/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * 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:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.scenegraph.utils;

import java.awt.FontMetrics;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;

public final class TextUtil {

    /**
     * @param text
     * @param g
     * @param bounds
     * @return
     */
    public static String[] wordWrap(String text, FontMetrics metrics, int maxLineWidth) {
        Collection<String> result = new ArrayList<String>();
        int[] whitespacePos = new int[8];
        int whitespaceTop = 0;

        int pos = 0;
        int length = text.length();

        int cumulatedLineWidth = 0;

        int dotWidth = metrics.charWidth('.');
        int dot3Width = 3*dotWidth;
        boolean nonWhitespaceFound = false;

        out:
            while (pos < length) {
                char c = text.charAt(pos);
                int cWidth = metrics.charWidth(c);
                if (Character.isWhitespace(c)) {
                    if (nonWhitespaceFound) {
                        if (whitespacePos.length <= whitespaceTop)
                            whitespacePos = Arrays.copyOf(whitespacePos, whitespacePos.length*2);
                        whitespacePos[whitespaceTop++] = pos;
                    }
                } else {
                    nonWhitespaceFound = true;
                }

//            System.out.println("cumulated: " + cumulatedLineWidth);
//            System.out.println("    width: " + cWidth);
//            System.out.println("    max:   " + maxLineWidth);
                if (cumulatedLineWidth + cWidth > maxLineWidth) {
//                System.out.println("overran line: " + (result.size() + 1) + ": '" + text.substring(0, pos) + "'");

                    // Look for last whitespace position to cut at
                    int nextLineStartPos = -1;
                    if (whitespaceTop > 0) {
                        int cutPos = whitespacePos[--whitespaceTop];
                        result.add(text.substring(0, cutPos));
                        nextLineStartPos = cutPos + 1;
                    } else {
                        // No whitespace available, just cut the string and insert "..." at the end.
                        int rollbackWidth = cumulatedLineWidth + dot3Width;
                        int rollbackPos = pos;
                        while (rollbackPos > 0 && rollbackWidth > maxLineWidth) {
                            rollbackWidth -= metrics.charWidth(text.charAt(--rollbackPos));
                        }
                        // Cannot word wrap a single character anything into the specified max width.
                        if (rollbackPos == 0) {
                            result.add(text);
                            break out;
                        }

                        result.add(text.substring(0, rollbackPos) + "...");

                        // Search for next whitespace in the text after pos and start the next line from there.
                        int nextWhitespacePos = pos;
                        for (;nextWhitespacePos < length && !Character.isWhitespace(text.charAt(nextWhitespacePos)); ++nextWhitespacePos);
                        nextLineStartPos = nextWhitespacePos < length ? nextWhitespacePos + 1 : nextWhitespacePos;
                    }
                    text = text.substring(nextLineStartPos);
                    length = text.length();
                    pos = 0;
                    cumulatedLineWidth = 0;
                    nonWhitespaceFound = false;
                    whitespaceTop = 0;
                    continue;
                }

                cumulatedLineWidth += cWidth;
                ++pos;
            }

        if (text.length() > 0)
            result.add(text);

        return result.toArray(new String[result.size()]);
    }

}