!-----------------------------------------------------------------
!
!  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) 2005-2013 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
!
! the data is stored in the global array dat
!
! THIS VERSION FOR ABDEL REHEAM's SPH CODE
!
! >> 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(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'
!-------------------------------------------------------------------------
!--local module to store header information so we can later set the labels
module alydataread
 use params
 use labels, only:lenlabel
 implicit none
 character(len=16), dimension(maxplot) :: compName

end module alydataread

subroutine read_data(rootname,indexstart,ipos,nstepsread)
 use particle_data,  only:npartoftype,masstype,time,gamma,dat,maxpart,maxstep,maxcol,iamtype
 use params
 use filenames,      only:nfiles
 use settings_data,  only:ndim,ndimV,ncolumns,ncalc, &
                          buffer_data,iverbose,debugmode,ntypes
 use mem_allocation, only:alloc
 use labels,         only:ipr,ivx,ih,irho,labeltype
 use alydataread,    only:compName
 implicit none
 integer,          intent(in)  :: indexstart,ipos
 integer,          intent(out) :: nstepsread
 character(len=*), intent(in)  :: rootname
 character(len=len(rootname)+4) :: datfile
 integer :: i,ierr,iunit,j,iblock
 integer :: npart_max,nstep_max

 integer, dimension(:), allocatable :: itype
 character(len=20) :: geomfile
 character(len=7)  :: keyword
 character(len=70) :: title
 character(len=1)  :: dumchar
 character(len=16) :: unitsys
 integer :: istep,jtype,np,ione,kk,idum,nblock
 real(kind=sing_prec) :: version,timesingle,dum
 real(kind=doub_prec) :: versiond,timedbl,dumd
 real :: timein,dx,dy
 logical :: singleprecision

 iunit = 11 ! file unit number
 nstepsread = 0
 if (rootname(1:1) /= ' ') then
    datfile = trim(rootname)
 else
    print*,' **** no data read **** '
    return
 endif

 if (iverbose >= 1) print "(1x,a)",'reading Aly format'
 write(*,"(23('-'),1x,a,1x,23('-'))") trim(datfile)

 ndim = 2
 ndimV = 2
 !
 !--open data file and read data
 !
 open(unit=iunit,iostat=ierr,file=datfile,status='old',form='unformatted',access='stream')
 if (ierr /= 0) then
    print*,' *** Error opening '//trim(datfile)//' ***'
    return
 endif
!
!--read first header line
!
 read(iunit,iostat=ierr,end=80) keyword
 read(iunit,iostat=ierr,end=80) version
 read(iunit,iostat=ierr,end=80) title
 read(iunit,iostat=ierr,end=80) istep
 read(iunit,iostat=ierr,end=80) timesingle
 timein = timesingle
 read(iunit,iostat=ierr,end=80) np
 read(iunit,iostat=ierr,end=80) ione
 if (ierr /= 0 .or. np <= 0 .or. timesingle < 0.) then
    !
    !--try single precision
    !
    rewind(iunit)
    read(iunit,iostat=ierr,end=80) keyword
    read(iunit,iostat=ierr,end=80) versiond
    version = versiond
    read(iunit,iostat=ierr,end=80) title
    read(iunit,iostat=ierr,end=80) istep
    read(iunit,iostat=ierr,end=80) timedbl
    timein = timedbl
    read(iunit,iostat=ierr,end=80) np
    read(iunit,iostat=ierr,end=80) ione
    singleprecision = .false.
    if (ierr /= 0 .or. np < 0 .or. timedbl < 0.) then
       print "(a)",' *** Error reading first header ***'
       close(iunit)
       return
    endif
 endif
 print "(a,f4.2)",' keyword = '//trim(keyword)//' version = ',version
 !print "(a)",' title = '//trim(title)
 print "(a,i6,a,es10.3,a,i6)",' step = ',istep,' time = ',timein,' np = ',np
!
!--allocate memory for data arrays
!
 if (buffer_data) then
    nstep_max = max(nfiles,maxstep,indexstart)
 else
    nstep_max = max(1,maxstep,indexstart)
 endif
 npart_max = max(int(1.1*np),maxpart)
 ncolumns = 7
 if (.not.allocated(dat) .or. npart_max > maxpart  &
       .or. nstep_max > maxstep .or. ncolumns+ncalc > maxcol) then
    call alloc(npart_max,nstep_max,ncolumns+ncalc,mixedtypes=.true.)
 endif

 i = indexstart
 nstepsread = 0
 time(i)  = timein
 gamma(i) = 5./3.
 npartoftype(1,i) = np

 do j=1,np
    read(iunit,iostat=ierr,end=67) idum,(dat(j,kk,i),kk=1,2),dum
 enddo
 read(iunit,iostat=ierr,end=67) nblock
 read(iunit,iostat=ierr,end=67) (idum,j=1,nblock)

 ntypes = 4
 allocate(itype(np))
 read(iunit,iostat=ierr,end=67) (itype(j),j=1,nblock)
 npartoftype(:,i) = 0
 do j=1,np
    jtype = itype(j)
    !--map types from code types to splash types
    select case(jtype)
    case(1)
       jtype = 2 ! boundary
    case(2)
       jtype = 1 ! water
    case default ! unknown
       jtype = 4
    end select
    iamtype(j,i) = jtype
    npartoftype(jtype,i) = npartoftype(jtype,i) + 1
 enddo
 deallocate(itype)
 read(iunit,iostat=ierr,end=67) (dumchar,j=1,nblock)
 read(iunit,iostat=ierr,end=67) (idum,j=1,nblock)

 call set_labels
 do iblock=1,1

    read(iunit,iostat=ierr,end=67) nblock
    read(iunit,iostat=ierr,end=67) idum

    do j=1,nblock
       read(iunit,iostat=ierr,end=67) compName(j),unitsys,idum,idum,dum
       !print*,trim(compName(j))
    enddo

    do j=1,np
       read(iunit,iostat=ierr,end=67) dum,dat(j,ipr,i),dat(j,ivx,i),dat(j,ivx+1,i),dat(j,1,i),dat(j,2,i)
       if (abs(dum) < tiny(0.)) then
          npartoftype(iamtype(j,i),i) = npartoftype(iamtype(j,i),i) - 1 ! remove from previous type
          iamtype(j,i) = 3
          npartoftype(3,i) = npartoftype(3,i) + 1 ! add to "box" type
       endif
    enddo
 enddo
 !
 !--fake other properties: density, mass, smoothing length etc.
 !
 masstype(1,i) = 1./npartoftype(1,i)
 !
 !--assume smoothing length to be the max dimension divided by the number of particles^(1/ndim)
 !
 dx = maxval(dat(1:np,1,i)) - minval(dat(1:np,1,i))
 dy = maxval(dat(1:np,2,i)) - minval(dat(1:np,2,i))
 dat(:,ih,i)   = dx/(npartoftype(1,i))**(1./ndim)*(dy/dx)
 print*,' WARNING: ASSUMING SMOOTHING LENGTH = ',dat(1,ih,i),' AND ARBITRARY PARTICLE MASSES'
 dat(:,irho,i) = 1.
 nstepsread = 1
 do jtype=1,ntypes
    write(*,"(' n(',a,') = ',i6)",advance="no") trim(labeltype(jtype)),npartoftype(jtype,i)
 enddo
 write(*,*)
 !read*


 goto 68
67 continue
 print "(a)",' > end of file reached <'
68 continue
 !
 !--close data file and return
 !
 close(unit=11)

 if (debugmode) print*,'DEBUG> Read steps ',indexstart,'->',indexstart + nstepsread - 1, &
       ' last step ntot = ',sum(npartoftype(:,indexstart+nstepsread-1))
 return

80 continue
 print*,' *** data file empty : no timesteps ***'
 return

end subroutine read_data

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

subroutine set_labels
 use labels, only:ix,ivx,ih,irho,ipr,&
             iamvec,labelvec,label,labeltype
 use params
 use settings_data, only:ndim,ndimV,UseTypeInRenderings
 use geometry,      only:labelcoord
 implicit none
 integer :: i

 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
 ivx = ndim + 1
 ipr = ndim + ndimV + 1
 irho = ipr + 1
 ih  = irho + 1
 label(ipr) = 'pressure'
 label(irho) = 'density'
 label(ih) = 'h'

 label(ix(1:ndim)) = labelcoord(1:ndim,1)
 !
 !--label vector quantities (e.g. velocity) appropriately
 !
 iamvec(ivx:ivx+ndimV-1) = ivx
 labelvec(ivx:ivx+ndimV-1) = 'v'

!
!--set labels for each type of particles
!
 labeltype(1) = 'water'
 labeltype(2) = 'boundary'
 labeltype(3) = 'box'
 labeltype(4) = 'unknown'
 UseTypeInRenderings(1) = .true.
 UseTypeInRenderings(2) = .false.
 UseTypeInRenderings(3) = .false.
 UseTypeInRenderings(4) = .false.

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

 return
end subroutine set_labels
