/*
 * Copyright © 2009 Reinier Zwitserloot and Roel Spilker.
 * 
 * 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.javac.handlers.PKG.*;
import lombok.AccessLevel;
import lombok.Setter;
import lombok.core.AnnotationValues;
import lombok.core.TransformationsUtil;
import lombok.core.AST.Kind;
import lombok.javac.Javac;
import lombok.javac.JavacAnnotationHandler;
import lombok.javac.JavacNode;

import org.mangosdk.spi.ProviderFor;

import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.tree.TreeMaker;
import com.sun.tools.javac.tree.JCTree.JCAnnotation;
import com.sun.tools.javac.tree.JCTree.JCAssign;
import com.sun.tools.javac.tree.JCTree.JCBlock;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.tree.JCTree.JCFieldAccess;
import com.sun.tools.javac.tree.JCTree.JCMethodDecl;
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.List;
import com.sun.tools.javac.util.Name;
import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;

/**
 * Handles the {@code lombok.Setter} annotation for javac.
 */
@ProviderFor(JavacAnnotationHandler.class)
public class HandleSetter implements JavacAnnotationHandler<Setter> {
	/**
	 * Generates a setter on the stated field.
	 * 
	 * Used by {@link HandleData}.
	 * 
	 * The difference between this call and the handle method is as follows:
	 * 
	 * If there is a {@code lombok.Setter} 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 setter 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.
	 */
	public void generateSetterForField(JavacNode fieldNode, DiagnosticPosition pos) {
		for (JavacNode child : fieldNode.down()) {
			if (child.getKind() == Kind.ANNOTATION) {
				if (Javac.annotationTypeMatches(Setter.class, child)) {
					//The annotation will make it happen, so we can skip it.
					return;
				}
			}
		}
		
		createSetterForField(AccessLevel.PUBLIC, fieldNode, fieldNode, pos, false);
	}
	
	@Override public boolean handle(AnnotationValues<Setter> annotation, JCAnnotation ast, JavacNode annotationNode) {
		JavacNode fieldNode = annotationNode.up();
		AccessLevel level = annotation.getInstance().value();
		if (level == AccessLevel.NONE) return true;
		
		return createSetterForField(level, fieldNode, annotationNode, annotationNode.get(), true);
	}
	
	private boolean createSetterForField(AccessLevel level,
			JavacNode fieldNode, JavacNode errorNode, DiagnosticPosition pos, boolean whineIfExists) {
		if (fieldNode.getKind() != Kind.FIELD) {
			fieldNode.addError("@Setter is only supported on a field.");
			return true;
		}
		
		JCVariableDecl fieldDecl = (JCVariableDecl)fieldNode.get();
		String methodName = toSetterName(fieldDecl);
		
		switch (methodExists(methodName, fieldNode)) {
		case EXISTS_BY_LOMBOK:
			return true;
		case EXISTS_BY_USER:
			if (whineIfExists) errorNode.addWarning(
					String.format("Not generating %s(%s %s): A method with that name already exists",
					methodName, fieldDecl.vartype, fieldDecl.name));
			return true;
		default:
		case NOT_EXISTS:
			//continue with creating the setter
		}
		
		long access = toJavacModifier(level) | (fieldDecl.mods.flags & Flags.STATIC);
		
		injectMethod(fieldNode.up(), createSetter(access, fieldNode, fieldNode.getTreeMaker()));
		
		return true;
	}
	
	private JCMethodDecl createSetter(long access, JavacNode field, TreeMaker treeMaker) {
		JCVariableDecl fieldDecl = (JCVariableDecl) field.get();
		
		JCFieldAccess thisX = treeMaker.Select(treeMaker.Ident(field.toName("this")), fieldDecl.name);
		JCAssign assign = treeMaker.Assign(thisX, treeMaker.Ident(fieldDecl.name));
		
		List<JCStatement> statements;
		List<JCAnnotation> nonNulls = findAnnotations(field, TransformationsUtil.NON_NULL_PATTERN);
		List<JCAnnotation> nullables = findAnnotations(field, TransformationsUtil.NULLABLE_PATTERN);
		
		if (nonNulls.isEmpty()) {
			statements = List.<JCStatement>of(treeMaker.Exec(assign));
		} else {
			JCStatement nullCheck = generateNullCheck(treeMaker, field);
			if (nullCheck != null) statements = List.<JCStatement>of(nullCheck, treeMaker.Exec(assign));
			else statements = List.<JCStatement>of(treeMaker.Exec(assign));
		}
		
		JCBlock methodBody = treeMaker.Block(0, statements);
		Name methodName = field.toName(toSetterName(fieldDecl));
		JCVariableDecl param = treeMaker.VarDef(treeMaker.Modifiers(Flags.FINAL, nonNulls.appendList(nullables)), fieldDecl.name, fieldDecl.vartype, null);
		JCExpression methodType = treeMaker.Type(field.getSymbolTable().voidType);
		
		List<JCTypeParameter> methodGenericParams = List.nil();
		List<JCVariableDecl> parameters = List.of(param);
		List<JCExpression> throwsClauses = List.nil();
		JCExpression annotationMethodDefaultValue = null;
		
		return treeMaker.MethodDef(treeMaker.Modifiers(access, List.<JCAnnotation>nil()), methodName, methodType,
				methodGenericParams, parameters, throwsClauses, methodBody, annotationMethodDefaultValue);
	}
}