/*******************************************************************************
 * Copyright (c) 2000, 2016 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.corext.refactoring.changes;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.SubProgressMonitor;

import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.ResourcesPlugin;

import org.eclipse.ltk.core.refactoring.Change;
import org.eclipse.ltk.core.refactoring.NullChange;
import org.eclipse.ltk.core.refactoring.RefactoringStatus;

import org.eclipse.jdt.core.ICompilationUnit;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.core.IPackageFragment;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.core.JavaModelException;

import org.eclipse.jdt.internal.corext.refactoring.AbstractJavaElementRenameChange;
import org.eclipse.jdt.internal.corext.refactoring.RefactoringCoreMessages;
import org.eclipse.jdt.internal.corext.refactoring.util.JavaElementUtil;
import org.eclipse.jdt.internal.corext.util.Messages;

import org.eclipse.jdt.ui.JavaElementLabels;

import org.eclipse.jdt.internal.core.manipulation.util.BasicElementLabels;

public final class RenamePackageChange extends AbstractJavaElementRenameChange {

	private static IPath createPath(String packageName) {
		return new Path(packageName.replace('.', IPath.SEPARATOR));
	}

	private Map<IResource, Long> fCompilationUnitStamps;

	private final boolean fRenameSubpackages;

	public RenamePackageChange(IPackageFragment pack, String newName, boolean renameSubpackages) {
		this(pack.getPath(), pack.getElementName(), newName, IResource.NULL_STAMP, null, renameSubpackages);
		Assert.isTrue(!pack.isReadOnly(), "package must not be read only"); //$NON-NLS-1$
	}

	private RenamePackageChange(IPath resourcePath, String oldName, String newName, long stampToRestore, Map<IResource, Long> compilationUnitStamps, boolean renameSubpackages) {
		super(resourcePath, oldName, newName, stampToRestore);
		fCompilationUnitStamps= compilationUnitStamps;
		fRenameSubpackages= renameSubpackages;

		setValidationMethod(VALIDATE_NOT_DIRTY);
	}

	private void addStamps(Map<IResource, Long> stamps, ICompilationUnit[] units) {
		for (ICompilationUnit unit : units) {
			IResource resource= unit.getResource();
			long stamp= IResource.NULL_STAMP;
			if (resource != null && (stamp= resource.getModificationStamp()) != IResource.NULL_STAMP) {
				stamps.put(resource, stamp);
			}
		}
	}

	@Override
	protected IPath createNewPath() {
		IPackageFragment oldPackage= getPackage();
		IPath oldPackageName= createPath(oldPackage.getElementName());
		IPath newPackageName= createPath(getNewName());
		return getResourcePath().removeLastSegments(oldPackageName.segmentCount()).append(newPackageName);
	}

	protected IPath createNewPath(IPackageFragment oldPackage) {
		IPath oldPackagePath= createPath(oldPackage.getElementName());
		IPath newPackagePath= createPath(getNewName(oldPackage));
		return oldPackage.getPath().removeLastSegments(oldPackagePath.segmentCount()).append(newPackagePath);
	}

	@Override
	protected Change createUndoChange(long stampToRestore) throws CoreException {
		IPackageFragment pack= getPackage();
		if (pack == null)
			return new NullChange();
		Map<IResource, Long> stamps= new HashMap<>();
		if (!fRenameSubpackages) {
			addStamps(stamps, pack.getCompilationUnits());
		} else {
			for (IPackageFragment currentPackage : JavaElementUtil.getPackageAndSubpackages(pack)) {
				addStamps(stamps, currentPackage.getCompilationUnits());
			}
		}
		return new RenamePackageChange(createNewPath(), getNewName(), getOldName(), stampToRestore, stamps, fRenameSubpackages);
		// Note: This reverse change only works if the renamePackage change did
		// not merge the source package into an existing target.
	}

	@Override
	protected void doRename(IProgressMonitor pm) throws CoreException {
		IPackageFragment pack= getPackage();
		if (pack == null)
			return;

		if (!fRenameSubpackages) {
			renamePackage(pack, pm, createNewPath(), getNewName());

		} else {
			IPackageFragment[] allPackages= JavaElementUtil.getPackageAndSubpackages(pack);
			Arrays.sort(allPackages, (o1, o2) -> {
				String p1= o1.getElementName();
				String p2= o2.getElementName();
				return p1.compareTo(p2);
			});
			int count= allPackages.length;
			pm.beginTask("", count); //$NON-NLS-1$
			// When renaming to subpackage (a -> a.b), do it inside-out:
			boolean insideOut= getNewName().startsWith(getOldName());
			try {
				for (int i= 0; i < count; i++) {
					IPackageFragment currentPackage= allPackages[insideOut ? count - i - 1 : i];
					renamePackage(currentPackage, new SubProgressMonitor(pm, 1), createNewPath(currentPackage), getNewName(currentPackage));
				}
			} finally {
				pm.done();
			}
		}
	}

	@Override
	public String getName() {
		String msg= fRenameSubpackages ? RefactoringCoreMessages.RenamePackageChange_name_with_subpackages : RefactoringCoreMessages.RenamePackageChange_name;
		String[] keys= { BasicElementLabels.getJavaElementName(getOldName()), BasicElementLabels.getJavaElementName(getNewName())};
		return Messages.format(msg, keys);
	}

	private String getNewName(IPackageFragment subpackage) {
		return getNewName() + subpackage.getElementName().substring(getOldName().length());
	}

	private IPackageFragment getPackage() {
		return (IPackageFragment) getModifiedElement();
	}

	@Override
	public RefactoringStatus isValid(IProgressMonitor pm) throws CoreException {
		pm.beginTask("", 2); //$NON-NLS-1$
		RefactoringStatus result;
		try {
			result= new RefactoringStatus();
			IJavaElement element= (IJavaElement) getModifiedElement();
			// don't check for read-only since we don't go through
			// validate edit.
			result.merge(super.isValid(new SubProgressMonitor(pm, 1)));
			if (result.hasFatalError())
				return result;
			if (element != null && element.exists() && element instanceof IPackageFragment) {
				IPackageFragment pack= (IPackageFragment) element;
				if (fRenameSubpackages) {
					IPackageFragment[] allPackages= JavaElementUtil.getPackageAndSubpackages(pack);
					SubProgressMonitor subPm= new SubProgressMonitor(pm, 1);
					subPm.beginTask("", allPackages.length); //$NON-NLS-1$
					for (IPackageFragment pckg : allPackages) {
						// don't check for read-only since we don't go through
						// validate edit.
						checkIfModifiable(result, pckg.getResource(), VALIDATE_NOT_DIRTY);
						if (result.hasFatalError())
							return result;
						isValid(result, pckg, new SubProgressMonitor(subPm, 1));
					}
				} else {
					isValid(result, pack, new SubProgressMonitor(pm, 1));
				}
			}
		} finally {
			pm.done();
		}
		return result;
	}

	private void isValid(RefactoringStatus result, IPackageFragment pack, IProgressMonitor pm) throws JavaModelException {
		ICompilationUnit[] units= pack.getCompilationUnits();
		pm.beginTask("", units.length); //$NON-NLS-1$
		for (ICompilationUnit unit : units) {
			pm.subTask(Messages.format(RefactoringCoreMessages.RenamePackageChange_checking_change, JavaElementLabels.getElementLabel(pack, JavaElementLabels.ALL_DEFAULT)));
			checkIfModifiable(result, unit.getResource(), VALIDATE_NOT_READ_ONLY | VALIDATE_NOT_DIRTY);
			pm.worked(1);
		}
		pm.done();
	}

	private void renamePackage(IPackageFragment pack, IProgressMonitor pm, IPath newPath, String newName) throws JavaModelException, CoreException {
		if (! pack.exists())
			return; // happens if empty parent with single subpackage is renamed, see https://bugs.eclipse.org/bugs/show_bug.cgi?id=199045
		pack.rename(newName, false, pm);
		if (fCompilationUnitStamps != null) {
			IPackageFragment newPack= (IPackageFragment) JavaCore.create(ResourcesPlugin.getWorkspace().getRoot().getFolder(newPath));
			if (newPack.exists()) {
				for (ICompilationUnit unit : newPack.getCompilationUnits()) {
					IResource resource= unit.getResource();
					if (resource != null) {
						Long stamp= fCompilationUnitStamps.get(resource);
						if (stamp != null) {
							resource.revertModificationStamp(stamp);
						}
					}
				}
			}
		}
	}
}
