TexCorrectIndentationAction.java

/*
 * $Id$
 *
 * Copyright (c) 2004-2005 by the TeXlapse Team.
 * 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
 */
package net.sourceforge.texlipse.actions;

import java.util.Arrays;

import net.sourceforge.texlipse.TexlipsePlugin;
import net.sourceforge.texlipse.editor.TexAutoIndentStrategy;
import net.sourceforge.texlipse.editor.TexEditorTools;
import net.sourceforge.texlipse.properties.TexlipseProperties;

import org.eclipse.jface.action.IAction;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.ITextSelection;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.ui.IEditorActionDelegate;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.texteditor.ITextEditor;


/**
 * @author Laura Takkinen
 * @author Boris von Loesch
 *
 * Handles indentation quick fix when user selects text area 
 * and performs "Correct Indentation" action. (Correct Indentation button or Ctrl+I)
 */
public class TexCorrectIndentationAction implements IEditorActionDelegate {
	private IEditorPart targetEditor;
	private TexSelections selection;
	private TexEditorTools tools;
	private String indentationString = "";
	private String[] indentationItems;
	private int tabWidth;
	
	/* (non-Javadoc)
	 * @see org.eclipse.ui.IEditorActionDelegate#setActiveEditor(org.eclipse.jface.action.IAction, org.eclipse.ui.IEditorPart)
	 */
	public void setActiveEditor(IAction action, IEditorPart targetEditor) {
		this.targetEditor = targetEditor;
	}
	
	/**
	 * Returns the TexEditor.
	 */
	private ITextEditor getTexEditor() {
		if (targetEditor instanceof ITextEditor) {
			return (ITextEditor) targetEditor;
		} else {
			throw new RuntimeException("Expecting text editor. Found:"+targetEditor.getClass().getName());
		}
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.ui.IActionDelegate#run(org.eclipse.jface.action.IAction)
	 */
	public void run(IAction action) {
		setIndetationPreferenceInfo();
		
		//no environments to indent
		if (this.indentationItems.length == 0) {
			return;
		} else {
			//check if environments have change
			selection = new TexSelections(getTexEditor());
			if (selection != null) {
				this.tools = new TexEditorTools();
				try {
					indent();
				} catch(BadLocationException e) {
					TexlipsePlugin.log("TexCorrectIndentationAction.run", e);
				}
			}
		}
	}
	
	/**
	 * Initializes indentation information from preferences
	 */
	private void setIndetationPreferenceInfo() {
        indentationItems = TexlipsePlugin.getPreferenceArray(TexlipseProperties.INDENTATION_ENVS);
        Arrays.sort(indentationItems);
		
		//this.tabWidth = editorPreferenceStore.getInt(AbstractDecoratedTextEditorPreferenceConstants.EDITOR_TAB_WIDTH);
		
		indentationString = TexAutoIndentStrategy.getIndentationString();
	}
	
	/**
	 * Checks if selection needs indentation and corrects it when necessary.
	 * @throws BadLocationException
	 */
	private void indent() throws BadLocationException {	
		//FIXME: Refactor
		int index = 0;
		boolean fix = false;
		IDocument document = selection.getDocument();
		selection.selectCompleteLines();
		String delimiter = document.getLineDelimiter(selection.getStartLineIndex());
		String[] lines;
		
		try {
			lines = document.get(document.getLineOffset(selection.getStartLineIndex()), selection.getSelLength()).split(delimiter);
		} catch(BadLocationException e) {//for example new empty file
			return;
		}	
		//fix lines on at the time
		String selectedLine = "";
		String originalIndentation = "";
		String correctIndentation = "";
		for (int line = selection.getStartLineIndex(); index < lines.length; line++) {	
			selectedLine = document.get(document.getLineOffset(line), document.getLineLength(line));
			originalIndentation = this.tools.getIndentation(selectedLine, this.tabWidth);
			correctIndentation = "";
			
			//first line of end of document
			if (line == 0 || line == document.getLength()-1) {
				
			} else if (line >= document.getLength()){
				return;
			} else if (selectedLine.indexOf("\\end") != -1) { //selected line is \end{...} -line
				String endText = this.tools.getEndLine(selectedLine.trim(), "\\end");
				
				if (Arrays.binarySearch(this.indentationItems, this.tools.getEnvironment(endText)) >= 0) {
					int matchingBegin = this.tools.findMatchingBeginEquation(document, line, this.tools.getEnvironment(endText));
					
					if (matchingBegin < selection.getStartLineIndex()) {
						correctIndentation = this.tools.getIndentation(document, matchingBegin, "\\begin", this.tabWidth);
					} else {
						correctIndentation = this.tools.getIndentation(lines[matchingBegin-selection.getStartLineIndex()], this.tabWidth);
					}				
				}
			} else { //otherwise indentation is determined by the previous line
				String lineText = "";
				
				//previous line is outside the selection
				if (index == 0) {
					lineText = document.get(document.getLineOffset(line-1), document.getLineLength(line-1));
				} else { //previous line is inside the selection
					lineText = lines[index-1];
				}
				
				//previous line is \begin{...} -line
				if (lineText.indexOf("\\begin") != -1) {
					String endText = this.tools.getEndLine(lineText.trim(), "\\begin");
					if (Arrays.binarySearch(this.indentationItems, this.tools.getEnvironment(endText)) >= 0) {
						correctIndentation = this.tools.getIndentation(lineText, this.tabWidth) + this.indentationString;
					}
				} else { //previous line is something else
					correctIndentation = this.tools.getIndentation(lineText, this.tabWidth);
				}
			}
			if (!correctIndentation.equals(originalIndentation)) {
				fix = true;
			}
			lines[index] = correctIndentation.concat(lines[index].trim());
			index++;
		}
		String newText = lines[0];
		for (int i = 1; i < lines.length; i++) {
			newText += delimiter;
			newText += lines[i];			
		}		
		if (fix) {
			document.replace(document.getLineOffset(selection.getStartLineIndex()), selection.getSelLength(), newText);
		}
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.ui.IActionDelegate#selectionChanged(org.eclipse.jface.action.IAction, org.eclipse.jface.viewers.ISelection)
	 */
	public void selectionChanged(IAction action, ISelection selection) {
		if (selection instanceof ITextSelection) {
			action.setEnabled(true);
			return;
		}
		action.setEnabled( targetEditor instanceof ITextEditor);
	}
}