/*

 * Copyright (c) 1997, 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

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 */

package javax.swing.text;

import java.util.Arrays;

import java.awt.*;

import java.awt.font.TextAttribute;

import javax.swing.event.*;

import javax.swing.SizeRequirements;

/**

 * View of a simple line-wrapping paragraph that supports

 * multiple fonts, colors, components, icons, etc.  It is

 * basically a vertical box with a margin around it.  The

 * contents of the box are a bunch of rows which are special

 * horizontal boxes.  This view creates a collection of

 * views that represent the child elements of the paragraph

 * element.  Each of these views are placed into a row

 * directly if they will fit, otherwise the <code>breakView</code>

 * method is called to try and carve the view into pieces

 * that fit.

 *

 * @author  Timothy Prinzing

 * @author  Scott Violet

 * @author  Igor Kushnirskiy

 * @see     View

 */

public class ParagraphView extends FlowView implements TabExpander {

    /**

     * Constructs a <code>ParagraphView</code> for the given element.

     *

     * @param elem the element that this view is responsible for

     */

    public ParagraphView(Element elem) {

        super(elem, View.Y_AXIS);

        setPropertiesFromAttributes();

        Document doc = elem.getDocument();

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

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

            try {

                if (i18nStrategy == null) {

                    // the classname should probably come from a property file.

                    String classname = "javax.swing.text.TextLayoutStrategy";

                    ClassLoader loader = getClass().getClassLoader();

                    if (loader != null) {

                        i18nStrategy = loader.loadClass(classname);

                    } else {

                        i18nStrategy = Class.forName(classname);

                    }

                }

                Object o = i18nStrategy.newInstance();

                if (o instanceof FlowStrategy) {

                    strategy = (FlowStrategy) o;

                }

            } catch (Throwable e) {

                throw new StateInvariantError("ParagraphView: Can't create i18n strategy: "

                                              + e.getMessage());

            }

        }

    }

    /**

     * Sets the type of justification.

     *

     * @param j one of the following values:

     * <ul>

     * <li><code>StyleConstants.ALIGN_LEFT</code>

     * <li><code>StyleConstants.ALIGN_CENTER</code>

     * <li><code>StyleConstants.ALIGN_RIGHT</code>

     * </ul>

     */

    protected void setJustification(int j) {

        justification = j;

    }

    /**

     * Sets the line spacing.

     *

     * @param ls the value is a factor of the line hight

     */

    protected void setLineSpacing(float ls) {

        lineSpacing = ls;

    }

    /**

     * Sets the indent on the first line.

     *

     * @param fi the value in points

     */

    protected void setFirstLineIndent(float fi) {

        firstLineIndent = (int) fi;

    }

    /**

     * Set the cached properties from the attributes.

     */

    protected void setPropertiesFromAttributes() {

        AttributeSet attr = getAttributes();

        if (attr != null) {

            setParagraphInsets(attr);

            Integer a = (Integer)attr.getAttribute(StyleConstants.Alignment);

            int alignment;

            if (a == null) {

                Document doc = getElement().getDocument();

                Object o = doc.getProperty(TextAttribute.RUN_DIRECTION);

                if ((o != null) && o.equals(TextAttribute.RUN_DIRECTION_RTL)) {

                    alignment = StyleConstants.ALIGN_RIGHT;

                } else {

                    alignment = StyleConstants.ALIGN_LEFT;

                }

            } else {

                alignment = a.intValue();

            }

            setJustification(alignment);

            setLineSpacing(StyleConstants.getLineSpacing(attr));

            setFirstLineIndent(StyleConstants.getFirstLineIndent(attr));

        }

    }

    /**

     * Returns the number of views that this view is

     * responsible for.

     * The child views of the paragraph are rows which

     * have been used to arrange pieces of the <code>View</code>s

     * that represent the child elements.  This is the number

     * of views that have been tiled in two dimensions,

     * and should be equivalent to the number of child elements

     * to the element this view is responsible for.

     *

     * @return the number of views that this <code>ParagraphView</code>

     *          is responsible for

     */

    protected int getLayoutViewCount() {

        return layoutPool.getViewCount();

    }

    /**

     * Returns the view at a given <code>index</code>.

     * The child views of the paragraph are rows which

     * have been used to arrange pieces of the <code>Views</code>

     * that represent the child elements.  This methods returns

     * the view responsible for the child element index

     * (prior to breaking).  These are the Views that were

     * produced from a factory (to represent the child

     * elements) and used for layout.

     *

     * @param index the <code>index</code> of the desired view

     * @return the view at <code>index</code>

     */

    protected View getLayoutView(int index) {

        return layoutPool.getView(index);

    }

    /**

     * Returns the next visual position for the cursor, in

     * either the east or west direction.

     * Overridden from <code>CompositeView</code>.

     * @param pos position into the model

     * @param b either <code>Position.Bias.Forward</code> or

     *          <code>Position.Bias.Backward</code>

     * @param a the allocated region to render into

     * @param direction either <code>SwingConstants.NORTH</code>

     *          or <code>SwingConstants.SOUTH</code>

     * @param biasRet an array containing the bias that were checked

     *  in this method

     * @return the location in the model that represents the

     *  next location visual position

     */

    protected int getNextNorthSouthVisualPositionFrom(int pos, Position.Bias b,

                                                      Shape a, int direction,

                                                      Position.Bias[] biasRet)

                                                throws BadLocationException {

        int vIndex;

        if(pos == -1) {

            vIndex = (direction == NORTH) ?

                     getViewCount() - 1 : 0;

        }

        else {

            if(b == Position.Bias.Backward && pos > 0) {

                vIndex = getViewIndexAtPosition(pos - 1);

            }

            else {

                vIndex = getViewIndexAtPosition(pos);

            }

            if(direction == NORTH) {

                if(vIndex == 0) {

                    return -1;

                }

                vIndex--;

            }

            else if(++vIndex >= getViewCount()) {

                return -1;

            }

        }

        // vIndex gives index of row to look in.

        JTextComponent text = (JTextComponent)getContainer();

        Caret c = text.getCaret();

        Point magicPoint;

        magicPoint = (c != null) ? c.getMagicCaretPosition() : null;

        int x;

        if(magicPoint == null) {

            Shape posBounds;

            try {

                posBounds = text.getUI().modelToView(text, pos, b);

            } catch (BadLocationException exc) {

                posBounds = null;

            }

            if(posBounds == null) {

                x = 0;

            }

            else {

                x = posBounds.getBounds().x;

            }

        }

        else {

            x = magicPoint.x;

        }

        return getClosestPositionTo(pos, b, a, direction, biasRet, vIndex, x);

    }

    /**

     * Returns the closest model position to <code>x</code>.

     * <code>rowIndex</code> gives the index of the view that corresponds

     * that should be looked in.

     * @param pos  position into the model

     * @param a the allocated region to render into

     * @param direction one of the following values:

     * <ul>

     * <li><code>SwingConstants.NORTH</code>

     * <li><code>SwingConstants.SOUTH</code>

     * </ul>

     * @param biasRet an array containing the bias that were checked

     *  in this method

     * @param rowIndex the index of the view

     * @param x the x coordinate of interest

     * @return the closest model position to <code>x</code>

     */

    // NOTE: This will not properly work if ParagraphView contains

    // other ParagraphViews. It won't raise, but this does not message

    // the children views with getNextVisualPositionFrom.

    protected int getClosestPositionTo(int pos, Position.Bias b, Shape a,

                                       int direction, Position.Bias[] biasRet,

                                       int rowIndex, int x)

              throws BadLocationException {

        JTextComponent text = (JTextComponent)getContainer();

        Document doc = getDocument();

        View row = getView(rowIndex);

        int lastPos = -1;

        // This could be made better to check backward positions too.

        biasRet[0] = Position.Bias.Forward;

        for(int vc = 0, numViews = row.getViewCount(); vc < numViews; vc++) {

            View v = row.getView(vc);

            int start = v.getStartOffset();

            boolean ltr = AbstractDocument.isLeftToRight(doc, start, start + 1);

            if(ltr) {

                lastPos = start;

                for(int end = v.getEndOffset(); lastPos < end; lastPos++) {

                    float xx = text.modelToView(lastPos).getBounds().x;

                    if(xx >= x) {

                        while (++lastPos < end &&

                               text.modelToView(lastPos).getBounds().x == xx) {

                        }

                        return --lastPos;

                    }

                }

                lastPos--;

            }

            else {

                for(lastPos = v.getEndOffset() - 1; lastPos >= start;

                    lastPos--) {

                    float xx = text.modelToView(lastPos).getBounds().x;

                    if(xx >= x) {

                        while (--lastPos >= start &&

                               text.modelToView(lastPos).getBounds().x == xx) {

                        }

                        return ++lastPos;

                    }

                }

                lastPos++;

            }

        }

        if(lastPos == -1) {

            return getStartOffset();

        }

        return lastPos;

    }

    /**

     * Determines in which direction the next view lays.

     * Consider the <code>View</code> at index n.

     * Typically the <code>View</code>s are layed out

     * from left to right, so that the <code>View</code>

     * to the EAST will be at index n + 1, and the

     * <code>View</code> to the WEST will be at index n - 1.

     * In certain situations, such as with bidirectional text,

     * it is possible that the <code>View</code> to EAST is not

     * at index n + 1, but rather at index n - 1,

     * or that the <code>View</code> to the WEST is not at

     * index n - 1, but index n + 1.  In this case this method

     * would return true, indicating the <code>View</code>s are

     * layed out in descending order.

     * <p>

     * This will return true if the text is layed out right

     * to left at position, otherwise false.

     *

     * @param position position into the model

     * @param bias either <code>Position.Bias.Forward</code> or

     *          <code>Position.Bias.Backward</code>

     * @return true if the text is layed out right to left at

     *         position, otherwise false.

     */

    protected boolean flipEastAndWestAtEnds(int position,

                                            Position.Bias bias) {

        Document doc = getDocument();

        position = getStartOffset();

        return !AbstractDocument.isLeftToRight(doc, position, position + 1);

    }

    // --- FlowView methods ---------------------------------------------

    /**

     * Fetches the constraining span to flow against for

     * the given child index.

     * @param index the index of the view being queried

     * @return the constraining span for the given view at

     *  <code>index</code>

     * @since 1.3

     */

    public int getFlowSpan(int index) {

        View child = getView(index);

        int adjust = 0;

        if (child instanceof Row) {

            Row row = (Row) child;

            adjust = row.getLeftInset() + row.getRightInset();

        }

        return (layoutSpan == Integer.MAX_VALUE) ? layoutSpan

                                                 : (layoutSpan - adjust);

    }

    /**

     * Fetches the location along the flow axis that the

     * flow span will start at.

     * @param index the index of the view being queried

     * @return the location for the given view at

     *  <code>index</code>

     * @since 1.3

     */

    public int getFlowStart(int index) {

        View child = getView(index);

        int adjust = 0;

        if (child instanceof Row) {

            Row row = (Row) child;

            adjust = row.getLeftInset();

        }

        return tabBase + adjust;

    }

    /**

     * Create a <code>View</code> that should be used to hold a

     * a row's worth of children in a flow.

     * @return the new <code>View</code>

     * @since 1.3

     */

    protected View createRow() {

        return new Row(getElement());

    }

    // --- TabExpander methods ------------------------------------------

    /**

     * Returns the next tab stop position given a reference position.

     * This view implements the tab coordinate system, and calls

     * <code>getTabbedSpan</code> on the logical children in the process

     * of layout to determine the desired span of the children.  The

     * logical children can delegate their tab expansion upward to

     * the paragraph which knows how to expand tabs.

     * <code>LabelView</code> is an example of a view that delegates

     * its tab expansion needs upward to the paragraph.

     * <p>

     * This is implemented to try and locate a <code>TabSet</code>

     * in the paragraph element's attribute set.  If one can be

     * found, its settings will be used, otherwise a default expansion

     * will be provided.  The base location for for tab expansion

     * is the left inset from the paragraphs most recent allocation

     * (which is what the layout of the children is based upon).

     *

     * @param x the X reference position

     * @param tabOffset the position within the text stream

     *   that the tab occurred at >= 0

     * @return the trailing end of the tab expansion >= 0

     * @see TabSet

     * @see TabStop

     * @see LabelView

     */

    public float nextTabStop(float x, int tabOffset) {

        // If the text isn't left justified, offset by 10 pixels!

        if(justification != StyleConstants.ALIGN_LEFT)

            return x + 10.0f;

        x -= tabBase;

        TabSet tabs = getTabSet();

        if(tabs == null) {

            // a tab every 72 pixels.

            return (float)(tabBase + (((int)x / 72 + 1) * 72));

        }

        TabStop tab = tabs.getTabAfter(x + .01f);

        if(tab == null) {

            // no tab, do a default of 5 pixels.

            // Should this cause a wrapping of the line?

            return tabBase + x + 5.0f;

        }

        int alignment = tab.getAlignment();

        int offset;

        switch(alignment) {

        default:

        case TabStop.ALIGN_LEFT:

            // Simple case, left tab.

            return tabBase + tab.getPosition();

        case TabStop.ALIGN_BAR:

            // PENDING: what does this mean?

            return tabBase + tab.getPosition();

        case TabStop.ALIGN_RIGHT:

        case TabStop.ALIGN_CENTER:

            offset = findOffsetToCharactersInString(tabChars,

                                                    tabOffset + 1);

            break;

        case TabStop.ALIGN_DECIMAL:

            offset = findOffsetToCharactersInString(tabDecimalChars,

                                                    tabOffset + 1);

            break;

        }

        if (offset == -1) {

            offset = getEndOffset();

        }

        float charsSize = getPartialSize(tabOffset + 1, offset);

        switch(alignment) {

        case TabStop.ALIGN_RIGHT:

        case TabStop.ALIGN_DECIMAL:

            // right and decimal are treated the same way, the new

            // position will be the location of the tab less the

            // partialSize.

            return tabBase + Math.max(x, tab.getPosition() - charsSize);

        case TabStop.ALIGN_CENTER:

            // Similar to right, but half the partialSize.

            return tabBase + Math.max(x, tab.getPosition() - charsSize / 2.0f);

        }

        // will never get here!

        return x;

    }

    /**

     * Gets the <code>Tabset</code> to be used in calculating tabs.

     *

     * @return the <code>TabSet</code>

     */

    protected TabSet getTabSet() {

        return StyleConstants.getTabSet(getElement().getAttributes());

    }

    /**

     * Returns the size used by the views between

     * <code>startOffset</code> and <code>endOffset</code>.

     * This uses <code>getPartialView</code> to calculate the

     * size if the child view implements the

     * <code>TabableView</code> interface. If a

     * size is needed and a <code>View</code> does not implement

     * the <code>TabableView</code> interface,

     * the <code>preferredSpan</code> will be used.

     *

     * @param startOffset the starting document offset >= 0

     * @param endOffset the ending document offset >= startOffset

     * @return the size >= 0

     */

    protected float getPartialSize(int startOffset, int endOffset) {

        float size = 0.0f;

        int viewIndex;

        int numViews = getViewCount();

        View view;

        int viewEnd;

        int tempEnd;

        // Have to search layoutPool!

        // PENDING: when ParagraphView supports breaking location

        // into layoutPool will have to change!

        viewIndex = getElement().getElementIndex(startOffset);

        numViews = layoutPool.getViewCount();

        while(startOffset < endOffset && viewIndex < numViews) {

            view = layoutPool.getView(viewIndex++);

            viewEnd = view.getEndOffset();

            tempEnd = Math.min(endOffset, viewEnd);

            if(view instanceof TabableView)

                size += ((TabableView)view).getPartialSpan(startOffset, tempEnd);

            else if(startOffset == view.getStartOffset() &&

                    tempEnd == view.getEndOffset())

                size += view.getPreferredSpan(View.X_AXIS);

            else

                // PENDING: should we handle this better?

                return 0.0f;

            startOffset = viewEnd;

        }

        return size;

    }

    /**