#!/usr/bin/perl
#
# Name : Matthew Reeves
#
# This is a program to duplicate the finger cmd while allowing for misspelling
# via the use of soundex
#
#use diagnostics;
use warnings;
use strict;
use feature ":5.10";

#checks if cmd line argument provided, if not, print usage statement and exit
if ($ARGV[0] ~~ undef)
{
        print "\nUsage: $0 <possiblematch>\n\n";
        exit;
}

#stores command line argument in a more friendly named scalar
my $input = $ARGV[0];

#saves soundex converted value to a scalar for easier comparisons later
my $inputSDX = &soundex($input);

#prints a statement echoing the input value, and its soundex converted value
print "\nPoss match: $input\nConv value: $inputSDX\n\n";

#open /etc/passwd file to find userid's first names's and last name's to compare
#against input value, stores contents in @wholeFile
open (IN,"/etc/passwd");
my @wholeFile = <IN>;

#close /etc/passwd file
close IN;

#declare @args with default value, which will be used to call finger cmd via system()
#also declares $check, which tracks if any sdx match was found in etc/passwd file
my @args = ("finger", $input);
my $check = 0;

#for loop will process /etc/passwd data line by line
foreach my $line (@wholeFile)
{
        my @pmatches;

	#sends current line to &getnames subroutine to get username, first name 
	#and last name, stores data in @pmatches
        @pmatches = &getNames($line);

	#converts each of the three names currently in @pmatches to soundex
	#value, compares against input's soundex, and if match found runs
	#finger using corresponding userid as arguement
	foreach (@pmatches)
	{
		if ($inputSDX ~~ &soundex($_))
		{			
			@args = ("finger", $pmatches[0]);
			system(@args); 
			$check = 1;
			say "";
		}
	}
}

#if no sdx matches were found in etc/passwd, calls finger with string
#entered at command line so user will get finger error message
system(@args) if $check~~0;

sub getNames
{
	#grabs the arguement passed to soundex
        my $parameter = shift;

	#initializes @results with default values
        my @results = ( "fakeuserid", "fake first name", "fake last name" );

	#splits line with : delimiter
        my @tmp = split(/:/ , $parameter);

	#stores username in $results[0]
        $results[0] = $tmp[0];

	#identifies first name and last name using regex
        $tmp[4] =~ /(\w*\s*.*?)\s*(\w*),/;

	#backreferencing stores first name and last name to @results
        $results[1] = $1;
        $results[2] = $2;

	#returns results
        return @results;
}


sub soundex
{

        my $temp = shift;       #grabs the argument passed to soundex

        $temp = uc $temp;       #uppercase the name passed in to normalize it

        my $sdxValue = "*** $temp not processed ***";   #default response

        #removes all non-alphabetic characters
        $temp =~ s/[^A-Za-z]//g;

        #stores first letter's value
        my $letter = substr($temp, 0, 1);

        #uses transliteration to change letters, to numeric code
        $temp =~ tr/BFPVCGJKQSXZDTLMNR/111122222222334556/;

        #eliminates consecutive duplicate code values
        $temp =~ tr/0-9//s;

        #deletes letters AEHIOUWY
        $temp =~ tr/AEHIOUWY//d;

        #pads 0's to the end of temp
        $temp .= "0000";

        #if/else block to check if first letter was AEHIOUWY, and reinserts
        #first letter onto temp as a letter as appropriate, either tacked on to
        #the front of temp, or overwriting the first value in temp to prevent
        #innaccuracies due to duplication of first character. Also serves to
        #fix final length of soundex code to 5 characters.
        if ($letter =~ /A|E|H|I|O|U|W|Y/)
        {
                $temp = $letter.substr($temp, 0, 4);
        }
        else
        {
                $temp = $letter.substr($temp, 1, 4);
        }

        #stores, then returns soundex value
        $sdxValue = $temp;
        return $sdxValue;
}