!> summary.txt の外部シース（matching-plane）receipt のキー表。
!! summary の writer と checkpoint の loader が同じ表からキー名・順序・必須条件を取る。
module bem_matching_plane_summary
  use bem_kinds, only: dp, i32
  use bem_types, only: matching_plane_stats
  use bem_string_utils, only: is_decimal_real_token, is_decimal_integer_token, is_logical_token
  implicit none
  private

  public :: matching_plane_summary_key_count
  public :: write_matching_plane_summary
  public :: read_matching_plane_summary_key
  public :: require_matching_plane_summary_keys
  public :: read_matching_summary_real

  integer, parameter :: value_real = 1, value_integer = 2, value_logical = 3, value_spectrum = 4

  !> summary の 1 キー。unique は重複を拒否し、required は schema 9 以降の checkpoint で必須、
  !! restored は再開時に読み戻す（top_cell_mean は snapshot から再計算するので読まない）。
  type :: receipt_key
    character(len=56) :: name = ''
    integer :: value_kind = value_real
    logical :: unique = .false.
    logical :: required = .false.
    logical :: restored = .true.
  end type receipt_key

  ! summary.txt に書く順。順序と名前は出力形式の一部なので変えない。
  type(receipt_key), parameter :: receipt_keys(*) = [ &
                                  receipt_key('matching_plane_secondary_share', value_real, .false., .false., .true.), &
                                  receipt_key('secondary_budget_residual_a_m2', value_real, .false., .false., .true.), &
                                  receipt_key('matching_plane_state_valid', value_logical, .true., .true., .true.), &
                                  receipt_key('matching_plane_displacement_C_m2', value_real, .true., .true., .true.), &
                                  receipt_key('matching_plane_phi_V', value_real, .true., .true., .true.), &
                                  receipt_key('matching_plane_top_cell_mean_V_m', value_real, .false., .false., .false.), &
                                  receipt_key('matching_plane_electron_inward_flux_m2_s', value_real, .true., .true., .true.), &
                                  receipt_key('matching_plane_ion_inward_flux_m2_s', value_real, .true., .true., .true.), &
                                  receipt_key('matching_plane_electron_access_potential_V', value_real, .true., .true., .true.), &
                                  receipt_key('matching_plane_ion_access_potential_V', value_real, .true., .true., .true.), &
                                  receipt_key( &
                                  'matching_plane_photoelectron_barrier_potential_V', value_real, .true., .true., .true.), &
                                  receipt_key( &
                                  'matching_plane_photoelectron_outward_flux_m2_s', value_real, .true., .true., .true.), &
                                  receipt_key( &
                                  'matching_plane_photoelectron_mean_normal_energy_eV', value_real, .true., .true., .true.), &
                                  receipt_key( &
                                  'matching_plane_photoelectron_spectrum_m2_s', value_spectrum, .true., .false., .true.), &
                                  receipt_key('matching_plane_electron_outward_flux_m2_s', value_real, .true., .true., .true.), &
                                  receipt_key('matching_plane_ion_outward_flux_m2_s', value_real, .true., .true., .true.), &
                                  receipt_key( &
                                  'matching_plane_photoelectron_return_flux_m2_s', value_real, .true., .true., .true.), &
                                  receipt_key( &
                                  'matching_plane_photoelectron_escape_flux_m2_s', value_real, .true., .true., .true.), &
                                  receipt_key('matching_plane_iterations', value_integer, .true., .true., .true.), &
                                  receipt_key('matching_plane_residual', value_real, .true., .true., .true.) &
                                  ]
  integer, parameter :: matching_plane_summary_key_count = size(receipt_keys)
  integer, parameter :: receipt_real_count = count(receipt_keys%value_kind == value_real)

contains

  !> receipt を表の順に summary.txt へ書く。
  subroutine write_matching_plane_summary(u, receipt)
    integer, intent(in) :: u
    type(matching_plane_stats), intent(in) :: receipt
    integer :: k, real_index
    real(dp) :: real_values(receipt_real_count)

    real_values = receipt_real_values(receipt)
    real_index = 0
    do k = 1, size(receipt_keys)
      select case (receipt_keys(k)%value_kind)
      case (value_logical)
        write (u, '(a,l1)') trim(receipt_keys(k)%name)//'=', receipt%state_valid
      case (value_integer)
        write (u, '(a,i0)') trim(receipt_keys(k)%name)//'=', receipt%iterations
      case (value_spectrum)
        write (u, '(a,*(1x,es24.16))') trim(receipt_keys(k)%name)//'=', receipt%photoelectron_spectrum_m2_s
      case (value_real)
        real_index = real_index + 1
        write (u, '(a,es24.16)') trim(receipt_keys(k)%name)//'=', real_values(real_index)
      end select
    end do
  end subroutine write_matching_plane_summary

  !> receipt のキーだけ value を読み戻す。found は表と同じ添字で、重複の検出に使う。
  subroutine read_matching_plane_summary_key(key, value, receipt, found)
    character(len=*), intent(in) :: key, value
    type(matching_plane_stats), intent(inout) :: receipt
    logical, intent(inout) :: found(matching_plane_summary_key_count)
    integer :: k, ios, real_index
    real(dp) :: x, real_values(receipt_real_count)

    k = key_index(key)
    if (k == 0) return
    if (.not. receipt_keys(k)%restored) return
    if (receipt_keys(k)%unique) then
      if (found(k)) error stop 'Resume checkpoint summary contains duplicate matching-plane key: '//trim(key)
    end if
    found(k) = .true.
    select case (receipt_keys(k)%value_kind)
    case (value_logical)
      call read_matching_summary_logical(value, key, receipt%state_valid)
    case (value_integer)
      call read_matching_summary_integer(value, key, receipt%iterations)
    case (value_spectrum)
      read (value, *, iostat=ios) receipt%photoelectron_spectrum_m2_s
      if (ios /= 0) error stop 'Resume checkpoint matching-plane photoelectron spectrum could not be parsed.'
    case (value_real)
      call read_matching_summary_real(value, key, x)
      real_values = receipt_real_values(receipt)
      real_index = count(receipt_keys(:k)%value_kind == value_real)
      real_values(real_index) = x
      call restore_receipt_real_values(receipt, real_values)
    end select
  end subroutine read_matching_plane_summary_key

  !> schema 9 以降の checkpoint では required のキーが全て揃っていなければ再開しない。
  subroutine require_matching_plane_summary_keys(found)
    logical, intent(in) :: found(matching_plane_summary_key_count)

    if (.not. all(found .or. .not. receipt_keys%required)) then
      error stop 'Resume checkpoint schema-v9 summary is missing required matching-plane keys.'
    end if
  end subroutine require_matching_plane_summary_keys

  integer function key_index(key) result(k)
    character(len=*), intent(in) :: key

    do k = 1, size(receipt_keys)
      if (trim(receipt_keys(k)%name) == trim(key)) return
    end do
    k = 0
  end function key_index

  !> 表の実数キー順に値を並べる。書き出しと読み戻しで同じ順を使う。
  function receipt_real_values(receipt) result(values)
    type(matching_plane_stats), intent(in) :: receipt
    real(dp) :: values(receipt_real_count)

    values = [receipt%secondary_share, receipt%secondary_budget_residual_a_m2, receipt%displacement_c_m2, &
              receipt%phi_v, receipt%top_cell_mean_v_m, receipt%response(2:6), receipt%feedback, &
              receipt%photoelectron_return_flux_m2_s, receipt%photoelectron_escape_flux_m2_s, receipt%residual]
  end function receipt_real_values

  !> 表の実数キー順の値を戻す。phi_V は応答の電位（response(1)）も兼ねる。
  subroutine restore_receipt_real_values(receipt, values)
    type(matching_plane_stats), intent(inout) :: receipt
    real(dp), intent(in) :: values(receipt_real_count)

    receipt%secondary_share = values(1)
    receipt%secondary_budget_residual_a_m2 = values(2)
    receipt%displacement_c_m2 = values(3)
    receipt%phi_v = values(4)
    receipt%top_cell_mean_v_m = values(5)
    receipt%response = [values(4), values(6:10)]
    receipt%feedback = values(11:14)
    receipt%photoelectron_return_flux_m2_s = values(15)
    receipt%photoelectron_escape_flux_m2_s = values(16)
    receipt%residual = values(17)
  end subroutine restore_receipt_real_values

  subroutine read_matching_summary_real(value, key, result_value)
    character(len=*), intent(in) :: value, key
    real(dp), intent(out) :: result_value
    integer :: ios

    if (.not. is_decimal_real_token(trim(value))) then
      error stop 'Resume checkpoint matching-plane key has an invalid real token: '//trim(key)
    end if
    read (value, *, iostat=ios) result_value
    if (ios /= 0) error stop 'Resume checkpoint matching-plane real value could not be parsed: '//trim(key)
  end subroutine read_matching_summary_real

  subroutine read_matching_summary_integer(value, key, result_value)
    character(len=*), intent(in) :: value, key
    integer(i32), intent(out) :: result_value
    integer :: ios

    if (.not. is_decimal_integer_token(trim(value))) then
      error stop 'Resume checkpoint matching-plane key has an invalid integer token: '//trim(key)
    end if
    read (value, *, iostat=ios) result_value
    if (ios /= 0) error stop 'Resume checkpoint matching-plane integer value could not be parsed: '//trim(key)
  end subroutine read_matching_summary_integer

  subroutine read_matching_summary_logical(value, key, result_value)
    character(len=*), intent(in) :: value, key
    logical, intent(out) :: result_value
    integer :: ios

    if (.not. is_logical_token(trim(value))) then
      error stop 'Resume checkpoint matching-plane key has an invalid logical token: '//trim(key)
    end if
    read (value, *, iostat=ios) result_value
    if (ios /= 0) error stop 'Resume checkpoint matching-plane logical value could not be parsed: '//trim(key)
  end subroutine read_matching_summary_logical

end module bem_matching_plane_summary