# This program demonstrates user input, string manipulation, basic
# control statements, file manipulation, and the mail command.
# 
# The program asks for a the user to enter their name.  If 
# the user's name is randal then the user is greeted otherwise,
# the user is asked to enter a secret word which must correspond
# to an entry in a preexising password file.  If the user fails
# to enter the correct password the the program sends mail to
# the programs's author notifying him of the users's failed attempt 
# to login.

init_words();
print "what is your name? ";
$name = <STDIN>;
chomp($name);
if ($name =~ /^randal\b/i) { # back to the other way :-)
    print "Hello, Randal! How good of you to be here!\n";
} else {
    print "Hello, $name!\n"; # ordinary greeting
    print "What is the secret word? ";
    $guess = <STDIN>;
    chomp $guess;
    while (! good_word($name,$guess)) {
        print "Wrong, try again. What is the secret word? ";
        $guess = <STDIN>;
        chomp $guess;
    }
}
dbmopen (%last_good,"lastdb",0666);
$last_good{$name} = time;
dbmclose (%last_good);
sub init_words {
    while ($filename = <*.secret>) {
        open (WORDSLIST, $filename)|| 
                              die "can't open $filename: $!";
        if (-M WORDSLIST < 7.0) {
            while ($name = <WORDSLIST>) {
                chomp ($name);
                $word = <WORDSLIST>;
                chomp ($word);
                $words{$name} = $word;
            }
        } else { # rename the file so it gets noticed
            rename ($filename,"$filename.old") || 
                          die "can't rename $filename.old: $!";
        }
        close WORDSLIST;
    }
}
sub good_word {
    my($somename,$someguess) = @_; # name the parameters
    $somename =~ s/\W.*//; # delete everything after first word
    $somename =~ tr/A-Z/a-z/; # lowercase everything
    if ($somename eq "randal") { # should not need to guess
        return 1; # return value is true
    } elsif (($words{$somename} || "groucho") eq $someguess) {
        return 1; # return value is true
    } else {
        open (MAIL, "|mail YOUR_ADDRESS_HERE");
        print MAIL "bad news: $somename guessed $someguess\n";
        close MAIL;
        return 0; # return value is false
    }
}