*> ============================================================
      *> main-validation-withdup : 重复CDR检测 (Duplicate CDR)
      *> Input : FILE-IN (INPUT.DAT: 排序済KEY付CDR)
      *> Output: FILE-PASS (PASS.DAT: 非重複)
      *> Coverage: VF-N003, VF-N004, VF-R001
      *> ============================================================
       IDENTIFICATION DIVISION.
       PROGRAM-ID. VALIDATE-DUP.

       ENVIRONMENT DIVISION.
       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
           SELECT FILE-IN    ASSIGN TO "INPUT.DAT"
               ORGANIZATION IS SEQUENTIAL
               FILE STATUS IS WS-FS.

           SELECT FILE-PASS   ASSIGN TO "PASS.DAT"
               ORGANIZATION IS SEQUENTIAL.

           SELECT FILE-ERR    ASSIGN TO "ERR.DAT"
               ORGANIZATION IS SEQUENTIAL.

       DATA DIVISION.
       FILE SECTION.
       FD FILE-IN RECORD CONTAINS 40 CHARACTERS.
       01 IN-REC.
           05 IN-KEY       PIC X(10).
           05 IN-VALUE     PIC 9(10).
           05 IN-DATA      PIC X(20).

       FD FILE-PASS RECORD CONTAINS 40 CHARACTERS.
       01 PASS-REC         PIC X(40).

       FD FILE-ERR RECORD CONTAINS 60 CHARACTERS.
       01 ERR-REC.
           05 ERR-KEY      PIC X(10).
           05 ERR-VALUE    PIC 9(10).
           05 ERR-MSG      PIC X(40).

       WORKING-STORAGE SECTION.
       01 WS-FS            PIC X(2).
       01 WS-EOF           PIC X(1) VALUE 'N'.
           88 WS-EOF-Y     VALUE 'Y' FALSE 'N'.
       01 WS-PREV-KEY      PIC X(10).
       01 WS-FIRST         PIC X(1) VALUE 'Y'.
           88 WS-FIRST-Y   VALUE 'Y' FALSE 'N'.
       01 WS-READ-COUNT    PIC 9(10).
       01 WS-PASS-COUNT    PIC 9(10).
       01 WS-DUP-COUNT     PIC 9(10).

       01 WS-TELECOM-REC.
           COPY "telecom/TEL-BILLING.cpy".

       PROCEDURE DIVISION.
       MAIN.
           DISPLAY "VALIDATE-DUP: Starting validation with dup detection"
           OPEN INPUT FILE-IN.
           IF WS-FS NOT = "00"
               DISPLAY "OPEN FAIL: " WS-FS
               STOP RUN RETURNING 1
           END-IF.
           OPEN OUTPUT FILE-PASS FILE-ERR.

           PERFORM UNTIL WS-EOF-Y
               READ FILE-IN INTO IN-REC
                   AT END
                       SET WS-EOF-Y TO TRUE
                   NOT AT END
                       ADD 1 TO WS-READ-COUNT
                       IF WS-FIRST-Y
                           MOVE IN-KEY TO WS-PREV-KEY
                           MOVE 'N' TO WS-FIRST
                           PERFORM WRITE-PASS
                       ELSE
                           IF IN-KEY = WS-PREV-KEY
                               PERFORM WRITE-DUP
                           ELSE
                               MOVE IN-KEY TO WS-PREV-KEY
                               PERFORM WRITE-PASS
                           END-IF
                       END-IF
               END-READ
           END-PERFORM.

           CLOSE FILE-IN FILE-PASS FILE-ERR.

           DISPLAY "VALIDATE-DUP: READ=" WS-READ-COUNT
                   " PASS=" WS-PASS-COUNT " DUP=" WS-DUP-COUNT

           IF WS-READ-COUNT = WS-PASS-COUNT + WS-DUP-COUNT
               DISPLAY "VALIDATE-DUP: PASS (R001 count match)"
               STOP RUN RETURNING 0
           ELSE
               DISPLAY "VALIDATE-DUP: FAIL - count mismatch"
               STOP RUN RETURNING 1
           END-IF
           .

       WRITE-PASS.
           ADD 1 TO WS-PASS-COUNT.
           MOVE IN-REC TO PASS-REC.
           WRITE PASS-REC.
           DISPLAY "PASS: " IN-KEY " (first occurrence)"
           .

       WRITE-DUP.
           ADD 1 TO WS-DUP-COUNT.
           MOVE IN-KEY TO ERR-KEY.
           MOVE IN-VALUE TO ERR-VALUE.
           STRING "DUPLICATE KEY DETECTED - previous key was "
                  WS-PREV-KEY DELIMITED BY SIZE INTO ERR-MSG
           END-STRING.
           WRITE ERR-REC.
           DISPLAY "DUP: " IN-KEY " (duplicate, rejected)"
           .

       END PROGRAM VALIDATE-DUP.