package Ernad::Pages;

use strict;
use warnings;

use Carp qw(confess);
use Encode;
use File::Path;
use XML::LibXML;

use Ernad::Files;
use Krichel::File;

## bad version for trabbi
sub install {
  my $doc=shift;
  my $out_file=shift;
  my $debug=shift // '';
  use File::Basename;
  use File::Copy;
  if(not ref($doc) eq 'XML::LibXML::Document') {
    confess "I need a document here.";
  }
  my $fh = File::Temp->new();
  my $tmp_file = $fh->filename;
  if(not -f $out_file) {
    &Krichel::File::prepare($out_file);
    if($debug) {
      print "I installed $out_file\n";
    }
    $doc->toFile($out_file,1);
    return 1;
  }
  $doc->toFile($tmp_file,1);
  my $diff=`diff -w $tmp_file $out_file`;
  chomp $diff;
  if(not $diff) {
    if($debug) {
      print "$out_file is unchanged.\n";
    }
    return 0;
  }
  $diff=decode('UTF-8', $diff);
  if(diff_matches_date_or_time($diff)) {
    if($debug) {
      print "I keep old version of $out_file\n";
    }
    return 0;
  }
  if($debug) {
    print "I install a new version of $out_file\n$diff\n";
  }
  copy($tmp_file,$out_file);
  return 1;
}

sub diff_matches_date_or_time {
  my $diff=shift;
  ## first case, date only
  my $dareg="\\d{4}\\x{2012}\\d{2}\\x{2012}\\d{2}";
  my $r="^\\d+c\\d+\\s*[<>]\\s*$dareg\\.\\s*---\\s*[<>]\\s+$dareg\\.\\s*".'$';
  if($diff=~m|$r|) {
    return 'date';
  }
  ## extent for the time
  $dareg.="\\s+at\\s+\\d{2}:\\d{2}:\\d{2}";
  ## same definition of r as above
  $r="^\\d+c\\d+\\s*[<>]\\s*$dareg\\.\\s*---\\s*[<>]\\s+$dareg\\.\\s*".'$';
  if($diff=~m|$r|) {
    return 'time';
  }
  return 0;
}

sub install_new  {
  my $doc=shift;
  my $out_file=shift;
  my $debug=shift // '';
  #use Text::Diff;
  if(not ref($doc) eq 'XML::LibXML::Document') {
    confess "I need a document here.";
  }
  if(not -f $out_file) {
    &Krichel::File::prepare($out_file);
    if($debug) {
      print "I installed $out_file\n";
    }
    $doc->toFile($out_file,1);
    return 1;
  }
  my $string=$doc->toString(1);
  my $diff;
  ### $diff = diff $out_file, \$string,  { STYLE => "OldStyle" };
  if(not $diff) {
    if($debug) {
      print "$out_file is unchanged.\n";
    }
    return 0;
  }
  $diff=decode('UTF-8', $diff);
  ## the datetime has to be a separate line, ending with a dot.
  my $dareg="\\d{4}\\x{2012}\\d{2}\\x{2012}\\d{2}";
  if($diff=~m|^\d+c\d+\s*[<>]\s*$dareg\.\s*---\s*[<>]\s+$dareg\.\s*$|) {
    if($debug) {
      print "I keep old version of $out_file\n$diff\n";
    }
    return 0;
  }
  ## continue with time added ...
  $dareg.=" at [012]:[0-9]:[0-5][0-9]:[0-5][0-9] UTC";
  if($debug) {
    print "I install a new version of $out_file\n$diff\n";
  }
  $doc->toFile($out_file,1);
  return 1;
}

1;