/*
 * Copyright (c) 2003, 2006, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * (C) Copyright IBM Corp. 1999-2003 - All Rights Reserved
 *
 * The original version of this source code and documentation is
 * copyrighted and owned by IBM. These materials are provided
 * under terms of a License Agreement between IBM and Sun.
 * This technology is protected by multiple US and International
 * patents. This notice and attribution to IBM may not be removed.
 */

/*
 * GlyphLayout is used to process a run of text into a run of run of
 * glyphs, optionally with position and char mapping info.
 *
 * The text has already been processed for numeric shaping and bidi.
 * The run of text that layout works on has a single bidi level.  It
 * also has a single font/style.  Some operations need context to work
 * on (shaping, script resolution) so context for the text run text is
 * provided.  It is assumed that the text array contains sufficient
 * context, and the offset and count delimit the portion of the text
 * that needs to actually be processed.
 *
 * The font might be a composite font.  Layout generally requires
 * tables from a single physical font to operate, and so it must
 * resolve the 'single' font run into runs of physical fonts.
 *
 * Some characters are supported by several fonts of a composite, and
 * in order to properly emulate the glyph substitution behavior of a
 * single physical font, these characters might need to be mapped to
 * different physical fonts.  The script code that is assigned
 * characters normally considered 'common script' can be used to
 * resolve which physical font to use for these characters. The input
 * to the char to glyph mapper (which assigns physical fonts as it
 * processes the glyphs) should include the script code, and the
 * mapper should operate on runs of a single script.
 *
 * To perform layout, call get() to get a new (or reuse an old)
 * GlyphLayout, call layout on it, then call done(GlyphLayout) when
 * finished.  There's no particular problem if you don't call done,
 * but it assists in reuse of the GlyphLayout.
 */

package sun.font;

import java.lang.ref.SoftReference;
import java.awt.Font;
import java.awt.font.FontRenderContext;
import java.awt.font.GlyphVector;
import java.awt.geom.AffineTransform;
import java.awt.geom.NoninvertibleTransformException;
import java.awt.geom.Point2D;
import java.util.ArrayList;
import java.util.concurrent.ConcurrentHashMap;
import java.util.logging.Logger;

import static java.lang.Character.*;

import sun.java2d.SunGraphicsEnvironment;

public final class GlyphLayout {
    // data for glyph vector
    private GVData _gvdata;

    // cached glyph layout data for reuse
    private static GlyphLayout cache;  // reusable

    private LayoutEngineFactory _lef;  // set when get is called, unset when done is called
    private TextRecord _textRecord;    // the text we're working on, used by iterators
    private ScriptRun _scriptRuns;     // iterator over script runs
    private FontRunIterator _fontRuns; // iterator over physical fonts in a composite
    private int _ercount;
    private ArrayList _erecords;
    private Point2D.Float _pt;
    private FontStrikeDesc _sd;
    private float[] _mat;
    private int _typo_flags;
    private int _offset;

    public static final class LayoutEngineKey {
        private Font2D font;
        private int script;
        private int lang;

        LayoutEngineKey() {
        }

        LayoutEngineKey(Font2D font, int script, int lang) {
            init(font, script, lang);
        }

        void init(Font2D font, int script, int lang) {
            this.font = font;
            this.script = script;
            this.lang = lang;
        }

        LayoutEngineKey copy() {
            return new LayoutEngineKey(font, script, lang);
        }

        Font2D font() {
            return font;
        }

        int script() {
            return script;
        }

        int lang() {
            return lang;
        }

        public boolean equals(Object rhs) {
            if (this == rhs) return true;
            if (rhs == null) return false;
            try {
                LayoutEngineKey that = (LayoutEngineKey)rhs;
                return this.script == that.script &&
                       this.lang == that.lang &&
                       this.font.equals(that.font);
            }
            catch (ClassCastException e) {
                return false;
            }
        }

        public int hashCode() {
            return script ^ lang ^ font.hashCode();
        }
    }

    public static interface LayoutEngineFactory {
        
Given a font, script, and language, determine a layout engine to use.
/**
         * Given a font, script, and language, determine a layout engine to use.
         */
        public LayoutEngine getEngine(Font2D font, int script, int lang);

        
Given a key, determine a layout engine to use.
/**
         * Given a key, determine a layout engine to use.
         */
        public LayoutEngine getEngine(LayoutEngineKey key);
    }

    public static interface LayoutEngine {
        
Given a strike descriptor, text, rtl flag, and starting point, append information about
glyphs, positions, and character indices to the glyphvector data, and advance the point.
If the GVData does not have room for the glyphs, throws an IndexOutOfBoundsException and
leave pt and the gvdata unchanged.
/**
         * Given a strike descriptor, text, rtl flag, and starting point, append information about
         * glyphs, positions, and character indices to the glyphvector data, and advance the point.
         *
         * If the GVData does not have room for the glyphs, throws an IndexOutOfBoundsException and
         * leave pt and the gvdata unchanged.
         */
        public void layout(FontStrikeDesc sd, float[] mat, int gmask,
                           int baseIndex, TextRecord text, int typo_flags, Point2D.Float pt, GVData data);
    }

    
Return a new instance of GlyphLayout, using the provided layout engine factory.
If null, the system layout engine factory will be used.
/**
     * Return a new instance of GlyphLayout, using the provided layout engine factory.
     * If null, the system layout engine factory will be used.
     */
    public static GlyphLayout get(LayoutEngineFactory lef) {
        if (lef == null) {
            lef = SunLayoutEngine.instance();
        }
        GlyphLayout result = null;
        synchronized(GlyphLayout.class) {
            if (cache != null) {
                result = cache;
                cache = null;
            }
        }
        if (result == null) {
            result = new GlyphLayout();
        }
        result._lef = lef;
        return result;
    }

    
Return the old instance of GlyphLayout when you are done.  This enables reuse
of GlyphLayout objects.
/**
     * Return the old instance of GlyphLayout when you are done.  This enables reuse
     * of GlyphLayout objects.
     */
    public static void done(GlyphLayout gl) {
        gl._lef = null;
        cache = gl; // object reference assignment is thread safe, it says here...
    }

    private static final class SDCache {
        public Font key_font;
        public FontRenderContext key_frc;

        public AffineTransform dtx;
        public AffineTransform invdtx;
        public AffineTransform gtx;
        public Point2D.Float delta;
        public FontStrikeDesc sd;

        private SDCache(Font font, FontRenderContext frc) {
            key_font = font;
            key_frc = frc;

            // !!! add getVectorTransform and hasVectorTransform to frc?  then
            // we could just skip this work...

            dtx = frc.getTransform();
            dtx.setTransform(dtx.getScaleX(), dtx.getShearY(),
                             dtx.getShearX(), dtx.getScaleY(),
                             0, 0);
            if (!dtx.isIdentity()) {
                try {
                    invdtx = dtx.createInverse();
                }
                catch (NoninvertibleTransformException e) {
                    throw new InternalError();
                }
            }

            float ptSize = font.getSize2D();
            if (font.isTransformed()) {
                gtx = font.getTransform();
                gtx.scale(ptSize, ptSize);
                delta = new Point2D.Float((float)gtx.getTranslateX(),
                                          (float)gtx.getTranslateY());
                gtx.setTransform(gtx.getScaleX(), gtx.getShearY(),
                                 gtx.getShearX(), gtx.getScaleY(),
                                 0, 0);
                gtx.preConcatenate(dtx);
            } else {
                delta = ZERO_DELTA;
                gtx = new AffineTransform(dtx);
                gtx.scale(ptSize, ptSize);
            }

            /* Similar logic to that used in SunGraphics2D.checkFontInfo().
             * Whether a grey (AA) strike is needed is size dependent if
             * AA mode is 'gasp'.
             */
            int aa =
                FontStrikeDesc.getAAHintIntVal(frc.getAntiAliasingHint(),
                                               FontManager.getFont2D(font),
                                               (int)Math.abs(ptSize));
            int fm = FontStrikeDesc.getFMHintIntVal
                (frc.getFractionalMetricsHint());
            sd = new FontStrikeDesc(dtx, gtx, font.getStyle(), aa, fm);
        }

        private static final Point2D.Float ZERO_DELTA = new Point2D.Float();

        private static
            SoftReference<ConcurrentHashMap<SDKey, SDCache>> cacheRef;

        private static final class SDKey {
            private final Font font;
            private final FontRenderContext frc;
            private final int hash;

            SDKey(Font font, FontRenderContext frc) {
                this.font = font;
                this.frc = frc;
                this.hash = font.hashCode() ^ frc.hashCode();
            }

            public int hashCode() {
                return hash;
            }

            public boolean equals(Object o) {
                try {
                    SDKey rhs = (SDKey)o;
                    return
                        hash == rhs.hash &&
                        font.equals(rhs.font) &&
                        frc.equals(rhs.frc);
                }
                catch (ClassCastException e) {
                }
                return false;
            }
        }

        public static SDCache get(Font font, FontRenderContext frc) {

            // It is possible a translation component will be in the FRC.
            // It doesn't affect us except adversely as we would consider
            // FRC's which are really the same to be different. If we
            // detect a translation component, then we need to exclude it
            // by creating a new transform which excludes the translation.
            if (frc.isTransformed()) {
                AffineTransform transform = frc.getTransform();
                if (transform.getTranslateX() != 0 ||
                    transform.getTranslateY() != 0) {
                    transform = new AffineTransform(transform.getScaleX(),
                                                    transform.getShearY(),
                                                    transform.getShearX(),
                                                    transform.getScaleY(),
                                                    0, 0);
                    frc = new FontRenderContext(transform,
                                                frc.getAntiAliasingHint(),
                                                frc.getFractionalMetricsHint()
                                                );
                }
            }

            SDKey key = new SDKey(font, frc); // garbage, yuck...
            ConcurrentHashMap<SDKey, SDCache> cache = null;
            SDCache res = null;
            if (cacheRef != null) {
                cache = cacheRef.get();
                if (cache != null) {
                    res = cache.get(key);
                }
            }
            if (res == null) {
                res = new SDCache(font, frc);
                if (cache == null) {
                    cache = new ConcurrentHashMap<SDKey, SDCache>(10);
                    cacheRef = new
                       SoftReference<ConcurrentHashMap<SDKey, SDCache>>(cache);
                }
                cache.put(key, res);
            }
            return res;
        }
    }

    
Create a glyph vector.
Params:
font – the font to use
frc – the font render context
text – the text, including optional context before start and after start + count
offset – the start of the text to lay out
count – the length of the text to lay out
flags – bidi and context flags {@see #java.awt.Font}
result – a StandardGlyphVector to modify, can be null
Returns:
the layed out glyphvector, if result was passed in, it is returned/**
     * Create a glyph vector.
     * @param font the font to use
     * @param frc the font render context
     * @param text the text, including optional context before start and after start + count
     * @param offset the start of the text to lay out
     * @param count the length of the text to lay out
     * @param flags bidi and context flags {@see #java.awt.Font}
     * @param result a StandardGlyphVector to modify, can be null
     * @return the layed out glyphvector, if result was passed in, it is returned
     */
    public StandardGlyphVector layout(Font font, FontRenderContext frc,
                                      char[] text, int offset, int count,
                                      int flags, StandardGlyphVector result)
    {
        if (text == null || offset < 0 || count < 0 || (count > text.length - offset)) {
            throw new IllegalArgumentException();
        }

        init(count);

        // need to set after init
        // go through the back door for this
        if (font.hasLayoutAttributes()) {
            AttributeValues values = ((AttributeMap)font.getAttributes()).getValues();
            if (values.getKerning() != 0) _typo_flags |= 0x1;
            if (values.getLigatures() != 0) _typo_flags |= 0x2;
        }

        _offset = offset;

        // use cache now - can we use the strike cache for this?

        SDCache txinfo = SDCache.get(font, frc);
        _mat[0] = (float)txinfo.gtx.getScaleX();
        _mat[1] = (float)txinfo.gtx.getShearY();
        _mat[2] = (float)txinfo.gtx.getShearX();
        _mat[3] = (float)txinfo.gtx.getScaleY();
        _pt.setLocation(txinfo.delta);

        int lim = offset + count;

        int min = 0;
        int max = text.length;
        if (flags != 0) {
            if ((flags & Font.LAYOUT_RIGHT_TO_LEFT) != 0) {
              _typo_flags |= 0x80000000; // RTL
            }

            if ((flags & Font.LAYOUT_NO_START_CONTEXT) != 0) {
                min = offset;
            }

            if ((flags & Font.LAYOUT_NO_LIMIT_CONTEXT) != 0) {
                max = lim;
            }
        }

        int lang = -1; // default for now

        Font2D font2D = FontManager.getFont2D(font);

        _textRecord.init(text, offset, lim, min, max);
        int start = offset;
        if (font2D instanceof CompositeFont) {
            _scriptRuns.init(text, offset, count); // ??? how to handle 'common' chars
            _fontRuns.init((CompositeFont)font2D, text, offset, lim);
            while (_scriptRuns.next()) {
                int limit = _scriptRuns.getScriptLimit();
                int script = _scriptRuns.getScriptCode();
                while (_fontRuns.next(script, limit)) {
                    Font2D pfont = _fontRuns.getFont();
                    /* layout can't deal with NativeFont instances. The
                     * native font is assumed to know of a suitable non-native
                     * substitute font. This currently works because
                     * its consistent with the way NativeFonts delegate
                     * in other cases too.
                     */
                    if (pfont instanceof NativeFont) {
                        pfont = ((NativeFont)pfont).getDelegateFont();
                    }
                    int gmask = _fontRuns.getGlyphMask();
                    int pos = _fontRuns.getPos();
                    nextEngineRecord(start, pos, script, lang, pfont, gmask);
                    start = pos;
                }
            }
        } else {
            _scriptRuns.init(text, offset, count); // ??? don't worry about 'common' chars
            while (_scriptRuns.next()) {
                int limit = _scriptRuns.getScriptLimit();
                int script = _scriptRuns.getScriptCode();
                nextEngineRecord(start, limit, script, lang, font2D, 0);
                start = limit;
            }
        }

        int ix = 0;
        int stop = _ercount;
        int dir = 1;

        if (_typo_flags < 0) { // RTL
            ix = stop - 1;
            stop = -1;
            dir = -1;
        }

        //        _sd.init(dtx, gtx, font.getStyle(), frc.isAntiAliased(), frc.usesFractionalMetrics());
        _sd = txinfo.sd;
        for (;ix != stop; ix += dir) {
            EngineRecord er = (EngineRecord)_erecords.get(ix);
            for (;;) {
                try {
                    er.layout();
                    break;
                }
                catch (IndexOutOfBoundsException e) {
                    if (_gvdata._count >=0) {
                        _gvdata.grow();
                    }
                }
            }
            // Break out of the outer for loop if layout fails.
            if (_gvdata._count < 0) {
                break;
            }
        }

        //        if (txinfo.invdtx != null) {
        //            _gvdata.adjustPositions(txinfo.invdtx);
        //        }

        // If layout fails (negative glyph count) create an un-laid out GV instead.
        // ie default positions. This will be a lot better than the alternative of
        // a complete blank layout.
        StandardGlyphVector gv;
        if (_gvdata._count < 0) {
            gv = new StandardGlyphVector(font, text, offset, count, frc);
            if (SunGraphicsEnvironment.debugFonts) {
               Logger.getLogger("sun.java2d").warning("OpenType layout failed on font: " +
						      font);
            }
        } else {
            gv = _gvdata.createGlyphVector(font, frc, result);
        }
        //        System.err.println("Layout returns: " + gv);
        return gv;
    }

    //
    // private methods
    //

    private GlyphLayout() {
        this._gvdata = new GVData();
        this._textRecord = new TextRecord();
        this._scriptRuns = new ScriptRun();
        this._fontRuns = new FontRunIterator();
        this._erecords = new ArrayList(10);
        this._pt = new Point2D.Float();
        this._sd = new FontStrikeDesc();
        this._mat = new float[4];
    }

    private void init(int capacity) {
        this._typo_flags = 0;
        this._ercount = 0;
        this._gvdata.init(capacity);
    }

    private void nextEngineRecord(int start, int limit, int script, int lang, Font2D font, int gmask) {
        EngineRecord er = null;
        if (_ercount == _erecords.size()) {
            er = new EngineRecord();
            _erecords.add(er);
        } else {
            er = (EngineRecord)_erecords.get(_ercount);
        }
        er.init(start, limit, font, script, lang, gmask);
        ++_ercount;
    }

    
Storage for layout to build glyph vector data, then generate a real GlyphVector
/**
     * Storage for layout to build glyph vector data, then generate a real GlyphVector
     */
    public static final class GVData {
        public int _count; // number of glyphs, >= number of chars
        public int _flags;
        public int[] _glyphs;
        public float[] _positions;
        public int[] _indices;

        private static final int UNINITIALIZED_FLAGS = -1;

        public void init(int size) {
            _count = 0;
            _flags = UNINITIALIZED_FLAGS;

            if (_glyphs == null || _glyphs.length < size) {
                if (size < 20) {
                    size = 20;
                }
                _glyphs = new int[size];
                _positions = new float[size * 2 + 2];
                _indices = new int[size];
            }
        }

        public void grow() {
            grow(_glyphs.length / 4); // always grows because min length is 20
        }

        public void grow(int delta) {
            int size = _glyphs.length + delta;
            int[] nglyphs = new int[size];
            System.arraycopy(_glyphs, 0, nglyphs, 0, _count);
            _glyphs = nglyphs;

            float[] npositions = new float[size * 2 + 2];
            System.arraycopy(_positions, 0, npositions, 0, _count * 2 + 2);
            _positions = npositions;

            int[] nindices = new int[size];
            System.arraycopy(_indices, 0, nindices, 0, _count);
            _indices = nindices;
        }

        public void adjustPositions(AffineTransform invdtx) {
            invdtx.transform(_positions, 0, _positions, 0, _count);
        }

        public StandardGlyphVector createGlyphVector(Font font, FontRenderContext frc, StandardGlyphVector result) {

            // !!! default initialization until we let layout engines do it
            if (_flags == UNINITIALIZED_FLAGS) {
                _flags = 0;

                if (_count > 1) { // if only 1 glyph assume LTR
                    boolean ltr = true;
                    boolean rtl = true;

                    int rtlix = _count; // rtl index
                    for (int i = 0; i < _count && (ltr || rtl); ++i) {
                        int cx = _indices[i];

                        ltr = ltr && (cx == i);
                        rtl = rtl && (cx == --rtlix);
                    }

                    if (rtl) _flags |= GlyphVector.FLAG_RUN_RTL;
                    if (!rtl && !ltr) _flags |= GlyphVector.FLAG_COMPLEX_GLYPHS;
                }

                // !!! layout engines need to tell us whether they performed
                // position adjustments. currently they don't tell us, so
                // we must assume they did
                _flags |= GlyphVector.FLAG_HAS_POSITION_ADJUSTMENTS;
            }

            int[] glyphs = new int[_count];
            System.arraycopy(_glyphs, 0, glyphs, 0, _count);

            float[] positions = null;
            if ((_flags & GlyphVector.FLAG_HAS_POSITION_ADJUSTMENTS) != 0) {
                positions = new float[_count * 2 + 2];
                System.arraycopy(_positions, 0, positions, 0, positions.length);
            }

            int[] indices = null;
            if ((_flags & GlyphVector.FLAG_COMPLEX_GLYPHS) != 0) {
                indices = new int[_count];
                System.arraycopy(_indices, 0, indices, 0, _count);
            }

            if (result == null) {
                result = new StandardGlyphVector(font, frc, glyphs, positions, indices, _flags);
            } else {
                result.initGlyphVector(font, frc, glyphs, positions, indices, _flags);
            }

            return result;
        }
    }

    
Utility class to keep track of script runs, which may have to be reordered rtl when we're
finished.
/**
     * Utility class to keep track of script runs, which may have to be reordered rtl when we're
     * finished.
     */
    private final class EngineRecord {
        private int start;
        private int limit;
        private int gmask;
        private int eflags;
        private LayoutEngineKey key;
        private LayoutEngine engine;

        EngineRecord() {
            key = new LayoutEngineKey();
        }

        void init(int start, int limit, Font2D font, int script, int lang, int gmask) {
            this.start = start;
            this.limit = limit;
            this.gmask = gmask;
            this.key.init(font, script, lang);
            this.eflags = 0;

            // only request canonical substitution if we have combining marks
            for (int i = start; i < limit; ++i) {
                int ch = _textRecord.text[i];
                if (isHighSurrogate((char)ch) &&
                    i < limit - 1 &&
                    isLowSurrogate(_textRecord.text[i+1])) {
                    // rare case
                    ch = toCodePoint((char)ch,_textRecord.text[++i]); // inc
                }
                int gc = getType(ch);
                if (gc == NON_SPACING_MARK ||
                    gc == ENCLOSING_MARK ||
                    gc == COMBINING_SPACING_MARK) { // could do range test also

                    this.eflags = 0x4;
                    break;
                }
            }

            this.engine = _lef.getEngine(key); // flags?
        }

        void layout() {
            _textRecord.start = start;
            _textRecord.limit = limit;
            engine.layout(_sd, _mat, gmask, start - _offset, _textRecord,
                          _typo_flags | eflags, _pt, _gvdata);
        }
    }
}