/*******************************************************************************
 * Copyright (c) 2008 Mateusz Matela 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:
 *     Mateusz Matela <mateusz.matela@gmail.com> -  Make StyledText work with ContentAssistCommandAdapter - https://bugs.eclipse.org/bugs/show_bug.cgi?id=246388
 *******************************************************************************/
package org.simantics.scl.ui.assist;

import org.eclipse.jface.fieldassist.ContentProposalAdapter;
import org.eclipse.jface.fieldassist.IControlContentAdapter;
import org.eclipse.jface.fieldassist.IControlContentAdapter2;
import org.eclipse.swt.custom.StyledText;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Control;

/**
 * An {@link IControlContentAdapter} for {@link org.eclipse.swt.custom.StyledText}. This is
 * a convenience class for easily creating a {@link ContentProposalAdapter} for text fields.
 * 
 * @since 3.5
 */
public class StyledTextContentAdapter implements IControlContentAdapter, IControlContentAdapter2 {
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jface.fieldassist.IControlContentAdapter#getControlContents(org.eclipse
	 * .swt.widgets.Control)
	 */
	public String getControlContents(Control control) {
		return ((StyledText)control).getText();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jface.fieldassist.IControlContentAdapter#getCursorPosition(org.eclipse
	 * .swt.widgets.Control)
	 */
	public int getCursorPosition(Control control) {
		return ((StyledText)control).getCaretOffset();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jface.fieldassist.IControlContentAdapter#getInsertionBounds(org.eclipse
	 * .swt.widgets.Control)
	 */
	public Rectangle getInsertionBounds(Control control) {
		StyledText text= (StyledText)control;
		Point caretOrigin= text.getLocationAtOffset(text.getCaretOffset());
		return new Rectangle(caretOrigin.x + text.getClientArea().x, caretOrigin.y + text.getClientArea().y + 3, 1, text.getLineHeight());
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jface.fieldassist.IControlContentAdapter#insertControlContents(org.eclipse
	 * .swt.widgets.Control, java.lang.String, int)
	 */
	public void insertControlContents(Control control, String contents, int cursorPosition) {
		StyledText text = ((StyledText)control);
		cursorPosition = Math.min(cursorPosition, contents.length());

		int caretOffset = text.getCaretOffset();
		String currentText = text.getText();
		int replacementOffset = findPrefixMatchOffset(currentText, caretOffset, contents);

//		System.out.println("text: " + currentText);
//		System.out.println("proposal to fill: " + contents);
//		System.out.format("longest match of proposed contents found from text @ offset %d: \"%s[%s]%s\"%n",
//				replacementOffset,
//				currentText.substring(0, replacementOffset),
//				currentText.substring(replacementOffset, caretOffset),
//				currentText.substring(caretOffset));

		// The text between [replaceOffset, caretOffset) will be replaced with `contents`
		text.setSelection(replacementOffset, caretOffset);
		text.insert(contents);
		text.setSelection(replacementOffset + contents.length());
	}

	/**
	 * Find offset of longest prefix match of <code>match</code> in
	 * <code>text</code> ending at offset <code>endOffset</code>.
	 * 
	 * Example:
	 * <pre>
	 * ...  res (=text)
	 * resource (=match)
	 *  resourc
	 *   resour
	 *    resou
	 *     reso
	 *      res match! return endOffset - 3
	 * </pre>
	 * 
	 * @param text the text from which to find the match
	 * @param endOffset endOffset until which to search for the longest match
	 * @param match the text to prefix-match
	 * @return
	 */
	private static int findPrefixMatchOffset(String text, int endOffset, String match) {
		for (int i = match.length(); i >= 0; --i) {
			if (text.regionMatches(true, endOffset - i, match, 0, i))
				return endOffset - i;
		}
		return 0;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jface.fieldassist.IControlContentAdapter#setControlContents(org.eclipse
	 * .swt.widgets.Control, java.lang.String, int)
	 */
	public void setControlContents(Control control, String contents, int cursorPosition) {
		((StyledText)control).setText(contents);
		((StyledText)control).setCaretOffset(cursorPosition);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jface.fieldassist.IControlContentAdapter#setCursorPosition(org.eclipse
	 * .swt.widgets.Control, int)
	 */
	public void setCursorPosition(Control control, int index) {
		((StyledText)control).setCaretOffset(index);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jface.fieldassist.IControlContentAdapter2#getSelection(org.eclipse.swt
	 * .widgets.Control)
	 */
	public Point getSelection(Control control) {
		return ((StyledText)control).getSelection();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jface.fieldassist.IControlContentAdapter2#setSelection(org.eclipse.swt
	 * .widgets.Control, org.eclipse.swt.graphics.Point)
	 */
	public void setSelection(Control control, Point range) {
		((StyledText)control).setSelection(range);
	}

}