// Copyright (C) 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
 * (C) Copyright IBM Corp. 1998-2015 - All Rights Reserved
 *
 */

#include "LETypes.h"
#include "LEGlyphFilter.h"
#include "OpenTypeTables.h"
#include "GlyphSubstitutionTables.h"
#include "LigatureSubstSubtables.h"
#include "GlyphIterator.h"
#include "LESwaps.h"

U_NAMESPACE_BEGIN

le_uint32 LigatureSubstitutionSubtable::process(const LETableReference &base, GlyphIterator *glyphIterator, LEErrorCode &success, const LEGlyphFilter *filter) const
{
    LEGlyphID glyph = glyphIterator->getCurrGlyphID();
    le_int32 coverageIndex = getGlyphCoverage(base, glyph, success);

    if (coverageIndex >= 0) {
        Offset ligSetTableOffset = SWAPW(ligSetTableOffsetArray[coverageIndex]);
        const LigatureSetTable *ligSetTable = (const LigatureSetTable *) ((char *) this + ligSetTableOffset);
        le_uint16 ligCount = SWAPW(ligSetTable->ligatureCount);

        for (le_uint16 lig = 0; lig < ligCount; lig += 1) {
            Offset ligTableOffset = SWAPW(ligSetTable->ligatureTableOffsetArray[lig]);
            const LigatureTable *ligTable = (const LigatureTable *) ((char *)ligSetTable + ligTableOffset);
            le_uint16 compCount = SWAPW(ligTable->compCount) - 1;
            LEReferenceToArrayOf<TTGlyphID>
                componentArrayRef(base, success, ligTable->componentArray, compCount);
            if (LE_FAILURE(success)) { return 0; }
            le_int32 startPosition = glyphIterator->getCurrStreamPosition();
            TTGlyphID ligGlyph = SWAPW(ligTable->ligGlyph);
            le_uint16 comp;

            for (comp = 0; comp < compCount; comp += 1) {
                if (! glyphIterator->next()) {
                    break;
                }

                if (LE_GET_GLYPH(glyphIterator->getCurrGlyphID()) != SWAPW(ligTable->componentArray[comp])) {
                    break;
                }
            }

            if (comp == compCount && (filter == NULL || filter->accept(LE_SET_GLYPH(glyph, ligGlyph)))) {
                GlyphIterator tempIterator(*glyphIterator);
                TTGlyphID deletedGlyph = tempIterator.ignoresMarks()? 0xFFFE : 0xFFFF;

                while (comp > 0) {
                    tempIterator.setCurrGlyphID(deletedGlyph);
                    tempIterator.prev();

                    comp -= 1;
                }

                tempIterator.setCurrGlyphID(ligGlyph);

                return compCount + 1;
            }

            glyphIterator->setCurrStreamPosition(startPosition);
        }

    }

    return 0;
}

U_NAMESPACE_END