/*******************************************************************************
 * Copyright (c) 2000, 2004 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.template.contentassist;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.eclipse.jface.text.Assert;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.DocumentEvent;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.contentassist.ICompletionProposal;
import org.eclipse.jface.text.contentassist.ICompletionProposalExtension2;
import org.eclipse.jface.text.contentassist.IContextInformation;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;

/**
 * Global state for templates. Selecting a proposal for the master template
 * variable will cause the value (and the proposals) for the slave variables to
 * change.
 * 
 * @see MultiVariable
 */
public class MultiVariableGuess {

	/**
	 * Implementation of the <code>ICompletionProposal</code> interface and
	 * extension.
	 */
	class Proposal implements ICompletionProposal,
			ICompletionProposalExtension2 {

		/** The string to be displayed in the completion proposal popup */
		private String fDisplayString;

		/** The replacement string */
		String fReplacementString;

		/** The replacement offset */
		private int fReplacementOffset;

		/** The replacement length */
		private int fReplacementLength;

		/** The cursor position after this proposal has been applied */
		private int fCursorPosition;

		/** The image to be displayed in the completion proposal popup */
		private Image fImage;

		/** The context information of this proposal */
		private IContextInformation fContextInformation;

		/** The additional info of this proposal */
		private String fAdditionalProposalInfo;

		/**
		 * Creates a new completion proposal based on the provided information.
		 * The replacement string is considered being the display string too.
		 * All remaining fields are set to <code>null</code>.
		 * 
		 * @param replacementString
		 *            the actual string to be inserted into the document
		 * @param replacementOffset
		 *            the offset of the text to be replaced
		 * @param replacementLength
		 *            the length of the text to be replaced
		 * @param cursorPosition
		 *            the position of the cursor following the insert relative
		 *            to replacementOffset
		 */
		public Proposal(String replacementString, int replacementOffset,
				int replacementLength, int cursorPosition) {
			this(replacementString, replacementOffset, replacementLength,
					cursorPosition, null, null, null, null);
		}

		/**
		 * Creates a new completion proposal. All fields are initialized based
		 * on the provided information.
		 * 
		 * @param replacementString
		 *            the actual string to be inserted into the document
		 * @param replacementOffset
		 *            the offset of the text to be replaced
		 * @param replacementLength
		 *            the length of the text to be replaced
		 * @param cursorPosition
		 *            the position of the cursor following the insert relative
		 *            to replacementOffset
		 * @param image
		 *            the image to display for this proposal
		 * @param displayString
		 *            the string to be displayed for the proposal
		 * @param contextInformation
		 *            the context information associated with this proposal
		 * @param additionalProposalInfo
		 *            the additional information associated with this proposal
		 */
		public Proposal(String replacementString, int replacementOffset,
				int replacementLength, int cursorPosition, Image image,
				String displayString, IContextInformation contextInformation,
				String additionalProposalInfo) {
			Assert.isNotNull(replacementString);
			Assert.isTrue(replacementOffset >= 0);
			Assert.isTrue(replacementLength >= 0);
			Assert.isTrue(cursorPosition >= 0);

			fReplacementString = replacementString;
			fReplacementOffset = replacementOffset;
			fReplacementLength = replacementLength;
			fCursorPosition = cursorPosition;
			fImage = image;
			fDisplayString = displayString;
			fContextInformation = contextInformation;
			fAdditionalProposalInfo = additionalProposalInfo;
		}

		/*
		 * @see ICompletionProposal#apply(IDocument)
		 */
		public void apply(IDocument document) {
			try {
				document.replace(fReplacementOffset, fReplacementLength,
						fReplacementString);
			} catch (BadLocationException x) {
				// ignore
			}
		}

		/*
		 * @see ICompletionProposal#getSelection(IDocument)
		 */
		public Point getSelection(IDocument document) {
			return new Point(fReplacementOffset + fCursorPosition, 0);
		}

		/*
		 * @see ICompletionProposal#getContextInformation()
		 */
		public IContextInformation getContextInformation() {
			return fContextInformation;
		}

		/*
		 * @see ICompletionProposal#getImage()
		 */
		public Image getImage() {
			return fImage;
		}

		/*
		 * @see ICompletionProposal#getDisplayString()
		 */
		public String getDisplayString() {
			if (fDisplayString != null)
				return fDisplayString;
			return fReplacementString;
		}

		/*
		 * @see ICompletionProposal#getAdditionalProposalInfo()
		 */
		public String getAdditionalProposalInfo() {
			return fAdditionalProposalInfo;
		}

		/*
		 * @see org.eclipse.jface.text.contentassist.ICompletionProposalExtension2#apply(org.eclipse.jface.text.ITextViewer,
		 *      char, int, int)
		 */
		public void apply(ITextViewer viewer, char trigger, int stateMask,
				int offset) {
			apply(viewer.getDocument());
		}

		/*
		 * @see org.eclipse.jface.text.contentassist.ICompletionProposalExtension2#selected(org.eclipse.jface.text.ITextViewer,
		 *      boolean)
		 */
		public void selected(ITextViewer viewer, boolean smartToggle) {
		}

		/*
		 * @see org.eclipse.jface.text.contentassist.ICompletionProposalExtension2#unselected(org.eclipse.jface.text.ITextViewer)
		 */
		public void unselected(ITextViewer viewer) {
		}

		/*
		 * @see org.eclipse.jface.text.contentassist.ICompletionProposalExtension2#validate(org.eclipse.jface.text.IDocument,
		 *      int, org.eclipse.jface.text.DocumentEvent)
		 */
		public boolean validate(IDocument document, int offset,
				DocumentEvent event) {
			try {
				String content = document.get(fReplacementOffset,
						fReplacementLength);
				if (content.startsWith(fReplacementString))
					return true;
			} catch (BadLocationException e) {
				// ignore concurrently modified document
			}
			return false;
		}
	}

	private final List fSlaves = new ArrayList();

	private MultiVariable fMaster;

	/**
	 * @param mv
	 */
	public MultiVariableGuess(MultiVariable mv) {
		fMaster = mv;
	}

	/**
	 * @param variable
	 * @return
	 */
	public ICompletionProposal[] getProposals(MultiVariable variable,
			int offset, int length) {
		if (variable.equals(fMaster)) {
			String[] choices = variable.getValues();

			ICompletionProposal[] ret = new ICompletionProposal[choices.length];
			for (int i = 0; i < ret.length; i++) {
				ret[i] = new Proposal(choices[i], offset, length, offset
						+ length) {

					/*
					 * @see org.eclipse.jface.text.link.MultiVariableGuess.Proposal#apply(org.eclipse.jface.text.IDocument)
					 */
					public void apply(IDocument document) {
						super.apply(document);

						try {
							Object old = fMaster.getSet();
							fMaster.setSet(fReplacementString);
							if (!fReplacementString.equals(old)) {
								for (Iterator it = fSlaves.iterator(); it
										.hasNext();) {
									VariablePosition pos = (VariablePosition) it
											.next();
									String[] values = pos.getVariable()
											.getValues(fReplacementString);
									if (values != null)
										document.replace(pos.getOffset(), pos
												.getLength(), values[0]);
								}
							}
						} catch (BadLocationException e) {
							// ignore and continue
						}

					}
				};
			}

			return ret;

		} else {

			String[] choices = variable.getValues(fMaster.getSet());

			if (choices == null || choices.length < 2)
				return null;

			ICompletionProposal[] ret = new ICompletionProposal[choices.length];
			for (int i = 0; i < ret.length; i++) {
				ret[i] = new Proposal(choices[i], offset, length, offset
						+ length);
			}

			return ret;
		}
	}

	/**
	 * @param position
	 */
	public void addSlave(VariablePosition position) {
		fSlaves.add(position);
	}

}
