SI: User Supplied Price Upcharge

[WillStrohl]

Is your feature request related to a problem?

When using user-supplied price products for donation-style products, it's very common for non-profit organizations to offer for customers to cover the credit card transaction fee. This is often presented using a radio button or checkbox in some websites.

A non-profit store owner would like to enable a similar feature in Hotcakes Commerce to allow for a specified upcharge to be applied to the order when this option is selected.

Describe the solution you'd like

Two new fields should be added to the product details view. They are listed below.

• Allow Upcharge? (checkbox, default to unchecked)
• Upcharge Amount (Use the same textbox and dropdown list combo option seen in promotions where a number and amount/percentage are seen. This field will only be visible and editable if the previous checkbox is checked. The default value for this field should be 3%. There should only be two possible choices, so front-end validation is not necessary.

When this new setting is enabled and a valid value is found for the upcharge amount, this amount is applied as a new line item in the cart.

• This line item should share some of the same behavior as the Free Item logic.
• The upcharge line item can't be deleted.
• The upcharge line item quantity can't be changed.
• If the donation product is deleted, so is the upcharge line item.
• If the donation product is added without the "Cover Credit Card Fees" checkbox being checked, this additional line item shouldn't exist.

Describe alternatives you've considered

None at this time.

Additional context

Customer support request 7671