Query on Works Contract service

As per GST law, construction of a complex, building, civil structure intended for sale to a buyer is considered a service and liable for GST – if any consideration is received before issuance of completion certificate. However, GST is not applicable if the whole of the consideration for a property is paid after issuance of completion certificate by a competent authority or after its first occupancy, whichever is earlier.

If sold before completion or any money received before completion then GST payable on the whole amount. If the first money received is after completion or its is sold after completion then there is no GST.

ITC is not available.

If sold before completion then He need to collect GST. In that case is he entitled to claim full ITC on construction materials purchased....like cement,steel etc.