C-----------------------------------------------------------------------
C --- HISTOGRAM MERGING UTILITY, VERSION 0.1
C --- DESIGNED TO BE USED IN CONJUNCTION WITH EERAD2 V0.4
C
C     VERSION 0.0 - 28th April 2026
C     VERSION 0.1 - 5th May 2026 - Added log binning.
C
C     WRITTEN BY G. CHIURATO
C
      PROGRAM MAIN
      IMPLICIT NONE
      INTEGER I
      CHARACTER*256 IPATH, OPATH, LPATH
      CHARACTER*30 OBS(5)
      COMMON /CONST/OBS

C --- TODO: ADD EXTERNALLY CONFIG. PATHS
      IPATH = './results/'
      OPATH = './merge/'
      LPATH = TRIM(OPATH)//'lists/'
      
      CALL PRINTHEADER
      CALL CREATEOUT(LPATH)
      CALL CREATEOUT(OPATH)
      CALL SCANDIR(IPATH, LPATH)
      DO 10 I = 1,5
C ------ TODO: FIXED IDS ARE NOT GREAT
         CALL MERGE(OBS(I), I, OPATH, LPATH)
 10   CONTINUE
      END PROGRAM
C-----------------------------------------------------------------------
      SUBROUTINE SCANDIR(IPATH, OPATH)
      IMPLICIT NONE
      INTEGER I
      INTEGER STAT
      CHARACTER*30 OBS(5), ESCOBS
      CHARACTER*256 IPATH, OPATH
      COMMON /CONST/OBS
      DATA OBS/'C-PARAMETER','D-PARAMETER',
     $ 'THRUST','y3(JADE,P)','EEC'/

C     CREATE FILE LIST USING SYSTEM COMMAND
      DO 10 I = 1, 5
         CALL BRACKETESC(OBS(I), ESCOBS)
         CALL SYSTEM('ls '//TRIM(IPATH)//'gtopdraw_'//TRIM(ESCOBS)//
     $    '_* > '//TRIM(OPATH)//'filelist_'//TRIM(ESCOBS)//'.txt', 
     $    STATUS=STAT)
10    CONTINUE

      END
C-----------------------------------------------------------------------
      SUBROUTINE MERGE(OBS, ID, OPATH, LPATH)
      IMPLICIT NONE
      CHARACTER*30 OBS
      CHARACTER*256 OPATH, LPATH
      CHARACTER*256 LINE
      CHARACTER*60 TITLE
      INTEGER LENTIT
      INTEGER ID, NX, LH
      DOUBLE PRECISION XMIN, XMAX

      NX = 0
      XMIN = 0
      XMAX = 0
      LH = 0

C --- NEED TO USE UNIT 20 TO AVOID CONFLICT WITH UNIT 10 USED BY GREAD
      OPEN(UNIT=20, FILE=TRIM(LPATH)//'filelist_'//TRIM(OBS)//'.txt', 
     $    STATUS='OLD', ERR=30)

C --- READ FIRST HIST AND SAVE BIN NUMBER AND TITLE
      READ(20, '(A)', END=20) LINE
      CALL GREAD(LINE)
      CALL GPROP1(ID, NX, XMIN, XMAX, LH)
C --- TODO: IN THIS WAY THE MERGED HIST HAS THE SAME NAME AS THE LAST 
C     OPENED HIST. NEED TO CHANGE THIS TO SOMETHING DIFFERENT
      CALL GTITLE(ID, TITLE, LENTIT)

C --- 2XX IS VALUE ACC., 3XX IS WEIGHT ACC.
      CALL GBOOK1(200+ID,TITLE,NX,XMIN,XMAX,LH)
      CALL GBOOK1(300+ID,TITLE,NX,XMIN,XMAX,LH)
      CALL GBOOK1(210+ID,TITLE,NX,XMIN,XMAX,LH)
      CALL GBOOK1(310+ID,TITLE,NX,XMIN,XMAX,LH)

C --- ACCUMULATE WEIGHTS
      CALL GOPERA(100+ID,'*',100+ID,100+ID,1D0,1D0)
      CALL GOPERA(100+ID,'I',     0,100+ID,1D0,1D0)
      CALL GOPERA(300+ID,'+',100+ID,300+ID,1D0,1D0)
      CALL GOPERA(110+ID,'*',110+ID,110+ID,1D0,1D0)
      CALL GOPERA(110+ID,'I',     0,110+ID,1D0,1D0)
      CALL GOPERA(310+ID,'+',110+ID,310+ID,1D0,1D0)
C --- ACCUMULATE VALUES
      CALL GOPERA(    ID,'*',100+ID,    ID,1D0,1D0)
      CALL GOPERA(200+ID,'+',    ID,200+ID,1D0,1D0)
      CALL GOPERA( 10+ID,'*',110+ID, 10+ID,1D0,1D0)
      CALL GOPERA(210+ID,'+', 10+ID,210+ID,1D0,1D0)

 10   CONTINUE
      CALL GRESET(ID)
      CALL GRESET(100+ID)
      READ(20, '(A)', END=20) LINE
      CALL GREAD(LINE)
C --- ACCUMULATE WEIGHTS
      CALL GOPERA(100+ID,'*',100+ID,100+ID,1D0,1D0)
      CALL GOPERA(100+ID,'I',     0,100+ID,1D0,1D0)
      CALL GOPERA(300+ID,'+',100+ID,300+ID,1D0,1D0)
      CALL GOPERA(110+ID,'*',110+ID,110+ID,1D0,1D0)
      CALL GOPERA(110+ID,'I',     0,110+ID,1D0,1D0)
      CALL GOPERA(310+ID,'+',110+ID,310+ID,1D0,1D0)
C --- ACCUMULATE VALUES
      CALL GOPERA(    ID,'*',100+ID,    ID,1D0,1D0)
      CALL GOPERA(200+ID,'+',    ID,200+ID,1D0,1D0)
      CALL GOPERA( 10+ID,'*',110+ID, 10+ID,1D0,1D0)
      CALL GOPERA(210+ID,'+', 10+ID,210+ID,1D0,1D0)
      GOTO 10

 20   CONTINUE
      CALL GRESET(ID)
      CALL GRESET(100+ID)
C --- COMPUTE FINAL VALUES
      CALL GOPERA(200+ID,'/',300+ID,ID,1D0,1D0)
      CALL GOPERA(210+ID,'/',310+ID,10+ID,1D0,1D0)
C --- COMPUTE FINAL ERRORS
      CALL GOPERA(300+ID,'I',0,300+ID,1D0,1D0)
      CALL GOPERA(300+ID,'S',0,100+ID,1D0,0D0)
      CALL GOPERA(310+ID,'I',0,310+ID,1D0,1D0)
      CALL GOPERA(310+ID,'S',0,110+ID,1D0,0D0)
C --- WRITE OUT RESULTS   
      CALL GTOPER(    ID,1,1,0,100+ID)
      CALL GTOPER( 10+ID,0,0,0,110+ID)

      CLOSE(10)
      RETURN
 30   PRINT *, 'Error opening filelist for observable '//TRIM(OBS)
      STOP
      END
C-----------------------------------------------------------------------
      SUBROUTINE BRACKETESC(IN, OUT)
C     Escapes ( and ) for Unix shell globbing
      CHARACTER*(*) IN, OUT
      INTEGER I, J, L
      CHARACTER C

      OUT = ' '
      J = 1
      L = LEN(IN)

      DO 10 I = 1, L
         C = IN(I:I)

         IF (C .EQ. '(') THEN
            OUT(J:J) = '\'
            J = J + 1
            OUT(J:J) = '('

         ELSE IF (C .EQ. ')') THEN
            OUT(J:J) = '\'
            J = J + 1
            OUT(J:J) = ')'

         ELSE
            OUT(J:J) = C
         END IF

         J = J + 1
 10   CONTINUE

      RETURN
      END
C----------------------------------------------------------------------- 
      SUBROUTINE PRINTHEADER
      IMPLICIT NONE 
C --- PRINT OPENING MESSAGE
      WRITE (*,'(/2A)')  ' This is EVENT2 merge utility, ',
     $      ' used to merge EVENT2 histogram from different runs.'
      WRITE (*,'(A)')    ' Results will be stored in merge folder.'
      WRITE (*,'(2A)')   ' If you use this program, on EVENT2 runs, ',
     $                   ' please reference:'
      WRITE (*,'(2A)')   ' S.Catani & M.H.Seymour,',
     $      ' Phys. Lett. B378 (1996) 287.'
      WRITE (*,'(/A)')   ' Written by Giorgio Chiurato, April 2026'
      WRITE (*,'(A/)')   ' Version 0.0, April 2026'
      END
C-----------------------------------------------------------------------