Copyright (c) 2019 IBM Corporation and others.
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:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2019 IBM Corporation and others.
 *
 * 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.ui.fix;

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

import org.eclipse.core.runtime.CoreException;

import org.eclipse.jdt.core.dom.CompilationUnit;
import org.eclipse.jdt.core.manipulation.CleanUpContextCore;
import org.eclipse.jdt.core.manipulation.CleanUpRequirementsCore;
import org.eclipse.jdt.core.manipulation.ICleanUpFixCore;

import org.eclipse.jdt.internal.corext.fix.CleanUpConstants;
import org.eclipse.jdt.internal.corext.fix.LambdaExpressionsFixCore;

public class LambdaExpressionsCleanUpCore extends AbstractCleanUpCore {

	public LambdaExpressionsCleanUpCore(Map<String, String> options) {
		super(options);
	}

	public LambdaExpressionsCleanUpCore() {
		super();
	}

	@Override
	public CleanUpRequirementsCore getRequirementsCore() {
		return new CleanUpRequirementsCore(requireAST(), false, false, null);
	}

	public boolean requireAST() {
		boolean convertFunctionalInterfaces= isEnabled(CleanUpConstants.CONVERT_FUNCTIONAL_INTERFACES);
		if (!convertFunctionalInterfaces)
			return false;

		return isEnabled(CleanUpConstants.USE_LAMBDA)
				|| isEnabled(CleanUpConstants.USE_ANONYMOUS_CLASS_CREATION);
	}

	@Override
	public ICleanUpFixCore createFixCore(CleanUpContextCore context) throws CoreException {
		CompilationUnit compilationUnit= context.getAST();
		if (compilationUnit == null)
			return null;

		boolean convertFunctionalInterfaces= isEnabled(CleanUpConstants.CONVERT_FUNCTIONAL_INTERFACES);
		if (!convertFunctionalInterfaces)
			return null;

		return LambdaExpressionsFixCore.createCleanUp(compilationUnit,
				isEnabled(CleanUpConstants.USE_LAMBDA),
				isEnabled(CleanUpConstants.USE_ANONYMOUS_CLASS_CREATION));
	}

	@Override
	public String[] getStepDescriptions() {
		List<String> result= new ArrayList<>();
		if (isEnabled(CleanUpConstants.CONVERT_FUNCTIONAL_INTERFACES)) {
			if (isEnabled(CleanUpConstants.USE_LAMBDA)) {
				result.add(MultiFixMessages.LambdaExpressionsCleanUp_use_lambda_where_possible);
			}
			if (isEnabled(CleanUpConstants.USE_ANONYMOUS_CLASS_CREATION)) {
				result.add(MultiFixMessages.LambdaExpressionsCleanUp_use_anonymous);
			}
		}

		return result.toArray(new String[result.size()]);
	}

	@Override
	public String getPreview() {
		StringBuilder buf= new StringBuilder();

		boolean convert= isEnabled(CleanUpConstants.CONVERT_FUNCTIONAL_INTERFACES);
		boolean useLambda= isEnabled(CleanUpConstants.USE_LAMBDA);
		boolean useAnonymous= isEnabled(CleanUpConstants.USE_ANONYMOUS_CLASS_CREATION);

		boolean firstLambda= convert && useLambda;
		boolean secondLambda= !(convert && useAnonymous);

		if (firstLambda) {
			buf.append("IntConsumer c = i -> {\n"); //$NON-NLS-1$
			buf.append("    System.out.println(i);\n"); //$NON-NLS-1$
			buf.append("};\n"); //$NON-NLS-1$
			buf.append("\n"); //$NON-NLS-1$
			buf.append("\n"); //$NON-NLS-1$
		} else {
			buf.append("IntConsumer c = new IntConsumer() {\n"); //$NON-NLS-1$
			buf.append("    @Override public void accept(int value) {\n"); //$NON-NLS-1$
			buf.append("        System.out.println(i);\n"); //$NON-NLS-1$
			buf.append("    }\n"); //$NON-NLS-1$
			buf.append("};\n"); //$NON-NLS-1$
		}

		if (secondLambda) {
			buf.append("Runnable r = () -> { /* do something */ };\n"); //$NON-NLS-1$
			buf.append("\n"); //$NON-NLS-1$
			buf.append("\n"); //$NON-NLS-1$
			buf.append("\n"); //$NON-NLS-1$
			buf.append("\n"); //$NON-NLS-1$
		} else {
			buf.append("Runnable r = new Runnable() {\n"); //$NON-NLS-1$
			buf.append("    @Override public void run() {\n"); //$NON-NLS-1$
			buf.append("        //do something\n"); //$NON-NLS-1$
			buf.append("    }\n"); //$NON-NLS-1$
			buf.append("};\n"); //$NON-NLS-1$
		}
		return buf.toString();
	}

}