Multiple Payroll "Configuration" modal will increase the base salary indefinitely if the currency is switched too many times.

[jniles]

In the Human Resources > Payroll Multiple configuration modal for an individual employee, when a user changes the currency two unexpected things occur:

1. The currency in the bh-currency-input does not update (it always shows the enterprise currency, I would assume).
2. The "base salary" increases indefinitely by running the exchange rate algorithm multiple times and updated the base value. This is a huge bug! Instead, the original base salary should be cached and all exchanges should be run against the cached value.

Here is a demonstration of the bug:

When fixing this issue, the following improvements could also be made:

1. Instead of "Employee Indice:2" in the header of the modal, we should display the employee's name in the modal body.
2. We could also put the payment period in the modal body as well.
3. Instead of disabled inputs, let's just use Static Controls to render the options that cannot be displayed.
4. The "Jours Feries", etc, are all days. Let's put the units on the inputs. For the best user experience, it should say "Holidays" "None", or "1 day", "2 days", etc. But "0 days" is also likely acceptable.
5. The "Money" input should occur above the "Base Salary" input.

[jniles]

I'm going to tackle this in my latest HR refactor.

[jniles]

So, according to our documentation (https://docs.bhi.ma/fr/payroll/payroll_multiple), the employees are always paid in the enterprise currency. Therefore, this currency selection should only change the view value.

However, this presents a problem. What happens if the user changes to view in a different currency (for example, USD$ instead of the enterprise FC), then makes a change to the base salary or advantages? What do we do? Do we modify the value using the exchange rate of today?

And what happens if the employee goes to be paid later (say, a week later)? Do we use the exchange rate of the configuration date or the payment date?

To avoid this confusion, I propose we remove the ability to be change currencies on this configuration modal. I think it just makes things confusing, and buggy. Instead, the salary will be fixed in the enterprise currency and paid using whatever currency they want at the cashbox.

@lomamech what do you think of the idea to remove the currency change on this page? Will it cause any issue for any production site? For example, IMCK?

[jniles]

A different option is that we could keep the ability to change currency, but erase all changes the user made to salary values when they switch currencies.

This would allow the user to modify the salary of an employee or benefits, in a non-enterprise currency, if that is needed. However, it would guarantee that we can't get into this kind of cycle bug where we keep running the exchange() operation on the same values over and over again.

[jniles]

I am going with the option of removing the currency from this modal, since production sites do not seem to choose other currencies in their configuration anyway.

See #4956 (comment) for more context.