#!/usr/local/bin/perl

#*******************************************
# Filename: phonebook.perl                **
# A simple phone book application in perl **
#*******************************************

# Send MIME Header
print "Content-type: text/plain\n\n";

# Check the CONTENT_LENGTH environment variable
$content_len = $ENV{"CONTENT_LENGTH"};
if ($content_len == 0)
{
    print "CONTENT_LENGTH is 0.";
    exit(1);
}

# read the data into the "cgistr" variable
read(STDIN, $cgistr, $content_len);

# split it into an array by the "&" character
@cgistr = split(/&/, $cgistr);

foreach $i (0 .. $#cgistr)
{
    # convert the "+" to space character
    $cgistr[$i] =~ s/\+/ /g;

    # convert the hex tokens to characters
    $cgistr[$i] =~ s/%(..)/pack("c", hex($1))/ge;

    # split into name and value
    ($name, $value) = split(/=/, $cgistr[$i],2);

    # create the associative element
    $cgistr{$name} = $value;
}

$found = 0;

if ($cgistr{"ACTION"} eq "ADD")
{
    &add_name;
}
elsif ($cgistr{"ACTION"} eq "DELETE")
{
    &del_name;
}
else
{
    &search_name;
}
exit(0);

#************************************
# subroutine to add a name/number  **
#************************************
sub add_name
{
    if (length($cgistr{"name"}) == 0)
    {
	print "Name is required!\n";
	exit(1);
    }
    if ( ! open(HNDL, ">>perl_phone.dat"))
    {
	print("Unable to open perl_phone.dat.\nContact Webmaster.\n");
	exit(1);
    }
    else
    {
	print(HNDL $cgistr{"name"}, "\n", $cgistr{"number"}, "\n");
    }
    close(HNDL);
    print "Entry added successfully!\n"
}

#**************************************
# subroutine to delete a name/number **
#**************************************
sub del_name
{
    if ( ! rename("perl_phone.dat", "perl_phone.tmp"))
    {
	print "Unable to rename perl_phone.dat to perl_phone.tmp.\n";
        print "Contact Webmaster.\n";
	exit(1);
    }

    if ( ! open(TMPHNDL, "perl_phone.tmp"))
    {
	print "Unable to open perl_phone.tmp. Contact Webmaster.\n";
	exit(1);
    }

    if ( ! open(HNDL, ">>perl_phone.dat"))
    {
	print "Unable to open perl_phone.dat. Contact Webmaster.\n";
	exit(1);
    }

    while ($nameline = <TMPHNDL>)
    {
	chop($nameline);
	$phoneline = <TMPHNDL>;

	if ($nameline ne $cgistr{"name"})
	{
	    print HNDL $nameline, "\n", $phoneline;
	}
	else
	{
	    $found = 1;
	}
    }
    close(TMPHNDL);
    close(HNDL);
    if ($found)
    {
	print "Entry successfully deleted!\n";
    }
    else
    {
	print "Entry not found!\n";
    }
}



#******************************************
# subroutine to search for a name/number **
#******************************************
sub search_name
{
    if ( ! open(HNDL, "perl_phone.dat"))
    {
	print "Unable to open perl_phone.dat. Contact Webmaster.\n";
	exit(1);
    }

    while ($nameline = <HNDL>)
    {
	chop($nameline);
	$phoneline = <HNDL>;

	if ($nameline eq $cgistr{"name"})
	{
	    print "Name  = ", $nameline, "\nPhone = ", $phoneline;
	    $found = 1;
	    last;
	}
    }
    close(HNDL);
    if (! $found )
    {
	print "Entry not found in the phonebook.\n";
    }
}