/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package net.sourceforge.phpdt.internal.ui.text.java;

import net.sourceforge.phpdt.ui.PreferenceConstants;
import net.sourceforge.phpeclipse.PHPeclipsePlugin;

import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.DefaultIndentLineAutoEditStrategy;
import org.eclipse.jface.text.DocumentCommand;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITypedRegion;
import org.eclipse.jface.text.TextUtilities;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.IWorkbenchPage;
import org.eclipse.ui.texteditor.ITextEditorExtension3;

/**
 * Auto indent strategy for single quoted PHP strings
 */
public class JavaStringAutoIndentStrategySQ extends
		DefaultIndentLineAutoEditStrategy {

	private String fPartitioning;

	/**
	 * The input string doesn't contain any line delimiter.
	 * 
	 * @param inputString
	 *            the given input string
	 * @return the displayable string.
	 */
	private String displayString (String inputString, String indentation, String delimiter) {
		int length = inputString.length();
		StringBuffer buffer = new StringBuffer(length);
		java.util.StringTokenizer tokenizer = 
				new java.util.StringTokenizer (inputString, "\n\r", true); //$NON-NLS-1$
		
		while (tokenizer.hasMoreTokens ()) {
			String token = tokenizer.nextToken ();

			if (token.equals("\r")) { //$NON-NLS-1$
				buffer.append("\\r"); //$NON-NLS-1$
				if (tokenizer.hasMoreTokens()) {
					token = tokenizer.nextToken();
					if (token.equals("\n")) { //$NON-NLS-1$
						buffer.append("\\n"); //$NON-NLS-1$
						buffer.append("\" . " + delimiter); //$NON-NLS-1$
						buffer.append(indentation);
						buffer.append("\'"); //$NON-NLS-1$
						continue;
					} else {
						buffer.append("\' . " + delimiter); //$NON-NLS-1$
						buffer.append(indentation);
						buffer.append("\'"); //$NON-NLS-1$
					}
				} else {
					continue;
				}
			} else if (token.equals("\n")) { //$NON-NLS-1$
				buffer.append("\\n"); //$NON-NLS-1$
				buffer.append("\' . " + delimiter); //$NON-NLS-1$
				buffer.append(indentation);
				buffer.append("\'"); //$NON-NLS-1$
				continue;
			}

			StringBuffer tokenBuffer = new StringBuffer();

			for (int i = 0; i < token.length(); i++) {
				char c = token.charAt(i);
				switch (c) {
				case '\r':
					tokenBuffer.append("\\r"); //$NON-NLS-1$
					break;
				case '\n':
					tokenBuffer.append("\\n"); //$NON-NLS-1$
					break;
				case '\b':
					tokenBuffer.append("\\b"); //$NON-NLS-1$
					break;
				case '\t':
					// keep tabs verbatim
					tokenBuffer.append("\t"); //$NON-NLS-1$
					break;
				case '\f':
					tokenBuffer.append("\\f"); //$NON-NLS-1$
					break;
				case '\"':
					tokenBuffer.append("\\\""); //$NON-NLS-1$
					break;
				case '\'':
					tokenBuffer.append("\\'"); //$NON-NLS-1$
					break;
				case '\\':
					tokenBuffer.append("\\\\"); //$NON-NLS-1$
					break;
				default:
					tokenBuffer.append(c);
				}
			}
			buffer.append(tokenBuffer);
		}

		return buffer.toString();
	}

	/**
	 * Creates a new Java string auto indent strategy for the given document
	 * partitioning.
	 * 
	 * @param partitioning
	 *            the document partitioning
	 */
	public JavaStringAutoIndentStrategySQ (String partitioning) {
		super();
		fPartitioning = partitioning;
	}

	/**
	 * Check whether the 'text' is one of the allowed line delimiters (e.g. \n \r)
	 * 
	 * @param document The document object for which we do the check
	 * @param text     The text with the possible delimiter
	 * @return
	 *  - true if 'text' is a valid delimiter
	 *  - false if 'text' is not a valid delimiter 
	 */
	private boolean isLineDelimiter(IDocument document, String text) {
		String[] delimiters = document.getLegalLineDelimiters();
		
		if (delimiters != null) {
			return TextUtilities.equals(delimiters, text) > -1;
		}
		
		return false;
	}

	/**
	 * Get back the indentation of the line to which the offset belongs.
	 * 
	 * It searches the first occurrence of a white space (non space/non tab)
	 * 
	 * @param document
	 * @param offset
	 * @return
	 * @throws BadLocationException
	 */
	private String getLineIndentation(IDocument document, int offset)
			throws BadLocationException {
		String indentation = "";
		int    start;
		int    end;
		int    length = 0;

		// find start of line
		int adjustedOffset = (offset == document.getLength() ? offset - 1 : offset);// Check whether the offset is not at the end of file
		IRegion line = document.getLineInformationOfOffset (adjustedOffset); 		// Get the start and the length of the line

		start = line.getOffset ();									// Get the start of the line
		end = findStringStart (document, start, offset);
		
		IPreferenceStore preferenceStore = PHPeclipsePlugin.getDefault().getPreferenceStore();
		
		int tabWidth = preferenceStore.getInt (PreferenceConstants.EDITOR_TAB_WIDTH);
		
		for (int pos = start; pos < end; pos++) {
			if (document.getChar (pos) == '\t') {		// If the character is a tab
				length += tabWidth;						// take the tab width for calculating the indentation length
			}
			else {										// If it's just a space
				length++;								// add one character to the indentation length
			}
		}
		
		if (preferenceStore.getBoolean (PreferenceConstants.EDITOR_SPACES_FOR_TABS)) {	// Indentation with spaces only
			if (length > 0) {
				indentation = String.format ("%" + length + "s", "");
			}
		}
		else {																			// Indentation with tabs
			if (length > 0) {
				int spaces;
				int tabs;

				tabs   = length / tabWidth;
				spaces = length % tabWidth;
				
				indentation  = new String (new char[tabs]).replace('\0', '\t');
				
				if (spaces > 0) {
					indentation += String.format ("%" + spaces + "s", "");
				}
			}
		}		

		return indentation;
	}
	
	/**
	 * Return the position of the string start (first occurrence of a quote or double quote) 
	 * 
	 * @param offset 
	 * @param start 
	 * @param document 
	 * @return
	 */
	private int findStringStart(IDocument document, int offset, int end) throws BadLocationException {
		while (offset < end) {
			char c = document.getChar (offset);
			
			if ((c == '\'') || (c == '\"')) {
				return offset;
			}
			
			offset++;
		}

		return end;
	}

	/**
	 * 
	 * @param string
	 * @param indentation
	 * @param delimiter
	 * @return
	 * @throws BadLocationException
	 */
	private String getModifiedText (String string, String indentation, String delimiter) 
			throws BadLocationException {
		return displayString(string, indentation, delimiter);
	}

	/**
	 * 
	 * @param document
	 * @param command
	 * @throws BadLocationException
	 */
	private void javaStringIndentAfterNewLine (IDocument document, DocumentCommand command) throws BadLocationException {
		ITypedRegion partition = TextUtilities.getPartition (document, fPartitioning, command.offset, false);
		int offset = partition.getOffset();
		int length = partition.getLength();

		if (command.offset == offset) {
			// we are really just before the string partition -> feet the event
			// through the java indenter
			// new
			// JavaAutoIndentStrategy(fPartitioning).customizeDocumentCommand(document,
			// command);
			return;
		}

		if ((command.offset == offset + length) && 
			(document.getChar (offset + length - 1) == '\'')) {
			return;
		}

		String indentation = getLineIndentation(document, command.offset);
		String delimiter = TextUtilities.getDefaultLineDelimiter(document);

		IRegion line = document.getLineInformationOfOffset(offset);
		String string = document.get (line.getOffset(), 
				                      offset - line.getOffset());		// Get the current line as string
/*		
		if (string.trim().length() != 0) {
			indentation += String.valueOf("\t\t"); //$NON-NLS-1$
		}
*/
		IPreferenceStore preferenceStore = PHPeclipsePlugin.getDefault ().getPreferenceStore();

		if (isLineDelimiter (document, command.text)) {
			command.text = "\' ." + command.text + indentation + "\'"; //$NON-NLS-1$//$NON-NLS-2$
		}
		else if ((command.text.length() > 1) && 
				 preferenceStore.getBoolean (PreferenceConstants.EDITOR_ESCAPE_STRINGS_SQ)) {
			command.text = getModifiedText(command.text, indentation, delimiter);
    	}
	}

	/**
	 * 
	 * @return
	 */
	private boolean isSmartMode() {
		IWorkbenchPage page = PHPeclipsePlugin.getActivePage();

		if (page != null) {
			IEditorPart part = page.getActiveEditor();

			if (part instanceof ITextEditorExtension3) {
				ITextEditorExtension3 extension = (ITextEditorExtension3) part;
				return extension.getInsertMode() == ITextEditorExtension3.SMART_INSERT;
			}
		}

		return false;
	}

	/*
	 * @see org.eclipse.jface.text.IAutoIndentStrategy#customizeDocumentCommand(IDocument,
	 *      DocumentCommand)
	 */
	public void customizeDocumentCommand(IDocument document, DocumentCommand command) {
		try {
			if ((command.length != 0) || 
                (command.text == null)) {
				return;
            }

			IPreferenceStore preferenceStore = PHPeclipsePlugin.getDefault().getPreferenceStore();

			if (preferenceStore.getBoolean (PreferenceConstants.EDITOR_WRAP_STRINGS_SQ) && isSmartMode()) {
				javaStringIndentAfterNewLine(document, command);
            }

		} catch (BadLocationException e) {
		}
	}
}