# 1. Goal
A golf club prices a tee time booking. The pro shop calls one function module
for each booking before it confirms the booking. The function module rejects an
invalid booking with a class-based exception and returns the green fee of a
valid booking.

# 2. Open questions
None.

# 3. Context
- Function group {{P}}FG_GOLF exists in package $TMP.
- The club sells rounds of 9 holes and rounds of 18 holes.
- The club has three player categories: members, guests and juniors.
- The pro shop calls the function module for each booking.

# 4. Contract
Exception class {{P}}CX_GOLF in package $TMP:
- The class is public, final and inherits from CX_STATIC_CHECK.
- The class has a public constructor with the importing parameters iv_reason
  (type string) and iv_message (type string).
- The class has the public read-only attributes mv_reason (type string) and
  mv_message (type string).
- The constructor stores iv_reason in mv_reason and iv_message in mv_message.

Function module {{P}}GOLF_FEE in function group {{P}}FG_GOLF:
- Importing parameters:
  - iv_category type string
  - iv_holes type i
  - iv_players type i
  - iv_tee_hour type i
- Exporting parameter:
  - ev_fee type decfloat34
- The function module raises the class-based exception {{P}}CX_GOLF. Declare
  this exception in the interface of the function module, because the caller
  handles it with CATCH {{P}}CX_GOLF.
- The function module has no classic exceptions.

# 5. Business rules
1. The number of players must be between 1 and 4. If it is not, raise
   {{P}}CX_GOLF with the reason INVALID_PLAYERS and the message
   "Number of players must be between 1 and 4".
2. The number of holes must be 9 or 18. If it is not, raise {{P}}CX_GOLF with
   the reason INVALID_HOLES and the message "Number of holes must be 9 or 18".
3. The player category must be M (member), G (guest) or J (junior). If it is
   not, raise {{P}}CX_GOLF with the reason INVALID_CATEGORY and the message
   "Player category must be M, G or J".
4. The tee hour must be between 6 and 20. If it is not, raise {{P}}CX_GOLF with
   the reason INVALID_TEE_HOUR and the message "Tee hour must be between 6 and
   20".
5. Check the rules 1 to 4 in this order. Raise only the first exception that
   applies.
6. The green fee per player for 18 holes is 25.00 for a member, 62.50 for a
   guest and 12.50 for a junior. For 9 holes the green fee per player is half
   of the green fee per player for 18 holes.
7. Twilight rate: if the tee hour is 18 or later, reduce the green fee per
   player by 25 %. Round the result half up to 2 decimals.
8. The total fee is the green fee per player times the number of players.
9. Group discount: if the booking has 4 players, reduce the total fee by 10 %.
   Round the result half up to 2 decimals. Apply this discount after the
   twilight rate.
10. If the booking is valid, return the total fee in ev_fee and raise no
    exception.

# 6. Constraints
- Release target: 8.16.
- Coding standards: Clean ABAP. Keep every method below 40 statements.
- Out of scope: none.

# 7. Acceptance
- The exception class and the function module are active and have no syntax
  error.
- The hidden tests pass.
- Write ABAP Unit tests for the function module in a global test class.