#!/usr/bin/perl
#
#  path_filter.pl - parse the PATH variable, and return a new path string with all
#  the duplicates removed, and any entries in the IGNORE hash removed.
#
#  Win/DOS doesn't care much about case sensitivity, so we'll map everything to lower
#  case on storage so we can remove dups in different cases (specifically for the
#  case of C:\Windows\System32 vs C:\Windows\system32)
#
# 20110309 roboticus
use strict;
use warnings;

my $DBG=0;

my %IGNORE = map { lc($_)=>0 } (
        "/DOS/c/Program Files/TortoiseSVN/bin",
        "/DOS/c/Program Files/QuickTime/QTSystem",
        "/DOS/c/WINDOWS/system32/WindowsPowerShell/v1.0",
        . . . snip! . . .
        # WBEM=Web-Based Enterprise Management (WMI), not likely needed in Cygwin
        "/DOS/c/WINDOWS/System32/Wbem",
);
my %DUP = ();

my @Path = split /:/, $ENV{PATH};
my @NewPath = ();

for my $dir (@Path) {
        if (! -d $dir) {
                print STDERR "MISSING: $dir\n"  if $DBG;
        }
        elsif (exists $IGNORE{lc $dir}) {
                ++$IGNORE{$dir};
                print STDERR "IGNORED: $dir\n"  if $DBG;
        }
        elsif (exists $DUP{lc $dir}) {
                print STDERR "DUP:     $dir\n"  if $DBG;
                ++$DUP{lc $dir};
        }
        else {
                print STDERR "ADDED:   $dir\n"  if $DBG;
                $DUP{lc $dir}=0;
                push @NewPath, $dir;
        }
}

# Output the new PATH variable
print join(":", @NewPath);