# 1. Goal
A leisure centre prices the entry tickets of its swimming pool. The ticket
desk calls the class for each visitor and prints the price. The desk also needs
one status code for each booking request.

# 2. Open questions
None.

# 3. Context
- No object of this task exists yet. Create everything that the contract lists.
- The leisure centre has four areas. Their area codes are IN (indoor pool),
  OU (outdoor pool), SA (sauna area) and AL (all areas).
- The visitor rates are A (adult), C (child) and S (senior).
- The day keys are MO, TU, WE, TH, FR, SA and SU.

# 4. Contract
- Create the class {{P}}POOL_TICKET in package $TMP.
- The class is public and final. It has a public constructor without parameters.
- The class has these public types:
  ty_zone TYPE c LENGTH 2, ty_rate TYPE c LENGTH 1, ty_day TYPE c LENGTH 2,
  ty_flag TYPE c LENGTH 1, ty_status TYPE c LENGTH 2,
  ty_amount TYPE p LENGTH 8 DECIMALS 2.
- The class has the public constant structure c_status with the components
  ok = 'OK', zone = 'ZN', rate = 'RT', day = 'DY'.
- The class has the public constant structure c_flag with the components
  member = 'X', guest = ' '.
- The class has these public methods:
  check_booking
    IMPORTING iv_zone TYPE ty_zone
              iv_rate TYPE ty_rate
              iv_day TYPE ty_day
    RETURNING VALUE(rv_status) TYPE ty_status.
  ticket_price
    IMPORTING iv_zone TYPE ty_zone
              iv_rate TYPE ty_rate
              iv_day TYPE ty_day
              iv_member TYPE ty_flag
    RETURNING VALUE(rv_price) TYPE ty_amount.
- Do not add other public methods.

# 5. Business rules
1. An area code is known if it is IN, OU, SA or AL. Compare the codes exactly.
   Do not convert the codes to upper case.
2. A rate code is known if it is A, C or S.
3. A day key is known if it is MO, TU, WE, TH, FR, SA or SU.
4. check_booking checks the area code, then the rate code, then the day key.
   It returns the status of the first check that fails. If all three checks
   pass, it returns OK.
5. ticket_price returns 0 if check_booking does not return OK.
6. Else the price is the base price of the area and the rate, plus the weekend
   surcharge, minus the member discount.
7. The base price in euro:
   IN: A 10.00, C 5.00, S 7.50
   OU: A 7.50, C 3.75, S 5.00
   SA: A 15.00, C 7.50, S 11.25
   AL: A 20.00, C 10.00, S 15.00
8. The weekend surcharge is 2.50. It applies when the day key is SA or SU.
9. The member discount is 20 per cent. It applies when iv_member is X. Apply
   the discount to the sum of the base price and the surcharge.

# 6. Constraints
- Release target: SAP_BASIS 816 (ABAP Platform 2025).
- Coding standards: Clean ABAP. Method length below 40 statements. No global
  variables. No comment that restates the code.
- Out of scope: do not change or create other objects.

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