/*
 * Copyright (C) 2012-2014 The Project Lombok Authors.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package lombok.javac.handlers;

import static lombok.core.handlers.HandlerUtil.*;
import static lombok.javac.Javac.*;
import static lombok.javac.handlers.JavacHandlerUtil.*;

import java.util.Collection;

import lombok.AccessLevel;
import lombok.ConfigurationKeys;
import lombok.core.AST.Kind;
import lombok.core.AnnotationValues;
import lombok.experimental.Wither;
import lombok.javac.JavacAnnotationHandler;
import lombok.javac.JavacNode;
import lombok.javac.JavacTreeMaker;
import lombok.javac.handlers.JavacHandlerUtil.CopyJavadoc;

import org.mangosdk.spi.ProviderFor;

import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.code.Symbol.ClassSymbol;
import com.sun.tools.javac.tree.JCTree.JCAnnotation;
import com.sun.tools.javac.tree.JCTree.JCBlock;
import com.sun.tools.javac.tree.JCTree.JCClassDecl;
import com.sun.tools.javac.tree.JCTree.JCConditional;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.tree.JCTree.JCMethodDecl;
import com.sun.tools.javac.tree.JCTree.JCNewClass;
import com.sun.tools.javac.tree.JCTree.JCReturn;
import com.sun.tools.javac.tree.JCTree.JCStatement;
import com.sun.tools.javac.tree.JCTree.JCTypeParameter;
import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.ListBuffer;
import com.sun.tools.javac.util.Name;

Handles the lombok.experimental.Wither annotation for javac. /**
 * Handles the {@code lombok.experimental.Wither} annotation for javac.
 */
@ProviderFor(JavacAnnotationHandler.class)
public class HandleWither extends JavacAnnotationHandler<Wither> {
	public void generateWitherForType(JavacNode typeNode, JavacNode errorNode, AccessLevel level, boolean checkForTypeLevelWither) {
		if (checkForTypeLevelWither) {
			if (hasAnnotation(Wither.class, typeNode)) {
				//The annotation will make it happen, so we can skip it.
				return;
			}
		}
		
		JCClassDecl typeDecl = null;
		if (typeNode.get() instanceof JCClassDecl) typeDecl = (JCClassDecl) typeNode.get();
		long modifiers = typeDecl == null ? 0 : typeDecl.mods.flags;
		boolean notAClass = (modifiers & (Flags.INTERFACE | Flags.ANNOTATION | Flags.ENUM)) != 0;
		
		if (typeDecl == null || notAClass) {
			errorNode.addError("@Wither is only supported on a class or a field.");
			return;
		}
		
		for (JavacNode field : typeNode.down()) {
			if (field.getKind() != Kind.FIELD) continue;
			JCVariableDecl fieldDecl = (JCVariableDecl) field.get();
			//Skip fields that start with $
			if (fieldDecl.name.toString().startsWith("$")) continue;
			//Skip static fields.
			if ((fieldDecl.mods.flags & Flags.STATIC) != 0) continue;
			//Skip final initialized fields.
			if ((fieldDecl.mods.flags & Flags.FINAL) != 0 && fieldDecl.init != null) continue;
			
			generateWitherForField(field, errorNode.get(), level);
		}
	}
	
	
Generates a wither on the stated field. Used by HandleValue. The difference between this call and the handle method is as follows: If there is a lombok.experimental.Wither annotation on the field, it is used and the same rules apply (e.g. warning if the method already exists, stated access level applies). If not, the wither is still generated if it isn't already there, though there will not be a warning if its already there. The default access level is used. 
Params:
fieldNode – The node representing the field you want a wither for.
pos – The node responsible for generating the wither (the @Value or @Wither annotation)./**
	 * Generates a wither on the stated field.
	 * 
	 * Used by {@link HandleValue}.
	 * 
	 * The difference between this call and the handle method is as follows:
	 * 
	 * If there is a {@code lombok.experimental.Wither} annotation on the field, it is used and the
	 * same rules apply (e.g. warning if the method already exists, stated access level applies).
	 * If not, the wither is still generated if it isn't already there, though there will not
	 * be a warning if its already there. The default access level is used.
	 * 
	 * @param fieldNode The node representing the field you want a wither for.
	 * @param pos The node responsible for generating the wither (the {@code @Value} or {@code @Wither} annotation).
	 */
	public void generateWitherForField(JavacNode fieldNode, DiagnosticPosition pos, AccessLevel level) {
		if (hasAnnotation(Wither.class, fieldNode)) {
			//The annotation will make it happen, so we can skip it.
			return;
		}
		
		createWitherForField(level, fieldNode, fieldNode, false, List.<JCAnnotation>nil(), List.<JCAnnotation>nil());
	}
	
	@Override public void handle(AnnotationValues<Wither> annotation, JCAnnotation ast, JavacNode annotationNode) {
		handleExperimentalFlagUsage(annotationNode, ConfigurationKeys.WITHER_FLAG_USAGE, "@Wither");
		
		Collection<JavacNode> fields = annotationNode.upFromAnnotationToFields();
		deleteAnnotationIfNeccessary(annotationNode, Wither.class);
		deleteImportFromCompilationUnit(annotationNode, "lombok.AccessLevel");
		JavacNode node = annotationNode.up();
		AccessLevel level = annotation.getInstance().value();
		
		if (level == AccessLevel.NONE || node == null) return;
		
		List<JCAnnotation> onMethod = unboxAndRemoveAnnotationParameter(ast, "onMethod", "@Wither(onMethod", annotationNode);
		List<JCAnnotation> onParam = unboxAndRemoveAnnotationParameter(ast, "onParam", "@Wither(onParam", annotationNode);
		
		switch (node.getKind()) {
		case FIELD:
			createWitherForFields(level, fields, annotationNode, true, onMethod, onParam);
			break;
		case TYPE:
			if (!onMethod.isEmpty()) annotationNode.addError("'onMethod' is not supported for @Wither on a type.");
			if (!onParam.isEmpty()) annotationNode.addError("'onParam' is not supported for @Wither on a type.");
			generateWitherForType(node, annotationNode, level, false);
			break;
		}
	}
	
	public void createWitherForFields(AccessLevel level, Collection<JavacNode> fieldNodes, JavacNode errorNode, boolean whineIfExists, List<JCAnnotation> onMethod, List<JCAnnotation> onParam) {
		for (JavacNode fieldNode : fieldNodes) {
			createWitherForField(level, fieldNode, errorNode, whineIfExists, onMethod, onParam);
		}
	}
	
	public void createWitherForField(AccessLevel level, JavacNode fieldNode, JavacNode source, boolean strictMode, List<JCAnnotation> onMethod, List<JCAnnotation> onParam) {
		JavacNode typeNode = fieldNode.up();
		boolean makeAbstract = typeNode != null && typeNode.getKind() == Kind.TYPE && (((JCClassDecl) typeNode.get()).mods.flags & Flags.ABSTRACT) != 0;
		
		if (fieldNode.getKind() != Kind.FIELD) {
			fieldNode.addError("@Wither is only supported on a class or a field.");
			return;
		}
		
		JCVariableDecl fieldDecl = (JCVariableDecl)fieldNode.get();
		String methodName = toWitherName(fieldNode);
		
		if (methodName == null) {
			fieldNode.addWarning("Not generating wither for this field: It does not fit your @Accessors prefix list.");
			return;
		}
		
		if ((fieldDecl.mods.flags & Flags.STATIC) != 0) {
			if (strictMode) {
				fieldNode.addWarning("Not generating wither for this field: Withers cannot be generated for static fields.");
			}
			return;
		}
		
		if ((fieldDecl.mods.flags & Flags.FINAL) != 0 && fieldDecl.init != null) {
			if (strictMode) {
				fieldNode.addWarning("Not generating wither for this field: Withers cannot be generated for final, initialized fields.");
			}
			return;
		}
		
		if (fieldDecl.name.toString().startsWith("$")) {
			if (strictMode) {
				fieldNode.addWarning("Not generating wither for this field: Withers cannot be generated for fields starting with $.");
			}
			return;
		}
		
		for (String altName : toAllWitherNames(fieldNode)) {
			switch (methodExists(altName, fieldNode, false, 1)) {
			case EXISTS_BY_LOMBOK:
				return;
			case EXISTS_BY_USER:
				if (strictMode) {
					String altNameExpl = "";
					if (!altName.equals(methodName)) altNameExpl = String.format(" (%s)", altName);
					fieldNode.addWarning(
						String.format("Not generating %s(): A method with that name already exists%s", methodName, altNameExpl));
				}
				return;
			default:
			case NOT_EXISTS:
				//continue scanning the other alt names.
			}
		}
		
		long access = toJavacModifier(level);
		
		JCMethodDecl createdWither = createWither(access, fieldNode, fieldNode.getTreeMaker(), source, onMethod, onParam, makeAbstract);
		ClassSymbol sym = ((JCClassDecl) fieldNode.up().get()).sym;
		Type returnType = sym == null ? null : sym.type;
		
		injectMethod(typeNode, createdWither, List.<Type>of(getMirrorForFieldType(fieldNode)), returnType);
	}
	
	public JCMethodDecl createWither(long access, JavacNode field, JavacTreeMaker maker, JavacNode source, List<JCAnnotation> onMethod, List<JCAnnotation> onParam, boolean makeAbstract) {
		String witherName = toWitherName(field);
		if (witherName == null) return null;
		
		JCVariableDecl fieldDecl = (JCVariableDecl) field.get();
		
		List<JCAnnotation> copyableAnnotations = findCopyableAnnotations(field);
		
		Name methodName = field.toName(witherName);
		
		JCExpression returnType = cloneSelfType(field);
		
		JCBlock methodBody = null;
		long flags = JavacHandlerUtil.addFinalIfNeeded(Flags.PARAMETER, field.getContext());
		List<JCAnnotation> annsOnParam = copyAnnotations(onParam).appendList(copyableAnnotations);
		
		JCVariableDecl param = maker.VarDef(maker.Modifiers(flags, annsOnParam), fieldDecl.name, fieldDecl.vartype, null);
		
		if (!makeAbstract) {
			ListBuffer<JCStatement> statements = new ListBuffer<JCStatement>();
			
			JCExpression selfType = cloneSelfType(field);
			if (selfType == null) return null;
			
			ListBuffer<JCExpression> args = new ListBuffer<JCExpression>();
			for (JavacNode child : field.up().down()) {
				if (child.getKind() != Kind.FIELD) continue;
				JCVariableDecl childDecl = (JCVariableDecl) child.get();
				// Skip fields that start with $
				if (childDecl.name.toString().startsWith("$")) continue;
				long fieldFlags = childDecl.mods.flags;
				// Skip static fields.
				if ((fieldFlags & Flags.STATIC) != 0) continue;
				// Skip initialized final fields.
				if (((fieldFlags & Flags.FINAL) != 0) && childDecl.init != null) continue;
				if (child.get() == field.get()) {
					args.append(maker.Ident(fieldDecl.name));
				} else {
					args.append(createFieldAccessor(maker, child, FieldAccess.ALWAYS_FIELD));
				}
			}
			
			JCNewClass newClass = maker.NewClass(null, List.<JCExpression>nil(), selfType, args.toList(), null);
			JCExpression identityCheck = maker.Binary(CTC_EQUAL, createFieldAccessor(maker, field, FieldAccess.ALWAYS_FIELD), maker.Ident(fieldDecl.name));
			JCConditional conditional = maker.Conditional(identityCheck, maker.Ident(field.toName("this")), newClass);
			JCReturn returnStatement = maker.Return(conditional);
			
			if (!hasNonNullAnnotations(field)) {
				statements.append(returnStatement);
			} else {
				JCStatement nullCheck = generateNullCheck(maker, field, source);
				if (nullCheck != null) statements.append(nullCheck);
				statements.append(returnStatement);
			}
			
			methodBody = maker.Block(0, statements.toList());
		}
		List<JCTypeParameter> methodGenericParams = List.nil();
		List<JCVariableDecl> parameters = List.of(param);
		List<JCExpression> throwsClauses = List.nil();
		JCExpression annotationMethodDefaultValue = null;
		
		List<JCAnnotation> annsOnMethod = copyAnnotations(onMethod);
		
		if (isFieldDeprecated(field)) {
			annsOnMethod = annsOnMethod.prepend(maker.Annotation(genJavaLangTypeRef(field, "Deprecated"), List.<JCExpression>nil()));
		}
		if (makeAbstract) access = access | Flags.ABSTRACT;
		JCMethodDecl decl = recursiveSetGeneratedBy(maker.MethodDef(maker.Modifiers(access, annsOnMethod), methodName, returnType,
				methodGenericParams, parameters, throwsClauses, methodBody, annotationMethodDefaultValue), source.get(), field.getContext());
		copyJavadoc(field, decl, CopyJavadoc.WITHER);
		return decl;
	}
}