#!/usr/bin/perl

use strict;
use File::Spec;
use File::Spec::Unix;

my $gnomepid    = `pidof gnome-session`;
my $kdepid      = `pidof ksmserver`;
my $xfcepid     = `pidof xfceserver`;
my $useaptget   = `which apt-get 2>/dev/null`;
my $useyum      = `which yum 2>/dev/null`;
my $userpm      = `which rpm 2>/dev/null`;
my $zenity      = `which zenity 2>/dev/null`;
my $kdialog     = `which kdialog 2>/dev/null`;
my $aescrypt    = `which aescrypt 2>/dev/null`;
my $prefergnome = 0;
my $preferkde   = 0;
my $filename;
my $extension;
my $direction;
my @passwordcmd;
my @errormsg;
my @warningmsg;
chomp($gnomepid);
chomp($kdepid);
chomp($xfcepid);
chomp($useaptget);
chomp($useyum);
chomp($userpm);
chomp($zenity);
chomp($kdialog);
chomp($aescrypt);

if (@ARGV == 1) {
   $filename  =  File::Spec->rel2abs($ARGV[0]);
   $extension = substr($filename, length($filename)-4);
}

# automatically choose decryption for files ending in ".aes".
if ($extension =~ /\.aes$/i) {
  print "Selected decryption for AES file\n";
  $direction = "decryption";
} else {
  print "Selected encryption for non-AES file\n";
  $direction = "encryption";
}
#print "AESCrypt    = '$aescrypt'\n";
#print "Filename    = '$filename'\n";
#print "Extension   = '$extension'\n";
#print "Direction   = '$direction'\n";
#print "zenity      = '$zenity'\n";
#print "kdialog     = '$kdialog'\n";

if (($zenity eq "") && ($kdialog eq "")) {
  print "No dialog prompting utility is available\n";
  if ($useaptget ne "") {
    print "try running 'apt-get install zenity' as root\n";
  } elsif ($useyum ne "") {
    print "try running 'yum install zenity' as root\n";
  } elsif ($userpm ne "") {
    print "try running 'rpm install zenity' as root\n";
  }
  exit(1);
} if (($gnomepid ne "") && ($zenity ne "")) {
  $prefergnome = 1;
} elsif (($kdepid ne "") && ($kdialog ne "")) {
  $preferkde   = 1;
} elsif ($zenity ne "") {
  $prefergnome = 1;
} else {
  $preferkde   = 1;
}
#print "prefergnome = '$prefergnome'\n";
#print "preferkde   = '$preferkde'\n";

if ($prefergnome) {
  print "Preferring Zenity\n";
  my $newdialog = `zenity --help | grep 'password' 2>&1`;
  # ("--width=350", "--no-wrap") are added to zenity calls as a workaround to 
  # https://bugs.launchpad.net/ubuntu/+source/zenity/+bug/1273981
  if ("$newdialog" ne "") {
    print "New Zenity dialog\n";
    @passwordcmd = ("zenity", "--title=AESCrypt", "--password");
    @warningmsg  = ("zenity", "--title=AESCrypt", "--width=350", "--no-wrap", "--timeout=1", "--warning", "--text");
  } else {
    print "Old Zenity dialog\n";
    @passwordcmd = ("zenity", "--title=AESCrypt", "--entry", "--text='Type your Password'", "--hide-text");
    @warningmsg  = ("zenity", "--title=AESCrypt", "--width=350", "--no-wrap", "--warning", "--text");
  }
  @errormsg    = ("zenity", "--title=AESCrypt", "--width=350", "--no-wrap", "--error", "--text");
} else {
  print "Preferring KDialog\n";
  @passwordcmd = ("kdialog", "--title", "AESCrypt", "--password", "Enter $direction password");
  @warningmsg  = ("kdialog", "--title", "AESCrypt", "--passivepopup");
  @errormsg    = ("kdialog", "--title", "AESCrypt", "--error");
}
if (! -x $aescrypt) {
  errorMsg("AESCrypt command is not found");
  exit(1);
}
if (@ARGV != 1) {
  errorMsg("Invalid arguments, a single filename is required");
  exit(2);
}
if (! -f $filename) {
  errorMsg("Invalid arguments, file not found");
  exit(3);
}

my $password = "";
while (1) {
  my ($result, $passmatch);

  # Get the password.
  ($result, $password) = execute(@passwordcmd);
  if ($result != 0) {
     exit(1);
  }
  chomp($password);

  if ($password eq "") {
    warnMsg("No password was supplied!\n\nPlease re-enter password.");
    next;
  }

  # If we're decrypting, we don't need to get a password match, we can just try it.
  if ($direction eq "decryption") {
    print "Decrypting; no password match required.\n";
    last;
  }

  # Otherwise, the user should retype.
  ($result, $passmatch) = execute(@passwordcmd);
  if ($result != 0) {
    exit(1);
  }
  chomp($passmatch);
  if ($password ne $passmatch) {
    warnMsg("Encryption passwords did not match.\n\nPlease re-enter password.");
    $password = "";
  } else { last; } # We matched, we're finished getting the password.
}

# Perform the actual encryption.
my ($encres, $encout) = execute($aescrypt, 
                               ($direction=~m/^enc/?"-e":"-d"),
                               "-p", $password, $filename);
if ($encres) {
   chomp($encout);
   errorMsg("An error occurred during $direction:\n\n$encout");
}
exit($encres);

# Display a warning dialog
sub warnMsg {
  my $message = $_[0];
  my ($result, $out) = execute(@warningmsg, $message);
  unless ($result == "0") {
    warn "Warning: $message\n";
    warn "Additionally, an error occurred while attempting to show this warning:\n";
    warn "$out\n";
  }
}

# Display an error dialog
sub errorMsg {
  my $message = $_[0];
  my ($result, $out) = execute(@errormsg, $message);
  unless ($result == 0) {
    warn "Error: $message\n";
    warn "Additionally, an error occurred while attempting to show this error:\n";
    warn "$out\n";
  }
}

# Execute runs the specified command, returning an array of [resultCode, output].
sub execute {
  my $command = shift;
  my (@args) = @_;

  # Encapsulate all the runargs in single quotes and push them onto an argset.
  my @runargs = ();
  for my $arg (@args) {
    my $quotedArg="'";
    my $escaped=0;
    for my $c (split //, $arg) {
      # escape all existing quotes.
      if ($c eq "'") {
        # Close squo (main) string, escape, squo, then char will reopen squo string
        # This allows users to use any character within their passwords.
        $quotedArg .= '\'\\\'';
      }
      $quotedArg .= $c;
    }
    push(@runargs, $quotedArg . "'");
  }
  my $allargs=join(' ',@runargs);
  my $out=qx($command $allargs 2>/dev/null);
  my $result=$?;

  return ($result, $out);
}