<Text*>(insertionPosition.node()), 0, nonBreakingSpaceString());

        }

    }

    setEndingSelection(VisibleSelection(Position(blockToInsert.get(), 0), DOWNSTREAM));

    applyStyleAfterInsertion(startBlock);

}

} // namespace WebCore