Copyright (c) 2017 GK Software AG, 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:
    Stephan Herrmann - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2017 GK Software AG, 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:
 *     Stephan Herrmann - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.core.builder;

import java.util.Locale;
import java.util.Map;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IResource;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.core.IJavaModelStatusConstants;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.IModuleDescription;
import org.eclipse.jdt.core.IPackageFragmentRoot;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.core.util.IAttributeNamesConstants;
import org.eclipse.jdt.internal.compiler.ClassFile;
import org.eclipse.jdt.internal.compiler.CompilationResult;
import org.eclipse.jdt.internal.compiler.Compiler;
import org.eclipse.jdt.internal.compiler.DefaultErrorHandlingPolicies;
import org.eclipse.jdt.internal.compiler.ICompilerRequestor;
import org.eclipse.jdt.internal.compiler.env.ICompilationUnit;
import org.eclipse.jdt.internal.compiler.env.IUpdatableModule.UpdateKind;
import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
import org.eclipse.jdt.internal.compiler.util.SimpleSetOfCharArray;
import org.eclipse.jdt.internal.core.CompilationGroup;
import org.eclipse.jdt.internal.core.JavaModelStatus;
import org.eclipse.jdt.internal.core.ModuleUpdater;

Implementation of JavaCore.compileWithAttributes(IModuleDescription, Map<String,String>). /** Implementation of {@link org.eclipse.jdt.core.JavaCore#compileWithAttributes(IModuleDescription, Map)}. */
public class ModuleInfoBuilder {
	
	static class BytecodeCollector implements ICompilerRequestor {
		byte[] bytes;

		@Override
		public void acceptResult(CompilationResult result) {
			assert this.bytes == null : "duplicate result"; //$NON-NLS-1$
			ClassFile[] classFiles = result.getClassFiles();
			assert classFiles.length == 1;
			this.bytes = classFiles[0].getBytes();
		}
	}
	
	public byte[] compileWithAttributes(IModuleDescription module, Map<String,String> classFileAttributes) throws JavaModelException {
		IJavaProject javaProject = module.getJavaProject();
		NameEnvironment nameEnvironment = new NameEnvironment(javaProject, CompilationGroup.MAIN);

		addModuleUpdates(module, nameEnvironment.moduleUpdater, classFileAttributes);
		
		ClasspathMultiDirectory sourceLocation = getSourceLocation(javaProject, nameEnvironment, module); 
		IFile file = (IFile) module.getCompilationUnit().getCorrespondingResource();
		ICompilationUnit[] sourceUnits = { new SourceFile(file, sourceLocation) };
		BytecodeCollector collector = new BytecodeCollector();
		Compiler newCompiler = new Compiler(
									nameEnvironment,
									DefaultErrorHandlingPolicies.exitOnFirstError(),
									new CompilerOptions(javaProject.getOptions(true)),
									collector,
									ProblemFactory.getProblemFactory(Locale.getDefault()));
		newCompiler.compile(sourceUnits);
		return collector.bytes;
	}

	private void addModuleUpdates(IModuleDescription module, ModuleUpdater moduleUpdater, Map<String,String> classFileAttributes) {
		String mainClassName = classFileAttributes.remove(String.valueOf(IAttributeNamesConstants.MODULE_MAIN_CLASS));
		if (mainClassName != null) {
			moduleUpdater.addModuleUpdate(module.getElementName(), m -> m.setMainClassName(mainClassName.toCharArray()), UpdateKind.MODULE);
		}
		String modulePackageNames = classFileAttributes.remove(String.valueOf(IAttributeNamesConstants.MODULE_PACKAGES));
		if (modulePackageNames != null) {
			SimpleSetOfCharArray namesSet = new SimpleSetOfCharArray();
			String[] providedNames = modulePackageNames.split(","); //$NON-NLS-1$
			for (int i = 0; i < providedNames.length; i++) {
				namesSet.add(providedNames[i].trim().toCharArray());
			}
			moduleUpdater.addModuleUpdate(module.getElementName(),  m -> m.setPackageNames(namesSet), UpdateKind.MODULE);
		}
		if (!classFileAttributes.isEmpty()) {
			throw new IllegalArgumentException("Unsupported key(s): "+classFileAttributes.keySet().toString()); //$NON-NLS-1$
		}
	}

	private ClasspathMultiDirectory getSourceLocation(IJavaProject javaProject, NameEnvironment nameEnvironment, IModuleDescription module)
			throws JavaModelException {
		IPackageFragmentRoot root = (IPackageFragmentRoot) module.getAncestor(IJavaElement.PACKAGE_FRAGMENT_ROOT);
		IResource rootResource = root.getCorrespondingResource(); 
		for (ClasspathMultiDirectory sourceLocation : nameEnvironment.sourceLocations) {
			if (sourceLocation.sourceFolder.equals(rootResource)) {
				return sourceLocation;
			}
		}
		throw new JavaModelException(new JavaModelStatus(IJavaModelStatusConstants.ELEMENT_NOT_ON_CLASSPATH, module));
	}
}