/*******************************************************************************
 * Copyright (c) 2005, 2017 IBM Corporation and others.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 * 
 * SPDX-License-Identifier: EPL-2.0
 *
 *******************************************************************************/
package org.eclipse.dltk.core;

import java.util.HashSet;
import java.util.Set;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.Platform;
import org.eclipse.dltk.annotations.Nullable;
import org.eclipse.dltk.ast.parser.ISourceParser;
import org.eclipse.dltk.ast.parser.SourceParserManager;
import org.eclipse.dltk.codeassist.ICompletionEngine;
import org.eclipse.dltk.codeassist.ISelectionEngine;
import org.eclipse.dltk.compiler.problem.DefaultProblemFactory;
import org.eclipse.dltk.compiler.problem.IProblemFactory;
import org.eclipse.dltk.core.PriorityDLTKExtensionManager.ElementInfo;
import org.eclipse.dltk.core.model.binary.IBinaryElementParser;
import org.eclipse.dltk.core.search.DLTKSearchParticipant;
import org.eclipse.dltk.core.search.IDLTKSearchScope;
import org.eclipse.dltk.core.search.IMatchLocatorParser;
import org.eclipse.dltk.core.search.SearchPatternProcessor;
import org.eclipse.dltk.core.search.indexing.SourceIndexerRequestor;
import org.eclipse.dltk.core.search.matching.IMatchLocator;
import org.eclipse.dltk.core.search.matching.MatchLocator;
import org.eclipse.dltk.core.search.matching.MatchLocatorParser;
import org.eclipse.dltk.internal.core.InternalDLTKLanguageManager;

public class DLTKLanguageManager {

	public static IDLTKLanguageToolkit getLanguageToolkit(String natureId) {
		return (IDLTKLanguageToolkit) InternalDLTKLanguageManager
				.getLanguageToolkitsManager().getObject(natureId);
	}

	public static IDLTKLanguageToolkit[] getLanguageToolkits() {

		final PriorityClassDLTKExtensionManager tkManager = InternalDLTKLanguageManager
				.getLanguageToolkitsManager();
		ElementInfo[] elementInfos = tkManager.getElementInfos();
		IDLTKLanguageToolkit[] toolkits = new IDLTKLanguageToolkit[elementInfos.length];
		for (int j = 0; j < elementInfos.length; j++) {
			toolkits[j] = (IDLTKLanguageToolkit) tkManager
					.getInitObject(elementInfos[j]);
		}
		return toolkits;
	}

	private static IDLTKLanguageToolkit findAppropriateToolkitByObject(
			Object object) {
		final PriorityClassDLTKExtensionManager toolkitManager = InternalDLTKLanguageManager
				.getLanguageToolkitsManager();
		final ElementInfo[] elementInfos = toolkitManager.getElementInfos();
		for (int j = 0; j < elementInfos.length; j++) {
			IDLTKLanguageToolkit toolkit = (IDLTKLanguageToolkit) toolkitManager
					.getInitObject(elementInfos[j]);
			if (toolkit == null) {
				// toolkit instantiation failed, skip it
				// TODO (alex) remove this ElementInfo entry
				continue;
			}
			if (object instanceof IResource) {
				if (DLTKContentTypeManager.isValidResourceForContentType(
						toolkit, (IResource) object)) {
					return toolkit;
				}
			} else if (object instanceof IPath) {
				if (DLTKContentTypeManager.isValidFileNameForContentType(
						toolkit, (IPath) object)) {
					return toolkit;
				}
			} else {
				return null;
			}
		}
		return null;
	}

	public static boolean hasScriptNature(IProject project) {
		return InternalDLTKLanguageManager.getLanguageToolkitsManager()
				.findScriptNature(project) != null;
	}

	public static IDLTKLanguageToolkit getLanguageToolkit(
			IModelElement element) {
		IDLTKLanguageToolkit toolkit = (IDLTKLanguageToolkit) InternalDLTKLanguageManager
				.getLanguageToolkitsManager().getObject(element);
		if (toolkit == null) {
			while (element != null && element
					.getElementType() != IModelElement.SOURCE_MODULE) {
				element = element.getParent();
			}
			if (element != null && element
					.getElementType() == IModelElement.SOURCE_MODULE) {
				if (element.getResource() != null) {
					IDLTKLanguageToolkit tk = findAppropriateToolkitByObject(
							element.getResource());
					if (tk != null) {
						return tk;
					}
				}
				return findAppropriateToolkitByObject(element.getPath());
			}
		}
		return toolkit;
	}

	/**
	 * The behavior of this method was not correct - it could return incorrect
	 * results for files without extension. For compatibility purposes and to
	 * allow smooth migration it is marked as deprecated -- AlexPanchenko
	 */
	@Deprecated
	public static IDLTKLanguageToolkit findToolkit(IResource resource) {
		IDLTKLanguageToolkit toolkit = findAppropriateToolkitByObject(resource);
		if (toolkit == null) {
			toolkit = findToolkit(resource.getProject());
		}
		return toolkit;
	}

	/**
	 * Returns the toolkit of the specified {@link IProject} or null if not
	 * found.
	 *
	 * @param project
	 * @return
	 */
	public static IDLTKLanguageToolkit findToolkit(IProject project) {
		return (IDLTKLanguageToolkit) InternalDLTKLanguageManager
				.getLanguageToolkitsManager().getObject(project);
	}

	/**
	 * Return the toolkit of the specified resource or <code>null</code>.
	 *
	 * @param resource
	 * @return
	 */
	public static IDLTKLanguageToolkit findToolkitForResource(
			IResource resource) {
		if (resource.getType() == IResource.PROJECT) {
			return findToolkit((IProject) resource);
		} else {
			final IModelElement parent = DLTKCore.create(resource.getParent());
			if (parent == null) {
				return null;
			}
			return DLTKLanguageManager.findToolkit(parent, resource, false);
		}
	}

	/**
	 * Return the language toolkit of the specified resource in the specified
	 * project. Until multiple languages are allowed for the same project - it
	 * will just return the first matching toolkit of the project.
	 *
	 * @param scriptProject
	 * @param resource
	 * @param useDefault
	 *            if resource does not match project toolkit - return project
	 *            toolkit or <code>null</code>
	 * @return
	 */
	public static IDLTKLanguageToolkit findToolkit(IModelElement parent,
			IResource resource, boolean useDefault) {
		final IDLTKLanguageToolkit toolkit = getLanguageToolkit(parent);
		if (toolkit != null) {
			if (DLTKContentTypeManager.isValidResourceForContentType(toolkit,
					resource)) {
				return toolkit;
			}
			/*
			 * TODO check other toolkits of the projects when projects will be
			 * supporting multiple DLTK languages
			 */
			return useDefault ? toolkit : null;
		} else {
			return findAppropriateToolkitByObject(resource);
		}
	}

	public static IDLTKLanguageToolkit findToolkit(IPath path) {
		return findAppropriateToolkitByObject(path);
	}

	public static ISourceElementParser getSourceElementParser(String nature) {
		return (ISourceElementParser) InternalDLTKLanguageManager
				.getSourceElementParsersManager().getObject(nature);
	}

	public static ISourceElementParser getSourceElementParser(
			IModelElement element) {
		return (ISourceElementParser) InternalDLTKLanguageManager
				.getSourceElementParsersManager().getObject(element);
	}

	/**
	 * @since 2.0
	 */
	public static IBinaryElementParser getBinaryElementParser(String nature) {
		return (IBinaryElementParser) InternalDLTKLanguageManager
				.getBinaryElementParsersManager().getObject(nature);
	}

	/**
	 * @since 2.0
	 */
	public static IBinaryElementParser getBinaryElementParser(
			IModelElement element) {
		return (IBinaryElementParser) InternalDLTKLanguageManager
				.getBinaryElementParsersManager().getObject(element);
	}

	// public static ISourceParser getSourceParser( String nature ) throws
	// CoreException {
	// return (ISourceElementParser) sourceParsersManager.getObject(nature);
	// }
	//
	// public static ISourceParser getSourceParser( IModelElement element )
	// throws
	// CoreException {
	// return (ISourceElementParser) sourceParsersManager.getObject(element);
	// }

	public static IProblemFactory getProblemFactory(String natureID) {
		IProblemFactory factory = (IProblemFactory) InternalDLTKLanguageManager
				.getProblemFactoryManager().getObject(natureID);
		if (factory != null) {
			return factory;
		}
		return new DefaultProblemFactory();
	}

	public static IProblemFactory getProblemFactory(IModelElement element) {
		IProblemFactory factory = (IProblemFactory) InternalDLTKLanguageManager
				.getProblemFactoryManager().getObject(element);
		if (factory != null) {
			return factory;
		}
		return new DefaultProblemFactory();
	}

	@Deprecated
	public static ICompletionEngine getCompletionEngine(String natureID) {
		final ICompletionEngine[] engines = getCompletionEngines(natureID);
		return engines != null ? engines[0] : null;
	}

	public static ICompletionEngine[] getCompletionEngines(String natureID) {
		return InternalDLTKLanguageManager.getCompletionEngineManager()
				.getInstances(natureID);
	}

	@Deprecated
	public static ISelectionEngine getSelectionEngine(String natureID) {
		final ISelectionEngine[] engines = getSelectionEngines(natureID);
		return engines != null ? engines[0] : null;
	}

	public static ISelectionEngine[] getSelectionEngines(String natureID) {
		return InternalDLTKLanguageManager.getSelectionEngineManager()
				.getInstances(natureID);
	}

	public static ISourceParser getSourceParser(String natureID) {
		return getSourceParser(null, natureID);
	}

	/**
	 * @param project
	 * @param natureID
	 * @return
	 * @since 2.0
	 */
	public static ISourceParser getSourceParser(IProject project,
			String natureID) {
		return SourceParserManager.getInstance().getSourceParser(project,
				natureID);
	}

	public static DLTKSearchParticipant createSearchParticipant(
			String natureID) {
		ISearchFactory factory = getSearchFactory(natureID);
		if (factory != null) {
			DLTKSearchParticipant participant = factory
					.createSearchParticipant();
			if (participant != null) {
				return participant;
			}
		}
		return new DLTKSearchParticipant();
	}

	public static ISearchFactory getSearchFactory(String natureId) {
		return (ISearchFactory) InternalDLTKLanguageManager.getSearchManager()
				.getObject(natureId);
	}

	public static IMatchLocator createMatchLocator(String natureID) {
		return InternalDLTKLanguageManager.createMatchLocator(natureID);
	}

	public static SourceIndexerRequestor createSourceRequestor(
			String natureID) {
		ISearchFactory factory = getSearchFactory(natureID);
		if (factory != null) {
			SourceIndexerRequestor requestor = factory.createSourceRequestor();
			if (requestor != null) {
				requestor.setSearchFactory(factory);
				return requestor;
			}
		}
		return new SourceIndexerRequestor();
	}

	public static IMatchLocatorParser createMatchParser(String natureID,
			MatchLocator matchLocator) {
		ISearchFactory factory = getSearchFactory(natureID);
		if (factory != null) {
			return factory.createMatchParser(matchLocator);
		}
		return new MatchLocatorParser(matchLocator) {
		};
	}

	public static ICalleeProcessor createCalleeProcessor(String natureID,
			IMethod member, IProgressMonitor progressMonitor,
			IDLTKSearchScope scope) {
		ICallHierarchyFactory factory = getCallHierarchyFactory(natureID);
		if (factory != null) {
			ICalleeProcessor processor = factory.createCalleeProcessor(member,
					progressMonitor, scope);
			return processor;
		}
		return null;
	}

	private static ICallHierarchyFactory getCallHierarchyFactory(
			String natureId) {
		return (ICallHierarchyFactory) InternalDLTKLanguageManager
				.getCallHierarchyManager().getObject(natureId);
	}

	public static ICallProcessor createCallProcessor(String natureID) {
		ICallHierarchyFactory factory = getCallHierarchyFactory(natureID);
		if (factory != null) {
			return factory.createCallProcessor();
		}
		return null;
	}

	public static IFileHierarchyResolver getFileHierarchyResolver(
			String natureId) {
		return (IFileHierarchyResolver) InternalDLTKLanguageManager
				.getFileHierarchyResolversManager().getObject(natureId);
	}

	/**
	 * @since 2.0
	 */
	@Nullable
	public static ISearchPatternProcessor getSearchPatternProcessor(
			String natureId) {
		final ISearchFactory factory = getSearchFactory(natureId);
		if (factory != null) {
			return factory.createSearchPatternProcessor();
		} else {
			return null;
		}
	}

	/**
	 * @since 2.0
	 */
	public static ISearchPatternProcessor getSearchPatternProcessor(
			IDLTKLanguageToolkit toolkit) {
		return getSearchPatternProcessor(toolkit, false);
	}

	/**
	 * @since 3.0
	 */
	public static ISearchPatternProcessor getSearchPatternProcessor(
			IDLTKLanguageToolkit toolkit, boolean allowDefault) {
		if (toolkit != null) {
			final ISearchPatternProcessor processor = getSearchPatternProcessor(
					toolkit.getNatureId());
			if (processor != null) {
				return processor;
			}
		}
		if (allowDefault) {
			return SearchPatternProcessor.getDefault();
		} else {
			return null;
		}
	}

	private static final String FILENAME_ASSOCIATION_EXT_POINT = DLTKCore.PLUGIN_ID
			+ ".filenameAssociation"; //$NON-NLS-1$

	/**
	 * @since 2.0
	 */
	public static Set<String> loadFilenameAssociations(final String natureId) {
		final IConfigurationElement[] elements = Platform.getExtensionRegistry()
				.getConfigurationElementsFor(FILENAME_ASSOCIATION_EXT_POINT);
		final Set<String> patterns = new HashSet<>();
		for (IConfigurationElement element : elements) {
			if (natureId.equals(element.getAttribute("nature"))) { //$NON-NLS-1$
				final String pattern = element.getAttribute("pattern"); //$NON-NLS-1$
				if (pattern != null && pattern.length() != 0) {
					patterns.add(pattern);
				}
			}
		}
		return patterns;
	}
}