Copyright (c) 2016, 2018 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) 2016, 2018 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.core;

import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.IModuleDescription;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.core.compiler.CharOperation;
import org.eclipse.jdt.internal.compiler.env.IModule;
import org.eclipse.jdt.internal.compiler.env.IModulePathEntry;

public class ModuleSourcePathManager {

	private Map<String, IModulePathEntry> knownModules = new HashMap<String, IModulePathEntry>(11);

	private IModulePathEntry getModuleRoot0(String name) {
		return this.knownModules.get(name);
	}
	public IModulePathEntry getModuleRoot(String name) {
		IModulePathEntry root = getModuleRoot0(name);
		if (root == null) {
			try {
				seekModule(name.toCharArray(),false, new JavaElementRequestor());
			} catch (JavaModelException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		root = this.knownModules.get(name);
		return root;
	}
	public void addEntry(IModuleDescription module, JavaProject project) throws JavaModelException {
		String moduleName = new String(module.getElementName().toCharArray());
		IModulePathEntry entry = getModuleRoot0(moduleName);
		if (entry != null) {
			// TODO : Should we signal error via JavaModelException
			return;
		}
		this.knownModules.put(moduleName, new ProjectEntry(project));
	}

	public void removeEntry(JavaProject javaProject) {
		Entry<String, IModulePathEntry> entry = this.knownModules.entrySet().stream()
			.filter(e -> ProjectEntry.representsProject(e.getValue(), javaProject))
			.findFirst()
			.orElse(null);

		String key = entry != null ? entry.getKey() : null;
		if (key != null) {
			this.knownModules.remove(key);
		}
	}
	interface IPrefixMatcherCharArray {
		boolean matches(char[] prefix, char[] name);
	}
	public void seekModule(char[] name, boolean prefixMatch, IJavaElementRequestor requestor) throws JavaModelException {
		if (name == null)
			return;
		IPrefixMatcherCharArray prefixMatcher = prefixMatch ? CharOperation.equals(name, CharOperation.ALL_PREFIX) ?
				(x, y) -> true : CharOperation::prefixEquals : CharOperation :: equals;
		IJavaProject[] projects = JavaModelManager.getJavaModelManager().getJavaModel().getJavaProjects();
		for (int i = 0; i < projects.length; i++) {
			IJavaProject project = projects[i];
			if (!project.getProject().isAccessible())
				continue;
			if (project instanceof JavaProject) {
				IModuleDescription module = ((JavaProject) project).getModuleDescription();
				if (module != null) {
					if (prefixMatcher.matches(name, module.getElementName().toCharArray())) {
						//addEntry(module, (JavaProject) project);
						requestor.acceptModule(module);
					}
				}
			}
		}
	}
	public IModule getModule(char[] name) {
		IModulePathEntry root = getModuleRoot0(CharOperation.charToString(name));
		if (root != null)
			try {
				return root.getModule();
			} catch (Exception e1) {
				//
				return null;
			}
		JavaElementRequestor requestor = new JavaElementRequestor();
		try {
			seekModule(name, false, requestor);
		} catch (JavaModelException e) {
			// 
		}
		IModuleDescription[] modules = requestor.getModules();
		if (modules.length > 0) {
			IModuleDescription module = modules[0];
			try {
				return (IModule) ((JavaElement) module).getElementInfo();
			} catch (JavaModelException e) {
				e.printStackTrace();
			}
		}
		return null; 
	}
//	public IModuleDeclaration[] getModules() {
//		if (this.knownModules.size() == 0) {
//			return new IModuleDeclaration[0];
//		}
//		List<IModuleDeclaration> modules = new ArrayList<IModuleDeclaration>();
//		for (IModulePathEntry val : this.knownModules.values()) {
//			try {
//				modules.add(val.getModule());
//			} catch (Exception e) {
//				// TODO Auto-generated catch block
//				e.printStackTrace();
//			}
//		}
//		return modules.toArray(new IModuleDeclaration[modules.size()]);
//	}
}