Create a Function in Google Sheets that shows the User's information

I would like to add a Function to my Google Sheets, so I can show in a cell the user that changed another cell (only the latest change), with the choice of showing the date and time of the change also.

Something like:

Function Name:SHOWUSER

• A1: Cell Changed by User
• B1: Cell that shows the name or the email or the time of the change

Parameters:

1. Show User's Name
2. Show User's Email
3. Show Date and Time of Change (the format of B1 will determine if it shows Date, Time or both)

B1 contains =SHOWUSER(A1;2)

Should show the email address of the latest user that changed the content of cell A1.

Notes: By default, the function will always assume the A1 cell is in the same sheet tab (ActiveSheet?) as where the B1 cell is located. Nevertheless, the function can also refer to another sheet using the same reference Google Sheets uses to refer to a cell in another sheet tab. For example, if B1 is on "Sheet 1" and A1 is on "Sheet 2" (a different sheet tab in the same Workbook):

B1 =SHOWUSER('Sheet 2'!A1;3) -> Should show the date and time of the latest change made on the cell A1 of "Sheet 2".

Thank you.