# 1. Goal
A dog walking service wants a summary of its walks. The office uses the list to
see how far each walker went in the period.

# 2. Open questions
None.

# 3. Context
- Table {{P}}WALK exists in package $TMP and contains data.
  Fields: WALK_ID (INT4, key), WALKER (CHAR 6), WALK_DATE (DATS),
  DIST_M (INT4, the distance of the walk in metres), STATUS (CHAR 1).
- STATUS has these values:
  - 'F': the walk is finished.
  - 'X': the walk is cancelled.
- Table {{P}}WALKSUM exists in package $TMP. It is the output structure of the
  list. Fields: WALKER (CHAR 6, key), DIST_M (INT4), WALKS (INT4).

# 4. Contract
- Create the executable program {{P}}WALKER_STATS in package $TMP.
- Selection screen:
  - Select-option S_DATE for WALK_DATE: the walk dates to include.
  - Select-option S_WALKER for WALKER: the walkers to include.
- Show the result with CL_SALV_TABLE. The output table has the row type of
  table {{P}}WALKSUM. The output columns are WALKER, DIST_M (the total distance
  in metres) and WALKS (the number of walks).

# 5. Business rules
1. Include a walk only if WALK_DATE is in S_DATE, WALKER is in S_WALKER and
   STATUS is 'F'.
2. An empty S_DATE or an empty S_WALKER does not restrict the result.
3. Show one line for each walker that has at least two included walks.
4. DIST_M is the sum of DIST_M of the included walks of the walker.
5. WALKS is the number of included walks of the walker.
6. Sort the lines by DIST_M, the highest number first. If two lines have the
   same DIST_M, sort them by WALKER in ascending order.

# 6. Constraints
- Release target: SAP_BASIS 816 (ABAP Platform 2025).
- Coding standards: Clean ABAP. Read table {{P}}WALK with one database access.
- Out of scope: do not change {{P}}WALK and {{P}}WALKSUM.

# 7. Acceptance
- The program is active and has no syntax error.
- The hidden tests pass.
- Write ABAP Unit tests as local test classes in the program.