/**
 * Copyright (c) 2008 Borland Software Corp.
 * 
 * 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:
 *    Alexander Shatalin (Borland) - initial API and implementation
 */
package org.eclipse.gmf.internal.xpand.migration;

import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;

import org.eclipse.emf.ecore.EPackage;

class ModeltypeImports extends AbstractImportsManager {

	private static final String DELIMITER = "_";

	private static final String DEFAULT_ALIAS = "metaModelRef";

	private boolean injectUnusedImports;

	private Set<String> modeltypeAliases = new HashSet<String>();

	private Map<String, String> nsURI2Aliases = new LinkedHashMap<String, String>();

	private Set<String> usedNsURIs = new HashSet<String>();

	private OclKeywordManager keywordManager;

	ModeltypeImports(StringBuilder stringBuilder, boolean injectUnusedImports, OclKeywordManager oclKeywordManager) {
		super(stringBuilder);
		this.injectUnusedImports = injectUnusedImports;
		keywordManager = oclKeywordManager;
	}
	
	void setInjectUnusedImports(boolean injectUnusedImports) {
		this.injectUnusedImports = injectUnusedImports;
	}

	Map<String, String> getModelTypes() {
		Map<String, String> result = new LinkedHashMap<String, String>();
		for (Entry<String, String> entry : nsURI2Aliases.entrySet()) {
			if (!injectUnusedImports && !usedNsURIs.contains(entry.getKey())) {
				// Skipping the entry if it was not used
				continue;
			}
			result.put(entry.getKey(), entry.getValue());
		}
		return result;
	}

	void registerModeltype(String nsURI) {
		assert nsURI.length() > 0;
		String modeltypeAlias = getUniqueModeltypeAlias(nsURI);
		nsURI2Aliases.put(nsURI, modeltypeAlias);
	}

	String getModeltypeAlias(EPackage ePackage) {
		String nsURI = ePackage.getNsURI();
		// Now we are registering models even if they was not imported before..
		if (!nsURI2Aliases.containsKey(nsURI)) {
			registerModeltype(nsURI);
		}
		usedNsURIs.add(nsURI);
		return nsURI2Aliases.get(nsURI);
	}

	private String getUniqueModeltypeAlias(String nsURI) {
		char[] charArray = nsURI.toCharArray();
		int i = charArray.length - 1;
		for (; i > -1 && Character.isJavaIdentifierPart(charArray[i]); i--) {
		}
		String aliasProposal;
		if (i < charArray.length - 1) {
			char[] alias = new char[charArray.length - 1 - i];
			System.arraycopy(charArray, i + 1, alias, 0, charArray.length - 1 - i);
			alias[0] = Character.toLowerCase(alias[0]);
			aliasProposal = new String(alias);
			if (!Character.isJavaIdentifierStart(alias[0])) {
				aliasProposal = DELIMITER + aliasProposal;
			}
		} else {
			aliasProposal = DEFAULT_ALIAS;
		}
		aliasProposal = keywordManager.getValidIdentifierValue(aliasProposal);
		String actualAlias = aliasProposal;
		for (int suffix = 1; modeltypeAliases.contains(actualAlias); suffix++) {
			actualAlias = aliasProposal + DELIMITER + suffix;
		}
		modeltypeAliases.add(actualAlias);
		return actualAlias;
	}

}