/*

 * Copyright (C) 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. 

 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of

 *     its contributors may be used to endorse or promote products derived

 *     from this software without specific prior written permission. 

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "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 OR ITS 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 "UniscribeController.h"

#include "Font.h"

#include "FontData.h"

#include "TextStyle.h"

#include <wtf/MathExtras.h>

namespace WebCore {

// FIXME: Rearchitect this to be more like WidthIterator in Font.cpp.  Have an advance() method

// that does stuff in that method instead of doing everything in the constructor.  Have advance()

// take the GlyphBuffer as an arg so that we don't have to populate the glyph buffer when

// measuring.

UniscribeController::UniscribeController(const Font* font, const TextRun& run, const TextStyle& style)

: m_font(*font)

, m_run(run)

, m_style(style)

, m_end(run.length())

, m_currentCharacter(0)

, m_runWidthSoFar(0)

, m_computingOffsetPosition(false)

, m_includePartialGlyphs(false)

, m_offsetX(0)

, m_offsetPosition(0)

{

    m_padding = m_style.padding();

    if (!m_padding)

        m_padPerSpace = 0;

    else {

        float numSpaces = 0;

        for (int s = 0; s < m_run.length(); s++)

            if (Font::treatAsSpace(m_run[s]))

                numSpaces++;

        if (numSpaces == 0)

            m_padPerSpace = 0;

        else

            m_padPerSpace = ceilf(m_style.padding() / numSpaces);

    }

    // Null out our uniscribe structs

    resetControlAndState();

}

int UniscribeController::offsetForPosition(int x, bool includePartialGlyphs)

{

    m_computingOffsetPosition = true;

    m_includePartialGlyphs = includePartialGlyphs;

    m_offsetX = x;

    m_offsetPosition = 0;

    advance(m_run.length());

    if (m_computingOffsetPosition) {

        // The point is to the left or to the right of the entire run.

        if (m_offsetX >= m_runWidthSoFar && m_style.ltr() || m_offsetX < 0 && m_style.rtl())

            m_offsetPosition = m_end;

    }

    m_computingOffsetPosition = false;

    return m_offsetPosition;

}

void UniscribeController::advance(unsigned offset, GlyphBuffer* glyphBuffer)

{

    // FIXME: We really want to be using a newer version of Uniscribe that supports the new OpenType

    // functions.  Those functions would allow us to turn off kerning and ligatures.  Without being able

    // to do that, we will have buggy line breaking and metrics when simple and complex text are close

    // together (the complex code path will narrow the text because of kerning and ligatures and then

    // when bidi processing splits into multiple runs, the simple portions will get wider and cause us to

    // spill off the edge of a line).

    if (static_cast<int>(offset) > m_end)

        offset = m_end;

    // Itemize the string.

    const UChar* cp = m_run.data(m_currentCharacter);

    int length = offset - m_currentCharacter;

    if (length <= 0)

        return;

    // We break up itemization of the string if small caps is involved.

    // Adjust the characters to account for small caps if it is set.

    if (m_font.isSmallCaps()) {

        // FIXME: It's inconsistent that we use logical order when itemizing, since this

        // does not match normal RTL.

        Vector<UChar> smallCapsBuffer(length);

        memcpy(smallCapsBuffer.data(), cp, length * sizeof(UChar));

        bool isSmallCaps = false;

        unsigned indexOfCaseShift = m_style.rtl() ? length - 1 : 0;

        const UChar* curr = m_style.rtl() ? cp + length  - 1: cp;

        const UChar* end = m_style.rtl() ? cp - 1: cp + length;

        while (curr != end) {

            int index = curr - cp;

            UChar c = smallCapsBuffer[index];

            UChar newC;

            curr = m_style.rtl() ? curr - 1 : curr + 1;

            if (U_GET_GC_MASK(c) & U_GC_M_MASK)

                continue;

            if (!u_isUUppercase(c) && (newC = u_toupper(c)) != c) {

                smallCapsBuffer[index] = newC;

                if (!isSmallCaps) {

                    isSmallCaps = true;

                    int itemStart = m_style.rtl() ? index : indexOfCaseShift;

                    int itemLength = m_style.rtl() ? indexOfCaseShift - index : index - indexOfCaseShift;

                    itemizeShapeAndPlace(smallCapsBuffer.data() + itemStart, itemLength, false, glyphBuffer);

                    indexOfCaseShift = index;

                }

            } else if (isSmallCaps) {

                isSmallCaps = false;

                int itemStart = m_style.rtl() ? index : indexOfCaseShift;

                int itemLength = m_style.rtl() ? indexOfCaseShift - index : index - indexOfCaseShift;

                itemizeShapeAndPlace(smallCapsBuffer.data() + itemStart, itemLength, true, glyphBuffer);

                indexOfCaseShift = index;

            }

        }

        int itemLength = m_style.rtl() ? indexOfCaseShift + 1 : length - indexOfCaseShift;

        if (itemLength) {

            int itemStart = m_style.rtl() ? 0 : indexOfCaseShift;

            itemizeShapeAndPlace(smallCapsBuffer.data() + itemStart, itemLength, isSmallCaps, glyphBuffer);

        }

    } else

        itemizeShapeAndPlace(cp, length, false, glyphBuffer);

}

void UniscribeController::itemizeShapeAndPlace(const UChar* cp, unsigned length, bool smallCaps, GlyphBuffer* glyphBuffer)

{

    // ScriptItemize (in Windows XP versions prior to SP2) can overflow by 1.  This is why there is an extra empty item

    // hanging out at the end of the array

    m_items.resize(6);

    int numItems = 0;

    while (ScriptItemize(cp, length, m_items.size() - 1, &m_control, &m_state, m_items.data(), &numItems) == E_OUTOFMEMORY) {

        m_items.resize(m_items.size() * 2);

        resetControlAndState();

    }

    m_items.resize(numItems + 1);

    if (m_style.rtl()) {

        for (int i = m_items.size() - 2; i >= 0; i--) {

            if (!shapeAndPlaceItem(cp, i, smallCaps, glyphBuffer))

                return;

        }

    } else {

        for (unsigned i = 0; i < m_items.size() - 1; i++) {

            if (!shapeAndPlaceItem(cp, i, smallCaps, glyphBuffer))

                return;

        }

    }

    m_currentCharacter += length;

}

void UniscribeController::resetControlAndState()

{

    memset(&m_control, 0, sizeof(SCRIPT_CONTROL));

    memset(&m_state, 0, sizeof(SCRIPT_STATE));

    // Set up the correct direction for the run.

    m_state.uBidiLevel = m_style.rtl();

    // Lock the correct directional override.

    m_state.fOverrideDirection = m_style.directionalOverride();

}

bool UniscribeController::shapeAndPlaceItem(const UChar* cp, unsigned i, bool smallCaps, GlyphBuffer* glyphBuffer)

{

    // Determine the string for this item.

    const UChar* str = cp + m_items[i].iCharPos;

    int len = m_items[i+1].iCharPos - m_items[i].iCharPos;

    SCRIPT_ITEM item = m_items[i];

    // Get our current FontData that we are using.

    unsigned dataIndex = 0;

    const FontData* fontData = m_font.fontDataAt(dataIndex);

    if (smallCaps)

        fontData = fontData->smallCapsFontData(m_font.fontDescription());

    // Set up buffers to hold the results of shaping the item.

    Vector<WORD> glyphs;

    Vector<WORD> clusters;

    Vector<SCRIPT_VISATTR> visualAttributes;

    clusters.resize(len);

    // Shape the item.  This will provide us with glyphs for the item.  We will

    // attempt to shape using the first available FontData.  If the shaping produces a result with missing

    // glyphs, then we will fall back to the next FontData.

    // FIXME: This isn't as good as per-glyph fallback, but in practice it should be pretty good, since

    // items are broken up by "shaping engine", meaning unique scripts will be broken up into

    // separate items.

    bool lastResortFontTried = false;

    while (fontData) {

        // The recommended size for the glyph buffer is 1.5 * the character length + 16 in the uniscribe docs.

        // Apparently this is a good size to avoid having to make repeated calls to ScriptShape.

        glyphs.resize(1.5 * len + 16);

        visualAttributes.resize(glyphs.size());

        if (shape(str, len, item, fontData, glyphs, clusters, visualAttributes))

            break;

        // Try again with the next font in the list.

        if (lastResortFontTried) {

            fontData = 0;

            break;

        }

        fontData = m_font.fontDataAt(++dataIndex);

        if (!fontData) {

            // Out of fonts.  Get a font data based on the actual characters.

            fontData = m_font.fontDataForCharacters(str, len);

            lastResortFontTried = true;

        }

        if (smallCaps)

            fontData = fontData->smallCapsFontData(m_font.fontDescription());

    }

    // Just give up.  We were unable to shape.

    if (!fontData)

        return true;

    // We now have a collection of glyphs.

    Vector<GOFFSET> offsets;

    Vector<int> advances;

    offsets.resize(glyphs.size());

    advances.resize(glyphs.size());

    int glyphCount = 0;

    HRESULT placeResult = ScriptPlace(0, fontData->scriptCache(), glyphs.data(), glyphs.size(), visualAttributes.data(),

                                      &item.a, advances.data(), offsets.data(), 0);

    if (placeResult == E_PENDING) {

        // The script cache isn't primed with enough info yet.  We need to select our HFONT into

        // a DC and pass the DC in to ScriptPlace.

        HDC hdc = GetDC(0);

        HFONT hfont = fontData->platformData().hfont();

        HFONT oldFont = (HFONT)SelectObject(hdc, hfont);

        placeResult = ScriptPlace(hdc, fontData->scriptCache(), glyphs.data(), glyphs.size(), visualAttributes.data(),

                                  &item.a, advances.data(), offsets.data(), 0);

        SelectObject(hdc, oldFont);

        ReleaseDC(0, hdc);

    }

    if (FAILED(placeResult) || glyphs.isEmpty())

        return true;

    // Convert all chars that should be treated as spaces to use the space glyph.

    // We also create a map that allows us to quickly go from space glyphs or rounding

    // hack glyphs back to their corresponding characters.

    Vector<int> spaceCharacters(glyphs.size());

    spaceCharacters.fill(-1);

    Vector<int> roundingHackCharacters(glyphs.size());

    roundingHackCharacters.fill(-1);

    Vector<int> roundingHackWordBoundaries(glyphs.size());

    roundingHackWordBoundaries.fill(-1);

    unsigned logicalSpaceWidth = fontData->m_spaceWidth * 32.0f;

    float roundedSpaceWidth = roundf(fontData->m_spaceWidth);

    for (int k = 0; k < len; k++) {

        UChar ch = *(str + k);

        if (Font::treatAsSpace(ch)) {

            // Substitute in the space glyph at the appropriate place in the glyphs

            // array.

            glyphs[clusters[k]] = fontData->m_spaceGlyph;

            advances[clusters[k]] = logicalSpaceWidth;

            spaceCharacters[clusters[k]] = m_currentCharacter + k + m_items[i].iCharPos;

        }

        if (Font::isRoundingHackCharacter(ch))

            roundingHackCharacters[clusters[k]] = m_currentCharacter + k + m_items[i].iCharPos;

        int boundary = k + m_currentCharacter + m_items[i].iCharPos;

        if (boundary < m_run.length() &&

            Font::isRoundingHackCharacter(*(str + k + 1)))

            roundingHackWordBoundaries[clusters[k]] = boundary;

    }

    // Populate our glyph buffer with this information.

    bool hasExtraSpacing = m_font.letterSpacing() || m_font.wordSpacing() || m_padding;

    float leftEdge = m_runWidthSoFar;

    for (unsigned k = 0; k < glyphs.size(); k++) {

        Glyph glyph = glyphs[k];

        float advance = advances[k] / 32.0f;

        float offsetX = offsets[k].du / 32.0f;

        float offsetY = offsets[k].dv / 32.0f;

        // Match AppKit's rules for the integer vs. non-integer rendering modes.

        float roundedAdvance = roundf(advance);

        if (!m_font.isPrinterFont() && !fontData->isSystemFont()) {

            advance = roundedAdvance;

            offsetX = roundf(offsetX);

            offsetY = roundf(offsetY);

        }

        // We special case spaces in two ways when applying word rounding.

        // First, we round spaces to an adjusted width in all fonts.

        // Second, in fixed-pitch fonts we ensure that all glyphs that

        // match the width of the space glyph have the same width as the space glyph.

        if (roundedAdvance == roundedSpaceWidth && (fontData->m_treatAsFixedPitch || glyph == fontData->m_spaceGlyph) &&

            m_style.applyWordRounding())

            advance = fontData->m_adjustedSpaceWidth;

        if (hasExtraSpacing) {

            // If we're a glyph with an advance, go ahead and add in letter-spacing.

            // That way we weed out zero width lurkers.  This behavior matches the fast text code path.

            if (advance && m_font.letterSpacing())

                advance += m_font.letterSpacing();

            // Handle justification and word-spacing.

            if (glyph == fontData->m_spaceGlyph) {

                // Account for padding. WebCore uses space padding to justify text.

                // We distribute the specified padding over the available spaces in the run.

                if (m_padding) {

                    // Use leftover padding if not evenly divisible by number of spaces.

                    if (m_padding < m_padPerSpace) {

                        advance += m_padding;

                        m_padding = 0;

                    } else {

                        advance += m_padPerSpace;

                        m_padding -= m_padPerSpace;

                    }

                }

                // Account for word-spacing.

                int characterIndex = spaceCharacters[k];

                if (characterIndex > 0 && !Font::treatAsSpace(*m_run.data(characterIndex-1)) && m_font.wordSpacing())

                    advance += m_font.wordSpacing();

            }

        }

        // Deal with the float/integer impedance mismatch between CG and WebCore. "Words" (characters 

        // followed by a character defined by isRoundingHackCharacter()) are always an integer width.

        // We adjust the width of the last character of a "word" to ensure an integer width.

        // Force characters that are used to determine word boundaries for the rounding hack

        // to be integer width, so the following words will start on an integer boundary.

        int roundingHackIndex = roundingHackCharacters[k];

        if (m_style.applyWordRounding() && roundingHackIndex != -1)

            advance = ceilf(advance);

        // Check to see if the next character is a "rounding hack character", if so, adjust the

        // width so that the total run width will be on an integer boundary.

        int position = m_currentCharacter + len;

        bool lastGlyph = (k == glyphs.size() - 1) && (m_style.rtl() ? i == 0 : i == m_items.size() - 2) && (position >= m_end);

        if ((m_style.applyWordRounding() && roundingHackWordBoundaries[k] != -1) ||

            (m_style.applyRunRounding() && lastGlyph)) { 

            float totalWidth = m_runWidthSoFar + advance;

            advance += ceilf(totalWidth) - totalWidth;

        }

        m_runWidthSoFar += advance;

        // FIXME: We need to take the GOFFSETS for combining glyphs and store them in the glyph buffer

        // as well, so that when the time comes to draw those glyphs, we can apply the appropriate

        // translation.

        if (glyphBuffer) {

            FloatSize size(offsetX, offsetY);

            glyphBuffer->add(glyph, fontData, advance, &size);

        }

        // Mutate the glyph array to contain our altered advances.

        if (m_computingOffsetPosition)

            advances[k] = advance;

    }

    while (m_computingOffsetPosition && m_offsetX >= leftEdge && m_offsetX < m_runWidthSoFar) {

        // The position is somewhere inside this run.

        int trailing = 0;

        ScriptXtoCP(m_offsetX - leftEdge, clusters.size(), glyphs.size(), clusters.data(), visualAttributes.data(),

                    advances.data(), &item.a, &m_offsetPosition, &trailing);

        if (trailing && m_includePartialGlyphs && m_offsetPosition < len - 1) {

            m_offsetPosition += m_currentCharacter + m_items[i].iCharPos;

            m_offsetX += m_style.rtl() ? -trailing : trailing;

        } else {

            m_computingOffsetPosition = false;

            m_offsetPosition += m_currentCharacter + m_items[i].iCharPos;

            if (trailing && m_includePartialGlyphs)

               m_offsetPosition++;

            return false;

        }

    }

    return true;

}

bool UniscribeController::shape(const UChar* str, int len, SCRIPT_ITEM item, const FontData* fontData,

                                Vector<WORD>& glyphs, Vector<WORD>& clusters,

                                Vector<SCRIPT_VISATTR>& visualAttributes)

{

    HDC hdc = 0;

    HFONT oldFont = 0;

    HRESULT shapeResult = E_PENDING;

    int glyphCount = 0;

    do {

        shapeResult = ScriptShape(hdc, fontData->scriptCache(), str, len, glyphs.size(), &item.a,

                                  glyphs.data(), clusters.data(), visualAttributes.data(), &glyphCount);

        if (shapeResult == E_PENDING) {

            // The script cache isn't primed with enough info yet.  We need to select our HFONT into

            // a DC and pass the DC in to ScriptShape.

            ASSERT(!hdc);

            hdc = GetDC(0);

            HFONT hfont = fontData->platformData().hfont();

            oldFont = (HFONT)SelectObject(hdc, hfont);

        } else if (shapeResult == E_OUTOFMEMORY) {

            // Need to resize our buffers.

            glyphs.resize(glyphs.size() * 2);

            visualAttributes.resize(glyphs.size());

        }

    } while (shapeResult == E_PENDING || shapeResult == E_OUTOFMEMORY);

    if (hdc) {

        SelectObject(hdc, oldFont);

        ReleaseDC(0, hdc);

    }

    if (FAILED(shapeResult))

        return false;

    // FIXME: We need to do better than this.  Falling back on the entire item is not good enough.

    // We may still have missing glyphs even if we succeeded.  We need to treat missing glyphs as

    // a failure so that we will fall back to another font.

    bool containsMissingGlyphs = false;

    SCRIPT_FONTPROPERTIES* fontProperties = fontData->scriptFontProperties();

    for (int i = 0; i < glyphCount; i++) {

        WORD glyph = glyphs[i];

        if (glyph == fontProperties->wgDefault) {

            containsMissingGlyphs = true;

            break;

        }

    }

    if (containsMissingGlyphs)

        return false;

    glyphs.resize(glyphCount);

    visualAttributes.resize(glyphCount);

    return true;

}

}