/**
 * Copyright (c) 2011, 2015 - Lunifera GmbH (Gross Enzersdorf, Austria), Loetz GmbH&Co.KG (69115 Heidelberg, Germany)
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0 
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *         Florian Pirchner - Initial implementation
 */
package org.eclipse.osbp.xtext.oxtype.linking;

import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EReference;
import org.eclipse.emf.ecore.EStructuralFeature;
import org.eclipse.xtext.common.types.JvmTypeReference;

// TODO: Auto-generated Javadoc
/**
 * A helper class to register jvmLinkingReferences.
 */
public class JvmTypeAwareLinkingHelper {

	/** The link mappings. */
	private Map<EReference, Set<EReference>> semanticToJvmlinkMappings = new HashMap<EReference, Set<EReference>>();

	private Map<EStructuralFeature, EReference> jvmToSemanticLinkMappings = new HashMap<EStructuralFeature, EReference>();

	/** The jvm link to enhancers. */
	private Map<EReference, IJvmLinkCrossRefStringEnhancer> jvmLinkToEnhancers = new HashMap<EReference, IJvmLinkCrossRefStringEnhancer>();

	/** The jvm link to finisher. */
	private Map<EReference, IJvmTypeRefFinisher> jvmLinkToFinisher = new HashMap<EReference, IJvmTypeRefFinisher>();

	/** The jvm links. */
	private Set<EReference> jvmLinks = new HashSet<EReference>();

	/**
	 * Instantiates a new lazy jvm type linking helper.
	 */
	public JvmTypeAwareLinkingHelper() {
	}

	/**
	 * Registers a jvmTypeReference for a given semanticReference.
	 *
	 * @param semanticReference
	 *            the semantic reference
	 * @param jvmTypeReference
	 *            the jvm type reference
	 * @return the e reference
	 */
	public EReference register(EReference semanticReference,
			EReference jvmTypeReference) {
		return register(semanticReference, jvmTypeReference, null, null);
	}

	/**
	 * Registers a jvmTypeReference for a given semanticReference.
	 *
	 * @param semanticReference
	 *            the semantic reference
	 * @param jvmTypeReference
	 *            the jvm type reference
	 * @param enhancer
	 *            the enhancer
	 * @param finisher
	 *            the finisher
	 * @return the e reference
	 */
	public EReference register(EReference semanticReference,
			EReference jvmTypeReference,
			IJvmLinkCrossRefStringEnhancer enhancer,
			IJvmTypeRefFinisher finisher) {

		Set<EReference> links = semanticToJvmlinkMappings
				.get(semanticReference);
		if (links == null) {
			links = new HashSet<EReference>();
			semanticToJvmlinkMappings.put(semanticReference, links);
		}
		links.add(jvmTypeReference);
		jvmLinks.add(jvmTypeReference);

		jvmToSemanticLinkMappings.put(jvmTypeReference, semanticReference);

		if (enhancer != null) {
			jvmLinkToEnhancers.put(jvmTypeReference, enhancer);
		}

		if (finisher != null) {
			jvmLinkToFinisher.put(jvmTypeReference, finisher);
		}

		return jvmTypeReference;
	}

	/**
	 * Returns true, if the semanticReference needs jvmLinking.
	 *
	 * @param semanticReference
	 *            the semantic reference
	 * @return true, if successful
	 */
	public boolean needsJvmLinking(EReference semanticReference) {
		return semanticToJvmlinkMappings.containsKey(semanticReference);
	}

	/**
	 * Returns true, if the given reference is a jvmLink.
	 *
	 * @param feature
	 *            the feature
	 * @return true, if is jvm link
	 */
	public boolean isJvmLink(EStructuralFeature feature) {
		if (feature instanceof EReference) {
			return jvmLinks.contains(feature);
		} else {
			return false;
		}
	}

	/**
	 * Returns the enhancer for the given feature.
	 *
	 * @param feature
	 *            the feature
	 * @return the enhancer
	 */
	public IJvmLinkCrossRefStringEnhancer getEnhancer(EStructuralFeature feature) {
		return jvmLinkToEnhancers.get(feature);
	}

	/**
	 * Returns the finisher for the given feature.
	 *
	 * @param feature
	 *            the feature
	 * @return the finisher
	 */
	public IJvmTypeRefFinisher getFinisher(EStructuralFeature feature) {
		return jvmLinkToFinisher.get(feature);
	}

	/**
	 * Returns the jvmLinkingReference for the given semanticReference.
	 *
	 * @param semanticReference
	 *            the semantic reference
	 * @return the jvm linking references
	 */
	public Set<EReference> getJvmLinkingReferences(EReference semanticReference) {
		return semanticToJvmlinkMappings.containsKey(semanticReference) ? semanticToJvmlinkMappings.get(semanticReference) : Collections.emptySet();
	}

	/**
	 * Returns the semantic {@link EReference} for the given jvmType
	 * {@link EStructuralFeature}. JvmType reference is the {@link EReference}
	 * pointing to the {@link JvmTypeReference}.
	 * 
	 * @param jvmReference
	 * @return
	 */
	public EReference getSemanticReference(EStructuralFeature jvmReference) {
		return jvmToSemanticLinkMappings.get(jvmReference);
	}

	/**
	 * The JvmLinks are a helper construct to provide proper proxies. But in
	 * some cases the cross reference String that is used for scoping needs to
	 * be enhanced. For instance if a DTO mapper is queried. The naming
	 * convention defines, that a mapper is called "{DTO-FQN}Mapper". So the
	 * jvmLink-proxy from LDto#mapperJvmType needs to become resolved with the
	 * name of the mapper.
	 */
	public interface IJvmLinkCrossRefStringEnhancer {

		/**
		 * Returns the crossRefString to be used.
		 * <p>
		 * Example: given "ItemDTO" and returned "ItemDTOMapper".
		 *
		 * @param context
		 *            the context
		 * @param feature
		 *            the feature
		 * @param crossRefString
		 *            the cross ref string
		 * @return the string
		 */
		String enhance(EObject context, EStructuralFeature feature,
				String crossRefString);

	}

	/**
	 * The JvmHelperProxies will be validated by Xbase. So it is necessary to
	 * add type arguments to raw types. This finisher gives access to the
	 * created {@link JvmTypeReference}.
	 */
	public interface IJvmTypeRefFinisher {

		/**
		 * Allows to manipulate the created type reference.
		 *
		 * @param jvmLinkFeature
		 *            the jvm link feature
		 * @param typeRef
		 *            the type ref
		 */
		void finish(EStructuralFeature jvmLinkFeature, JvmTypeReference typeRef);

	}

}