/*******************************************************************************
 * Copyright (c) 2000, 2007 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
module dwt.graphics.TextLayout;

import dwt.dwthelper.utils;

import dwt.DWT;
import dwt.DWTException;
import dwt.internal.cocoa.NSColor;
import dwt.internal.cocoa.NSFont;
import dwt.internal.cocoa.NSLayoutManager;
import dwt.internal.cocoa.NSMutableParagraphStyle;
import dwt.internal.cocoa.NSNumber;
import dwt.internal.cocoa.NSPoint;
import dwt.internal.cocoa.NSRange;
import dwt.internal.cocoa.NSRect;
import dwt.internal.cocoa.NSSize;
import dwt.internal.cocoa.NSString;
import dwt.internal.cocoa.NSTextContainer;
import dwt.internal.cocoa.NSTextStorage;
import dwt.internal.cocoa.OS;

/**
 * <code>TextLayout</code> is a graphic object that represents
 * styled text.
 * <p>
 * Instances of this class provide support for drawing, cursor
 * navigation, hit testing, text wrapping, alignment, tab expansion
 * line breaking, etc.  These are aspects required for rendering internationalized text.
 * </p><p>
 * Application code must explicitly invoke the <code>TextLayout#dispose()</code> 
 * method to release the operating system resources managed by each instance
 * when those instances are no longer required.
 * </p>
 * 
 *  @since 3.0
 */
public final class TextLayout extends Resource {
    
    NSTextStorage textStorage;
    NSLayoutManager layoutManager;
    NSTextContainer textContainer;
    Font font;
    String text;
    StyleItem[] styles;
    int spacing, ascent, descent, indent;
    bool justify;
    int alignment;
    int[] tabs;
    int[] segments;
    int wrapWidth;
    int orientation;
    
    int[] lineOffsets;
    NSRect[] lineBounds;

    static class StyleItem {
        TextStyle style;
        int start;

        public String toString () {
            return "StyleItem {" + start + ", " + style + "}";
        }
    }

//  static final int TAB_COUNT = 32;
//  static final char ZWS = '\u200B';
//  
//  static final int UNDERLINE_IME_INPUT = 1 << 16;
//  static final int UNDERLINE_IME_TARGET_CONVERTED = 2 << 16;
//  static final int UNDERLINE_IME_CONVERTED = 3 << 16;
    
/**  
 * Constructs a new instance of this class on the given device.
 * <p>
 * You must dispose the text layout when it is no longer required. 
 * </p>
 * 
 * @param device the device on which to allocate the text layout
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if device is null and there is no current device</li>
 * </ul>
 * 
 * @see #dispose()
 */
public TextLayout (Device device) {
    super(device);
    wrapWidth = ascent = descent = -1;
    alignment = DWT.LEFT;
    orientation = DWT.LEFT_TO_RIGHT;
    text = "";
    styles = new StyleItem[2];
    styles[0] = new StyleItem();
    styles[1] = new StyleItem();
    init();
}

void checkLayout() {
    if (isDisposed()) DWT.error(DWT.ERROR_GRAPHIC_DISPOSED);
}

void computeRuns() {
    if (textStorage !is null) return;
    NSString str = NSString.stringWith(text);
    textStorage = ((NSTextStorage)new NSTextStorage().alloc());
    textStorage.initWithString_(str);
    layoutManager = (NSLayoutManager)new NSLayoutManager().alloc().init();
    textContainer = (NSTextContainer)new NSTextContainer().alloc();
    NSSize size = new NSSize();
    size.width = wrapWidth !is -1 ? wrapWidth : Float.MAX_VALUE;
    size.height = Float.MAX_VALUE;
    textContainer.initWithContainerSize(size);
    textStorage.addLayoutManager(layoutManager);
    layoutManager.addTextContainer(textContainer);
    
    textStorage.beginEditing();
    Font defaultFont = font !is null ? font : device.systemFont;
    NSRange range = new NSRange();
    range.length = str.length();
    textStorage.addAttribute(OS.NSFontAttributeName(), defaultFont.handle, range);
    
    NSMutableParagraphStyle paragraph = (NSMutableParagraphStyle)new NSMutableParagraphStyle().alloc().init();
    int align = OS.NSLeftTextAlignment;
    if (justify) {
        align = OS.NSJustifiedTextAlignment;
    } else {
        switch (alignment) {
            case DWT.CENTER:
                align = OS.NSCenterTextAlignment;
                break;
            case DWT.RIGHT:
                align = OS.NSRightTextAlignment;
        }
    }
    paragraph.setAlignment(align);
    paragraph.setLineSpacing(spacing);
    paragraph.setFirstLineHeadIndent(indent);
    
    //TODO tabs ascend descent wrap
    
    textStorage.addAttribute(OS.NSParagraphStyleAttributeName(), paragraph, range);
    paragraph.release();
    
    int textLength = str.length();
    for (int i = 0; i < styles.length - 1; i++) {
        StyleItem run = styles[i];
        if (run.style is null) continue;
        TextStyle style = run.style;        
        range.location = textLength !is 0 ? translateOffset(run.start) : 0;
        range.length = translateOffset(styles[i + 1].start) - range.location;
        Font font = style.font;
        if (font !is null) {
            textStorage.addAttribute(OS.NSFontAttributeName(), font.handle, range);
        }
        Color foreground = style.foreground;
        if (foreground !is null) {
            NSColor color = NSColor.colorWithDeviceRed(foreground.handle[0], foreground.handle[1], foreground.handle[2], 1);
            textStorage.addAttribute(OS.NSForegroundColorAttributeName(), color, range);
        }
        Color background = style.background;
        if (background !is null) {
            NSColor color = NSColor.colorWithDeviceRed(background.handle[0], background.handle[1], background.handle[2], 1);
            textStorage.addAttribute(OS.NSBackgroundColorAttributeName(), color, range);
        }
        if (style.strikeout) {
            textStorage.addAttribute(OS.NSStrikethroughStyleAttributeName(), NSNumber.numberWithInt(OS.NSUnderlineStyleSingle), range);
            Color strikeColor = style.strikeoutColor;
            if (strikeColor !is null) {
                NSColor color = NSColor.colorWithDeviceRed(strikeColor.handle[0], strikeColor.handle[1], strikeColor.handle[2], 1);
                textStorage.addAttribute(OS.NSStrikethroughColorAttributeName(), color, range);
            }
        }
        if (style.underline) {
            //TODO - IME - thick
            int underlineStyle = 0;
            switch (style.underlineStyle) {
                case DWT.UNDERLINE_SINGLE:
                    underlineStyle = OS.NSUnderlineStyleSingle;
                    break;
                case DWT.UNDERLINE_DOUBLE:
                    underlineStyle = OS.NSUnderlineStyleDouble;
                    break;
            }
            if (underlineStyle !is 0) {
                textStorage.addAttribute(OS.NSUnderlineStyleAttributeName(), NSNumber.numberWithInt(underlineStyle), range);
                Color underlineColor = style.underlineColor;
                if (underlineColor !is null) {
                    NSColor color = NSColor.colorWithDeviceRed(underlineColor.handle[0], underlineColor.handle[1], underlineColor.handle[2], 1);
                    textStorage.addAttribute(OS.NSUnderlineColorAttributeName(), color, range);
                }
            }
        }
        if (style.rise !is 0) {
            textStorage.addAttribute(OS.NSBaselineOffsetAttributeName(), NSNumber.numberWithInt(style.rise), range);
        }
        if (style.metrics !is null) {
            //TODO
        }
    }
    textStorage.endEditing();
    
    textContainer.setLineFragmentPadding(0);    
    layoutManager.glyphRangeForTextContainer(textContainer);
    
    int numberOfLines, index, numberOfGlyphs = layoutManager.numberOfGlyphs();
    int rangePtr = OS.malloc(NSRange.sizeof);
    NSRange lineRange = new NSRange();
    for (numberOfLines = 0, index = 0; index < numberOfGlyphs; numberOfLines++){
        layoutManager.lineFragmentUsedRectForGlyphAtIndex_effectiveRange_withoutAdditionalLayout_(index, rangePtr, true);
        OS.memmove(lineRange, rangePtr, NSRange.sizeof);
        index = lineRange.location + lineRange.length;
    }
    if (numberOfLines is 0) numberOfLines++;
    int[] offsets = new int[numberOfLines + 1];
    NSRect[] bounds = new NSRect[numberOfLines];
    for (numberOfLines = 0, index = 0; index < numberOfGlyphs; numberOfLines++){
        bounds[numberOfLines] = layoutManager.lineFragmentUsedRectForGlyphAtIndex_effectiveRange_withoutAdditionalLayout_(index, rangePtr, true);
        OS.memmove(lineRange, rangePtr, NSRange.sizeof);
        offsets[numberOfLines] = lineRange.location;
        index = lineRange.location + lineRange.length;
    }
    if (numberOfLines is 0) {
        Font font = this.font !is null ? this.font : device.systemFont;
        NSFont nsFont = font.handle;
        bounds[0] = new NSRect();
        bounds[0].height = Math.max(layoutManager.defaultLineHeightForFont(nsFont), ascent + descent);
    }
    OS.free(rangePtr);
    offsets[numberOfLines] = textStorage.length();
    this.lineOffsets = offsets;
    this.lineBounds = bounds;
}

void destroy() {
    freeRuns();
    font = null;
    text = null;
    styles = null;
}

/**
 * Draws the receiver's text using the specified GC at the specified
 * point.
 * 
 * @param gc the GC to draw
 * @param x the x coordinate of the top left corner of the rectangular area where the text is to be drawn
 * @param y the y coordinate of the top left corner of the rectangular area where the text is to be drawn
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the gc is null</li>
 * </ul>
 */
public void draw(GC gc, int x, int y) {
    draw(gc, x, y, -1, -1, null, null);
}

/**
 * Draws the receiver's text using the specified GC at the specified
 * point.
 * 
 * @param gc the GC to draw
 * @param x the x coordinate of the top left corner of the rectangular area where the text is to be drawn
 * @param y the y coordinate of the top left corner of the rectangular area where the text is to be drawn
 * @param selectionStart the offset where the selections starts, or -1 indicating no selection
 * @param selectionEnd the offset where the selections ends, or -1 indicating no selection
 * @param selectionForeground selection foreground, or NULL to use the system default color
 * @param selectionBackground selection background, or NULL to use the system default color
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the gc is null</li>
 * </ul>
 */
public void draw(GC gc, int x, int y, int selectionStart, int selectionEnd, Color selectionForeground, Color selectionBackground) {
    draw(gc, x, y, selectionStart, selectionEnd, selectionForeground, selectionBackground, 0);
}

/**
 * Draws the receiver's text using the specified GC at the specified
 * point.
 * <p>
 * The parameter <code>flags</code> can include one of <code>DWT.DELIMITER_SELECTION</code>
 * or <code>DWT.FULL_SELECTION</code> to specify the selection behavior on all lines except
 * for the last line, and can also include <code>DWT.LAST_LINE_SELECTION</code> to extend
 * the specified selection behavior to the last line.
 * </p>
 * @param gc the GC to draw
 * @param x the x coordinate of the top left corner of the rectangular area where the text is to be drawn
 * @param y the y coordinate of the top left corner of the rectangular area where the text is to be drawn
 * @param selectionStart the offset where the selections starts, or -1 indicating no selection
 * @param selectionEnd the offset where the selections ends, or -1 indicating no selection
 * @param selectionForeground selection foreground, or NULL to use the system default color
 * @param selectionBackground selection background, or NULL to use the system default color
 * @param flags drawing options
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the gc is null</li>
 * </ul>
 * 
 * @since 3.3
 */
public void draw(GC gc, int x, int y, int selectionStart, int selectionEnd, Color selectionForeground, Color selectionBackground, int flags) {
    checkLayout ();
    computeRuns();
    if (gc is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    if (gc.isDisposed()) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    if (selectionForeground !is null && selectionForeground.isDisposed()) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    if (selectionBackground !is null && selectionBackground.isDisposed()) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    gc.checkGC(GC.CLIPPING | GC.TRANSFORM | GC.FOREGROUND);
//  float[] foreground = gc.data.foreground;
//  NSColor color = NSColor.colorWithDeviceRed(foreground[0], foreground[1], foreground[2], foreground[3]);
//  textStorage.setForegroundColor(color);
    NSPoint pt = new NSPoint();
    pt.x = x;
    pt.y = y;
    NSRange range = new NSRange();
    range.length = layoutManager.numberOfGlyphs();
    bool hasSelection = selectionStart <= selectionEnd && selectionStart !is -1 && selectionEnd !is -1;
    NSRange selectionRange = null;
    if (hasSelection) {
        selectionRange = new NSRange();
        selectionRange.location = selectionStart;
        selectionRange.length = selectionEnd - selectionStart + 1;
        if (selectionBackground is null) selectionBackground = device.getSystemColor(DWT.COLOR_LIST_SELECTION);
        NSColor selectionColor = NSColor.colorWithDeviceRed(selectionBackground.handle[0], selectionBackground.handle[1], selectionBackground.handle[2], selectionBackground.handle[3]);
        layoutManager.addTemporaryAttribute(OS.NSBackgroundColorAttributeName, selectionColor, selectionRange);
    }
    //TODO draw selection for flags (LAST_LINE_SELECTION and FULL_SELECTION)
    if (range.length > 0) {
        layoutManager.drawBackgroundForGlyphRange(range, pt);
        layoutManager.drawGlyphsForGlyphRange(range, pt);
    }
    if (selectionRange !is null) {
        layoutManager.removeTemporaryAttribute(OS.NSBackgroundColorAttributeName, selectionRange);
    }
}

void freeRuns() {
    if (textStorage is null) return;
    if (textStorage !is null) {
        textStorage.release();
    }
    if (layoutManager !is null) {
        layoutManager.release();
    }
    if (textContainer !is null) {
        textContainer.release();
    }
    textStorage = null;
    layoutManager = null;
    textContainer = null;
}

/** 
 * Returns the receiver's horizontal text alignment, which will be one
 * of <code>DWT.LEFT</code>, <code>DWT.CENTER</code> or
 * <code>DWT.RIGHT</code>.
 *
 * @return the alignment used to positioned text horizontally
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int getAlignment() {
    checkLayout();
    return alignment;
}

/**
 * Returns the ascent of the receiver.
 *
 * @return the ascent
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #getDescent()
 * @see #setDescent(int)
 * @see #setAscent(int)
 * @see #getLineMetrics(int)
 */
public int getAscent () {
    checkLayout();  
    return ascent;
}

/**
 * Returns the bounds of the receiver.
 * 
 * @return the bounds of the receiver
 * 
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public Rectangle getBounds() {
    checkLayout();
    computeRuns();
    NSRect rect = layoutManager.usedRectForTextContainer(textContainer);
    if (wrapWidth !is -1) rect.width = wrapWidth;
    if (text.length() is 0) {
        Font font = this.font !is null ? this.font : device.systemFont;
        NSFont nsFont = font.handle;
        rect.height = Math.max(rect.height, layoutManager.defaultLineHeightForFont(nsFont));
    }
    rect.height = Math.max(rect.height, ascent + descent);
    return new Rectangle(0, 0, (int)rect.width, (int)rect.height);
}

/**
 * Returns the bounds for the specified range of characters. The
 * bounds is the smallest rectangle that encompasses all characters
 * in the range. The start and end offsets are inclusive and will be
 * clamped if out of range.
 * 
 * @param start the start offset
 * @param end the end offset
 * @return the bounds of the character range
 * 
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public Rectangle getBounds(int start, int end) {
    checkLayout();
    computeRuns();
    int length = text.length();
    if (length is 0) return new Rectangle(0, 0, 0, 0);
    if (start > end) return new Rectangle(0, 0, 0, 0);
    start = Math.min(Math.max(0, start), length - 1);
    end = Math.min(Math.max(0, end), length - 1);
    start = translateOffset(start);
    end = translateOffset(end);
    NSRange range = new NSRange();
    range.location = layoutManager.glyphIndexForCharacterAtIndex(start);
    range.length = layoutManager.glyphIndexForCharacterAtIndex(end + 1) - range.location;
    NSRect rect = layoutManager.boundingRectForGlyphRange(range, textContainer);
    return new Rectangle((int)rect.x, (int)rect.y, (int)Math.ceil(rect.width), (int)Math.ceil(rect.height));
}

/**
 * Returns the descent of the receiver.
 *
 * @return the descent
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #getAscent()
 * @see #setAscent(int)
 * @see #setDescent(int)
 * @see #getLineMetrics(int)
 */
public int getDescent () {
    checkLayout();  
    return descent;
}

/** 
 * Returns the default font currently being used by the receiver
 * to draw and measure text.
 *
 * @return the receiver's font
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public Font getFont () {
    checkLayout();
    return font;
}

/**
* Returns the receiver's indent.
*
* @return the receiver's indent
* 
* @exception DWTException <ul>
*    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
* 
* @since 3.2
*/
public int getIndent () {
    checkLayout();  
    return indent;
}

/**
* Returns the receiver's justification.
*
* @return the receiver's justification
* 
* @exception DWTException <ul>
*    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
* 
* @since 3.2
*/
public bool getJustify () {
    checkLayout();
    return justify;
}

/**
 * Returns the embedding level for the specified character offset. The
 * embedding level is usually used to determine the directionality of a
 * character in bidirectional text.
 * 
 * @param offset the character offset
 * @return the embedding level
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the character offset is out of range</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 */
public int getLevel(int offset) {
    checkLayout();
    computeRuns();
    int length = text.length();
    if (!(0 <= offset && offset <= length)) DWT.error(DWT.ERROR_INVALID_RANGE);
    offset = translateOffset(offset);   
    int level = 0;
    //TODO
    return level;
}

/**
 * Returns the line offsets.  Each value in the array is the
 * offset for the first character in a line except for the last
 * value, which contains the length of the text.
 * 
 * @return the line offsets
 *  
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int[] getLineOffsets() {
    checkLayout ();
    computeRuns();
    int[] offsets = new int[lineOffsets.length];
    for (int i = 0; i < offsets.length; i++) {
        offsets[i] = untranslateOffset(lineOffsets[i]);
    }
    return offsets;
}

/**
 * Returns the index of the line that contains the specified
 * character offset.
 * 
 * @param offset the character offset
 * @return the line index
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the character offset is out of range</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int getLineIndex(int offset) {
    checkLayout ();
    computeRuns();
    int length = text.length();
    if (!(0 <= offset && offset <= length)) DWT.error(DWT.ERROR_INVALID_RANGE);
    offset = translateOffset(offset);
    for (int line=0; line<lineOffsets.length - 1; line++) {
        if (lineOffsets[line + 1] > offset) {
            return line;
        }
    }
    return lineBounds.length - 1;
}

/**
 * Returns the bounds of the line for the specified line index.
 * 
 * @param lineIndex the line index
 * @return the line bounds 
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the line index is out of range</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public Rectangle getLineBounds(int lineIndex) {
    checkLayout();
    computeRuns();
    if (!(0 <= lineIndex && lineIndex < lineBounds.length)) DWT.error(DWT.ERROR_INVALID_RANGE);
    NSRect rect = lineBounds[lineIndex];
    return new Rectangle((int)rect.x, (int)rect.y, (int)rect.width, (int)rect.height);
}

/**
 * Returns the receiver's line count. This includes lines caused
 * by wrapping.
 *
 * @return the line count
 * 
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int getLineCount() {
    checkLayout ();
    computeRuns();  
    return lineOffsets.length - 1;
}

/**
 * Returns the font metrics for the specified line index.
 * 
 * @param lineIndex the line index
 * @return the font metrics 
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the line index is out of range</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public FontMetrics getLineMetrics (int lineIndex) {
    checkLayout ();
    computeRuns();
    int lineCount = getLineCount();
    if (!(0 <= lineIndex && lineIndex < lineCount)) DWT.error(DWT.ERROR_INVALID_RANGE);
    int length = text.length();
    if (length is 0) {
        Font font = this.font !is null ? this.font : device.systemFont;
        NSFont nsFont = font.handle;
        int ascent = (int)(0.5f + nsFont.ascender());
        int descent = (int)(0.5f + (-nsFont.descender() + nsFont.leading()));   
        ascent = Math.max(ascent, this.ascent);
        descent = Math.max(descent, this.descent);
        return FontMetrics.cocoa_new(ascent, descent, 0, 0, ascent + descent);
    }
    Rectangle rect = getLineBounds(lineIndex);
    int baseline = (int)layoutManager.typesetter().baselineOffsetInLayoutManager(layoutManager, getLineOffsets()[lineIndex]);
    return FontMetrics.cocoa_new(rect.height - baseline, baseline, 0, 0, rect.height);
}

/**
 * Returns the location for the specified character offset. The
 * <code>trailing</code> argument indicates whether the offset
 * corresponds to the leading or trailing edge of the cluster.
 * 
 * @param offset the character offset
 * @param trailing the trailing flag
 * @return the location of the character offset
 *  
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #getOffset(Point, int[])
 * @see #getOffset(int, int, int[])
 */
public Point getLocation(int offset, bool trailing) {
    checkLayout();
    computeRuns();
    int length = text.length();
    if (!(0 <= offset && offset <= length)) DWT.error(DWT.ERROR_INVALID_RANGE);
    if (length is 0) return new Point(0, 0);
    offset = translateOffset(offset);
    int glyphIndex = layoutManager.glyphIndexForCharacterAtIndex(offset);
    NSRect rect = layoutManager.lineFragmentUsedRectForGlyphAtIndex_effectiveRange_(glyphIndex, 0);
    NSPoint point = layoutManager.locationForGlyphAtIndex(glyphIndex);
    if (trailing) {
        NSRange range = new NSRange();
        range.location = glyphIndex;
        range.length = 1;
        NSRect bounds = layoutManager.boundingRectForGlyphRange(range, textContainer);
        point.x += bounds.width;
    }
    return new Point((int)point.x, (int)rect.y);
}

/**
 * Returns the next offset for the specified offset and movement
 * type.  The movement is one of <code>DWT.MOVEMENT_CHAR</code>, 
 * <code>DWT.MOVEMENT_CLUSTER</code>, <code>DWT.MOVEMENT_WORD</code>,
 * <code>DWT.MOVEMENT_WORD_END</code> or <code>DWT.MOVEMENT_WORD_START</code>.
 * 
 * @param offset the start offset
 * @param movement the movement type 
 * @return the next offset
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the offset is out of range</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #getPreviousOffset(int, int)
 */
public int getNextOffset (int offset, int movement) {
    return _getOffset(offset, movement, true);
}

int _getOffset (int offset, int movement, bool forward) {
    checkLayout();
    computeRuns();
    int length = text.length();
    if (!(0 <= offset && offset <= length)) DWT.error(DWT.ERROR_INVALID_RANGE);
    if (length is 0) return 0;
    offset = translateOffset(offset);
    switch (movement) {
        case DWT.MOVEMENT_CLUSTER://TODO cluster
        case DWT.MOVEMENT_CHAR: {
            if (forward) {
                offset++;
            } else {
                offset--;
            }
            return untranslateOffset(offset);
        }
        case DWT.MOVEMENT_WORD: {
            return untranslateOffset(textStorage.nextWordFromIndex(offset, forward));
        }
        case DWT.MOVEMENT_WORD_END: {
            NSRange range = textStorage.doubleClickAtIndex(length is offset ? length - 1 : offset);
            return untranslateOffset(range.location + range.length);
        }
        case DWT.MOVEMENT_WORD_START: {
            NSRange range = textStorage.doubleClickAtIndex(length is offset ? length - 1 : offset);
            return untranslateOffset(range.location);
        }
        default:
            break;
    }
    return -1;
}

/**
 * Returns the character offset for the specified point.  
 * For a typical character, the trailing argument will be filled in to 
 * indicate whether the point is closer to the leading edge (0) or
 * the trailing edge (1).  When the point is over a cluster composed 
 * of multiple characters, the trailing argument will be filled with the 
 * position of the character in the cluster that is closest to
 * the point.
 * 
 * @param point the point
 * @param trailing the trailing buffer
 * @return the character offset
 *  
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the trailing length is less than <code>1</code></li>
 *    <li>ERROR_NULL_ARGUMENT - if the point is null</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #getLocation(int, bool)
 */
public int getOffset(Point point, int[] trailing) {
    checkLayout();
    computeRuns();
    if (point is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    return getOffset(point.x, point.y, trailing);
}

/**
 * Returns the character offset for the specified point.  
 * For a typical character, the trailing argument will be filled in to 
 * indicate whether the point is closer to the leading edge (0) or
 * the trailing edge (1).  When the point is over a cluster composed 
 * of multiple characters, the trailing argument will be filled with the 
 * position of the character in the cluster that is closest to
 * the point.
 * 
 * @param x the x coordinate of the point
 * @param y the y coordinate of the point
 * @param trailing the trailing buffer
 * @return the character offset
 *  
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the trailing length is less than <code>1</code></li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #getLocation(int, bool)
 */
public int getOffset(int x, int y, int[] trailing) {
    checkLayout();
    computeRuns();
    if (trailing !is null && trailing.length < 1) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    int length = text.length();
    if (length is 0) return 0;
    NSPoint pt = new NSPoint();
    pt.x = x;
    pt.y = y;
    float[] partialFration = new float[1];
    int glyphIndex = layoutManager.glyphIndexForPoint_inTextContainer_fractionOfDistanceThroughGlyph_(pt, textContainer, partialFration);
    int offset = layoutManager.characterIndexForGlyphAtIndex(glyphIndex);
    if (trailing !is null) trailing[0] = Math.round(partialFration[0]);
    return Math.min(untranslateOffset(offset), length - 1);
}

/**
 * Returns the orientation of the receiver.
 *
 * @return the orientation style
 * 
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int getOrientation() {
    checkLayout();
    return orientation;
}

/**
 * Returns the previous offset for the specified offset and movement
 * type.  The movement is one of <code>DWT.MOVEMENT_CHAR</code>, 
 * <code>DWT.MOVEMENT_CLUSTER</code> or <code>DWT.MOVEMENT_WORD</code>,
 * <code>DWT.MOVEMENT_WORD_END</code> or <code>DWT.MOVEMENT_WORD_START</code>.
 * 
 * @param offset the start offset
 * @param movement the movement type 
 * @return the previous offset
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the offset is out of range</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #getNextOffset(int, int)
 */
public int getPreviousOffset (int index, int movement) {
    return _getOffset(index, movement, false);
}

/**
 * Gets the ranges of text that are associated with a <code>TextStyle</code>.
 *
 * @return the ranges, an array of offsets representing the start and end of each
 * text style. 
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #getStyles()
 * 
 * @since 3.2
 */
public int[] getRanges () {
    checkLayout();
    int[] result = new int[styles.length * 2];
    int count = 0;
    for (int i=0; i<styles.length - 1; i++) {
        if (styles[i].style !is null) {
            result[count++] = styles[i].start;
            result[count++] = styles[i + 1].start - 1;
        }
    }
    if (count !is result.length) {
        int[] newResult = new int[count];
        System.arraycopy(result, 0, newResult, 0, count);
        result = newResult;
    }
    return result;
}

/**
 * Returns the text segments offsets of the receiver.
 *
 * @return the text segments offsets
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int[] getSegments() {
    checkLayout();
    return segments;
}

/**
 * Returns the line spacing of the receiver.
 *
 * @return the line spacing
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int getSpacing () {
    checkLayout();  
    return spacing;
}

/**
 * Gets the style of the receiver at the specified character offset.
 *
 * @param offset the text offset
 * @return the style or <code>null</code> if not set
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the character offset is out of range</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public TextStyle getStyle (int offset) {
    checkLayout();
    int length = text.length();
    if (!(0 <= offset && offset < length)) DWT.error(DWT.ERROR_INVALID_RANGE);
    for (int i=1; i<styles.length; i++) {
        StyleItem item = styles[i];
        if (item.start > offset) {
            return styles[i - 1].style;
        }
    }
    return null;
}

/**
 * Gets all styles of the receiver.
 *
 * @return the styles
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #getRanges()
 * 
 * @since 3.2
 */
public TextStyle[] getStyles () {
    checkLayout();
    TextStyle[] result = new TextStyle[styles.length];
    int count = 0;
    for (int i=0; i<styles.length; i++) {
        if (styles[i].style !is null) {
            result[count++] = styles[i].style;
        }
    }
    if (count !is result.length) {
        TextStyle[] newResult = new TextStyle[count];
        System.arraycopy(result, 0, newResult, 0, count);
        result = newResult;
    }
    return result;
}

/**
 * Returns the tab list of the receiver.
 *
 * @return the tab list
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int[] getTabs() {
    checkLayout();
    return tabs;
}

/**
 * Gets the receiver's text, which will be an empty
 * string if it has never been set.
 *
 * @return the receiver's text
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public String getText () {
    checkLayout ();
    return text;
}

/**
 * Returns the width of the receiver.
 *
 * @return the width
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int getWidth () {
    checkLayout();
    return wrapWidth;
}

/**
 * Returns <code>true</code> if the text layout has been disposed,
 * and <code>false</code> otherwise.
 * <p>
 * This method gets the dispose state for the text layout.
 * When a text layout has been disposed, it is an error to
 * invoke any other method using the text layout.
 * </p>
 *
 * @return <code>true</code> when the text layout is disposed and <code>false</code> otherwise
 */
public bool isDisposed () {
    return device is null;
}

/**
 * Sets the text alignment for the receiver. The alignment controls
 * how a line of text is positioned horizontally. The argument should
 * be one of <code>DWT.LEFT</code>, <code>DWT.RIGHT</code> or <code>DWT.CENTER</code>.
 * <p>
 * The default alignment is <code>DWT.LEFT</code>.  Note that the receiver's
 * width must be set in order to use <code>DWT.RIGHT</code> or <code>DWT.CENTER</code>
 * alignment.
 * </p>
 *
 * @param alignment the new alignment 
 *
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #setWidth(int)
 */
public void setAlignment (int alignment) {
    checkLayout();
    int mask = DWT.LEFT | DWT.CENTER | DWT.RIGHT;
    alignment &= mask;
    if (alignment is 0) return;
    if ((alignment & DWT.LEFT) !is 0) alignment = DWT.LEFT;
    if ((alignment & DWT.RIGHT) !is 0) alignment = DWT.RIGHT;
    if (this.alignment is alignment) return;
    freeRuns();
    this.alignment = alignment;
}

/**
 * Sets the ascent of the receiver. The ascent is distance in pixels
 * from the baseline to the top of the line and it is applied to all
 * lines. The default value is <code>-1</code> which means that the
 * ascent is calculated from the line fonts.
 *
 * @param ascent the new ascent
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the ascent is less than <code>-1</code></li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #setDescent(int)
 * @see #getLineMetrics(int)
 */
public void setAscent (int ascent) {
    checkLayout ();
    if (ascent < -1) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    if (this.ascent is ascent) return;
    freeRuns();
    this.ascent = ascent;
}

/**
 * Sets the descent of the receiver. The descent is distance in pixels
 * from the baseline to the bottom of the line and it is applied to all
 * lines. The default value is <code>-1</code> which means that the
 * descent is calculated from the line fonts.
 *
 * @param descent the new descent
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the descent is less than <code>-1</code></li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #setAscent(int)
 * @see #getLineMetrics(int)
 */
public void setDescent (int descent) {
    checkLayout ();
    if (descent < -1) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    if (this.descent is descent) return;
    freeRuns();
    this.descent = descent;
}

/** 
 * Sets the default font which will be used by the receiver
 * to draw and measure text. If the
 * argument is null, then a default font appropriate
 * for the platform will be used instead. Note that a text
 * style can override the default font.
 *
 * @param font the new font for the receiver, or null to indicate a default font
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the font has been disposed</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public void setFont (Font font) {
    checkLayout ();
    if (font !is null && font.isDisposed()) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    Font oldFont = this.font;
    if (oldFont is font) return;
    this.font = font;
    if (oldFont !is null && oldFont.equals(font)) return;
    freeRuns();
}

/**
 * Sets the indent of the receiver. This indent it applied of the first line of 
 * each paragraph.  
 *
 * @param indent new indent
 * 
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @since 3.2
 */
public void setIndent (int indent) {
    checkLayout ();
    if (indent < 0) return;
    if (this.indent is indent) return;
    freeRuns();
    this.indent = indent;
}

/**
 * Sets the justification of the receiver. Note that the receiver's
 * width must be set in order to use justification. 
 *
 * @param justify new justify
 * 
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @since 3.2
 */
public void setJustify (bool justify) {
    checkLayout ();
    if (justify is this.justify) return;
    freeRuns();
    this.justify = justify;
}

/**
 * Sets the orientation of the receiver, which must be one
 * of <code>DWT.LEFT_TO_RIGHT</code> or <code>DWT.RIGHT_TO_LEFT</code>.
 *
 * @param orientation new orientation style
 * 
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public void setOrientation(int orientation) {
    checkLayout();
    int mask = DWT.LEFT_TO_RIGHT | DWT.RIGHT_TO_LEFT;
    orientation &= mask;
    if (orientation is 0) return;
    if ((orientation & DWT.LEFT_TO_RIGHT) !is 0) orientation = DWT.LEFT_TO_RIGHT;
    if (this.orientation is orientation) return;
    this.orientation = orientation;
    freeRuns();
}

/**
 * Sets the offsets of the receiver's text segments. Text segments are used to
 * override the default behaviour of the bidirectional algorithm.
 * Bidirectional reordering can happen within a text segment but not 
 * between two adjacent segments.
 * <p>
 * Each text segment is determined by two consecutive offsets in the 
 * <code>segments</code> arrays. The first element of the array should 
 * always be zero and the last one should always be equals to length of
 * the text.
 * </p>
 * 
 * @param segments the text segments offset
 * 
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public void setSegments(int[] segments) {
    checkLayout();
    if (this.segments is null && segments is null) return;
    if (this.segments !is null && segments !isnull) {
        if (this.segments.length is segments.length) {
            int i;
            for (i = 0; i <segments.length; i++) {
                if (this.segments[i] !is segments[i]) break;
            }
            if (i is segments.length) return;
        }
    }
    freeRuns();
    this.segments = segments;
}

/**
 * Sets the line spacing of the receiver.  The line spacing
 * is the space left between lines.
 *
 * @param spacing the new line spacing 
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the spacing is negative</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public void setSpacing (int spacing) {
    checkLayout();
    if (spacing < 0) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    if (this.spacing is spacing) return;
    freeRuns();
    this.spacing = spacing;
}

/**
 * Sets the style of the receiver for the specified range.  Styles previously
 * set for that range will be overwritten.  The start and end offsets are
 * inclusive and will be clamped if out of range.
 * 
 * @param style the style
 * @param start the start offset
 * @param end the end offset
 * 
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public void setStyle (TextStyle style, int start, int end) {
    checkLayout();
    int length = text.length();
    if (length is 0) return;
    if (start > end) return;
    start = Math.min(Math.max(0, start), length - 1);
    end = Math.min(Math.max(0, end), length - 1);
    int low = -1;
    int high = styles.length;
    while (high - low > 1) {
        int index = (high + low) / 2;
        if (styles[index + 1].start > start) {
            high = index;
        } else {
            low = index;
        }
    }
    if (0 <= high && high < styles.length) {
        StyleItem item = styles[high];
        if (item.start is start && styles[high + 1].start - 1 is end) {
            if (style is null) {
                if (item.style is null) return;
            } else {
                if (style.equals(item.style)) return;
            }
        }
    }
    freeRuns();
    int modifyStart = high;
    int modifyEnd = modifyStart;
    while (modifyEnd < styles.length) {
        if (styles[modifyEnd + 1].start > end) break;
        modifyEnd++;
    }
    if (modifyStart is modifyEnd) {
        int styleStart = styles[modifyStart].start; 
        int styleEnd = styles[modifyEnd + 1].start - 1;
        if (styleStart is start && styleEnd is end) {
            styles[modifyStart].style = style;
            return;
        }
        if (styleStart !is start && styleEnd !is end) {
            StyleItem[] newStyles = new StyleItem[styles.length + 2];
            System.arraycopy(styles, 0, newStyles, 0, modifyStart + 1);
            StyleItem item = new StyleItem();
            item.start = start;
            item.style = style;
            newStyles[modifyStart + 1] = item;  
            item = new StyleItem();
            item.start = end + 1;
            item.style = styles[modifyStart].style;
            newStyles[modifyStart + 2] = item;
            System.arraycopy(styles, modifyEnd + 1, newStyles, modifyEnd + 3, styles.length - modifyEnd - 1);
            styles = newStyles;
            return;
        }
    }
    if (start is styles[modifyStart].start) modifyStart--;
    if (end is styles[modifyEnd + 1].start - 1) modifyEnd++;
    int newLength = styles.length + 1 - (modifyEnd - modifyStart - 1);
    StyleItem[] newStyles = new StyleItem[newLength];
    System.arraycopy(styles, 0, newStyles, 0, modifyStart + 1); 
    StyleItem item = new StyleItem();
    item.start = start;
    item.style = style;
    newStyles[modifyStart + 1] = item;
    styles[modifyEnd].start = end + 1;
    System.arraycopy(styles, modifyEnd, newStyles, modifyStart + 2, styles.length - modifyEnd);
    styles = newStyles;
}

/**
 * Sets the receiver's tab list. Each value in the tab list specifies
 * the space in pixels from the origin of the text layout to the respective
 * tab stop.  The last tab stop width is repeated continuously.
 * 
 * @param tabs the new tab list
 * 
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public void setTabs(int[] tabs) {
    checkLayout();
    if (this.tabs is null && tabs is null) return;
    if (this.tabs !is null && tabs !isnull) {
        if (this.tabs.length is tabs.length) {
            int i;
            for (i = 0; i < tabs.length; i++) {
                if (this.tabs[i] !is tabs[i]) break;
            }
            if (i is tabs.length) return;
        }
    }
    freeRuns();
    this.tabs = tabs;
}

/**
 * Sets the receiver's text.
 *
 * @param text the new text
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the text is null</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public void setText (String text) {
    checkLayout ();
    if (text is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    if (text.equals(this.text)) return;
    freeRuns();
    this.text = text;
    styles = new StyleItem[2];
    styles[0] = new StyleItem();
    styles[1] = new StyleItem();
    styles[styles.length - 1].start = text.length();
}

/**
 * Sets the line width of the receiver, which determines how
 * text should be wrapped and aligned. The default value is
 * <code>-1</code> which means wrapping is disabled.
 *
 * @param width the new width 
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the width is <code>0</code> or less than <code>-1</code></li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #setAlignment(int)
 */
public void setWidth (int width) {
    checkLayout();
    if (width < -1 || width is 0) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    if (this.wrapWidth is width) return;
    freeRuns();
    this.wrapWidth = width;
}

/**
 * Returns a string containing a concise, human-readable
 * description of the receiver.
 *
 * @return a string representation of the receiver
 */
public String toString () {
    if (isDisposed()) return "TextLayout {*DISPOSED*}";
    return "TextLayout {" + text + "}";
}

/*
 *  Translate a client offset to an internal offset
 */
int translateOffset (int offset) {
    return offset;
}

/*
 *  Translate an internal offset to a client offset
 */
int untranslateOffset (int offset) {
    return offset;
}

}