Here is a short thread looking at the timeline:
The draft was finalised on 24 November 2018, after month of careful negotiations on the text.
The UK has not put forward alternative proposals for Northern Ireland yet. /2
Main argument was that it could not wait until the December European Council, as the UK would need 4 month to get the WA through the Commons. /3
Johnson claims to be able to do that in less than 14 days.
The government has a majority of -43, the Withdrawal Agreement Bill has not published /4
The EP has - with reason - decided to only vote on the WA after a meaningful vote has been won in the House of Commons
EP officials have hinted that the Parliament needs ~6 weeks to consent to the WA /5
Even if a deal were possible, and he had a majority in Parliament, he would need to be much much closer now. /ends