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.TPred;
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.kinds.Kinds;

public class CreateMVector extends FunctionValue {
    private static final TVar A = Types.var(Kinds.STAR);
    public static final CreateMVector INSTANCE = new CreateMVector();    
    
    private CreateMVector() {
        super(new TVar[] {A}, Types.PROC, Types.mvector(A), Types.pred(Types.VEC_COMP, A), Types.INTEGER);
    }
    
    @Override
    public Type applyExact(MethodBuilder mb, Val[] parameters) {
        Val constraintVar = parameters[0];
        Val lengthVar = parameters[1];

        Type pred_ = Types.canonical(constraintVar.getType());
        if(!(pred_ instanceof TPred))
            throw new InternalCompilerError();
        TPred pred = (TPred)pred_;
        Type elementType = pred.parameters[0];
        if(elementType instanceof TVar) {
            constraintVar.push(mb);
            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);
        }
    }   

}