# 1. Goal
Calculate the price of a sightseeing flight for a helicopter operator. The
booking program calls one function module for each flight that a customer books.
The function module must use the interface of the sample module, because the
booking program calls all flight modules in the same way.

# 2. Open questions
None.

# 3. Context
- Function group {{P}}FG_HELI exists in package $TMP.
- Function module {{P}}HELI_FEE exists in this group. It has the correct
  interface, but its implementation is empty.
- Function module {{P}}HELI_SAMPLE exists in this group. It is the sample
  module. Its interface is the interface that all flight modules must use.
- A flight has a tour type, a number of passengers, and a flight time in
  minutes.
- A customer is a member of the flying club or not.

# 4. Contract
- Implement the function module {{P}}HELI_FEE in function group {{P}}FG_HELI.
- Keep exactly the interface of {{P}}HELI_SAMPLE: the same parameter names,
  kinds, types, and exceptions.

# 5. Business rules
1. If the number of passengers is less than 1 or greater than 6, raise the
   exception INVALID_PASSENGERS.
2. If the flight time is less than 5 minutes, raise the exception
   INVALID_MINUTES.
3. Set the skip flag to false, except in rule 6.
4. Tour type SC (sightseeing circuit):
   - The gross price is 8.00 per minute plus 15.00 per passenger.
   - If the customer is a member, subtract 12.5 % of the gross price.
   - Round the result half up to 2 decimals.
   - The minimum price is 50.00. The maximum price is 1500.00.
5. Tour type TR (training flight):
   - The gross price is 12.00 per minute. There is no passenger surcharge.
   - The member discount does not apply.
   - Round the result half up to 2 decimals.
   - The minimum price is 50.00. The maximum price is 1500.00.
6. Tour type CH (charter flight): set the skip flag to true. Do not change the
   price.
7. All other tour types: the price is 0.

# 6. Constraints
- Release target: SAP_BASIS 816.
- Use Clean ABAP. Keep every method below 40 statements.
- Out of scope: do not change {{P}}HELI_SAMPLE.

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