!-----------------------------------------------------------------
!
!  This file is (or was) part of SPLASH, a visualisation tool
!  for Smoothed Particle Hydrodynamics written by Daniel Price:
!
!  http://users.monash.edu.au/~dprice/splash
!
!  SPLASH comes with ABSOLUTELY NO WARRANTY.
!  This is free software; and you are welcome to redistribute
!  it under the terms of the GNU General Public License
!  (see LICENSE file for details) and the provision that
!  this notice remains intact. If you modify this file, please
!  note section 2a) of the GPLv2 states that:
!
!  a) You must cause the modified files to carry prominent notices
!     stating that you changed the files and the date of any change.
!
!  Copyright (C) 2005-2016 Daniel Price. All rights reserved.
!  Contact: daniel.price@monash.edu
!
!-----------------------------------------------------------------

!-------------------------------------------------------------------------
! this subroutine reads from the data file(s)
! change this to change the format of data input
!
! THIS VERSION IS FOR READING UNFORMATTED OUTPUT FROM ANDREAS BAUSWEIN'S CODE
! (ie. STRAIGHT FROM THE DATA DUMP)
!
! *** CONVERTS TO SINGLE PRECISION ***
!
! SOME CHOICES FOR THIS FORMAT CAN BE SET USING THE FOLLOWING
!  ENVIRONMENT VARIABLES:
!
! BSPLASH_R8 if 'YES' or 'TRUE' then assumes data is double precision
! BSPLASH_NCOL to change the number of columns read from the file,
! e.g. setenv BSPLASH_NCOL=22
!
! the data is stored in the global array dat
!
! >> this subroutine must return values for the following: <<
!
! ncolumns    : number of data columns
! ndim, ndimV : number of spatial, velocity dimensions
! nstepsread  : number of steps read from this file
!
! maxplot,maxpart,maxstep      : dimensions of main data array
! dat(maxplot,maxpart,maxstep) : main data array
!
! npartoftype(1:6,maxstep) : number of particles of each type in each timestep
!
! time(maxstep)       : time at each step
! gamma(maxstep)      : gamma at each step
!
! most of these values are stored in global arrays
! in the module 'particle_data'
!-------------------------------------------------------------------------

subroutine read_data(rootname,indexstart,ipos,nstepsread)
 use particle_data, only:dat,time,npartoftype,gamma,maxpart,maxcol
 use params
 use settings_data, only:ndim,ndimV,ncolumns
 use mem_allocation, only:alloc
 use system_utils, only:lenvironment,ienvironment
 implicit none
 integer, intent(in) :: indexstart,ipos
 integer, intent(out) :: nstepsread
 character(len=*), intent(in) :: rootname
 integer :: i,j,k,ierr
 integer :: nprint,n1,npart_max,nstep_max
 integer :: ncol,nread,nerr,ncoltemp
 logical :: iexist,doubleprec
 character(len=len(rootname)) :: dumpfile
 real :: timei,dti
 real(doub_prec), dimension(maxcol) :: datdb
 real(doub_prec) :: timedb,dtdb

 nstepsread = 0
 nstep_max = 0
 npart_max = maxpart
 dumpfile = trim(rootname)
 !
 !--check if first data file exists
 !
 inquire(file=dumpfile,exist=iexist)
 if (.not.iexist) then
    print "(a)",' *** error: '//trim(dumpfile)//': file not found ***'
    return
 endif
 !
 !--fix number of spatial dimensions
 !
 ndim = 3
 ndimV = 3

 !--number of columns to read from file
 ncol = 21
 doubleprec = .false.

 !--can override these settings with environment variables
 if (lenvironment('BSPLASH_R8')) doubleprec = .true.
 ncoltemp = ienvironment('BSPLASH_NCOL')
 if (ncoltemp > 0) ncol = ncoltemp
 !
 !--allocate memory initially
 !
 nstep_max = max(nstep_max,indexstart,1)
 j = indexstart
 nstepsread = 0

 print "(1x,a)",'reading Andreas Bauswein format'
 write(*,"(26('>'),1x,a,1x,26('<'))") trim(dumpfile)
 !
 !--open the (unformatted) binary file and read the number of particles
 !
 open(unit=15,file=dumpfile,status='old',form='unformatted',iostat=ierr)
 if (ierr /= 0) then
    print "(a)",'*** ERROR OPENING '//trim(dumpfile)//' ***'
    return
 else
    !
    !--read the number of particles in the header and allocate memory
    !
    if (doubleprec) then
       read(15,end=55,iostat=ierr) nprint,n1,timedb,dtdb
       timei = real(timedb)
       dti = real(dtdb)
    else
       read(15,end=55,iostat=ierr) nprint,n1,timei,dti
    endif
    print "(a,f10.2,a,i10,a,i10,a,f10.4)",' time: ',timei,' npart: ',nprint,' n1: ',n1,' dt = ',dti
    !--barf if stupid values read
    if (nprint <= 0 .or. nprint > 1e10) then
       print "(a)",' *** ERRORS IN TIMESTEP HEADER: WRONG ENDIAN? ***'
       close(15)
       return
    elseif (ierr /= 0) then
       print "(a)",'*** WARNING: ERRORS READING HEADER ***'
    endif
    if (timei < 0. .or. dti < 0.) print "(a)",'*** ERROR: t < 0: use setenv BSPLASH_R8=TRUE for double precision'
    ncolumns = ncol

    if (.not.allocated(dat) .or. nprint > npart_max) then
       npart_max = max(npart_max,nprint)
       call alloc(npart_max,nstep_max,ncolumns)
    endif
    !
    !--now read the timestep data in the dumpfile
    !
    dat(:,:,j) = 0.
    time(j) = timei

    if (doubleprec) then
       nread = 0
       nerr = 0
       do i=1,nprint
          nread = nread + 1
          read(15,end=44,iostat=ierr) (datdb(k),k=1,ncol)
          if (ierr /= 0) nerr = nerr + 1
          dat(i,4,j) = real(datdb(1))
          dat(i,1:3,j) = real(datdb(2:4))
          dat(i,5:ncol,j) = real(datdb(5:ncol))
       enddo
    else
       nread = 0
       nerr = 0
       do i=1,nprint
          nread = nread + 1
          read(15,end=44,iostat=ierr) dat(i,4,j),dat(i,1:3,j),(dat(i,k,j),k=5,ncol)
          if (ierr /= 0) nerr = nerr + 1
       enddo
    endif

44  continue
    if (nerr > 0) print *,'*** WARNING: ERRORS DURING READ ON ',nerr,' LINES'

    if (nread < nprint) then
       print "(a)",' WARNING: END OF FILE: read to particle ',nread
       nprint = nread
    endif

    nstepsread = nstepsread + 1
    npartoftype(1,j) = nprint
    gamma(j) = 1.666666666667
    j = j + 1

 endif

55 continue
 !
 !--reached end of file during header read
 !
 close(15)

 if (allocated(npartoftype)) then
    print*,'>> end of dump file: nsteps =',j-1,'ntot = ',sum(npartoftype(:,j-1))
 endif
 return

end subroutine read_data

!!------------------------------------------------------------
!! set labels for each column of data
!!------------------------------------------------------------

subroutine set_labels
 use labels, only:label,labelvec,labeltype,iamvec,&
              ix,ivx,ih,irho,iutherm,ipmass,make_vector_label
 use settings_data, only:ndim,ndimV,ntypes,UseTypeInRenderings
 use geometry, only:labelcoord
 !use settings_units, only:units,unitslabel
 implicit none
 integer :: i,ipmom

 if (ndim <= 0 .or. ndim > 3) then
    print*,'*** ERROR: ndim = ',ndim,' in set_labels ***'
    return
 endif
 if (ndimV <= 0 .or. ndimV > 3) then
    print*,'*** ERROR: ndimV = ',ndimV,' in set_labels ***'
    return
 endif

 do i=1,ndim
    ix(i) = i
 enddo
 ih = 4
 ivx = 5
 ipmom = 8
 iutherm = 11
 ipmass = 14
 irho = 17

 label(ix(1:ndim)) = labelcoord(1:ndim,1)
 label(ih) = 'h'
 if (iutherm > 0) label(iutherm) = 'u'
 label(12) = 'psi_{pot}'
 label(13) = 'alpha_{pot}'
 label(ipmass) = 'particle mass'
 label(15) = '\gr'
 label(16) = 'P\deff'
 label(irho) = '\gr*'
 label(18) = 'tau'
 label(19) = '\ga_{visc}'
 label(20) = 'Ye'
 label(21) = 'temperature'

 call make_vector_label('v',ivx,ndimV,iamvec,labelvec,label,labelcoord(:,1))
 call make_vector_label('momentum',ipmom,ndimV,iamvec,labelvec,label,labelcoord(:,1))
 !
 !--set labels for each particle type
 !
 ntypes = 1
 labeltype(1) = 'gas'
 UseTypeInRenderings(1) = .true.

!-----------------------------------------------------------

 return
end subroutine set_labels
