! This file is part of SACAMOS, State of the Art CAble MOdels in Spice. 
! It was developed by the University of Nottingham and the Netherlands Aerospace 
! Centre (NLR) for ESA under contract number 4000112765/14/NL/HK.
! 
! Copyright (C) 2016-2017 University of Nottingham
! 
! SACAMOS is free software: you can redistribute it and/or modify it under the 
! terms of the GNU General Public License as published by the Free Software 
! Foundation, either version 3 of the License, or (at your option) any later 
! version.
! 
! SACAMOS is distributed in the hope that it will be useful, but 
! WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
! or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License 
! for more details.
! 
! A copy of the GNU General Public License version 3 can be found in the 
! file GNU_GPL_v3 in the root or at <http://www.gnu.org/licenses/>.
! 
! SACAMOS uses the EISPACK library (in /SRC/EISPACK). EISPACK is subject to 
! the GNU Lesser General Public License. A copy of the GNU Lesser General Public 
! License version can be found in the file GNU_LGPL in the root of EISPACK 
! (/SRC/EISPACK ) or at <http://www.gnu.org/licenses/>.
! 
! The University of Nottingham can be contacted at: ggiemr@nottingham.ac.uk
!
! File Contents:
! SUBROUTINE write_spice_subcircuit_header
!
! NAME
!     write_spice_subcircuit_header
!
! AUTHORS
!     Chris Smartt
!
! DESCRIPTION
!     Create the node numbering for the external conductors and 
!     write the subcircuit header
!
!     INPUTS REQUIRED
!     1. The total number of conductors
!     2. The first free node available
!     3. Flag indicating whether an incident field excitation is present
!     4. Numbers for the incident field excitation termination nodes
!
!     OUTPUTS
!     1. The subcircuit header information including the termination nodes at both ends
!        the subcircuit file
!     2. The termination nodes at both ends are created in the subroutine and
!        are returned to the calling process
!     
! COMMENTS
!     
!     The reference node is no longer included here, it goes the other side of the d.c. resistance on the reference conductor
!
!     We could maybe include comments to include some meaningful labelling of the external conductor numbers
!     i.e. relate them to individual cables and conductors within them.
!
! HISTORY
!
!     STAGE 2 developments started 2/2/2016
!     STAGE 4 developments started 22/4/2016
!     24/8/2016 CJS: Change the writing format for the transmission line model subcircuit to remove long lines (this is a problem for Pspice)
!     4/8/2017 CJS: use n_conductors_without_ground_plane rather than n_conductors when
!                   writing the cable information
!     18/10/2017 CJS: Improve the conductor labelling based on revised cable and bundle conductor labels
!     16/11/2017 CJS Include network synthesis process to replace s-domain transfer functions
!     12/3/2018 CJS: Add more header information about SACAMOS
!
  SUBROUTINE write_spice_subcircuit_header(spice_cable_bundle_model,                         &
                    next_free_node,tot_n_conductors,external_end1_nodes,external_end2_nodes, &
                    include_incident_field,Einc_node1,Einc_node2)

USE type_specifications
USE general_module
USE cable_module
USE cable_bundle_module
USE spice_cable_bundle_module

IMPLICIT NONE

! variables passed to the subroutine

  type(spice_model_specification_type),intent(IN) :: spice_cable_bundle_model

  integer,intent(INOUT) :: next_free_node                          ! spice node number counter

  integer,intent(IN)    :: tot_n_conductors
  
  integer,intent(INOUT)    :: external_end1_nodes(1:tot_n_conductors)  ! list of the external nodes at end 1
  integer,intent(INOUT)    :: external_end2_nodes(1:tot_n_conductors)  ! list of the external nodes at end 2
  
  logical,intent(IN)    :: include_incident_field                   ! flag indicating whether and incident field excitation source is required
  integer,intent(IN)    :: Einc_node1                               ! node numbers for the external incident field excitation voltage
  integer,intent(IN)    :: Einc_node2

! local variables

  character(len=line_length) :: bundle_name
  character(len=line_length) :: spice_model_name

! string used to generate comments
  character(len=max_spice_line_length)    :: comment
  
! variables to assemble the conductor label
  integer :: conductor

  integer :: i     ! loop variable

! START

  bundle_name=spice_cable_bundle_model%bundle%bundle_name
  spice_model_name=spice_cable_bundle_model%spice_model_name
  
! set the external connection node numbers.

  do i=1,tot_n_conductors
    external_end1_nodes(i)=next_free_node
    next_free_node=next_free_node+1
  end do

  do i=1,tot_n_conductors
    external_end2_nodes(i)=next_free_node
    next_free_node=next_free_node+1
  end do
  
! write some general information into the spice subcircuit file

 if (spice_version.EQ.ngspice) then
    write(spice_model_file_unit,'(A)')'* Ngspice multi-conductor transmission line model'   
  else if (spice_version.EQ.LTspice) then
    write(spice_model_file_unit,'(A)')'* LTspice multi-conductor transmission line model'   
  else if (spice_version.EQ.Pspice) then
    write(spice_model_file_unit,'(A)')'* Pspice multi-conductor transmission line model'   
  end if ! spice version
   
  write(spice_model_file_unit,'(A)')  '*'
  write(spice_model_file_unit,'(A)')  '* Created by SACAMOS (State-of-the-Art CAble MOdels for Spice) '
  write(spice_model_file_unit,'(A,A)')'* Spice cable model builder ',trim(SPICE_CABLE_MODEL_BUILDER_version)
  write(spice_model_file_unit,'(A)')  '* www.sacamos.org'
  write(spice_model_file_unit,'(A)')  '*'
  
  write(comment,'(A,A)')'* Cable bundle name: ',trim(bundle_name)

! Write the transmission line subcircuit interface information
  
  CALL write_spice_comment('Transmission line subcircuit')
  
! write the node labels here
    
  CALL write_spice_comment('End 1 nodes:')
  do conductor=1,tot_n_conductors
    write(spice_model_file_unit,'(A7,I3,A,I3,A,A,A,A,A,A,I3)')'* node:',external_end1_nodes(conductor),   &
                                                              trim(spice_cable_bundle_model%bundle%conductor_label(conductor))
  
  end do
  
  CALL write_spice_comment('End 2 nodes:')
  do conductor=1,tot_n_conductors
    write(spice_model_file_unit,'(A7,I3,A,I3,A,A,A,A,A,A,I3)')'* node:',external_end2_nodes(conductor),   &
                                                              trim(spice_cable_bundle_model%bundle%conductor_label(conductor))
  
  end do
  
  if (include_incident_field) then
    CALL write_spice_comment('Incident field function nodes:')
    write(spice_model_file_unit,'(A2,2I6)')'* ',Einc_node1,Einc_node2
  end if
  
  write(spice_model_file_unit,'(A)')'*'
  
  write(spice_model_file_unit,'(A,A)')'.subckt  ',trim(spice_model_name)
  
  CALL write_long_node_list(tot_n_conductors,external_end1_nodes,max_spice_line_length,spice_model_file_unit)
  CALL write_long_node_list(tot_n_conductors,external_end2_nodes,max_spice_line_length,spice_model_file_unit)
  
  if (include_incident_field) then
    write(spice_model_file_unit,'(A,2I6)')'+',Einc_node1,Einc_node2
  end if

END SUBROUTINE write_spice_subcircuit_header