package lombok.javac.handlers;

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

import org.mangosdk.spi.ProviderFor;

import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.TreeMaker;
import com.sun.tools.javac.tree.JCTree.JCAnnotation;
import com.sun.tools.javac.tree.JCTree.JCBlock;
import com.sun.tools.javac.tree.JCTree.JCCase;
import com.sun.tools.javac.tree.JCTree.JCCatch;
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.JCVariableDecl;
import com.sun.tools.javac.util.List;

@ProviderFor(JavacAnnotationHandler.class)
public class HandleCleanup implements JavacAnnotationHandler<Cleanup> {
	@Override public boolean handle(AnnotationValues<Cleanup> annotation, JCAnnotation ast, Node annotationNode) {
		String cleanupName = annotation.getInstance().cleanupMethod();
		if ( cleanupName.length() == 0 ) {
			annotationNode.addError("cleanupName cannot be the empty string.");
			return true;
		}
		
		if ( annotationNode.up().getKind() != Kind.LOCAL ) {
			annotationNode.addError("@Cleanup is legal only on local variable declarations.");
			return true;
		}
		
		JCVariableDecl decl = (JCVariableDecl)annotationNode.up().get();
		
		Node ancestor = annotationNode.up().directUp();
		JCTree blockNode = ancestor.get();
		
		final List<JCStatement> statements;
		if ( blockNode instanceof JCBlock ) {
			statements = ((JCBlock)blockNode).stats;
		} else if ( blockNode instanceof JCCase ) {
			statements = ((JCCase)blockNode).stats;
		} else if ( blockNode instanceof JCMethodDecl ) {
			statements = ((JCMethodDecl)blockNode).body.stats;
		} else {
			annotationNode.addError("@Cleanup is legal only on a local variable declaration inside a block.");
			return true;
		}
		
		boolean seenDeclaration = false;
		List<JCStatement> tryBlock = List.nil();
		List<JCStatement> newStatements = List.nil();
		for ( JCStatement statement : statements ) {
			if ( !seenDeclaration ) {
				if ( statement == decl ) seenDeclaration = true;
				newStatements = newStatements.append(statement);
			} else tryBlock = tryBlock.append(statement);
		}
		
		if ( !seenDeclaration ) {
			annotationNode.addError("LOMBOK BUG: Can't find this local variable declaration inside its parent.");
			return true;
		}
		
		TreeMaker maker = annotationNode.getTreeMaker();
		JCFieldAccess cleanupCall = maker.Select(maker.Ident(decl.name), annotationNode.toName(cleanupName));
		List<JCStatement> finalizerBlock = List.<JCStatement>of(maker.Exec(
				maker.Apply(List.<JCExpression>nil(), cleanupCall, List.<JCExpression>nil())));
		
		JCBlock finalizer = maker.Block(0, finalizerBlock);
		newStatements = newStatements.append(maker.Try(maker.Block(0, tryBlock), List.<JCCatch>nil(), finalizer));
		
		if ( blockNode instanceof JCBlock ) {
			((JCBlock)blockNode).stats = newStatements;
		} else if ( blockNode instanceof JCCase ) {
			((JCCase)blockNode).stats = newStatements;
		} else if ( blockNode instanceof JCMethodDecl ) {
			((JCMethodDecl)blockNode).body.stats = newStatements;
		} else throw new AssertionError("Should not get here");
		
		ancestor.rebuild();
		
		return true;
	}
}