package abstractSyntaxTree.Statement;

import TypeCheck.TypeCheckResult;
import TypeCheck.AbstractType;
import abstractSyntaxTree.Expression.IExpression;
import org.objectweb.asm.*;

public class ReturnStatement extends AbstractType implements IStatement{
    IExpression expression;

    public ReturnStatement(IExpression expression) {
        this.expression = expression;
    }

    @Override
    public TypeCheckResult typeCheck() throws Exception {
        TypeCheckResult result = new TypeCheckResult();

        if (expression == null) {
            result.type = "void";
        } else {
            TypeCheckResult typedExpression = expression.typeCheck();
            result.type = typedExpression.type;
        }

        return result;
    }


    //TODO: We do not differentiate between primitive types and reference types
    //      This is a problem at "BinaryExpression" and here because we need to know the type to return
    //      At this point in time we can either return reference types or have an error message
    @Override
    public void codeGen(MethodVisitor mv) throws Exception {

        if (expression != null) {
            expression.codeGen(mv);
            //Get the Type of the expression
            String type = expression.typeCheck().type;

            if (type.equals("int") || type.equals("bool") || type.equals("char")) {
                mv.visitInsn(Opcodes.IRETURN);
            } else {
                mv.visitInsn(Opcodes.ARETURN);

            }
        } else {
            mv.visitInsn(Opcodes.RETURN);
        }
    }
}