/*******************************************************************************
 * Copyright (c) 2000, 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
 *     Microsoft Corporation - copied to jdt.core.manipulation
 *******************************************************************************/
package org.eclipse.jdt.internal.corext.dom;

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

import org.eclipse.core.runtime.Assert;

import org.eclipse.text.edits.TextEditGroup;

import org.eclipse.jdt.core.dom.AST;
import org.eclipse.jdt.core.dom.ASTNode;
import org.eclipse.jdt.core.dom.AbstractTypeDeclaration;
import org.eclipse.jdt.core.dom.AnonymousClassDeclaration;
import org.eclipse.jdt.core.dom.Block;
import org.eclipse.jdt.core.dom.FieldDeclaration;
import org.eclipse.jdt.core.dom.IExtendedModifier;
import org.eclipse.jdt.core.dom.Modifier;
import org.eclipse.jdt.core.dom.SingleVariableDeclaration;
import org.eclipse.jdt.core.dom.SwitchStatement;
import org.eclipse.jdt.core.dom.Type;
import org.eclipse.jdt.core.dom.VariableDeclarationExpression;
import org.eclipse.jdt.core.dom.VariableDeclarationFragment;
import org.eclipse.jdt.core.dom.VariableDeclarationStatement;
import org.eclipse.jdt.core.dom.rewrite.ASTRewrite;
import org.eclipse.jdt.core.dom.rewrite.ListRewrite;

/**
 * Rewrite helper for variable declarations.
 *
 * see JDTUIHelperClasses
 */
public class VariableDeclarationRewrite {

	public static void rewriteModifiers(final SingleVariableDeclaration declarationNode, final int includedModifiers, final int excludedModifiers, final ASTRewrite rewrite, final TextEditGroup group) {
		ModifierRewrite listRewrite= ModifierRewrite.create(rewrite, declarationNode);
		listRewrite.setModifiers(includedModifiers, excludedModifiers, group);
	}

	public static void rewriteModifiers(final VariableDeclarationExpression declarationNode, final int includedModifiers, final int excludedModifiers, final ASTRewrite rewrite, final TextEditGroup group) {
		ModifierRewrite listRewrite= ModifierRewrite.create(rewrite, declarationNode);
		listRewrite.setModifiers(includedModifiers, excludedModifiers, group);
	}

	public static void rewriteModifiers(final FieldDeclaration declarationNode, final VariableDeclarationFragment[] toChange, final int includedModifiers, final int excludedModifiers, final ASTRewrite rewrite, final TextEditGroup group) {
		final List<VariableDeclarationFragment> fragmentsToChange= Arrays.asList(toChange);
		AST ast= declarationNode.getAST();
/*
 * Problem: Same declarationNode can be the subject of multiple calls to this method.
 * For the 2nd++ calls, the original declarationNode has already been rewritten, and this has to be taken into account.
 *
 * Assumption:
 * - Modifiers for each VariableDeclarationFragment are modified at most once.
 *
 * Solution:
 * - Maintain a map from original VariableDeclarationFragments to their new FieldDeclaration.
 * - Original modifiers in declarationNode belong to the first fragment.
 * - When a later fragment needs different modifiers, we create a new FieldDeclaration and move all successive fragments into that declaration
 * - When a fragment has been moved to a new declaration, make sure we don't create a new move target again, but instead use the already created one
 */
		List<VariableDeclarationFragment> fragments= declarationNode.fragments();
		Iterator<VariableDeclarationFragment> iter= fragments.iterator();

		ListRewrite blockRewrite;
		if (declarationNode.getParent() instanceof AbstractTypeDeclaration) {
			blockRewrite= rewrite.getListRewrite(declarationNode.getParent(), ((AbstractTypeDeclaration)declarationNode.getParent()).getBodyDeclarationsProperty());
		} else {
			blockRewrite= rewrite.getListRewrite(declarationNode.getParent(), AnonymousClassDeclaration.BODY_DECLARATIONS_PROPERTY);
		}

		VariableDeclarationFragment lastFragment= iter.next();
		ASTNode lastStatement= declarationNode;

		if (fragmentsToChange.contains(lastFragment)) {
			ModifierRewrite modifierRewrite= ModifierRewrite.create(rewrite, declarationNode);
			modifierRewrite.setModifiers(includedModifiers, excludedModifiers, group);
		}

		ListRewrite fragmentsRewrite= null;
		while (iter.hasNext()) {
			VariableDeclarationFragment currentFragment= iter.next();

			@SuppressWarnings("unchecked")
			Map<VariableDeclarationFragment, MovedFragment> lookup= (Map<VariableDeclarationFragment, MovedFragment>) rewrite.getProperty(MovedFragment.class.getName());
			if (lookup == null) {
				lookup= new HashMap<>();
				rewrite.setProperty(MovedFragment.class.getName(), lookup);
			}
			MovedFragment currentMovedFragment= lookup.get(currentFragment);

			boolean changeLast= fragmentsToChange.contains(lastFragment);
			boolean changeCurrent= fragmentsToChange.contains(currentFragment);
			if (changeLast != changeCurrent || lookup.containsKey(lastFragment)) {
				ModifierRewrite modifierRewrite= null;
				if (currentMovedFragment != null) {
					// Current fragment has already been moved.

					if (currentMovedFragment.fUsesOriginalModifiers) {
						// Need to put in the right modifiers (removing any existing ones).
						modifierRewrite= ModifierRewrite.create(rewrite, currentMovedFragment.fDeclaration);
						ListRewrite listRewrite= rewrite.getListRewrite(currentMovedFragment.fDeclaration, FieldDeclaration.MODIFIERS2_PROPERTY);
						List<IExtendedModifier> extendedList= listRewrite.getRewrittenList();
						for (IExtendedModifier element : extendedList) {
							ASTNode curr= (ASTNode)element;
							if (curr instanceof Modifier)
								rewrite.remove(curr, group);
						}
					}
					// otherwise, don't need to touch the modifiers, so leave modifierRewrite null

				} else { // need to split an existing field declaration
					VariableDeclarationFragment moveTarget;
					moveTarget= (VariableDeclarationFragment)rewrite.createMoveTarget(currentFragment);

					FieldDeclaration newStatement= (FieldDeclaration)ast.createInstance(FieldDeclaration.class);
					rewrite.getListRewrite(newStatement, FieldDeclaration.FRAGMENTS_PROPERTY).insertLast(moveTarget, group);
					lookup.put(currentFragment, new MovedFragment(moveTarget, newStatement, !changeCurrent));
					rewrite.set(newStatement, FieldDeclaration.TYPE_PROPERTY, rewrite.createCopyTarget(declarationNode.getType()), group);

					modifierRewrite= ModifierRewrite.create(rewrite, newStatement);
					modifierRewrite.copyAllAnnotations(declarationNode, group);
					blockRewrite.insertAfter(newStatement, lastStatement, group);

					fragmentsRewrite= rewrite.getListRewrite(newStatement, FieldDeclaration.FRAGMENTS_PROPERTY);
					lastStatement= newStatement;
				}

				if (modifierRewrite != null) {
					if (changeCurrent) {
						int newModifiers= (declarationNode.getModifiers() & ~excludedModifiers) | includedModifiers;
						modifierRewrite.setModifiers(newModifiers, excludedModifiers, group);
					} else {
						int newModifiers= declarationNode.getModifiers();
						modifierRewrite.setModifiers(newModifiers, Modifier.NONE, group);
					}
				}

			} else if (fragmentsRewrite != null) {
				VariableDeclarationFragment fragment0;
				boolean usesOriginalModifiers= true;
				if (currentMovedFragment != null) {
					fragment0= currentMovedFragment.fMoveTarget;
					usesOriginalModifiers= currentMovedFragment.fUsesOriginalModifiers;
					rewrite.getListRewrite(currentMovedFragment.fDeclaration, FieldDeclaration.FRAGMENTS_PROPERTY).remove(fragment0, group);
				} else {
					fragment0= (VariableDeclarationFragment)rewrite.createMoveTarget(currentFragment);
				}
				lookup.put(currentFragment, new MovedFragment(fragment0, lastStatement, usesOriginalModifiers));
				fragmentsRewrite.insertLast(fragment0, group);
			}
			lastFragment= currentFragment;
		}
	}

	private static class MovedFragment {
		final VariableDeclarationFragment fMoveTarget;
		final ASTNode fDeclaration;
		boolean fUsesOriginalModifiers;

		public MovedFragment(VariableDeclarationFragment moveTarget, ASTNode declaration, boolean usesOriginalModifiers) {
			fMoveTarget= moveTarget;
			fDeclaration= declaration;
			fUsesOriginalModifiers= usesOriginalModifiers;
		}
	}

	public static void rewriteModifiers(final VariableDeclarationStatement declarationNode, final VariableDeclarationFragment[] toChange, final int includedModifiers, final int excludedModifiers, ASTRewrite rewrite, final TextEditGroup group) {
		final List<VariableDeclarationFragment> fragmentsToChange= Arrays.asList(toChange);
		AST ast= declarationNode.getAST();

		List<VariableDeclarationFragment> fragments= declarationNode.fragments();
		Iterator<VariableDeclarationFragment> iter= fragments.iterator();

		ListRewrite blockRewrite= null;
		ASTNode parentStatement= declarationNode.getParent();
		if (parentStatement instanceof SwitchStatement) {
			blockRewrite= rewrite.getListRewrite(parentStatement, SwitchStatement.STATEMENTS_PROPERTY);
		} else if (parentStatement instanceof Block) {
			blockRewrite= rewrite.getListRewrite(parentStatement, Block.STATEMENTS_PROPERTY);
		} else {
			// should not happen. VariableDeclaration's can not be in a control statement body
			Assert.isTrue(false);
		}

		VariableDeclarationFragment lastFragment= iter.next();
		ASTNode lastStatement= declarationNode;

		boolean modifiersModified= false;
		if (fragmentsToChange.contains(lastFragment)) {
			ModifierRewrite modifierRewrite= ModifierRewrite.create(rewrite, declarationNode);
			modifierRewrite.setModifiers(includedModifiers, excludedModifiers, group);
			modifiersModified= true;
		}

		ListRewrite fragmentsRewrite= null;
		while (iter.hasNext()) {
			VariableDeclarationFragment currentFragment= iter.next();

			if (fragmentsToChange.contains(lastFragment) != fragmentsToChange.contains(currentFragment)) {

					VariableDeclarationStatement newStatement= ast.newVariableDeclarationStatement((VariableDeclarationFragment)rewrite.createMoveTarget(currentFragment));
					newStatement.setType((Type)rewrite.createCopyTarget(declarationNode.getType()));

					ModifierRewrite modifierRewrite= ModifierRewrite.create(rewrite, newStatement);
					if (fragmentsToChange.contains(currentFragment)) {
						modifierRewrite.copyAllAnnotations(declarationNode, group);
						int newModifiers= (declarationNode.getModifiers() & ~excludedModifiers) | includedModifiers;
						modifierRewrite.setModifiers(newModifiers, excludedModifiers, group);
					} else {
						modifierRewrite.copyAllModifiers(declarationNode, group, modifiersModified);
					}
					blockRewrite.insertAfter(newStatement, lastStatement, group);

					fragmentsRewrite= rewrite.getListRewrite(newStatement, VariableDeclarationStatement.FRAGMENTS_PROPERTY);
					lastStatement= newStatement;
			} else if (fragmentsRewrite != null) {
				ASTNode fragment0= rewrite.createMoveTarget(currentFragment);
				fragmentsRewrite.insertLast(fragment0, group);
			}
			lastFragment= currentFragment;
		}
	}

	private VariableDeclarationRewrite() {
	}
}
