/*

 * Copyright (c) 1999, 2008, 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.

 */

package javax.swing.text;

import java.util.*;

import java.awt.*;

import java.text.AttributedCharacterIterator;

import java.text.BreakIterator;

import java.awt.font.*;

import java.awt.geom.AffineTransform;

import javax.swing.JComponent;

import javax.swing.event.DocumentEvent;

import sun.font.BidiUtils;

/**

 * A flow strategy that uses java.awt.font.LineBreakMeasureer to

 * produce java.awt.font.TextLayout for i18n capable rendering.

 * If the child view being placed into the flow is of type

 * GlyphView and can be rendered by TextLayout, a GlyphPainter

 * that uses TextLayout is plugged into the GlyphView.

 *

 * @author  Timothy Prinzing

 */

class TextLayoutStrategy extends FlowView.FlowStrategy {

    /**

     * Constructs a layout strategy for paragraphs based

     * upon java.awt.font.LineBreakMeasurer.

     */

    public TextLayoutStrategy() {

        text = new AttributedSegment();

    }

    // --- FlowStrategy methods --------------------------------------------

    /**

     * Gives notification that something was inserted into the document

     * in a location that the given flow view is responsible for.  The

     * strategy should update the appropriate changed region (which

     * depends upon the strategy used for repair).

     *

     * @param e the change information from the associated document

     * @param alloc the current allocation of the view inside of the insets.

     *   This value will be null if the view has not yet been displayed.

     * @see View#insertUpdate

     */

    public void insertUpdate(FlowView fv, DocumentEvent e, Rectangle alloc) {

        sync(fv);

        super.insertUpdate(fv, e, alloc);

    }

    /**

     * Gives notification that something was removed from the document

     * in a location that the given flow view is responsible for.

     *

     * @param e the change information from the associated document

     * @param alloc the current allocation of the view inside of the insets.

     * @see View#removeUpdate

     */

    public void removeUpdate(FlowView fv, DocumentEvent e, Rectangle alloc) {

        sync(fv);

        super.removeUpdate(fv, e, alloc);

    }

    /**

     * Gives notification from the document that attributes were changed

     * in a location that this view is responsible for.

     *

     * @param changes the change information from the associated document

     * @param a the current allocation of the view

     * @param f the factory to use to rebuild if the view has children

     * @see View#changedUpdate

     */

    public void changedUpdate(FlowView fv, DocumentEvent e, Rectangle alloc) {

        sync(fv);

        super.changedUpdate(fv, e, alloc);

    }

    /**

     * Does a a full layout on the given View.  This causes all of

     * the rows (child views) to be rebuilt to match the given

     * constraints for each row.  This is called by a FlowView.layout

     * to update the child views in the flow.

     *

     * @param fv the view to reflow

     */

    public void layout(FlowView fv) {

        super.layout(fv);

    }

    /**

     * Creates a row of views that will fit within the

     * layout span of the row.  This is implemented to execute the

     * superclass functionality (which fills the row with child

     * views or view fragments) and follow that with bidi reordering

     * of the unidirectional view fragments.

     *

     * @param row the row to fill in with views.  This is assumed

     *   to be empty on entry.

     * @param pos  The current position in the children of

     *   this views element from which to start.

     * @return the position to start the next row

     */

    protected int layoutRow(FlowView fv, int rowIndex, int p0) {

        int p1 = super.layoutRow(fv, rowIndex, p0);

        View row = fv.getView(rowIndex);

        Document doc = fv.getDocument();

        Object i18nFlag = doc.getProperty(AbstractDocument.I18NProperty);

        if ((i18nFlag != null) && i18nFlag.equals(Boolean.TRUE)) {

            int n = row.getViewCount();

            if (n > 1) {

                AbstractDocument d = (AbstractDocument)fv.getDocument();

                Element bidiRoot = d.getBidiRootElement();

                byte[] levels = new byte[n];

                View[] reorder = new View[n];

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

                    View v = row.getView(i);

                    int bidiIndex =bidiRoot.getElementIndex(v.getStartOffset());

                    Element bidiElem = bidiRoot.getElement( bidiIndex );

                    levels[i] = (byte)StyleConstants.getBidiLevel(bidiElem.getAttributes());

                    reorder[i] = v;

                }

                BidiUtils.reorderVisually( levels, reorder );

                row.replace(0, n, reorder);

            }

        }

        return p1;

    }

    /**

     * Adjusts the given row if possible to fit within the

     * layout span.  Since all adjustments were already

     * calculated by the LineBreakMeasurer, this is implemented

     * to do nothing.

     *

     * @param r the row to adjust to the current layout

     *  span.

     * @param desiredSpan the current layout span >= 0

     * @param x the location r starts at.

     */

    protected void adjustRow(FlowView fv, int rowIndex, int desiredSpan, int x) {

    }

    /**

     * Creates a unidirectional view that can be used to represent the

     * current chunk.  This can be either an entire view from the

     * logical view, or a fragment of the view.

     *

     * @param fv the view holding the flow

     * @param startOffset the start location for the view being created

     * @param spanLeft the about of span left to fill in the row

     * @param rowIndex the row the view will be placed into

     */

    protected View createView(FlowView fv, int startOffset, int spanLeft, int rowIndex) {

        // Get the child view that contains the given starting position

        View lv = getLogicalView(fv);

        View row = fv.getView(rowIndex);

        boolean requireNextWord = (viewBuffer.size() == 0) ? false : true;

        int childIndex = lv.getViewIndex(startOffset, Position.Bias.Forward);

        View v = lv.getView(childIndex);

        int endOffset = getLimitingOffset(v, startOffset, spanLeft, requireNextWord);

        if (endOffset == startOffset) {

            return null;

        }

        View frag;

        if ((startOffset==v.getStartOffset()) && (endOffset == v.getEndOffset())) {

            // return the entire view

            frag = v;

        } else {

            // return a unidirectional fragment.

            frag = v.createFragment(startOffset, endOffset);

        }

        if ((frag instanceof GlyphView) && (measurer != null)) {

            // install a TextLayout based renderer if the view is responsible

            // for glyphs.  If the view represents a tab, the default

            // glyph painter is used (may want to handle tabs differently).

            boolean isTab = false;

            int p0 = frag.getStartOffset();

            int p1 = frag.getEndOffset();

            if ((p1 - p0) == 1) {

                // check for tab

                Segment s = ((GlyphView)frag).getText(p0, p1);

                char ch = s.first();

                if (ch == '\t') {

                    isTab = true;

                }

            }

            TextLayout tl = (isTab) ? null :

                measurer.nextLayout(spanLeft, text.toIteratorIndex(endOffset),

                                    requireNextWord);

            if (tl != null) {

                ((GlyphView)frag).setGlyphPainter(new GlyphPainter2(tl));

            }

        }

        return frag;

    }

    /**

     * Calculate the limiting offset for the next view fragment.

     * At most this would be the entire view (i.e. the limiting

     * offset would be the end offset in that case).  If the range

     * contains a tab or a direction change, that will limit the

     * offset to something less.  This value is then fed to the

     * LineBreakMeasurer as a limit to consider in addition to the

     * remaining span.

     *

     * @param v the logical view representing the starting offset.

     * @param startOffset the model location to start at.

     */

    int getLimitingOffset(View v, int startOffset, int spanLeft, boolean requireNextWord) {

        int endOffset = v.getEndOffset();

        // check for direction change

        Document doc = v.getDocument();

        if (doc instanceof AbstractDocument) {

            AbstractDocument d = (AbstractDocument) doc;

            Element bidiRoot = d.getBidiRootElement();

            if( bidiRoot.getElementCount() > 1 ) {

                int bidiIndex = bidiRoot.getElementIndex( startOffset );

                Element bidiElem = bidiRoot.getElement( bidiIndex );

                endOffset = Math.min( bidiElem.getEndOffset(), endOffset );

            }

        }

        // check for tab

        if (v instanceof GlyphView) {

            Segment s = ((GlyphView)v).getText(startOffset, endOffset);

            char ch = s.first();

            if (ch == '\t') {

                // if the first character is a tab, create a dedicated

                // view for just the tab

                endOffset = startOffset + 1;

            } else {

                for (ch = s.next(); ch != Segment.DONE; ch = s.next()) {

                    if (ch == '\t') {

                        // found a tab, don't include it in the text

                        endOffset = startOffset + s.getIndex() - s.getBeginIndex();

                        break;

                    }

                }

            }

        }

        // determine limit from LineBreakMeasurer

        int limitIndex = text.toIteratorIndex(endOffset);

        if (measurer != null) {

            int index = text.toIteratorIndex(startOffset);

            if (measurer.getPosition() != index) {

                measurer.setPosition(index);

            }

            limitIndex = measurer.nextOffset(spanLeft, limitIndex, requireNextWord);

        }

        int pos = text.toModelPosition(limitIndex);

        return pos;

    }

    /**

     * Synchronize the strategy with its FlowView.  Allows the strategy

     * to update its state to account for changes in that portion of the

     * model represented by the FlowView.  Also allows the strategy

     * to update the FlowView in response to these changes.

     */

    void sync(FlowView fv) {

        View lv = getLogicalView(fv);

        text.setView(lv);

        Container container = fv.getContainer();

        FontRenderContext frc = sun.swing.SwingUtilities2.

                                    getFontRenderContext(container);

        BreakIterator iter;

        Container c = fv.getContainer();

        if (c != null) {

            iter = BreakIterator.getLineInstance(c.getLocale());

        } else {

            iter = BreakIterator.getLineInstance();

        }

        Object shaper = null;

        if (c instanceof JComponent) {

            shaper = ((JComponent) c).getClientProperty(

                                            TextAttribute.NUMERIC_SHAPING);

        }

        text.setShaper(shaper);

        measurer = new LineBreakMeasurer(text, iter, frc);

        // If the children of the FlowView's logical view are GlyphViews, they

        // need to have their painters updated.

        int n = lv.getViewCount();

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

            View child = lv.getView(i);

            if( child instanceof GlyphView ) {

                int p0 = child.getStartOffset();

                int p1 = child.getEndOffset();

                measurer.setPosition(text.toIteratorIndex(p0));

                TextLayout layout

                    = measurer.nextLayout( Float.MAX_VALUE,

                                           text.toIteratorIndex(p1), false );

                ((GlyphView)child).setGlyphPainter(new GlyphPainter2(layout));

            }

        }

        // Reset measurer.

        measurer.setPosition(text.getBeginIndex());

    }

    // --- variables -------------------------------------------------------

    private LineBreakMeasurer measurer;

    private AttributedSegment text;

    /**

     * Implementation of AttributedCharacterIterator that supports

     * the GlyphView attributes for rendering the glyphs through a

     * TextLayout.

     */

    static class AttributedSegment extends Segment implements AttributedCharacterIterator {

        AttributedSegment() {

        }

        View getView() {

            return v;

        }

        void setView(View v) {

            this.v = v;

            Document doc = v.getDocument();

            int p0 = v.getStartOffset();

            int p1 = v.getEndOffset();

            try {

                doc.getText(p0, p1 - p0, this);

            } catch (BadLocationException bl) {

                throw new IllegalArgumentException("Invalid view");

            }

            first();

        }

        /**

         * Get a boundary position for the font.

         * This is implemented to assume that two fonts are

         * equal if their references are equal (i.e. that the

         * font came from a cache).

         *

         * @return the location in model coordinates.  This is

         *  not the same as the Segment coordinates.

         */

        int getFontBoundary(int childIndex, int dir) {

            View child = v.getView(childIndex);

            Font f = getFont(childIndex);

            for (childIndex += dir; (childIndex >= 0) && (childIndex < v.getViewCount());

                 childIndex += dir) {

                Font next = getFont(childIndex);

                if (next != f) {

                    // this run is different

                    break;

                }

                child = v.getView(childIndex);

            }

            return (dir < 0) ? child.getStartOffset() : child.getEndOffset();

        }

        /**

         * Get the font at the given child index.

         */

        Font getFont(int childIndex) {

            View child = v.getView(childIndex);

            if (child instanceof GlyphView) {

                return ((GlyphView)child).getFont();

            }

            return null;

        }

        int toModelPosition(int index) {

            return v.getStartOffset() + (index - getBeginIndex());

        }

        int toIteratorIndex(int pos) {

            return pos - v.getStartOffset() + getBeginIndex();

        }

        private void setShaper(Object shaper) {

            this.shaper = shaper;

        }

        // --- AttributedCharacterIterator methods -------------------------

        /**

         * Returns the index of the first character of the run

         * with respect to all attributes containing the current character.

         */

        public int getRunStart() {

            int pos = toModelPosition(getIndex());

            int i = v.getViewIndex(pos, Position.Bias.Forward);

            View child = v.getView(i);

            return toIteratorIndex(child.getStartOffset());

        }

        /**

         * Returns the index of the first character of the run

         * with respect to the given attribute containing the current character.

         */

        public int getRunStart(AttributedCharacterIterator.Attribute attribute) {

            if (attribute instanceof TextAttribute) {

                int pos = toModelPosition(getIndex());

                int i = v.getViewIndex(pos, Position.Bias.Forward);

                if (attribute == TextAttribute.FONT) {

                    return toIteratorIndex(getFontBoundary(i, -1));

                }

            }

            return getBeginIndex();

        }

        /**

         * Returns the index of the first character of the run

         * with respect to the given attributes containing the current character.

         */

        public int getRunStart(Set<? extends Attribute> attributes) {

            int index = getBeginIndex();

            Object[] a = attributes.toArray();

            for (int i = 0; i < a.length; i++) {

                TextAttribute attr = (TextAttribute) a[i];

                index = Math.max(getRunStart(attr), index);

            }

            return Math.min(getIndex(), index);

        }

        /**

         * Returns the index of the first character following the run

         * with respect to all attributes containing the current character.

         */

        public int getRunLimit() {

            int pos = toModelPosition(getIndex());

            int i = v.getViewIndex(pos, Position.Bias.Forward);

            View child = v.getView(i);

            return toIteratorIndex(child.getEndOffset());

        }

        /**

         * Returns the index of the first character following the run

         * with respect to the given attribute containing the current character.

         */

        public int getRunLimit(AttributedCharacterIterator.Attribute attribute) {

            if (attribute instanceof TextAttribute) {

                int pos = toModelPosition(getIndex());

                int i = v.getViewIndex(pos, Position.Bias.Forward);

                if (attribute == TextAttribute.FONT) {

                    return toIteratorIndex(getFontBoundary(i, 1));

                }

            }

            return getEndIndex();

        }

        /**

         * Returns the index of the first character following the run

         * with respect to the given attributes containing the current character.

         */

        public int getRunLimit(Set<? extends Attribute> attributes) {

            int index = getEndIndex();

            Object[] a = attributes.toArray();

            for (int i = 0; i < a.length; i++) {

                TextAttribute attr = (TextAttribute) a[i];

                index = Math.min(getRunLimit(attr), index);

            }

            return Math.max(getIndex(), index);

        }

        /**

         * Returns a map with the attributes defined on the current

         * character.

         */

        public Map<Attribute, Object> getAttributes() {

            Object[] ka = keys.toArray();

            Hashtable<Attribute, Object> h = new Hashtable<Attribute, Object>();

            for (int i = 0; i < ka.length; i++) {

                TextAttribute a = (TextAttribute) ka[i];

                Object value = getAttribute(a);

                if (value != null) {

                    h.put(a, value);

                }

            }

            return h;

        }

        /**

         * Returns the value of the named attribute for the current character.

         * Returns null if the attribute is not defined.

         * @param attribute the key of the attribute whose value is requested.

         */

        public Object getAttribute(AttributedCharacterIterator.Attribute attribute) {

            int pos = toModelPosition(getIndex());

            int childIndex = v.getViewIndex(pos, Position.Bias.Forward);

            if (attribute == TextAttribute.FONT) {

                return getFont(childIndex);

            } else if( attribute == TextAttribute.RUN_DIRECTION ) {

                return

                    v.getDocument().getProperty(TextAttribute.RUN_DIRECTION);

            } else if (attribute == TextAttribute.NUMERIC_SHAPING) {