MT5 Script to Close a Percentage of all Positions

I need a script that will close a percentage of all open positions. For example, if the script is set to 40%, then all open positions should close 40% of the current open positions...if all positions have 1 lot open, this script would close .4 lots for each open position and .6 lots for all positions would remain.

There should be an input for the following...

- Percentage to Close All Open Positions

I will also need the source file once finished.