#!/usr/bin/perl
use strict;
use warnings;
use Tie::File;
use feature "switch";
no warnings 'experimental';

# Declare constants
use constant false => 0;
use constant true  => 1;


# Declare variables
my $ip_filename = '/home/mimir/mb_ip.cfg';  # The ip info entered by the user into the GUI
my $dhcpcd_filename = '/home/mimir/d.conf'; # The dhcp configuration file to be written to
#my $dhcpcd_filename = '/etc/dhcpcd.conf';

# A hash of config parameters to be updated in order 
# of how they should be saved.
# Initiate with reasonable start values.
my %ip_params = ( interface      => "usb0",
                  ip_address     => "1.1.1.0",
                  routers        => "127.0.0.0",
                  domain_servers => "1.1.1.1");

my $ip_line;    # whole parameter line
my @ip_fields;  # parameter fields in a line

# The list of saved user param variables
tie my @ip_array, 'Tie::File',  $ip_filename
    or die "Cannot tie file '$ip_filename': $!";

########### Get param values from the GUI input file mb_ip.cfg
### Read the values from mb_ip.cfg and save to a hash
for $ip_line (@ip_array)
   {
   @ip_fields = split /=/, $ip_line;  # get the parameter name and value
      given ($ip_fields[0]){
         when ( /interface/ ) {
              $ip_params{'interface'} = $ip_fields[1]; }
         when ( /ip_address/ ) {
              $ip_params{'ip_address'} = $ip_fields[1]; }
         when ( /routers/ ) {
              $ip_params{'routers'} = $ip_fields[1]; }
         when ( /domain_name_servers/ ) {
              $ip_params{'domain_servers'} = $ip_fields[1]; }
         default { 
              	      print "no match to params\n\n"
 	 }
      }
}

                   print "Network parameters loaded into the array \n";
                   for(keys %ip_params){
                     print("   $_ is $ip_params{$_}\n");
                   }
untie @ip_array;
    
########### Find the lines in the config file to be replaced.
# Find the required interface section
# Initiate the boolean variables that only change one parameter
# in the config file section.
# When all are found and changed, jump out.
my $isFoundInterface = false;  
my $isFoundIP = false;
my $isFoundRouters = false;
my $isFoundDNS = false;

# The config file to search and replace variables
tie my @dhcpcd_array, 'Tie::File',  $dhcpcd_filename
    or die "Cannot tie file '$dhcpcd_filename': $!";

                   print "  \n\n\n";
# Find and replace the config lines
for $ip_line (@dhcpcd_array){
                   print "$ip_line\n";
   # look for 'profile static_eth0' that marks start of the section
   if ( $ip_line =~ /^.*profile\s*static_$ip_params{'interface'}\s*/ ) {
     $isFoundInterface = true;    # Found the first line of the section.
                   print "##############   Found profile line\n" ;
     next;  # Jump to the next line in the file.  
   }

# When the profile interface section is found, look for the parameters to change
   if ( $isFoundInterface == true ) {
      given ($ip_line){
         when ( /^.*static\s*ip_address=/ ) {
              $ip_line = "  static ip_address=$ip_params{'ip_address'}";
              $isFoundIP = true;
	      }
         when ( /^.*static\s*routers=/ ) {
              $ip_line = "  static routers=$ip_params{'routers'}";
              $isFoundRouters = true;
              }
         when ( /^.*static\s*domain_name_servers=/ ) {
              $ip_line = "  static domain_name_servers=$ip_params{'domain_servers'}";
              $isFoundDNS = true;
	      }			
         default { if ($isFoundInterface 
                   and $isFoundIP 
                   and $isFoundRouters 
                   and $isFoundDNS ) { last; }  #stop searching the config file when changes all done.
 	      }
      }
   }
                print "isIP : $isFoundIP\n";
                print "isRouters : $isFoundRouters\n";
                print "isDNS     : $isFoundDNS\n\n";
                print "looking for the ip config params\n";
}

untie @dhcpcd_array;