sw_get_flux_data Subroutine

   subroutine sw_get_flux_data(me, mjd, flux_data, status)
      class(sw_data_type), intent(inout) :: me
      real(dp), intent(in) :: mjd !! Modified Julian Date
      type(flux_data_type), intent(out) :: flux_data !! Output flux data structure
      logical, intent(out) :: status !! Output status (true=success, false=not initialized)

      integer(ip) :: idx, i
      integer(ip) :: daily_end_idx

      if (.not. me%initialized) then
         write(*,'(A)') 'ERROR: Space weather module not initialized'
         status = .false.
         return
      end if

      status = .true.

      ! Handle epoch before data starts
      if (mjd < me%historic_start) then
         if (me%warn_epoch_before) then
            write(*,'(A)') 'WARNING: Requested epoch is earlier than space weather data start'
            write(*,'(A)') '         Using first file entry'
            me%warn_epoch_before = .false.
         end if
         flux_data = me%get_record(1)
         return
      end if

      ! Handle epoch after data ends
      if (mjd >= me%historic_end) then
         if (me%warn_epoch_after) then
            write(*,'(A)') 'WARNING: Requested epoch is later than space weather data end'
            write(*,'(A)') '         Using last file entry'
            me%warn_epoch_after = .false.
         end if
         flux_data = me%get_record(me%n_records)
         return
      end if

      ! Within data range
      ! For daily data: direct index calculation (O(1))
      ! For monthly data: linear search through monthly section only

      if (mjd <= me%historic_daily_end) then
         ! Daily data: use direct index calculation
         idx = int(mjd - me%historic_start) + 1

         ! Bounds check
         if (idx < 1) idx = 1
         if (idx > me%n_records) idx = me%n_records

         flux_data = me%get_record(idx)
      else
         ! Monthly data: search from daily_end to end of array
         ! Find the index where daily data ends
         daily_end_idx = int(me%historic_daily_end - me%historic_start) + 1

         ! Search monthly data for the record at or before mjd
         idx = daily_end_idx
         do i = daily_end_idx, me%n_records
            if (me%mjd(i) > mjd) exit
            idx = i
         end do

         flux_data = me%get_record(idx)
      end if

   end subroutine sw_get_flux_data