/*

 * (C) 1999 Lars Knoll (knoll@kde.org)

 * (C) 2000 Dirk Mueller (mueller@kde.org)

 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Library General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library 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

 * Library General Public License for more details.

 *

 * You should have received a copy of the GNU Library General Public License

 * along with this library; see the file COPYING.LIB.  If not, write to

 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,

 * Boston, MA 02110-1301, USA.

 *

 */

#include "config.h"

#include "InlineTextBox.h"

#include "Chrome.h"

#include "ChromeClient.h"

#include "Document.h"

#include "Editor.h"

#include "EllipsisBox.h"

#include "Frame.h"

#include "GraphicsContext.h"

#include "HitTestResult.h"

#include "Page.h"

#include "RenderArena.h"

#include "RenderBlock.h"

#include "RenderTheme.h"

#include "Text.h"

#include "break_lines.h"

#include <wtf/AlwaysInline.h>

using namespace std;

namespace WebCore {

int InlineTextBox::selectionTop()

{

    return root()->selectionTop();

}

int InlineTextBox::selectionHeight()

{

    return root()->selectionHeight();

}

bool InlineTextBox::isSelected(int startPos, int endPos) const

{

    int sPos = max(startPos - m_start, 0);

    int ePos = min(endPos - m_start, (int)m_len);

    return (sPos < ePos);

}

RenderObject::SelectionState InlineTextBox::selectionState()

{

    RenderObject::SelectionState state = renderer()->selectionState();

    if (state == RenderObject::SelectionStart || state == RenderObject::SelectionEnd || state == RenderObject::SelectionBoth) {

        int startPos, endPos;

        renderer()->selectionStartEnd(startPos, endPos);

        // The position after a hard line break is considered to be past its end.

        int lastSelectable = start() + len() - (isLineBreak() ? 1 : 0);

        bool start = (state != RenderObject::SelectionEnd && startPos >= m_start && startPos < m_start + m_len);

        bool end = (state != RenderObject::SelectionStart && endPos > m_start && endPos <= lastSelectable);

        if (start && end)

            state = RenderObject::SelectionBoth;

        else if (start)

            state = RenderObject::SelectionStart;

        else if (end)

            state = RenderObject::SelectionEnd;

        else if ((state == RenderObject::SelectionEnd || startPos < m_start) &&

                 (state == RenderObject::SelectionStart || endPos > lastSelectable))

            state = RenderObject::SelectionInside;

        else if (state == RenderObject::SelectionBoth)

            state = RenderObject::SelectionNone;

    }

    // If there are ellipsis following, make sure their selection is updated.

    if (m_truncation != cNoTruncation && root()->ellipsisBox()) {

        EllipsisBox* ellipsis = root()->ellipsisBox();

        if (state != RenderObject::SelectionNone) {

            int start, end;

            selectionStartEnd(start, end);

            // The ellipsis should be considered to be selected if the end of

            // the selection is past the beginning of the truncation and the

            // beginning of the selection is before or at the beginning of the

            // truncation.

            ellipsis->setSelectionState(end >= m_truncation && start <= m_truncation ?

                RenderObject::SelectionInside : RenderObject::SelectionNone);

        } else

            ellipsis->setSelectionState(RenderObject::SelectionNone);

    }

    return state;

}

typedef Vector<UChar, 256> BufferForAppendingHyphen;

static void adjustCharactersAndLengthForHyphen(BufferForAppendingHyphen& charactersWithHyphen, RenderStyle* style, const UChar*& characters, int& length)

{

    const AtomicString& hyphenString = style->hyphenString();

    charactersWithHyphen.reserveCapacity(length + hyphenString.length());

    charactersWithHyphen.append(characters, length);

    charactersWithHyphen.append(hyphenString.characters(), hyphenString.length());

    characters = charactersWithHyphen.data();

    length += hyphenString.length();

}

IntRect InlineTextBox::selectionRect(int tx, int ty, int startPos, int endPos)

{

    int sPos = max(startPos - m_start, 0);

    int ePos = min(endPos - m_start, (int)m_len);

    if (sPos > ePos)

        return IntRect();

    RenderText* textObj = textRenderer();

    int selTop = selectionTop();

    int selHeight = selectionHeight();

    RenderStyle* styleToUse = textObj->style(m_firstLine);

    const Font& f = styleToUse->font();

    const UChar* characters = textObj->text()->characters() + m_start;

    int len = m_len;

    BufferForAppendingHyphen charactersWithHyphen;

    if (ePos == len && hasHyphen()) {

        adjustCharactersAndLengthForHyphen(charactersWithHyphen, styleToUse, characters, len);

        ePos = len;

    }

    IntRect r = enclosingIntRect(f.selectionRectForText(TextRun(characters, len, textObj->allowTabs(), textPos(), m_toAdd, direction() == RTL, m_dirOverride),

                                                        IntPoint(tx + m_x, ty + selTop), selHeight, sPos, ePos));

    if (r.x() > tx + m_x + m_width)

        r.setWidth(0);

    else if (r.right() - 1 > tx + m_x + m_width)

        r.setWidth(tx + m_x + m_width - r.x());

    return r;

}

void InlineTextBox::deleteLine(RenderArena* arena)

{

    toRenderText(renderer())->removeTextBox(this);

    destroy(arena);

}

void InlineTextBox::extractLine()

{

    if (m_extracted)

        return;

    toRenderText(renderer())->extractTextBox(this);

}

void InlineTextBox::attachLine()

{

    if (!m_extracted)

        return;

    toRenderText(renderer())->attachTextBox(this);

}

int InlineTextBox::placeEllipsisBox(bool flowIsLTR, int visibleLeftEdge, int visibleRightEdge, int ellipsisWidth, bool& foundBox)

{

    if (foundBox) {

        m_truncation = cFullTruncation;

        return -1;

    }

    // For LTR this is the left edge of the box, for RTL, the right edge in parent coordinates.

    int ellipsisX = flowIsLTR ? visibleRightEdge - ellipsisWidth : visibleLeftEdge + ellipsisWidth;

    // Criteria for full truncation:

    // LTR: the left edge of the ellipsis is to the left of our text run.

    // RTL: the right edge of the ellipsis is to the right of our text run.

    bool ltrFullTruncation = flowIsLTR && ellipsisX <= m_x;

    bool rtlFullTruncation = !flowIsLTR && ellipsisX >= (m_x + m_width);

    if (ltrFullTruncation || rtlFullTruncation) {

        // Too far.  Just set full truncation, but return -1 and let the ellipsis just be placed at the edge of the box.

        m_truncation = cFullTruncation;

        foundBox = true;

        return -1;

    }

    bool ltrEllipsisWithinBox = flowIsLTR && (ellipsisX < m_x + m_width);

    bool rtlEllipsisWithinBox = !flowIsLTR && (ellipsisX > m_x);

    if (ltrEllipsisWithinBox || rtlEllipsisWithinBox) {

        foundBox = true;

        // The inline box may have different directionality than it's parent.  Since truncation

        // behavior depends both on both the parent and the inline block's directionality, we

        // must keep track of these separately.

        bool ltr = direction() == LTR;

        if (ltr != flowIsLTR) {

          // Width in pixels of the visible portion of the box, excluding the ellipsis.

          int visibleBoxWidth = visibleRightEdge - visibleLeftEdge  - ellipsisWidth;

          ellipsisX = ltr ? m_x + visibleBoxWidth : m_x + m_width - visibleBoxWidth;

        }

        int offset = offsetForPosition(ellipsisX, false);

        if (offset == 0) {

            // No characters should be rendered.  Set ourselves to full truncation and place the ellipsis at the min of our start

            // and the ellipsis edge.

            m_truncation = cFullTruncation;

            return min(ellipsisX, m_x);

        }

        // Set the truncation index on the text run.

        m_truncation = offset;

        // If we got here that means that we were only partially truncated and we need to return the pixel offset at which

        // to place the ellipsis.

        int widthOfVisibleText = toRenderText(renderer())->width(m_start, offset, textPos(), m_firstLine);

        // The ellipsis needs to be placed just after the last visible character.

        // Where "after" is defined by the flow directionality, not the inline

        // box directionality.

        // e.g. In the case of an LTR inline box truncated in an RTL flow then we can

        // have a situation such as |Hello| -> |...He|

        if (flowIsLTR)

            return m_x + widthOfVisibleText;

        else

            return (m_x + m_width) - widthOfVisibleText - ellipsisWidth;

    }

    return -1;

}

Color correctedTextColor(Color textColor, Color backgroundColor) 

{

    // Adjust the text color if it is too close to the background color,

    // by darkening or lightening it to move it further away.

    int d = differenceSquared(textColor, backgroundColor);

    // semi-arbitrarily chose 65025 (255^2) value here after a few tests; 

    if (d > 65025) {

        return textColor;

    }

    int distanceFromWhite = differenceSquared(textColor, Color::white);

    int distanceFromBlack = differenceSquared(textColor, Color::black);

    if (distanceFromWhite < distanceFromBlack) {

        return textColor.dark();

    }

    return textColor.light();

}

void updateGraphicsContext(GraphicsContext* context, const Color& fillColor, const Color& strokeColor, float strokeThickness, ColorSpace colorSpace)

{

    int mode = context->textDrawingMode();

    if (strokeThickness > 0) {

        int newMode = mode | cTextStroke;

        if (mode != newMode) {

            context->setTextDrawingMode(newMode);

            mode = newMode;

        }

    }

    if (mode & cTextFill && (fillColor != context->fillColor() || colorSpace != context->fillColorSpace()))

        context->setFillColor(fillColor, colorSpace);

    if (mode & cTextStroke) {

        if (strokeColor != context->strokeColor())

            context->setStrokeColor(strokeColor, colorSpace);

        if (strokeThickness != context->strokeThickness())

            context->setStrokeThickness(strokeThickness);

    }

}

bool InlineTextBox::isLineBreak() const

{

    return renderer()->isBR() || (renderer()->style()->preserveNewline() && len() == 1 && (*textRenderer()->text())[start()] == '\n');

}

bool InlineTextBox::nodeAtPoint(const HitTestRequest&, HitTestResult& result, int x, int y, int tx, int ty)

{

    if (isLineBreak())

        return false;

    IntRect rect(tx + m_x, ty + m_y, m_width, height());

    if (m_truncation != cFullTruncation && visibleToHitTesting() && rect.intersects(result.rectFromPoint(x, y))) {

        renderer()->updateHitTestResult(result, IntPoint(x - tx, y - ty));

        if (!result.addNodeToRectBasedTestResult(renderer()->node(), x, y, rect))

            return true;

    }

    return false;

}

FloatSize InlineTextBox::applyShadowToGraphicsContext(GraphicsContext* context, const ShadowData* shadow, const FloatRect& textRect, bool stroked, bool opaque)

{

    if (!shadow)

        return FloatSize();

    FloatSize extraOffset;

    FloatSize shadowOffset(shadow->x(), shadow->y());

    int shadowBlur = shadow->blur();

    const Color& shadowColor = shadow->color();

    if (shadow->next() || stroked || !opaque) {

        FloatRect shadowRect(textRect);

        shadowRect.inflate(shadowBlur);

        shadowRect.move(shadowOffset);

        context->save();

        context->clip(shadowRect);

        extraOffset = FloatSize(0, 2 * textRect.height() + max(0.0f, shadowOffset.height()) + shadowBlur);

        shadowOffset -= extraOffset;

    }

    context->setShadow(shadowOffset, shadowBlur, shadowColor, context->fillColorSpace());

    return extraOffset;

}

static void paintTextWithShadows(GraphicsContext* context, const Font& font, const TextRun& textRun, int startOffset, int endOffset, int truncationPoint, const IntPoint& textOrigin, int x, int y, int w, int h, const ShadowData* shadow, bool stroked)

{

    Color fillColor = context->fillColor();

    ColorSpace fillColorSpace = context->fillColorSpace();

    bool opaque = fillColor.alpha() == 255;

    if (!opaque)

        context->setFillColor(Color::black, fillColorSpace);

    do {

        IntSize extraOffset;

        if (shadow)

            extraOffset = roundedIntSize(InlineTextBox::applyShadowToGraphicsContext(context, shadow, FloatRect(x, y, w, h), stroked, opaque));

        else if (!opaque)

            context->setFillColor(fillColor, fillColorSpace);

        if (startOffset <= endOffset)

            context->drawText(font, textRun, textOrigin + extraOffset, startOffset, endOffset);

        else {

            if (endOffset > 0)

                context->drawText(font, textRun, textOrigin + extraOffset,  0, endOffset);

            if (startOffset < truncationPoint)

                context->drawText(font, textRun, textOrigin + extraOffset, startOffset, truncationPoint);

        }

        if (!shadow)

            break;

        if (shadow->next() || stroked || !opaque)

            context->restore();

        else

            context->clearShadow();

        shadow = shadow->next();

    } while (shadow || stroked || !opaque);

}

void InlineTextBox::paint(PaintInfo& paintInfo, int tx, int ty)

{

    if (isLineBreak() || !paintInfo.shouldPaintWithinRoot(renderer()) || renderer()->style()->visibility() != VISIBLE ||

        m_truncation == cFullTruncation || paintInfo.phase == PaintPhaseOutline)

        return;

    ASSERT(paintInfo.phase != PaintPhaseSelfOutline && paintInfo.phase != PaintPhaseChildOutlines);

    // FIXME: Technically we're potentially incorporating other visual overflow that had nothing to do with us.

    // Would it be simpler to just check our own shadow and stroke overflow by hand here?

    int leftOverflow = parent()->x() - parent()->leftVisualOverflow();

    int rightOverflow = parent()->rightVisualOverflow() - (parent()->x() + parent()->width());

    int xPos = tx + m_x - leftOverflow;

    int w = width() + leftOverflow + rightOverflow;

    if (xPos >= paintInfo.rect.right() || xPos + w <= paintInfo.rect.x())

        return;

    bool isPrinting = textRenderer()->document()->printing();

    // Determine whether or not we're selected.

    bool haveSelection = !isPrinting && paintInfo.phase != PaintPhaseTextClip && selectionState() != RenderObject::SelectionNone;

    if (!haveSelection && paintInfo.phase == PaintPhaseSelection)

        // When only painting the selection, don't bother to paint if there is none.

        return;

    if (m_truncation != cNoTruncation) {

        TextDirection flowDirection = renderer()->containingBlock()->style()->direction();

        if (flowDirection != direction()) {

            // Make the visible fragment of text hug the edge closest to the rest of the run by moving the origin

            // at which we start drawing text.

            // e.g. In the case of LTR text truncated in an RTL Context, the correct behavior is:

            // |Hello|CBA| -> |...He|CBA|

            // In order to draw the fragment "He" aligned to the right edge of it's box, we need to start drawing

            // farther to the right.

            // NOTE: WebKit's behavior differs from that of IE which appears to just overlay the ellipsis on top of the

            // truncated string i.e.  |Hello|CBA| -> |...lo|CBA|

            int widthOfVisibleText = toRenderText(renderer())->width(m_start, m_truncation, textPos(), m_firstLine);

            int widthOfHiddenText = m_width - widthOfVisibleText;

            // FIXME: The hit testing logic also needs to take this translation int account.

            tx += direction() == LTR ? widthOfHiddenText : -widthOfHiddenText;

        }

    }

    GraphicsContext* context = paintInfo.context;

    // Determine whether or not we have composition underlines to draw.

    bool containsComposition = renderer()->node() && renderer()->frame()->editor()->compositionNode() == renderer()->node();

    bool useCustomUnderlines = containsComposition && renderer()->frame()->editor()->compositionUsesCustomUnderlines();

    // Set our font.

    RenderStyle* styleToUse = renderer()->style(m_firstLine);

    int d = styleToUse->textDecorationsInEffect();

    const Font& font = styleToUse->font();

    // 1. Paint backgrounds behind text if needed. Examples of such backgrounds include selection

    // and composition underlines.

    if (paintInfo.phase != PaintPhaseSelection && paintInfo.phase != PaintPhaseTextClip && !isPrinting) {

#if PLATFORM(MAC)

        // Custom highlighters go behind everything else.

        if (styleToUse->highlight() != nullAtom && !context->paintingDisabled())

            paintCustomHighlight(tx, ty, styleToUse->highlight());

#endif

        if (containsComposition && !useCustomUnderlines)

            paintCompositionBackground(context, tx, ty, styleToUse, font,

                renderer()->frame()->editor()->compositionStart(),

                renderer()->frame()->editor()->compositionEnd());

        paintDocumentMarkers(context, tx, ty, styleToUse, font, true);

        if (haveSelection && !useCustomUnderlines)

            paintSelection(context, tx, ty, styleToUse, font);

    }

    // 2. Now paint the foreground, including text and decorations like underline/overline (in quirks mode only).

    if (m_len <= 0)

        return;

    Color textFillColor;

    Color textStrokeColor;

    float textStrokeWidth = styleToUse->textStrokeWidth();

    const ShadowData* textShadow = paintInfo.forceBlackText ? 0 : styleToUse->textShadow();

    if (paintInfo.forceBlackText) {

        textFillColor = Color::black;

        textStrokeColor = Color::black;

    } else {

        textFillColor = styleToUse->visitedDependentColor(CSSPropertyWebkitTextFillColor);

        // Make the text fill color legible against a white background

        if (styleToUse->forceBackgroundsToWhite())

            textFillColor = correctedTextColor(textFillColor, Color::white);

        textStrokeColor = styleToUse->visitedDependentColor(CSSPropertyWebkitTextStrokeColor);

        // Make the text stroke color legible against a white background

        if (styleToUse->forceBackgroundsToWhite())

            textStrokeColor = correctedTextColor(textStrokeColor, Color::white);

    }

    bool paintSelectedTextOnly = (paintInfo.phase == PaintPhaseSelection);

    bool paintSelectedTextSeparately = false;

    Color selectionFillColor = textFillColor;

    Color selectionStrokeColor = textStrokeColor;

    float selectionStrokeWidth = textStrokeWidth;

    const ShadowData* selectionShadow = textShadow;

    if (haveSelection) {

        // Check foreground color first.

        Color foreground = paintInfo.forceBlackText ? Color::black : renderer()->selectionForegroundColor();

        if (foreground.isValid() && foreground != selectionFillColor) {

            if (!paintSelectedTextOnly)

                paintSelectedTextSeparately = true;

            selectionFillColor = foreground;

        }

        if (RenderStyle* pseudoStyle = renderer()->getCachedPseudoStyle(SELECTION)) {

            const ShadowData* shadow = paintInfo.forceBlackText ? 0 : pseudoStyle->textShadow();

            if (shadow != selectionShadow) {

                if (!paintSelectedTextOnly)

                    paintSelectedTextSeparately = true;

                selectionShadow = shadow;

            }

            float strokeWidth = pseudoStyle->textStrokeWidth();

            if (strokeWidth != selectionStrokeWidth) {

                if (!paintSelectedTextOnly)

                    paintSelectedTextSeparately = true;

                selectionStrokeWidth = strokeWidth;

            }

            Color stroke = paintInfo.forceBlackText ? Color::black : pseudoStyle->visitedDependentColor(CSSPropertyWebkitTextStrokeColor);

            if (stroke != selectionStrokeColor) {

                if (!paintSelectedTextOnly)

                    paintSelectedTextSeparately = true;

                selectionStrokeColor = stroke;

            }

        }

    }

    const UChar* characters = textRenderer()->text()->characters() + m_start;

    int length = m_len;

    BufferForAppendingHyphen charactersWithHyphen;

    if (hasHyphen())

        adjustCharactersAndLengthForHyphen(charactersWithHyphen, styleToUse, characters, length);

    int baseline = renderer()->style(m_firstLine)->font().ascent();

    IntPoint textOrigin(m_x + tx, m_y + ty + baseline);

    TextRun textRun(characters, length, textRenderer()->allowTabs(), textPos(), m_toAdd, direction() == RTL, m_dirOverride || styleToUse->visuallyOrdered());

    int sPos = 0;

    int ePos = 0;

    if (paintSelectedTextOnly || paintSelectedTextSeparately)

        selectionStartEnd(sPos, ePos);

    if (m_truncation != cNoTruncation) {

        sPos = min<int>(sPos, m_truncation);

        ePos = min<int>(ePos, m_truncation);

        length = m_truncation;

    }

    if (!paintSelectedTextOnly) {

        // For stroked painting, we have to change the text drawing mode.  It's probably dangerous to leave that mutated as a side

        // effect, so only when we know we're stroking, do a save/restore.

        if (textStrokeWidth > 0)

            context->save();

        updateGraphicsContext(context, textFillColor, textStrokeColor, textStrokeWidth, styleToUse->colorSpace());

        if (!paintSelectedTextSeparately || ePos <= sPos) {

            // FIXME: Truncate right-to-left text correctly.

            paintTextWithShadows(context, font, textRun, 0, length, length, textOrigin, m_x + tx, m_y + ty, width(), height(), textShadow, textStrokeWidth > 0);