/*******************************************************************************
 * Copyright (c) 2000, 2011 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.corext.refactoring.delegates;

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

import org.eclipse.core.runtime.Assert;

import org.eclipse.text.edits.TextEdit;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.Document;
import org.eclipse.jface.text.IDocument;

import org.eclipse.ltk.core.refactoring.CategorizedTextEditGroup;
import org.eclipse.ltk.core.refactoring.GroupCategory;
import org.eclipse.ltk.core.refactoring.GroupCategorySet;

import org.eclipse.jdt.core.JavaModelException;
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.BodyDeclaration;
import org.eclipse.jdt.core.dom.ChildListPropertyDescriptor;
import org.eclipse.jdt.core.dom.ChildPropertyDescriptor;
import org.eclipse.jdt.core.dom.Expression;
import org.eclipse.jdt.core.dom.IBinding;
import org.eclipse.jdt.core.dom.ITypeBinding;
import org.eclipse.jdt.core.dom.Javadoc;
import org.eclipse.jdt.core.dom.Name;
import org.eclipse.jdt.core.dom.TagElement;
import org.eclipse.jdt.core.dom.TextElement;
import org.eclipse.jdt.core.dom.Type;
import org.eclipse.jdt.core.dom.rewrite.ITrackedNodePosition;
import org.eclipse.jdt.core.dom.rewrite.ListRewrite;

import org.eclipse.jdt.internal.corext.codemanipulation.CodeGenerationSettings;
import org.eclipse.jdt.internal.corext.dom.ASTNodeFactory;
import org.eclipse.jdt.internal.corext.dom.ASTNodes;
import org.eclipse.jdt.internal.corext.refactoring.RefactoringCoreMessages;
import org.eclipse.jdt.internal.corext.refactoring.structure.CompilationUnitRewrite;
import org.eclipse.jdt.internal.corext.util.Strings;

import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.jdt.internal.ui.preferences.JavaPreferencesSettings;

/**
 * <p>
 * This class implements functionality for creating delegates of renamed or moved
 * members pointing to the original element and containing a
 * deprecation message. The delegate is always created in the source file of the
 * original element and is either added directly after the original element or
 * replaces it. Use this class as follows:
 * </p>
 *
 * <pre>
 *     DelegateCreator myCreator= new DelegateMethodCreator();
 *     myCreator.setRewrite(... cu-rewrite of modified file...);
 *     myCreator.setDeclaration(... declaration of moved/renamed member ...);
 *
 *     ... additional initialization methods, see below...
 *
 *     myCreator.prepareDelegate();
 *
 *     ... do something with the delegate before the edit is created ...
 *
 *     myCreator.createEdit();
 * </pre>
 *
 * <p>
 * Before prepareDelegate(), depending on whether the member is moved or
 * renamed, or both, as well as other concerns, the following methods may be
 * called:
 * </p>
 *
 * <pre>
 *     myCreator.setNewLocation(... new location where the member was moved ...);
 *     myCreator.setNewName(... new name of the member if renamed ...);
 *     myCreator.setDeclareDeprecated(... false or true ...);
 *     myCreator.setCopy(... false or true...);
 * </pre>
 *
 * <p>
 * Note that removing or adding imports related to delegate creation is
 * generally the responsibility of the caller. As an exception, the import for a
 * target type set via setNewLocation() will be added by this class.
 * </p>
 *
 * <p>
 * This class is intended to be subclassed by specialized creators for concrete
 * element types like methods or fields.
 * </p>
 *
 * @since 3.2
 *
 */
public abstract class DelegateCreator {

	public static final GroupCategorySet CATEGORY_DELEGATE= new GroupCategorySet(new GroupCategory("org.eclipse.jdt.internal.corext.refactoring.delegates.delegate", RefactoringCoreMessages.DelegateCreator_change_category_title, RefactoringCoreMessages.DelegateCreator_change_category_description)); //$NON-NLS-1$

	/*
	 * We are dealing with two CURewrites here:
	 *
	 * 1) The original rewrite which is passed in from the outside. One import may
	 * 	  be registered with this CURewrite in case setNewLocation() is called.
	 * 	  On createEdit(), the complete delegate code will be added to the CURewrite's
	 * 	  ASTRewrite (add or replace).
	 *
	 * 2) A new CuRewrite from which we'll only use the ASTRewrite to build the new delegate.
	 *
	 */
	private CompilationUnitRewrite fOriginalRewrite;
	private CompilationUnitRewrite fDelegateRewrite;

	private boolean fIsMoveToAnotherFile;
	private boolean fCopy;
	private boolean fDeclareDeprecated;
	private boolean fInsertBefore;

	private BodyDeclaration fDeclaration;
	private String fNewElementName;
	private ITypeBinding fDestinationTypeBinding;
	private Type fDestinationType;
	private ITrackedNodePosition fTrackedPosition;

	private CodeGenerationSettings fPreferences;

	public DelegateCreator() {
		fCopy= true;
		fDeclareDeprecated= true;
		fInsertBefore= false;
	}

	/**
	 * Sets the compilation unit rewrite of the declaration to create a delegate
	 * for. Must always be called prior to prepareDelegate(). Bindings need not
	 * be resolved.
	 *
	 * @param rewrite the CompilationUnitRewrite.
	 */
	public void setSourceRewrite(CompilationUnitRewrite rewrite) {
		fOriginalRewrite= rewrite;
		fPreferences= JavaPreferencesSettings.getCodeGenerationSettings(rewrite.getCu().getJavaProject());

		fDelegateRewrite= new CompilationUnitRewrite(rewrite.getCu(), rewrite.getRoot());
		fDelegateRewrite.getASTRewrite().setTargetSourceRangeComputer(rewrite.getASTRewrite().getExtendedSourceRangeComputer());
	}

	/**
	 * Sets the old member declaration. Must always be called prior to
	 * prepareDelegate().
	 *
	 * @param declaration the BodyDeclaration
	 */
	public void setDeclaration(BodyDeclaration declaration) {
		fDeclaration= declaration;
	}

	/**
	 * Set the name of the new element. This is optional, but if set it must be
	 * called prior to prepareDelegate().
	 *
	 * @param newName the String with the new name
	 */
	public void setNewElementName(String newName) {
		fNewElementName= newName;
	}

	/**
	 * Set the location of the new element. This is optional, but if set it must
	 * be called prior to prepareDelegate().
	 *
	 * @param binding the ITypeBinding of the old type
	 */
	public void setNewLocation(ITypeBinding binding) {
		fDestinationTypeBinding= binding;
	}

	/**
	 * Set whether the existing element should be copied and the copy made
	 * delegate (true), or the original element should be changed to become the
	 * delegate (false). This is optional, but if set it must be called prior to
	 * prepareDelegate().
	 *
	 * The default is true (create a copy).
	 *
	 * @param isCopy true if a copy should be created
	 */
	public void setCopy(boolean isCopy) {
		fCopy= isCopy;
	}

	/**
	 * Sets whether a deprecation message including a link to the new element
	 * should be added to the javadoc of the delegate. This is optional, but if
	 * set it must be called prior to prepareDelegate().
	 *
	 * The default is true (create deprecation message).
	 *
	 * @param declareDeprecated true if the member should be deprecated
	 */
	public void setDeclareDeprecated(boolean declareDeprecated) {
		fDeclareDeprecated= declareDeprecated;
	}

	/**
	 * When in copy mode, use this method to control the insertion point of the
	 * delegate. If the parameter is true, the delegate gets inserted before the
	 * original declaration. If false, the delegate gets inserted after the
	 * original declaration.
	 *
	 * The default is false (do not insert before).
	 *
	 * @param insertBefore insertion point
	 */
	public void setInsertBefore(boolean insertBefore) {
		fInsertBefore= insertBefore;
	}

	// Methods to be overridden by subclasses

	/**
	 * Initializes the creator. Must set the "new" name of the element if not
	 * already set.
	 *
	 */
	protected abstract void initialize();

	/**
	 *
	 * Creates the body of the delegate.
	 *
	 * @param declaration the member declaration
	 * @return the body of the delegate
	 * @throws JavaModelException
	 */
	protected abstract ASTNode createBody(BodyDeclaration declaration) throws JavaModelException;

	/**
	 * Creates the javadoc reference to the old member to be put inside the
	 * javadoc comment.
	 *
	 * This method is only called if isDeclareDeprecated() == true.
	 *
	 * @param declaration the member declaration
	 * @return the javadoc link node
	 * @throws JavaModelException
	 */
	protected abstract ASTNode createDocReference(BodyDeclaration declaration) throws JavaModelException;

	/**
	 * Returns the node of the declaration on which to add the body.
	 *
	 * @param declaration the member declaration
	 * @return the body head
	 */
	protected abstract ASTNode getBodyHead(BodyDeclaration declaration);

	/**
	 * Returns the javadoc property descriptor. The javadoc will be added using
	 * this descriptor.
	 *
	 * @return property descriptor
	 */
	protected abstract ChildPropertyDescriptor getJavaDocProperty();

	/**
	 * Returns the body property descriptor. The body of the delegate will be
	 * added using this descriptor.
	 *
	 * @return property descriptor
	 */
	protected abstract ChildPropertyDescriptor getBodyProperty();


	// Getters for subclasses

	protected boolean isMoveToAnotherFile() {
		return fIsMoveToAnotherFile;
	}

	protected AST getAst() {
		return fDelegateRewrite.getAST();
	}

	protected BodyDeclaration getDeclaration() {
		return fDeclaration;
	}

	protected String getNewElementName() {
		return fNewElementName;
	}

	/**
	 * Prepares the delegate member. The delegate member will have the same
	 * signature as the old member and contain a call to the new member and a
	 * javadoc reference with a reference to the new member.
	 *
	 * All references to the new member will contain the new name of the member
	 * and/or new declaring type, if any.
	 *
	 */
	public void prepareDelegate() throws JavaModelException {
		Assert.isNotNull(fDelegateRewrite);
		Assert.isNotNull(fDeclaration);

		initialize();

		// Moving to a new type?
		if (fDestinationTypeBinding != null) {
			fDestinationType= fOriginalRewrite.getImportRewrite().addImport(fDestinationTypeBinding, getAst());
			fIsMoveToAnotherFile= true;
		} else
			fIsMoveToAnotherFile= false;

		fTrackedPosition= fDelegateRewrite.getASTRewrite().track(fDeclaration);

		ASTNode delegateBody= createBody(fDeclaration);
		if (delegateBody != null) {
			// is null for interface and abstract methods
			fDelegateRewrite.getASTRewrite().set(getBodyHead(fDeclaration), getBodyProperty(), delegateBody, null);
		}

		if (fDeclareDeprecated) {
			createJavadoc();
		}
	}

	/**
	 * Creates the javadoc for the delegate.
	 *
	 * @throws JavaModelException
	 */
	private void createJavadoc() throws JavaModelException {
		TagElement tag= getDelegateJavadocTag(fDeclaration);

		Javadoc comment= fDeclaration.getJavadoc();
		if (comment == null) {
			comment= getAst().newJavadoc();
			comment.tags().add(tag);
			fDelegateRewrite.getASTRewrite().set(fDeclaration, getJavaDocProperty(), comment, null);
		} else
			fDelegateRewrite.getASTRewrite().getListRewrite(comment, Javadoc.TAGS_PROPERTY).insertLast(tag, null);
	}

	/**
	 * Performs the actual rewriting and adds an edit to the ASTRewrite set with
	 * {@link #setSourceRewrite(CompilationUnitRewrite)}.
	 *
	 * @throws JavaModelException
	 */
	public void createEdit() throws JavaModelException {
		try {
			IDocument document= new Document(fDelegateRewrite.getCu().getBuffer().getContents());
			TextEdit edit= fDelegateRewrite.getASTRewrite().rewriteAST(document, fDelegateRewrite.getCu().getJavaProject().getOptions(true));
			edit.apply(document, TextEdit.UPDATE_REGIONS);

			String newSource= Strings.trimIndentation(document.get(fTrackedPosition.getStartPosition(), fTrackedPosition.getLength()),
					fPreferences.tabWidth, fPreferences.indentWidth, false);

			ASTNode placeholder= fOriginalRewrite.getASTRewrite().createStringPlaceholder(newSource, fDeclaration.getNodeType());

			CategorizedTextEditGroup groupDescription= fOriginalRewrite.createCategorizedGroupDescription(getTextEditGroupLabel(), CATEGORY_DELEGATE);
			ListRewrite bodyDeclarationsListRewrite= fOriginalRewrite.getASTRewrite().getListRewrite(fDeclaration.getParent(), getTypeBodyDeclarationsProperty());
			if (fCopy)
				if (fInsertBefore)
					bodyDeclarationsListRewrite.insertBefore(placeholder, fDeclaration, groupDescription);
				else
					bodyDeclarationsListRewrite.insertAfter(placeholder, fDeclaration, groupDescription);
			else
				bodyDeclarationsListRewrite.replace(fDeclaration, placeholder, groupDescription);

		} catch (BadLocationException e) {
			JavaPlugin.log(e);
		}
	}

	protected abstract String getTextEditGroupLabel();

	/**
	 * Returns the binding of the declaration.
	 *
	 * @return the binding of the declaration
	 */
	protected abstract IBinding getDeclarationBinding();

	/**
	 * Returns a new rewrite with the delegate changes registered. This rewrite
	 * can be used in-between calls to prepareDelegate() and createEdit() to add
	 * additional changes to the delegate.
	 *
	 * @return CompilationUnitRewrite the new rewrite
	 */
	public CompilationUnitRewrite getDelegateRewrite() {
		return fDelegateRewrite;
	}

	// ******************* INTERNAL HELPERS ***************************

	private TagElement getDelegateJavadocTag(BodyDeclaration declaration) throws JavaModelException {
		Assert.isNotNull(declaration);

		String msg= RefactoringCoreMessages.DelegateCreator_use_member_instead;
		int firstParam= msg.indexOf("{0}"); //$NON-NLS-1$
		Assert.isTrue(firstParam != -1);

		List<ASTNode> fragments= new ArrayList<ASTNode>();
		TextElement text= getAst().newTextElement();
		text.setText(msg.substring(0, firstParam).trim());
		fragments.add(text);

		fragments.add(createJavadocMemberReferenceTag(declaration, getAst()));

		text= getAst().newTextElement();
		text.setText(msg.substring(firstParam + 3).trim());
		fragments.add(text);

		final TagElement tag= getAst().newTagElement();
		tag.setTagName(TagElement.TAG_DEPRECATED);
		tag.fragments().addAll(fragments);
		return tag;
	}

	private TagElement createJavadocMemberReferenceTag(BodyDeclaration declaration, final AST ast) throws JavaModelException {
		Assert.isNotNull(ast);
		Assert.isNotNull(declaration);
		ASTNode javadocReference= createDocReference(declaration);
		final TagElement element= ast.newTagElement();
		element.setTagName(TagElement.TAG_LINK);
		element.fragments().add(javadocReference);
		return element;
	}

	protected Expression getAccess() {
		return isMoveToAnotherFile() ? createDestinationTypeName() : null;
	}

	protected Name createDestinationTypeName() {
		return ASTNodeFactory.newName(getAst(), ASTNodes.asString(fDestinationType));
	}

	private ChildListPropertyDescriptor getTypeBodyDeclarationsProperty() {
		ASTNode parent= fDeclaration.getParent();

		if (parent instanceof AbstractTypeDeclaration)
			return ((AbstractTypeDeclaration) parent).getBodyDeclarationsProperty();
		else if (parent instanceof AnonymousClassDeclaration)
			return AnonymousClassDeclaration.BODY_DECLARATIONS_PROPERTY;

		Assert.isTrue(false);
		return null;
	}
}
