/*******************************************************************************
 * Copyright (c) 2009, 2016 Red Hat Inc. 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
 *
 * Contributors:
 *     Alexander Kurtakov - initial API and implementation
 *******************************************************************************/
package org.eclipse.dltk.sh.internal.ui.selection;

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

import org.eclipse.dltk.ast.ASTVisitor;
import org.eclipse.dltk.ast.declarations.MethodDeclaration;
import org.eclipse.dltk.ast.declarations.ModuleDeclaration;
import org.eclipse.dltk.ast.expressions.Expression;
import org.eclipse.dltk.ast.expressions.MethodCallExpression;
import org.eclipse.dltk.ast.references.VariableReference;
import org.eclipse.dltk.codeassist.ScriptSelectionEngine;
import org.eclipse.dltk.compiler.env.IModuleSource;
import org.eclipse.dltk.core.DLTKCore;
import org.eclipse.dltk.core.IModelElement;
import org.eclipse.dltk.core.ISourceModule;
import org.eclipse.dltk.core.ModelException;
import org.eclipse.dltk.core.SourceParserUtil;

public class ShelledSelectionEngine extends ScriptSelectionEngine {
	private ISourceModule sourceModule;

	@Override
	public IModelElement[] select(IModuleSource module, final int offset, int i) {
		sourceModule = (ISourceModule) module.getModelElement();
		ModuleDeclaration moduleDeclaration = SourceParserUtil.getModuleDeclaration(sourceModule, null);
		final List<IModelElement> results = new ArrayList<>();
		try {
			moduleDeclaration.traverse(new ASTVisitor() {
				@Override
				public boolean visit(Expression s) throws Exception {
					if ((s.sourceStart() <= offset) && (offset <= s.sourceEnd())) {
						if (s instanceof MethodCallExpression) {
							findDeclaration(((MethodCallExpression) s).getName(), results);
						}
						if (s instanceof VariableReference) {
							findDeclaration(((VariableReference) s).getName(), results);
						}
					}
					return super.visit(s);
				}

				@Override
				public boolean visit(MethodDeclaration s) throws Exception {
					if ((s.getNameStart() <= offset) && (offset <= s.getNameEnd())) {
						findDeclaration(s.getName(), results);
					}
					return super.visit(s);
				}

			});
		} catch (Exception e) {
			if (DLTKCore.DEBUG) {
				e.printStackTrace();
			}
		}
		return results.toArray(new IModelElement[results.size()]);
	}

	private void findDeclaration(final String name, final List<IModelElement> results) {
		try {
			this.sourceModule.accept(element -> {
				if (element.getElementName().equals(name)) {
					results.add(element);
				}
				return true;
			});
		} catch (ModelException e) {
			if (DLTKCore.DEBUG) {
				e.printStackTrace();
			}
		}
	}

}