MODULE moduleTable

  TYPE:: table1D
    REAL(8):: xMin, xMax
    REAL(8):: fMin, fMax
    REAL(8), ALLOCATABLE, DIMENSION(:):: x, f, k
    CONTAINS
      PROCEDURE, PASS:: init    => initTable1D
      PROCEDURE, PASS:: get     => getValueTable1D
      PROCEDURE, PASS:: convert => convertUnits

  END TYPE table1D

  CONTAINS
    SUBROUTINE initTable1D(self, tableFile)
      USE moduleErrors
      IMPLICIT NONE

      CLASS(table1D), INTENT(inout):: self
      CHARACTER(:), ALLOCATABLE, INTENT(IN):: tableFile
      CHARACTER(100):: dummy
      INTEGER:: amount
      INTEGER:: i
      INTEGER:: stat
      INTEGER:: id = 20

      OPEN(id, file = tableFile)
      amount = 0
      DO
        READ(id, '(A)', iostat = stat) dummy
        !If EOF or error, exit file
        IF (stat /= 0) EXIT
        !Skip comment
        IF (INDEX(dummy,'#') /= 0) CYCLE
        !Add row
        amount = amount + 1

      END DO

      IF (amount == 0) CALL criticalError('Table ' // tableFile // ' is empty', 'initTable1D')
      IF (amount == 1) CALL criticalError('Table ' // tableFile // ' has only one row', 'initTable1D')
      
      !Go bback to initial point
      REWIND(id)

      !Allocate table arrays
      ALLOCATE(self%x(1:amount), self%f(1:amount), self%k(1:amount))
      self%x = 0.D0
      self%f = 0.D0
      self%k = 0.D0

      i = 0
      DO 
        READ(id, '(A)', iostat = stat) dummy
        !TODO: Make this a function
        IF (INDEX(dummy,'#') /= 0) CYCLE
        IF (stat /= 0) EXIT
        !Add data
        !TODO: substitute with extracting information from dummy
        BACKSPACE(id)
        i = i + 1
        READ(id, *) self%x(i), self%f(i)

      END DO

      CLOSE(id)

      self%xMin = self%x(1)
      self%xMax = self%x(amount)
      self%fMin = self%f(1)
      self%fMax = self%f(amount)

      DO i = 1, amount - 1
        self%k(i) = (self%f(i+1) - self%f(i))/(self%x(i+1) - self%x(i))

      END DO

    END SUBROUTINE initTable1D

    FUNCTION getValueTable1D(self, x) RESULT(f)
      IMPLICIT NONE

      CLASS(table1D), INTENT(in):: self
      REAL(8):: x
      REAL(8):: f
      REAL(8):: deltaX
      INTEGER:: i

      IF     (x <= self%xMin) THEN
        f = self%fMin

      ELSEIF (x >= self%xMax) THEN
        f = self%fMax

      ELSE
        i = MINLOC(ABS(x - self%x), 1)
        deltaX = x - self%x(i)
        IF (deltaX < 0 ) THEN 
          i = i - 1
          deltaX = x - self%x(i)
          
        END IF

        f = self%f(i) + self%k(i)*deltaX

      END IF

    END FUNCTION getValueTable1D

    SUBROUTINE convertUnits(self, data_x, data_f)
      IMPLICIT NONE

      CLASS(table1D), INTENT(inout):: self
      REAL(8):: data_x, data_f

      self%x = self%x * data_x
      self%xMin = self%xMin * data_x
      self%xMax = self%xMax * data_x
      self%f = self%f * data_f
      self%fMin = self%fMin * data_f
      self%fMax = self%fMax * data_f
      self%k = self%k * data_f / data_x

    END SUBROUTINE convertUnits

END MODULE moduleTable