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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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package javax.swing.text;

import java.lang.reflect.Method;

import java.awt.Component;

import java.awt.Rectangle;

import java.awt.Graphics;

import java.awt.FontMetrics;

import java.awt.Shape;

import java.awt.Toolkit;

import java.awt.Graphics2D;

import java.awt.font.FontRenderContext;

import java.awt.font.TextLayout;

import java.awt.font.TextAttribute;

import java.text.*;

import javax.swing.JComponent;

import javax.swing.SwingConstants;

import javax.swing.text.ParagraphView.Row;

import sun.swing.SwingUtilities2;

/**

 * A collection of methods to deal with various text

 * related activities.

 *

 * @author  Timothy Prinzing

 */

public class Utilities {

    /**

     * If <code>view</code>'s container is a <code>JComponent</code> it

     * is returned, after casting.

     */

    static JComponent getJComponent(View view) {

        if (view != null) {

            Component component = view.getContainer();

            if (component instanceof JComponent) {

                return (JComponent)component;

            }

        }

        return null;

    }

    /**

     * Draws the given text, expanding any tabs that are contained

     * using the given tab expansion technique.  This particular

     * implementation renders in a 1.1 style coordinate system

     * where ints are used and 72dpi is assumed.

     *

     * @param s  the source of the text

     * @param x  the X origin >= 0

     * @param y  the Y origin >= 0

     * @param g  the graphics context

     * @param e  how to expand the tabs.  If this value is null,

     *   tabs will be expanded as a space character.

     * @param startOffset starting offset of the text in the document >= 0

     * @return  the X location at the end of the rendered text

     */

    public static final int drawTabbedText(Segment s, int x, int y, Graphics g,

                                           TabExpander e, int startOffset) {

        return drawTabbedText(null, s, x, y, g, e, startOffset);

    }

    /**

     * Draws the given text, expanding any tabs that are contained

     * using the given tab expansion technique.  This particular

     * implementation renders in a 1.1 style coordinate system

     * where ints are used and 72dpi is assumed.

     *

     * @param view View requesting rendering, may be null.

     * @param s  the source of the text

     * @param x  the X origin >= 0

     * @param y  the Y origin >= 0

     * @param g  the graphics context

     * @param e  how to expand the tabs.  If this value is null,

     *   tabs will be expanded as a space character.

     * @param startOffset starting offset of the text in the document >= 0

     * @return  the X location at the end of the rendered text

     */

    static final int drawTabbedText(View view,

                                Segment s, int x, int y, Graphics g,

                                TabExpander e, int startOffset) {

        return drawTabbedText(view, s, x, y, g, e, startOffset, null);

    }

    // In addition to the previous method it can extend spaces for

    // justification.

    //

    // all params are the same as in the preious method except the last

    // one:

    // @param justificationData justificationData for the row.

    // if null not justification is needed

    static final int drawTabbedText(View view,

                                Segment s, int x, int y, Graphics g,

                                TabExpander e, int startOffset,

                                int [] justificationData) {

        JComponent component = getJComponent(view);

        FontMetrics metrics = SwingUtilities2.getFontMetrics(component, g);

        int nextX = x;

        char[] txt = s.array;

        int txtOffset = s.offset;

        int flushLen = 0;

        int flushIndex = s.offset;

        int spaceAddon = 0;

        int spaceAddonLeftoverEnd = -1;

        int startJustifiableContent = 0;

        int endJustifiableContent = 0;

        if (justificationData != null) {

            int offset = - startOffset + txtOffset;

            View parent = null;

            if (view != null

                  && (parent = view.getParent()) != null) {

                offset += parent.getStartOffset();

            }

            spaceAddon =

                justificationData[Row.SPACE_ADDON];

            spaceAddonLeftoverEnd =

                justificationData[Row.SPACE_ADDON_LEFTOVER_END] + offset;

            startJustifiableContent =

                justificationData[Row.START_JUSTIFIABLE] + offset;

            endJustifiableContent =

                justificationData[Row.END_JUSTIFIABLE] + offset;

        }

        int n = s.offset + s.count;

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

            if (txt[i] == '\t'

                || ((spaceAddon != 0 || i <= spaceAddonLeftoverEnd)

                    && (txt[i] == ' ')

                    && startJustifiableContent <= i

                    && i <= endJustifiableContent

                    )) {

                if (flushLen > 0) {

                    nextX = SwingUtilities2.drawChars(component, g, txt,

                                                flushIndex, flushLen, x, y);

                    flushLen = 0;

                }

                flushIndex = i + 1;

                if (txt[i] == '\t') {

                    if (e != null) {

                        nextX = (int) e.nextTabStop((float) nextX, startOffset + i - txtOffset);

                    } else {

                        nextX += metrics.charWidth(' ');

                    }

                } else if (txt[i] == ' ') {

                    nextX += metrics.charWidth(' ') + spaceAddon;

                    if (i <= spaceAddonLeftoverEnd) {

                        nextX++;

                    }

                }

                x = nextX;

            } else if ((txt[i] == '\n') || (txt[i] == '\r')) {

                if (flushLen > 0) {

                    nextX = SwingUtilities2.drawChars(component, g, txt,

                                                flushIndex, flushLen, x, y);

                    flushLen = 0;

                }

                flushIndex = i + 1;

                x = nextX;

            } else {

                flushLen += 1;

            }

        }

        if (flushLen > 0) {

            nextX = SwingUtilities2.drawChars(component, g,txt, flushIndex,

                                              flushLen, x, y);

        }

        return nextX;

    }

    /**

     * Determines the width of the given segment of text taking tabs

     * into consideration.  This is implemented in a 1.1 style coordinate

     * system where ints are used and 72dpi is assumed.

     *

     * @param s  the source of the text

     * @param metrics the font metrics to use for the calculation

     * @param x  the X origin >= 0

     * @param e  how to expand the tabs.  If this value is null,

     *   tabs will be expanded as a space character.

     * @param startOffset starting offset of the text in the document >= 0

     * @return  the width of the text

     */

    public static final int getTabbedTextWidth(Segment s, FontMetrics metrics, int x,

                                               TabExpander e, int startOffset) {

        return getTabbedTextWidth(null, s, metrics, x, e, startOffset, null);

    }

    // In addition to the previous method it can extend spaces for

    // justification.

    //

    // all params are the same as in the preious method except the last

    // one:

    // @param justificationData justificationData for the row.

    // if null not justification is needed

    static final int getTabbedTextWidth(View view, Segment s, FontMetrics metrics, int x,

                                        TabExpander e, int startOffset,

                                        int[] justificationData) {

        int nextX = x;

        char[] txt = s.array;

        int txtOffset = s.offset;

        int n = s.offset + s.count;

        int charCount = 0;

        int spaceAddon = 0;

        int spaceAddonLeftoverEnd = -1;

        int startJustifiableContent = 0;

        int endJustifiableContent = 0;

        if (justificationData != null) {

            int offset = - startOffset + txtOffset;

            View parent = null;

            if (view != null

                  && (parent = view.getParent()) != null) {

                offset += parent.getStartOffset();

            }

            spaceAddon =

                justificationData[Row.SPACE_ADDON];

            spaceAddonLeftoverEnd =

                justificationData[Row.SPACE_ADDON_LEFTOVER_END] + offset;

            startJustifiableContent =

                justificationData[Row.START_JUSTIFIABLE] + offset;

            endJustifiableContent =

                justificationData[Row.END_JUSTIFIABLE] + offset;

        }

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

            if (txt[i] == '\t'

                || ((spaceAddon != 0 || i <= spaceAddonLeftoverEnd)

                    && (txt[i] == ' ')

                    && startJustifiableContent <= i

                    && i <= endJustifiableContent

                    )) {

                nextX += metrics.charsWidth(txt, i-charCount, charCount);

                charCount = 0;

                if (txt[i] == '\t') {

                    if (e != null) {

                        nextX = (int) e.nextTabStop((float) nextX,

                                                    startOffset + i - txtOffset);

                    } else {

                        nextX += metrics.charWidth(' ');

                    }

                } else if (txt[i] == ' ') {

                    nextX += metrics.charWidth(' ') + spaceAddon;

                    if (i <= spaceAddonLeftoverEnd) {

                        nextX++;

                    }

                }

            } else if(txt[i] == '\n') {

            // Ignore newlines, they take up space and we shouldn't be

            // counting them.

                nextX += metrics.charsWidth(txt, i - charCount, charCount);

                charCount = 0;

            } else {

                charCount++;

        }

        }

        nextX += metrics.charsWidth(txt, n - charCount, charCount);

        return nextX - x;

    }

    /**

     * Determines the relative offset into the given text that

     * best represents the given span in the view coordinate

     * system.  This is implemented in a 1.1 style coordinate

     * system where ints are used and 72dpi is assumed.

     *

     * @param s  the source of the text

     * @param metrics the font metrics to use for the calculation

     * @param x0 the starting view location representing the start

     *   of the given text >= 0.

     * @param x  the target view location to translate to an

     *   offset into the text >= 0.

     * @param e  how to expand the tabs.  If this value is null,

     *   tabs will be expanded as a space character.

     * @param startOffset starting offset of the text in the document >= 0

     * @return  the offset into the text >= 0

     */

    public static final int getTabbedTextOffset(Segment s, FontMetrics metrics,

                                             int x0, int x, TabExpander e,

                                             int startOffset) {

        return getTabbedTextOffset(s, metrics, x0, x, e, startOffset, true);

    }

    static final int getTabbedTextOffset(View view, Segment s, FontMetrics metrics,

                                         int x0, int x, TabExpander e,

                                         int startOffset,

                                         int[] justificationData) {

        return getTabbedTextOffset(view, s, metrics, x0, x, e, startOffset, true,

                                   justificationData);

    }

    public static final int getTabbedTextOffset(Segment s,

                                                FontMetrics metrics,

                                                int x0, int x, TabExpander e,

                                                int startOffset,

                                                boolean round) {

        return getTabbedTextOffset(null, s, metrics, x0, x, e, startOffset, round, null);

    }

    // In addition to the previous method it can extend spaces for

    // justification.

    //

    // all params are the same as in the preious method except the last

    // one:

    // @param justificationData justificationData for the row.

    // if null not justification is needed

    static final int getTabbedTextOffset(View view,

                                         Segment s,

                                         FontMetrics metrics,

                                         int x0, int x, TabExpander e,

                                         int startOffset,

                                         boolean round,

                                         int[] justificationData) {

        if (x0 >= x) {

            // x before x0, return.

            return 0;

        }

        int currX = x0;

        int nextX = currX;

        // s may be a shared segment, so it is copied prior to calling

        // the tab expander

        char[] txt = s.array;

        int txtOffset = s.offset;

        int txtCount = s.count;

        int spaceAddon = 0 ;

        int spaceAddonLeftoverEnd = -1;

        int startJustifiableContent = 0 ;

        int endJustifiableContent = 0;

        if (justificationData != null) {

            int offset = - startOffset + txtOffset;

            View parent = null;

            if (view != null

                  && (parent = view.getParent()) != null) {

                offset += parent.getStartOffset();

            }

            spaceAddon =

                justificationData[Row.SPACE_ADDON];

            spaceAddonLeftoverEnd =

                justificationData[Row.SPACE_ADDON_LEFTOVER_END] + offset;

            startJustifiableContent =

                justificationData[Row.START_JUSTIFIABLE] + offset;

            endJustifiableContent =

                justificationData[Row.END_JUSTIFIABLE] + offset;

        }

        int n = s.offset + s.count;

        for (int i = s.offset; i < n; i++) {

            if (txt[i] == '\t'

                || ((spaceAddon != 0 || i <= spaceAddonLeftoverEnd)

                    && (txt[i] == ' ')

                    && startJustifiableContent <= i

                    && i <= endJustifiableContent

                    )){

                if (txt[i] == '\t') {

                    if (e != null) {

                        nextX = (int) e.nextTabStop((float) nextX,

                                                    startOffset + i - txtOffset);

                    } else {

                        nextX += metrics.charWidth(' ');

                    }

                } else if (txt[i] == ' ') {

                    nextX += metrics.charWidth(' ') + spaceAddon;

                    if (i <= spaceAddonLeftoverEnd) {

                        nextX++;

                    }

                }

            } else {

                nextX += metrics.charWidth(txt[i]);

            }

            if ((x >= currX) && (x < nextX)) {

                // found the hit position... return the appropriate side

                int offset = ((round == false) || ((x - currX) < (nextX - x))) ?

                        (i - txtOffset) : (i + 1 - txtOffset);

                // the length of the string measured as a whole may differ from

                // the sum of individual character lengths, for example if

                // fractional metrics are enabled; and we must guard from this.

                while (metrics.charsWidth(txt, txtOffset, offset + 1) > (x - x0)) {

                    offset--;

                }

                return (offset < 0 ? 0 : offset);

            }

            currX = nextX;

        }

        // didn't find, return end offset

        return txtCount;

    }

    /**

     * Determine where to break the given text to fit

     * within the given span. This tries to find a word boundary.

     * @param s  the source of the text

     * @param metrics the font metrics to use for the calculation

     * @param x0 the starting view location representing the start

     *   of the given text.

     * @param x  the target view location to translate to an

     *   offset into the text.

     * @param e  how to expand the tabs.  If this value is null,

     *   tabs will be expanded as a space character.

     * @param startOffset starting offset in the document of the text

     * @return  the offset into the given text

     */

    public static final int getBreakLocation(Segment s, FontMetrics metrics,

                                             int x0, int x, TabExpander e,

                                             int startOffset) {

        char[] txt = s.array;

        int txtOffset = s.offset;

        int txtCount = s.count;

        int index = Utilities.getTabbedTextOffset(s, metrics, x0, x,

                                                  e, startOffset, false);

        if (index >= txtCount - 1) {

            return txtCount;

        }

        for (int i = txtOffset + index; i >= txtOffset; i--) {

            char ch = txt[i];

            if (ch < 256) {

                // break on whitespace

                if (Character.isWhitespace(ch)) {

                    index = i - txtOffset + 1;

                    break;

                }

            } else {

                // a multibyte char found; use BreakIterator to find line break

                BreakIterator bit = BreakIterator.getLineInstance();

                bit.setText(s);

                int breakPos = bit.preceding(i + 1);

                if (breakPos > txtOffset) {

                    index = breakPos - txtOffset;

                }

                break;

            }

        }

        return index;

    }

    /**

     * Determines the starting row model position of the row that contains

     * the specified model position.  The component given must have a

     * size to compute the result.  If the component doesn't have a size

     * a value of -1 will be returned.

     *

     * @param c the editor

     * @param offs the offset in the document >= 0

     * @return the position >= 0 if the request can be computed, otherwise

     *  a value of -1 will be returned.

     * @exception BadLocationException if the offset is out of range

     */

    public static final int getRowStart(JTextComponent c, int offs) throws BadLocationException {

        Rectangle r = c.modelToView(offs);

        if (r == null) {

            return -1;

        }

        int lastOffs = offs;

        int y = r.y;

        while ((r != null) && (y == r.y)) {

            // Skip invisible elements

            if(r.height !=0) {

                offs = lastOffs;

            }

            lastOffs -= 1;

            r = (lastOffs >= 0) ? c.modelToView(lastOffs) : null;

        }

        return offs;

    }

    /**

     * Determines the ending row model position of the row that contains

     * the specified model position.  The component given must have a

     * size to compute the result.  If the component doesn't have a size

     * a value of -1 will be returned.

     *

     * @param c the editor

     * @param offs the offset in the document >= 0

     * @return the position >= 0 if the request can be computed, otherwise

     *  a value of -1 will be returned.

     * @exception BadLocationException if the offset is out of range

     */

    public static final int getRowEnd(JTextComponent c, int offs) throws BadLocationException {

        Rectangle r = c.modelToView(offs);

        if (r == null) {

            return -1;

        }

        int n = c.getDocument().getLength();

        int lastOffs = offs;

        int y = r.y;

        while ((r != null) && (y == r.y)) {

            // Skip invisible elements

            if (r.height !=0) {

                offs = lastOffs;

            }

            lastOffs += 1;

            r = (lastOffs <= n) ? c.modelToView(lastOffs) : null;

        }

        return offs;

    }

    /**

     * Determines the position in the model that is closest to the given

     * view location in the row above.  The component given must have a

     * size to compute the result.  If the component doesn't have a size

     * a value of -1 will be returned.

     *

     * @param c the editor

     * @param offs the offset in the document >= 0