# -*- mode: perl; -*-
package CheckURL;

# file CheckURL.pm
#
# This file is part of LyX, the document processor.
# Licence details can be found in the file COPYING.
#
# authors: Kornel Benko <kornel@lyx.org>
#          Scott Kostyshak <skotysh@lyx.org>
#

# Check if given URL exists and is accessible
#
use strict;

our (@EXPORT, @ISA);

BEGIN {
  use Exporter ();
  @ISA    = qw(Exporter);
  @EXPORT = qw(check_url);
}

# Prototypes
sub check_http_url($$$$);
sub check_ftp_dir_entry($$);
sub check_ftp_url($$$$);
sub check_unknown_url($$$$);
sub check_url($$$$);
################

my $fe;
my $fs;

sub check_http_url($$$$) {
  require LWP::UserAgent;

  my ($protocol, $host, $path, $file) = @_;

  my $ua   = LWP::UserAgent->new(timeout => 20);
  my $getp = "/";
  if ($path ne "") {
    $getp .= $path;
  }
  if (defined($file)) {
    if ($getp =~ /\/$/) {
      $getp .= $file;
    }
    else {
      $getp .= "/$file";
    }
  }
  my $buf;
  $ua->agent("Firefox/43.0");
  my $response = $ua->get("$protocol://$host$getp");
  if ($response->is_success) {
    $buf = $response->decoded_content;
  }
  else {
    print $fe " " . $response->status_line . ": ";
    return 3;
  }
  my @title = ();
  my $res   = 0;
  while ($buf =~ s/\<title\>([^\<]*)\<\/title\>//i) {
    my $title = $1;
    $title =~ s/[\r\n]/ /g;
    $title =~ s/  +/ /g;
    $title =~ s/^ //;
    $title =~ s/ $//;
    push(@title, $title);
    print $fe "title = \"$title\": ";
    if ($title =~ /Error 404|Not Found/) {
      print $fe " Page reports 'Not Found' from \"$protocol://$host$getp\": ";
      $res = 3;
    }
  }
  return $res;
}

# Returns ($err, $isdir)
# returns 0, x if file does not match entry
#         1, x everything OK
#         2, x if not accesible (permission)
sub check_ftp_dir_entry($$) {
  my ($file, $e) = @_;
  my $other = '---';
  my $isdir = 0;

  #print $fe "Checking '$file' against '$e'\n";
  $file =~ s/^\///;
  $isdir = 1 if ($e =~ /^d/);
  return (0, $isdir) if ($e !~ /\s$file$/);
  if ($e =~ /^.[-rwx]{6}([-rwx]{3})\s/) {
    $other = $1;
  }
  else {
    #print $fe "Invalid entry\n";
    # Invalid entry
    return (0, $isdir);
  }
  return (2, $isdir) if ($other !~ /^r/);    # not readable
  if ($isdir) {

    #return(2,$isdir) if ($other !~ /x$/); # directory, but not executable
  }
  return (1, $isdir);
}

sub check_ftp2_url($$$$) {
  my ($protocol, $host, $path, $file) = @_;

  my $checkentry = 1;

  #print $fe "\nhost $host\n";
  #print $fe "path $path\n";
  #print $fe "file $file\n";
  my $url = "$protocol://$host";
  $path =~ s/\/$//;
  if (defined($file)) {
    $url = "$url/$path/$file";
  }
  else {
    $url = "$url/$path/.";
  }

  #print $fe "curl $url, file = $file\n";
  my %listfiles = ();
  if (open(FFTP, "curl --anyauth -l $url|")) {
    while (my $l = <FFTP>) {
      chomp($l);
      $listfiles{$l} = 1;
    }
    close(FFTP);
  }
  if (%listfiles) {
    if (!defined($file)) {
      return (0, "OK");
    }
    elsif (defined($listfiles{$file})) {
      return (0, "OK");
    }
    elsif (defined($listfiles{"ftpinfo.txt"})) {
      return (0, "Probably a directory");
    }
    else {
      return (1, "Not found");
    }
  }
  else {
    return (1, "Error");
  }
}

sub check_ftp_url($$$$) {
  use Net::FTP;

  my ($protocol, $host, $path, $file) = @_;
  my $res     = 0;
  my $message = "";

  my $ftp = Net::FTP->new($host, Debug => 0, Timeout => 20);
  if (!$ftp) {
    return (3, "Cannot connect to $host");
  }
  if (!$ftp->login("anonymous", '-anonymous@')) {
    $message = $ftp->message;
    $res     = 3;
  }
  else {
    my $rEntries;
    if ($path ne "") {

      #print $fe "Path = $path\n";
      #if (!$ftp->cwd($path)) {
      # $message = $ftp->message;
      # $res = 3;
      #}
      $rEntries = $ftp->dir($path);
    }
    else {
      $rEntries = $ftp->dir();
    }
    if (!$rEntries) {
      $res     = 3;
      $message = "Could not read directory \"$path\"";
    }
    elsif (defined($file)) {
      my $found  = 0;
      my $found2 = 0;
      for my $f (@{$rEntries}) {

        #print $fe "Entry: $path $f\n";
        my ($res1, $isdir) = check_ftp_dir_entry($file, $f);
        if ($res1 == 1) {
          $found = 1;
          last;
        }
        elsif ($res1 == 2) {

          # found, but not accessible
          $found2  = 1;
          $message = "Permission denied for '$file'";
        }
      }
      if (!$found) {
        $res = 4;
        if (!$found2) {
          $message = "File or directory '$file' not found";
        }
      }
    }
  }
  $ftp->quit;

  #print $fe "returning ($res,$message)\n";
  return ($res, $message);
}

sub check_unknown_url($$$$) {
  use LWP::Simple;

  my ($protocol, $host, $path, $file) = @_;
  my $res = 1;

  my $url = "$protocol://$host";
  if ($path ne "") {
    if ($path =~ /^\//) {
      $url .= $path;
    }
    else {
      $url .= "/$path";
    }
  }
  if (defined($file)) {

    #print $fe "Trying $url$file\n";
    $res = head("$url/$file");
    if (!$res) {

      # try to check for directory '/';
      #print $fe "Trying $url$file/\n";
      $res = head("$url/$file/");
    }
  }
  else {
    #print $fe "Trying $url\n";
    $res = head($url);
  }
  return (!$res);
}

#
# Main entry
sub check_url($$$$) {
  my ($url, $use_curl, $fex, $fsx) = @_;
  $fe = $fex;
  $fs = $fsx;
  my $file = undef;
  my ($protocol, $host, $path);

  my $res = 0;

  # Split the url to protocol,host,path
  if ($url =~ /^([a-z]+):\/\/([^\/]+)(.*)$/) {
    $protocol = $1;
    $host     = $2;
    $path     = $3;
    $path =~ s/^\///;
    if ($path =~ s/\/([^\/]+)$//) {
      $file = $1;
      if ($file =~ / /) {

        # Filename contains ' ', maybe invalid. Don't check
        $file = undef;
      }
      $path .= "/";
    }
  }
  else {
    print $fe " Invalid url '$url'";
    return 2;
  }
  if ($protocol =~ /^https?$/) {
    return check_http_url($protocol, $host, $path, $file);
  }
  elsif ($protocol eq "ftp") {
    my $message;
    if ($use_curl) {
      ($res, $message) = check_ftp2_url($protocol, $host, $path, $file);
    }
    else {
      ($res, $message) = check_ftp_url($protocol, $host, $path, $file);
    }
    return $res;
  }
  else {
    # it never should reach this point
    print $fe " What protocol is '$protocol'?";
    $res = check_unknown_url($protocol, $host, $path, $file);
    return $res;
  }
}

1;