!----------------------------------------------------------------------------------------------------
!> @brief internal microstructure state for all thermal sources and kinematics constitutive models
!----------------------------------------------------------------------------------------------------
submodule(phase) thermal

  type :: tThermalParameters
    real(pReal) :: C_p = 0.0_pReal                                                                  !< heat capacity
    real(pReal), dimension(3,3) :: K = 0.0_pReal                                                    !< thermal conductivity
    character(len=pStringLen), allocatable, dimension(:) :: output
  end type tThermalParameters

  integer, dimension(:), allocatable :: &
    thermal_Nsources

  type(tSourceState),  allocatable, dimension(:) :: &
    thermalState

  enum, bind(c); enumerator :: &
    THERMAL_UNDEFINED_ID ,&
    THERMAL_DISSIPATION_ID, &
    THERMAL_EXTERNALHEAT_ID
  end enum

  type :: tDataContainer             ! ?? not very telling name. Better: "fieldQuantities" ??
    real(pReal), dimension(:), allocatable :: T, dot_T
  end type tDataContainer
  integer(kind(THERMAL_UNDEFINED_ID)),  dimension(:,:), allocatable :: &
    thermal_source

  type(tDataContainer), dimension(:), allocatable :: current          ! ?? not very telling name. Better: "field" ?? MD: current(ho)%T(en) reads quite good

  type(tThermalParameters), dimension(:), allocatable :: param

  integer :: thermal_source_maxSizeDotState


  interface

    module function dissipation_init(source_length) result(mySources)
      integer, intent(in) :: source_length
      logical, dimension(:,:), allocatable :: mySources
    end function dissipation_init

    module function externalheat_init(source_length) result(mySources)
      integer, intent(in) :: source_length
      logical, dimension(:,:), allocatable :: mySources
    end function externalheat_init


    module subroutine externalheat_dotState(ph, en)
      integer, intent(in) :: &
        ph, &
        en
    end subroutine externalheat_dotState

    module function dissipation_f_T(ph,en) result(f_T)
      integer, intent(in) :: &
        ph, &
        en
      real(pReal) :: f_T
    end function dissipation_f_T

    module function externalheat_f_T(ph,en)  result(f_T)
      integer, intent(in) :: &
        ph, &
        en
      real(pReal) :: f_T
    end function externalheat_f_T

 end interface

contains

!----------------------------------------------------------------------------------------------
!< @brief Initializes thermal sources and kinematics mechanism.
!----------------------------------------------------------------------------------------------
module subroutine thermal_init(phases)

  type(tDict), pointer :: &
    phases

  type(tDict), pointer :: &
    phase, &
    thermal
  type(tList), pointer :: &
    sources

  integer :: &
    ph, so, &
    Nmembers


  print'(/,1x,a)', '<<<+-  phase:thermal init  -+>>>'


  allocate(current(phases%length))
  allocate(thermalState(phases%length))
  allocate(thermal_Nsources(phases%length),source = 0)
  allocate(param(phases%length))

  do ph = 1, phases%length
    Nmembers = count(material_ID_phase == ph)
    allocate(current(ph)%T(Nmembers),source=T_ROOM)
    allocate(current(ph)%dot_T(Nmembers),source=0.0_pReal)
    phase => phases%get_dict(ph)
    thermal => phase%get_dict('thermal',defaultVal=emptyDict)

    ! ToDo: temperature dependency of K and C_p
    if (thermal%length > 0) then
      param(ph)%C_p = thermal%get_asFloat('C_p')
      param(ph)%K(1,1) = thermal%get_asFloat('K_11')
      if (any(phase_lattice(ph) == ['hP','tI'])) param(ph)%K(3,3) = thermal%get_asFloat('K_33')
      param(ph)%K = lattice_symmetrize_33(param(ph)%K,phase_lattice(ph))

#if defined(__GFORTRAN__)
      param(ph)%output = output_as1dString(thermal)
#else
      param(ph)%output = thermal%get_as1dString('output',defaultVal=emptyStringArray)
#endif
      sources => thermal%get_list('source',defaultVal=emptyList)
      thermal_Nsources(ph) = sources%length
    else
      thermal_Nsources(ph) = 0
    end if

    allocate(thermalstate(ph)%p(thermal_Nsources(ph)))

  end do

  allocate(thermal_source(maxval(thermal_Nsources),phases%length), source = THERMAL_UNDEFINED_ID)

  if (maxval(thermal_Nsources) /= 0) then
    where(dissipation_init (maxval(thermal_Nsources))) thermal_source = THERMAL_DISSIPATION_ID
    where(externalheat_init(maxval(thermal_Nsources))) thermal_source = THERMAL_EXTERNALHEAT_ID
  end if

  thermal_source_maxSizeDotState = 0
  do ph = 1,phases%length

    do so = 1,thermal_Nsources(ph)
      thermalState(ph)%p(so)%state  = thermalState(ph)%p(so)%state0
    end do

    thermal_source_maxSizeDotState  = max(thermal_source_maxSizeDotState, &
                                          maxval(thermalState(ph)%p%sizeDotState))
  end do

end subroutine thermal_init


!----------------------------------------------------------------------------------------------
!< @brief Calculate thermal source.
!----------------------------------------------------------------------------------------------
module function phase_f_T(ph,en) result(f)

  integer, intent(in) :: ph, en
  real(pReal) :: f


  integer :: so


  f = 0.0_pReal

  do so = 1, thermal_Nsources(ph)
   select case(thermal_source(so,ph))

     case (THERMAL_DISSIPATION_ID)
       f = f + dissipation_f_T(ph,en)

     case (THERMAL_EXTERNALHEAT_ID)
       f = f + externalheat_f_T(ph,en)

   end select

  end do

end function phase_f_T


!--------------------------------------------------------------------------------------------------
!> @brief tbd.
!--------------------------------------------------------------------------------------------------
function phase_thermal_collectDotState(ph,en) result(broken)

  integer, intent(in) :: ph, en
  logical :: broken

  integer :: i


  broken = .false.

  SourceLoop: do i = 1, thermal_Nsources(ph)

    if (thermal_source(i,ph) == THERMAL_EXTERNALHEAT_ID) &
      call externalheat_dotState(ph,en)

    broken = broken .or. any(IEEE_is_NaN(thermalState(ph)%p(i)%dotState(:,en)))

  end do SourceLoop

end function phase_thermal_collectDotState


!--------------------------------------------------------------------------------------------------
!> @brief Thermal viscosity.
!--------------------------------------------------------------------------------------------------
module function phase_mu_T(co,ce) result(mu)

  integer, intent(in) :: co, ce
  real(pReal) :: mu


  mu = phase_rho(material_ID_phase(co,ce)) &
     * param(material_ID_phase(co,ce))%C_p

end function phase_mu_T


!--------------------------------------------------------------------------------------------------
!> @brief Thermal conductivity in reference configuration.
!--------------------------------------------------------------------------------------------------
module function phase_K_T(co,ce) result(K)

  integer, intent(in) :: co, ce
  real(pReal), dimension(3,3) :: K


  K = crystallite_push33ToRef(co,ce,param(material_ID_phase(co,ce))%K)

end function phase_K_T


module function phase_thermal_constitutive(Delta_t,ph,en) result(converged_)

  real(pReal), intent(in) :: Delta_t
  integer, intent(in) :: ph, en
  logical :: converged_


  converged_ = .not. integrateThermalState(Delta_t,ph,en)

end function phase_thermal_constitutive


!--------------------------------------------------------------------------------------------------
!> @brief integrate state with 1st order explicit Euler method
!--------------------------------------------------------------------------------------------------
function integrateThermalState(Delta_t, ph,en) result(broken)

  real(pReal), intent(in) :: Delta_t
  integer, intent(in) :: ph, en
  logical :: &
    broken

  integer :: &
    so, &
    sizeDotState


  broken = phase_thermal_collectDotState(ph,en)
  if (broken) return

  do so = 1, thermal_Nsources(ph)
    sizeDotState = thermalState(ph)%p(so)%sizeDotState
    thermalState(ph)%p(so)%state(1:sizeDotState,en) = thermalState(ph)%p(so)%state0(1:sizeDotState,en) &
                                                    + thermalState(ph)%p(so)%dotState(1:sizeDotState,en) * Delta_t
  end do

end function integrateThermalState


module subroutine thermal_restartWrite(groupHandle,ph)

  integer(HID_T), intent(in) :: groupHandle
  integer, intent(in) :: ph

  integer :: so


  do so = 1,thermal_Nsources(ph)
    call HDF5_write(thermalState(ph)%p(so)%state,groupHandle,'omega_thermal')
  end do

end subroutine thermal_restartWrite


module subroutine thermal_restartRead(groupHandle,ph)

  integer(HID_T), intent(in) :: groupHandle
  integer, intent(in) :: ph

  integer :: so


  do so = 1,thermal_Nsources(ph)
    call HDF5_read(thermalState(ph)%p(so)%state0,groupHandle,'omega_thermal')
  end do

end subroutine thermal_restartRead


module subroutine thermal_forward()

  integer :: ph, so


  do ph = 1, size(thermalState)
    do so = 1, size(thermalState(ph)%p)
      thermalState(ph)%p(so)%state0 = thermalState(ph)%p(so)%state
    end do
  end do

end subroutine thermal_forward


!----------------------------------------------------------------------------------------------
!< @brief Get temperature (for use by non-thermal physics)
!----------------------------------------------------------------------------------------------
pure module function thermal_T(ph,en) result(T)

  integer, intent(in) :: ph, en
  real(pReal) :: T


  T = current(ph)%T(en)

end function thermal_T


!----------------------------------------------------------------------------------------------
!< @brief Get rate of temperature (for use by non-thermal physics)
!----------------------------------------------------------------------------------------------
module function thermal_dot_T(ph,en) result(dot_T)

  integer, intent(in) :: ph, en
  real(pReal) :: dot_T


  dot_T = current(ph)%dot_T(en)

end function thermal_dot_T


!----------------------------------------------------------------------------------------------
!< @brief Set temperature
!----------------------------------------------------------------------------------------------
module subroutine phase_thermal_setField(T,dot_T, co,ce)

  real(pReal), intent(in) :: T, dot_T
  integer, intent(in) :: ce, co


  current(material_ID_phase(co,ce))%T(material_entry_phase(co,ce)) = T
  current(material_ID_phase(co,ce))%dot_T(material_entry_phase(co,ce)) = dot_T

end subroutine phase_thermal_setField



!--------------------------------------------------------------------------------------------------
!> @brief checks if a source mechanism is active or not
!--------------------------------------------------------------------------------------------------
function thermal_active(source_label,src_length)  result(active_source)

  character(len=*), intent(in)         :: source_label                                              !< name of source mechanism
  integer,          intent(in)         :: src_length                                                !< max. number of sources in system
  logical, dimension(:,:), allocatable :: active_source

  type(tDict), pointer :: &
    phases, &
    phase, &
    thermal, &
    src
  type(tList), pointer :: &
    sources
  integer :: p,s

  phases => config_material%get_dict('phase')
  allocate(active_source(src_length,phases%length), source = .false. )
  do p = 1, phases%length
    phase => phases%get_dict(p)
    thermal => phase%get_dict('thermal',defaultVal=emptyDict)
    sources => thermal%get_list('source',defaultVal=emptyList)
    do s = 1, sources%length
      src => sources%get_dict(s)
      active_source(s,p) = src%get_asString('type') == source_label
    end do
  end do


end function thermal_active


!----------------------------------------------------------------------------------------------
!< @brief Write thermal sources results to HDF5 output file.
!----------------------------------------------------------------------------------------------
module subroutine thermal_result(group,ph)

  character(len=*), intent(in) :: group
  integer,          intent(in) :: ph


  integer :: ou

  if (.not. allocated(param(ph)%output)) return

  call result_closeGroup(result_addGroup(group//'thermal'))

  do ou = 1, size(param(ph)%output)

    select case(trim(param(ph)%output(ou)))

      case ('T')
        call result_writeDataset(current(ph)%T,group//'thermal','T', 'temperature','K')

    end select

  end do

end subroutine thermal_result


end submodule thermal