IDENTIFICATION DIVISION.
       PROGRAM-ID. CHANGE-LIGHT-BULB.
       AUTHOR. MAINFRAME-VETERAN.
       DATE-WRITTEN. 1972-01-01.
       DATE-COMPILED. 2023-12-14.
      *
       ENVIRONMENT DIVISION.
       CONFIGURATION SECTION.
       SOURCE-COMPUTER. IBM-370.
       OBJECT-COMPUTER. IBM-370.
      *
       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
           SELECT BULB-MASTER-FILE
               ASSIGN TO 'BULBMAST'
               ORGANIZATION IS INDEXED
               ACCESS MODE IS RANDOM
               RECORD KEY IS BULB-ID
               FILE STATUS IS WS-FILE-STATUS.
      *
       DATA DIVISION.
       FILE SECTION.
       FD  BULB-MASTER-FILE
           LABEL RECORDS ARE STANDARD
           BLOCK CONTAINS 0 RECORDS.
       01  BULB-RECORD.
           05  BULB-ID              PIC X(6).
           05  BULB-STATUS          PIC X(1).
           05  BULB-WATTAGE         PIC 9(3).
           05  BULB-INSTALL-DATE    PIC 9(8).
           05  BULB-CHANGE-COUNT    PIC 9(4).
           05  FILLER               PIC X(58).
      *
       WORKING-STORAGE SECTION.
       01  WS-FILE-STATUS          PIC XX.
       01  WS-CURRENT-DATE.
           05  WS-YEAR             PIC 9(4).
           05  WS-MONTH            PIC 99.
           05  WS-DAY              PIC 99.
      *
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           PERFORM 100-INITIALIZE
           PERFORM 200-PROCESS-BULB
           PERFORM 900-TERMINATE
           GOBACK.
      *
       100-INITIALIZE.
           OPEN I-O BULB-MASTER-FILE
           IF WS-FILE-STATUS NOT = "00"
               DISPLAY "ERROR OPENING FILE: " WS-FILE-STATUS
               PERFORM 900-TERMINATE
               STOP RUN
           END-IF.
      *
       200-PROCESS-BULB.
           MOVE "000001" TO BULB-ID
           READ BULB-MASTER-FILE
               INVALID KEY
                   DISPLAY "BULB NOT FOUND IN MASTER FILE"
                   PERFORM 900-TERMINATE
                   STOP RUN
           END-READ
      *
           IF BULB-STATUS = "W"
               PERFORM 300-CHANGE-BULB
           ELSE
               DISPLAY "BULB STATUS IS NOT WARRANTING CHANGE"
           END-IF.
      *
       300-CHANGE-BULB.
           ACCEPT WS-CURRENT-DATE FROM DATE YYYYMMDD
           MOVE "A" TO BULB-STATUS
           ADD 1 TO BULB-CHANGE-COUNT
           MOVE WS-CURRENT-DATE TO BULB-INSTALL-DATE
           REWRITE BULB-RECORD
               INVALID KEY
                   DISPLAY "ERROR UPDATING BULB RECORD"
           END-REWRITE.
      *
       900-TERMINATE.
           CLOSE BULB-MASTER-FILE.