# 1. Goal
A scaffolding company hires out scaffold parts to building sites. A quotation
program calls the fee calculation for each hire order before it prints the
quotation. The program needs the final fee and the long-hire discount of the
hire order.

# 2. Open questions
None.

# 3. Context
- The interface {{P}}IF_HIRE_FEE exists in package $TMP. It is active.
- The interface has the type TY_AMOUNT (packed, length 8, 2 decimals) and the
  structure type TY_RESULT with the components FEE and DISCOUNT. Both
  components have the type TY_AMOUNT.
- The interface has one method:
  CALCULATE_FEE
    IMPORTING iv_days    TYPE i
              iv_parts   TYPE i
              iv_express TYPE abap_bool
    RETURNING VALUE(rs_result) TYPE ty_result.

# 4. Contract
- Create the class {{P}}SCAFFOLD_FEE in package $TMP.
- The class is public, final, and has a public constructor without parameters.
- The class implements {{P}}IF_HIRE_FEE.
- Do not add other public methods.

# 5. Business rules
1. The daily rate of one scaffold part is 4.20 EUR.
2. The base fee is IV_DAYS multiplied by IV_PARTS multiplied by the daily rate.
3. If IV_EXPRESS is true, the express surcharge is 12 percent of the base fee.
   Round the express surcharge up to the next full cent.
4. If IV_DAYS is greater than 30, the long-hire discount is 6 percent of the
   base fee.
5. The final fee is the base fee plus the express surcharge minus the long-hire
   discount.
6. The result contains the final fee in the component FEE and the long-hire
   discount in the component DISCOUNT.
7. The final fee and the discount are amounts in EUR. Each amount is exact to
   the cent.
8. If IV_DAYS is not greater than 30, the discount is zero.

# 6. Constraints
- Release target: 8.16.
- Coding standards: Clean ABAP. Method length below 40 statements. No global
  variables. No comment that restates the code.
- Out of scope: do not change {{P}}IF_HIRE_FEE.

# 7. Acceptance
- The class is active and has no syntax error.
- Write your own ABAP Unit tests for the class.