Make Loan Type non-submittable

[bosue]

I think, the loan type needs to editable, not submittable.

While I can see that many of these settings affect all loans based on this type, and should therefore only be changed with caution, almost every single of these fields may have to be changed at a later point, purposely affecting the loans based on this type:

• The maximum loan amount, a grace period is a business strategy decision
• The Rate of Interest may or may not be variable. In some loan types it might be adapted to the Central Bank’s new reference rate or by refinance rates.
• The penalty interest rate is usually governed by the Central Bank reference rate, so may change as well.
• Days past due threshold for NPL will often be subject to changed regulations or risk assessments.
• The mode of payment may have to change, based on available options.
• Accounts may be restructured as well.

The only field that probably won’t and shouldn’t change is “Is Term Loan”. Actually, this is the real Loan Type (or at least one of the variants, others including Bullet Loans, Revolving Loans and various other types). Next step, a sensible approach would be a two-tiered structure with just a few basic Loan Types, each with various variants / subtypes / products. Atm, this is out of scope though.

Implementation:

Just turn the loan type into an editable DocType.

The only really tricky part is a potentially changing Rate of Interest here. We need to accommodate at least a choice of:

• fixed-rate loan
• variable-rate loan

with further types to be added later.

I will come up with yet another feature request focussing on this aspect, but here, in this issue, further considerations would be way out of scope.

In the meantime, let‘s just use the Loan Type‘s interest rate as an editable default when creating a new individual Loan of this type. So for now, if the Loan Type‘s interest rate changes, the individual loan will not be affected, effectively making it a fixed-rate loan for now.

The amortization structure (currently „Is term loan“) should be more prominent, too. There are several types possible, so even if we may currently only support two of them, we should use a Select field, not a checkbox.

The mode of repayment and some other aspects also need further considerations, but that’d be out of scope here. Let‘s start with what we have here!