# 1. Goal
A bookbinding workshop prices binding jobs. The order desk calls one function
module for each job. The function module calculates the fee of the job and
reports whether the job is a rush job.

# 2. Open questions
None.

# 3. Context
- Function group {{P}}FG_BIND exists in package $TMP.
- Function module {{P}}BIND_SAMPLE exists in this group. It shows the interface
  that the order desk uses.

# 4. Contract
- Create the function module {{P}}BIND_FEE in function group {{P}}FG_BIND.
- The interface of {{P}}BIND_FEE:
  - importing iv_binding TYPE string
  - importing iv_pages TYPE i
  - importing iv_member TYPE abap_bool
  - exporting ev_rush TYPE abap_bool
  - changing cv_fee TYPE decfloat34
  - exceptions invalid_pages

# 5. Business rules
1. If the number of pages is less than 1, raise the exception INVALID_PAGES.
2. Set the rush flag to false, except in rule 7.
3. Binding type PB: the fee is 0.05 per page, rounded half up to 2 decimals.
4. Binding type HB: the fee is 0.12 per page, rounded half up to 2 decimals.
   The minimum fee for hardback binding is 15.00.
5. A member receives a discount of 10 % on the fee. The discount is the last
   step of the calculation and is applied after the minimum fee of rule 4.
6. The minimum fee of rule 4 is the last step of the calculation and is applied
   after all discounts.
7. Binding type EX: set the rush flag to true. The fee is 0.20 per page,
   rounded half up to 2 decimals.
8. Other binding types: the fee is 0.

# 6. Constraints
- Release target: 8.16.
- Coding standards: Clean ABAP.
- Out of scope: do not change {{P}}BIND_SAMPLE.

# 7. Acceptance
- The function module is active and has no syntax error.
- Write ABAP Unit tests for the function module in a global test class.