#!/usr/local/bin/perl
# Jaime Prilusky, 2012
use GDBM_File ;
use Term::ReadLine;

  my $phoneDB = "./phonesDB";
  
  local(*HIST);
# binds a GDBM file to a hash
  tie %HIST, 'GDBM_File', $phoneDB, GDBM_WRCREAT, 0640;
 
# creates a Term::ReadLine object
  $term = new Term::ReadLine 'PhonesDB';
  $prompt = "Phones >";
  $OUT = $term->OUT || STDOUT;

# get input from user until 'q'
  while ( defined ($command = $term->readline($prompt)) ) {
    last if ($command eq "q");
    if ($command eq "d") {
      dumpAllData();
    } elsif ($command eq "e") {
      enterData();
    } elsif ($command eq "s") {
      searchDatabase();
    } else {
      giveUsage();
    }
    $term->addhistory($_) if /\S/;
  }

# breaks the binding between a DBM file and a hash
  untie %HIST ;

sub searchDatabase {
  my $name = $term->readline("search for name");
  if (!defined $HIST{$name}) {
    print "[$name] unknown\n";
  } else {
    ($name,$address) = split(/\t/,$HIST{$name});
    print "$name\t$phone\t$address\n";
  }
}

sub enterData {
  print "\nEnter new data\n";
  my $name    = $term->readline("Name   ");
  my $phone   = $term->readline("Phone  ");
  my $address = $term->readline("Address");
  $HIST{$name} = join("\t",$phone,$address);
  return;
}

sub giveUsage {
  print qq{
  Phones Database commands:
    q  Save and Quit
    d  Dump all data
    e  Enter new data
    s  Search database
};
}

sub dumpAllData {
  my $numOfRecords = scalar (keys %HIST);
  if (!$numOfRecords) {
    print "Database empty\n";
  } else {
    $s = ($numOfRecords == 1) ? "" : "s";
    print "Your database contains $numOfRecords record$s\n";
    while (($key,$val) = each %HIST) {
      print "$key\t$val\n";
    }
  }
  return;
}

# suggestions as exercise:
# display number of available records on the 'd  Dump all data' usage line
# use regexp when retrieving data from database
# warn if name already in database before changing current phone or address
# dump all data matching partial name
# dump data sorted by name, phone or address