Count time in insert mode for this project

Question

I'm trying to code some projects in flutter by the dart language.
I want to count the time that spends in insert mode to finish this project

:call Startchrono()
0 : wait to go in insert mode ...
chrono++...
7 wait to go in insert mode ...
...

Answer 1

Use InsertEnter and InsertLeave autocommands to count it:

let g:time_total = 0
let g:time_step = 0
augroup counter | au!
    au InsertEnter * let g:time_step = localtime()
    au InsertLeave * let g:time_total += localtime() - g:time_step
augroup END

Here in g:time_total there would be number of seconds you spent in insert mode.