!--------------------------------------------------------------------------------------------------
!> @author Franz Roters, Max-Planck-Institut für Eisenforschung GmbH
!> Philip Eisenlohr, Max-Planck-Institut für Eisenforschung GmbH
!> @brief triggering reading in of restart information when doing a restart
!> @todo Descriptions for public variables needed
!--------------------------------------------------------------------------------------------------
module FEsolving
  use prec
  use debug
  use IO
  use DAMASK_interface
   
  implicit none
  private
  integer, public :: &
    restartInc   =  1                                                                               !< needs description

  logical, public :: & 
    symmetricSolver   = .false., &                                                                  !< use a symmetric FEM solver
    restartWrite      = .false., &                                                                  !< write current state to enable restart
    restartRead       = .false., &                                                                  !< restart information to continue calculation from saved state
    terminallyIll     = .false.                                                                     !< at least one material point is terminally ill

  integer, dimension(:,:), allocatable, public :: &
    FEsolving_execIP                                                                                !< for ping-pong scheme always range to max IP, otherwise one specific IP
    
  integer, dimension(2), public :: &
    FEsolving_execElem                                                                              !< for ping-pong scheme always whole range, otherwise one specific element
    
  character(len=1024), public :: &
    modelName                                                                                       !< needs description
    
  logical, dimension(:,:), allocatable, public :: &
    calcMode                                                                                        !< do calculation or simply collect when using ping pong scheme

  public :: FE_init

contains


!--------------------------------------------------------------------------------------------------
!> @brief determine whether a symmetric solver is used and whether restart is requested
!> @details restart information is found in input file in case of FEM solvers, in case of spectal
!> solver the information is provided by the interface module
!--------------------------------------------------------------------------------------------------
subroutine FE_init
 
#if defined(Marc4DAMASK) || defined(Abaqus)
  integer, parameter :: &
    FILEUNIT = 222
  integer :: j
  character(len=65536) :: tag, line
  integer, allocatable, dimension(:) :: chunkPos
#endif

  write(6,'(/,a)')   ' <<<+-  FEsolving init  -+>>>'

  modelName = getSolverJobName()

#if defined(Grid) || defined(FEM)
  restartInc = interface_RestartInc

  if(restartInc < 0) then
    call IO_warning(warning_ID=34)
    restartInc = 0
  endif
  restartRead = restartInc > 0                                                                      ! only read in if "true" restart requested
#else
  call IO_open_inputFile(FILEUNIT,modelName)
  rewind(FILEUNIT)
  do
    read (FILEUNIT,'(a1024)',END=100) line
    chunkPos = IO_stringPos(line)
    tag = IO_lc(IO_stringValue(line,chunkPos,1))                                                    ! extract key
    select case(tag)
      case ('solver')
        read (FILEUNIT,'(a1024)',END=100) line                                                      ! next line
        chunkPos = IO_stringPos(line)
        symmetricSolver = (IO_intValue(line,chunkPos,2) /= 1)
      case ('restart')
        read (FILEUNIT,'(a1024)',END=100) line                                                      ! next line
        chunkPos = IO_stringPos(line)
        restartWrite = iand(IO_intValue(line,chunkPos,1),1) > 0
        restartRead  = iand(IO_intValue(line,chunkPos,1),2) > 0
      case ('*restart')
        do j=2,chunkPos(1)
          restartWrite = (IO_lc(IO_StringValue(line,chunkPos,j)) == 'write') .or. restartWrite
          restartRead  = (IO_lc(IO_StringValue(line,chunkPos,j)) == 'read')  .or. restartRead
        enddo
        if(restartWrite) then
          do j=2,chunkPos(1)
            restartWrite = (IO_lc(IO_StringValue(line,chunkPos,j)) /= 'frequency=0') .and. restartWrite
          enddo
        endif
    end select
  enddo
  100 close(FILEUNIT)

  if (restartRead) then
#ifdef Marc4DAMASK
    call IO_open_logFile(FILEUNIT)
    rewind(FILEUNIT)
    do
      read (FILEUNIT,'(a1024)',END=200) line
      chunkPos = IO_stringPos(line)
      if (   IO_lc(IO_stringValue(line,chunkPos,1)) == 'restart' &
       .and. IO_lc(IO_stringValue(line,chunkPos,2)) == 'file'    &
       .and. IO_lc(IO_stringValue(line,chunkPos,3)) == 'job'     &
       .and. IO_lc(IO_stringValue(line,chunkPos,4)) == 'id' )    &
         modelName = IO_StringValue(line,chunkPos,6)
    enddo
#else
    call IO_open_inputFile(FILEUNIT,modelName)
    rewind(FILEUNIT)
    do
      read (FILEUNIT,'(a1024)',END=200) line
      chunkPos = IO_stringPos(line)
      if (IO_lc(IO_stringValue(line,chunkPos,1))=='*heading') then
        read (FILEUNIT,'(a1024)',END=200) line
        chunkPos = IO_stringPos(line)
        modelName = IO_StringValue(line,chunkPos,1)
      endif
    enddo
#endif
  200 close(FILEUNIT)
  endif

#endif
  if (iand(debug_level(debug_FEsolving),debug_levelBasic) /= 0) then
    write(6,'(a21,l1)') ' restart writing:    ', restartWrite
    write(6,'(a21,l1)') ' restart reading:    ', restartRead
    if (restartRead) write(6,'(a,/)') ' restart Job:        '//trim(modelName)
  endif

end subroutine FE_init

end module FEsolving