package Ernad::Xslt;

use strict;
use warnings;
use Carp qw(confess);
use XML::LibXML;
use XML::LibXSLT;

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

use base 'Ernad';


## string as first param --> file
## doc as first param --> doc
## run gets the result
## chars transforms to chars
## text transforms to text

sub transform_empty {
  my $x=shift;
  my $name=shift // confess "I need a name here.";
  my $string="<root/>\n";
  my $doc = XML::LibXML->load_xml(string => $string);
  my $output=$x->transform($doc,$name);
  return $output;
}

## get a stylesheet, formerly get_stylesheet
sub get_sheet {
  my $x=shift;
  my $e=$main::e // $x->{'e'} // confess "I don't see the erimp.";
  my $name=shift or confess "no stylesheet name parameter";
  if(defined($e->{'sheet'}->{$name})) {
    return $e->{'sheet'}->{$name};
  }
  my $sheet=$x->read_stylesheet($name);
  $e->{'sheet'}->{$name}=$sheet;
  return $sheet;
}

sub read_stylesheet {
  my $x=shift;
  my $e=$main::e // $x->{'e'} // confess "I don't see the erimp.";
  my $name=shift or confess "I have no stylesheet name parameter";
  my $style_dir=$e->{'dir'}->{'style'};
  my $xslt_dir=$e->{'dir'}->{'xslt'};
  my $sheet_file;
  ## normally the sheet is in style/impna, but can also be in xslt
  my $style_file=$style_dir.'/'.$name.$e->{'const'}->{'xsl_ext'};
  my $xslt_file=$xslt_dir.'/'.$name.$e->{'const'}->{'xsl_ext'};
  if(-f $style_file) {
    $sheet_file=$style_file;
  }
  elsif(-l $style_file) {
    $sheet_file=readlink $style_file;
  }
  elsif(-f $xslt_file) {
    $sheet_file=$xslt_file;
  }
  elsif(-l $xslt_file) {
    $sheet_file=readlink $xslt_file;
  }
  elsif(-f $name) {
    $sheet_file=$name;
  }
  elsif(not defined($sheet_file)) {
    confess "I don't have a sheet file for sheet '$name'";
  }
  else {
    confess "I can't see the sheet file for sheet '$name' at '$sheet_file'";
  }
  my $xslt=XML::LibXSLT->new();
  $xslt->max_depth(1000000);
  ## version on trabbi does not have max_vars
  eval {
    $xslt->max_vars(1500000);
  };
  if(not -f $sheet_file) {
    confess "I don't have $sheet_file";
  }
  my $style_doc=XML::LibXML->load_xml('location'=>$sheet_file, 'no_cdata'=>1);
  my $sheet=$xslt->parse_stylesheet($style_doc);
  return $sheet;
}

## FixMe: there should be one transform and one transform_to_text
## doc, sheet name
sub run {
  my $x=shift;
  my $doc=shift or confess "I need a doc parameter.";
  if(not ref $doc eq 'XML::LibXML::Document') {
    confess "I see no document to transform.";
  }
  my $name=shift or confess "I need a stylesheet name.";
  my $e=$main::e // $x->{'e'} // confess "I don't see the erimp.";
  my $sheet=$x->get_sheet($name) or confess "I can't get stylesheet '$name'.";
  my $params=shift;
  my $results;
  if(defined($params)) {
    $results=$sheet->transform($doc, %$params);
  }
  else {
    $results=$sheet->transform($doc);
  }
  if($e->{'testing'}) {
    my $out_file=$e->{'dir'}->{'test'}."/transform_$name.xml";
    &Krichel::File::prepare($out_file);
    $results->toFile($out_file);
  }
  return $results;
}

## referenced in publish, has to stay for now
sub transform {
  my $x=shift;
  my $e=$main::e // $x->{'e'} // confess "I don't see the erimp.";
  my $doc=shift or confess "I need a doc parameter.";
  if(not ref $doc eq 'XML::LibXML::Document') {
    confess "I see no document to transform.";
  }
  my $name=shift or confess "no name parameter";
  my $sheet=$x->get_sheet($name) or confess;
  my $params=shift;
  my $results;
  if(defined($params)) {
    $results=$sheet->transform($doc, %$params);
  }
  else {
    $results=$sheet->transform($doc);
  }
  if($e->{'testing'}) {
    my $out_file=$e->{'dir'}->{'test'}."/transform_$name.xml";
    &Krichel::File::prepare($out_file);
    $results->toFile($out_file);
  }
  return $results;
}

## should go to e->x
## check first argument
sub get_doc {
  my $x=shift;
  my $in=shift;
  my $in_ref=ref $in;
  if($in_ref eq 'XML::LibXML::Document') {
    return $in;
  }
  if(not (-f $in or -l $in)) {
    confess "I can not open your file '$in'";
  }
  my $doc;
  eval {
    $doc=&Krichel::File::load($in);
  };
  if(ref $doc ne 'XML::LibXML::Document') {
    confess "I can't parse your file '$in'";
  }
  return $doc;
}

## <-- new
sub to_text {
  my $x=shift;
  my $in=shift // confess "I need an input to transform.";
  my $name=shift or confess "I don't have a stylsheet name parameter.";
  my $params=shift;
  my $doc=$x->get_doc($in);
  my $sheet=$x->get_sheet($name) // confess "I could not get the sheet $name";
  my $results;
  if(defined($params)) {
    $results=$sheet->transform($doc, %$params);
  }
  else {
    $results=$sheet->transform($doc);
  }
  my $string=$sheet->output_as_bytes($results);
  return $string;
}

## doc, sheet name, params (or params and type)
sub t {
  my $x=shift;
  my $in=shift // confess "I don't have something to transform.\n";
  ## accept an empty input
  my $doc;
  my $in_ref=ref $in;
  if($in eq '') {
    my $string="<root/>\n";
    $doc = XML::LibXML->load_xml(string => $string);
  }
  elsif(not $in_ref) {
    if(not -f $in) {
      confess "I can't open your file '$in'.";
    }
    $doc=Krichel::File::load_xml($in);
  }
  elsif($in_ref ne 'XML::LibXML::Document') {
    confess "I want a document to transform, but I got a $in_ref.\n";
  }
  else {
    $doc=$in;
  }
  my $name=shift or confess "I don't have a stylesheet name parameter.";
  my $after_name=shift;
  ## no params
  my $do='bytes';
  my $out_file='';
  my $params;
  my $ref_after_name='';
  my $after_name_is_do = 0;
  if($after_name) {
    if(not $after_name) {
      $after_name_is_do = 1;
      $do='doc'
    }
    elsif($after_name eq 'chars') {
      $after_name_is_do = 1;
      $do='chars'
    }
    elsif($after_name eq 'bytes') {
      $after_name_is_do = 1;
      $do='bytes'
    }
    elsif($ref_after_name=ref($after_name)) {
      if($ref_after_name eq 'HASH')  {
        $params = $after_name;
      }
      else {
        confess "I can't deal with a $ref_after_name\n";
      }
    }
    $out_file=$after_name;
    if($out_file eq 'bytes') {
      #confess "out_file must not be 'bytes'";
      ## emergency fix of 2019-06-19
      $out_file = '';
    }
    if(not $after_name_is_do and not -W $out_file) {
      confess "I can't write to your file '$out_file'.";
    }
  }
  my $final = shift;
  if(not $params) {
    my $ref_final=ref($final);
    #if(not $ref_final) {
    #  $do=$final;
    #}
    if($ref_final eq 'HASH')  {
      $params = $final;
    }
    #else {
    #  confess "I can't handle this yet."
    #}
  }
  my $sheet=$x->get_sheet($name) or confess 'I can\'t get your stylesheet $name';
  my $results;
  if(defined($params)) {
    $results=$sheet->transform($doc, %$params);
  }
  else {
    $results=$sheet->transform($doc);
  }
  if($do eq 'chars') {
    my $bytes=$sheet->output_as_bytes($results);
    return $bytes;
  }
  if($do eq 'chars' or $out_file) {
    my $chars=$sheet->output_as_chars($results);
    if(not $out_file) {
      return $chars;
    }
    return Ernad::Files::save_if_diff($out_file,$chars);
  }
  else {
    return $results;
  }
  return $sheet;
}

# ## doc, sheet name 2016-12-29 for use with slurper
# sub transform_to_chars {
#   my $x=shift;
#   my $doc=shift or confess "I don't have something to transform.\n";
#   my $doc_ref=ref $doc;
#   if(not $doc_ref) {
#     confess "You gave me a string to transform. I need a document.";
#   }
#   if(not $doc_ref eq 'XML::LibXML::Document') {
#     confess "I want a document to transform, but got a $doc_ref.\n";
#   }
#   my $name=shift or confess "I don't have a stylsheet name parameter.";
#   my $params=shift;
#   my $sheet=$x->get($name) or confess;
#   my $results;
#   if(defined($params)) {
#     $results=$sheet->transform($doc, %$params);
#   }
#   else {
#     $results=$sheet->transform($doc);
#   }
#   my $string=$sheet->output_as_chars($results);
#   return $string;
# }

## doc, sheet name
sub transform_file {
  my $x=shift;
  my $file=shift or confess "no doc parameter";
  if(not -f $file) {
    confess "no such file '$file'";
  }
  my $name=shift or confess "no stylesheet name parameter";
  my $params=shift;
  my $doc=&Krichel::File::load($file);
  return $x->transform($doc,$name,$params);
}

# ## doc, sheet name
# sub transform_file_to_text {
#   my $x=shift;
#   my $file=shift or confess "I have no file (first) parameter";
#   if(not -f $file) {
#     confess "no such file '$file'";
#   }
#   my $name=shift or confess "no stylesheet name parameter";
#   my $params=shift;
#   my $doc=&Ernad::Common::load_and_return_xml($file);
#   return $x->transform_to_text($doc,$name,$params);
# }


1;