package lombok.javac.handlers;

import static lombok.javac.handlers.PKG.*;

import org.mangosdk.spi.ProviderFor;

import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.code.TypeTags;
import com.sun.tools.javac.tree.TreeMaker;
import com.sun.tools.javac.tree.JCTree.JCAnnotation;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.tree.JCTree.JCMethodDecl;
import com.sun.tools.javac.tree.JCTree.JCNewArray;
import com.sun.tools.javac.tree.JCTree.JCStatement;
import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
import com.sun.tools.javac.util.List;

import lombok.Synchronized;
import lombok.core.AnnotationValues;
import lombok.core.AST.Kind;
import lombok.javac.JavacAnnotationHandler;
import lombok.javac.JavacAST.Node;

@ProviderFor(JavacAnnotationHandler.class)
public class HandleSynchronized implements JavacAnnotationHandler<Synchronized> {
	private static final String INSTANCE_LOCK_NAME = "$lock";
	private static final String STATIC_LOCK_NAME = "$LOCK";
	
	@Override public boolean handle(AnnotationValues<Synchronized> annotation, JCAnnotation ast, Node annotationNode) {
		Node methodNode = annotationNode.up();
		
		if ( methodNode == null || methodNode.getKind() != Kind.METHOD || !(methodNode.get() instanceof JCMethodDecl) ) {
			annotationNode.addError("@Synchronized is legal only on methods.");
			return true;
		}
		
		JCMethodDecl method = (JCMethodDecl)methodNode.get();
		
		if ( (method.mods.flags & Flags.ABSTRACT) != 0 ) {
			annotationNode.addError("@Synchronized is legal only on concrete methods.");
			return true;
		}
		boolean isStatic = (method.mods.flags & Flags.STATIC) != 0;
		String lockName = annotation.getInstance().value();
		if ( lockName.length() == 0 ) lockName = isStatic ? STATIC_LOCK_NAME : INSTANCE_LOCK_NAME;
		
		TreeMaker maker = methodNode.getTreeMaker();
		
		if ( fieldExists(lockName, methodNode) == MemberExistsResult.NOT_EXISTS ) {
			JCExpression objectType = chainDots(maker, methodNode, "java", "lang", "Object");
			//We use 'new Object[0];' because quite unlike 'new Object();', empty arrays *ARE* serializable!
			JCNewArray newObjectArray = maker.NewArray(chainDots(maker, methodNode, "java", "lang", "Object"),
					List.<JCExpression>of(maker.Literal(TypeTags.INT, 0)), null);
			JCVariableDecl fieldDecl = maker.VarDef(
					maker.Modifiers(Flags.FINAL | (isStatic ? Flags.STATIC : 0)),
					methodNode.toName(lockName), objectType, newObjectArray);
			injectField(methodNode.up(), fieldDecl);
		}
		
		if ( method.body == null ) return false;
		
		JCExpression lockNode = maker.Ident(methodNode.toName(lockName));
		
		method.body = maker.Block(0, List.<JCStatement>of(maker.Synchronized(lockNode, method.body)));
		
		methodNode.rebuild();
		
		return true;
	}
}