How to get total score?

ive got a problem when im trying to custom the score processing.
im going to use "(_score/TotalScore)CustomTotalScoreweight" to calculate my own score.
i think this can map the _score to a controllable score space.

TotalScore should be the max score the elasticsearch could give in one query.
CustomTotalScore is the max score i set. it could be 100, 50 or any other scores that i give.

the finally score could be the sum of the result of this full formula and the result of other formula.

but now, i cant find the TotalScore the elasticsearch give.

so, what is the totalscore in query?

::: ive analysed the "explain" from elasticsearch to the query, im finding that, the total score is calculated with the score of each term. im wondering, if i can caculate the total score myself of each query when i know the term number and the total score for each term.

so, i think the term number of each query can be easily obtained, but still, what could the total score of each term be in one query?