package org.simantics.scl.compiler.elaboration.java;

import org.cojen.classfile.TypeDesc;
import org.simantics.scl.compiler.common.exceptions.InternalCompilerError;
import org.simantics.scl.compiler.constants.FunctionValue;
import org.simantics.scl.compiler.internal.codegen.references.Val;
import org.simantics.scl.compiler.internal.codegen.utils.Constants;
import org.simantics.scl.compiler.internal.codegen.utils.MethodBuilder;
import org.simantics.scl.compiler.types.TVar;
import org.simantics.scl.compiler.types.Type;
import org.simantics.scl.compiler.types.Types;
import org.simantics.scl.compiler.types.exceptions.MatchException;
import org.simantics.scl.compiler.types.kinds.Kinds;

public class CreateMVectorProto extends FunctionValue {
    private static final TVar A = Types.var(Kinds.STAR);
    public static final CreateMVectorProto INSTANCE = new CreateMVectorProto();    

    private CreateMVectorProto() {
        super(new TVar[] {A}, Types.PROC, Types.mvector(A), Types.vector(A), Types.INTEGER);
    }

    @Override
    public Type applyExact(MethodBuilder mb, Val[] parameters) {
        Val prototypeVar = parameters[0];
        Val lengthVar = parameters[1];

        try {
            Type elementType = Types.canonical(
                    Types.matchApply(Types.VECTOR, prototypeVar.getType()));
            if(elementType instanceof TVar) {
                prototypeVar.push(mb);
                mb.invokeVirtual("java/lang/Object", "getClass", Constants.CLASS, Constants.EMPTY_TYPEDESC_ARRAY);
                mb.invokeVirtual("java/lang/Class", "getComponentType", Constants.CLASS, Constants.EMPTY_TYPEDESC_ARRAY);
                lengthVar.push(mb);
                mb.invokeStatic("java/lang/reflect/Array", "newInstance", TypeDesc.OBJECT, 
                        new TypeDesc[] {Constants.CLASS, TypeDesc.INT});

                return Types.mvector(A);
            }
            else {
                TypeDesc desc = mb.getJavaTypeTranslator().toTypeDesc(elementType);
                TypeDesc arrayDesc = desc.toArrayType();      

                lengthVar.push(mb);
                mb.newObject(arrayDesc, 1);                                

                return Types.mvector(elementType);
            }
        } catch(MatchException e) {
            throw new InternalCompilerError(e);
        }
    }   

}