package Ernad::Sort;

use strict;
use warnings;

use Carp qw(cluck longmess shortmess croak confess);
use Data::Dumper;

use Ernad::Common;
use Ernad::Constant;
use Ernad::Lenu;

my $ernad_ns = $Ernad::Constant::c->{'ernad_ns'};
my $amf_ns = $Ernad::Constant::c->{'amf_ns'};
# my $xpc = &Ernad::Common::create_xpc;

## injects an array of weights
## can also deal with a hash
sub inject_sort {
  my $doc=shift;
  my $weights=shift;
  my $criterion=shift // '';
  if(not $criterion) {
    die "no criterion name";
  }
  my $ref_doc;
  $ref_doc=ref $doc or $ref_doc=$doc;
  if($ref_doc ne 'XML::LibXML::Document') {
    confess "I need an XML document, but you gave me '$ref_doc'";
  }
  my @papers_elements=$doc->getElementsByTagNameNS($amf_ns,'text')->get_nodelist();
  my $papers_count=$doc->getElementsByTagNameNS($amf_ns,'text')->size();
  my $count_text=0;
  my $sort_element=$doc->createElementNS($ernad_ns,'sort');
  $sort_element->setAttribute('criterion',$criterion);
  my $printed=0;
  while($count_text < $papers_count) {
    my $item_element=$doc->createElementNS($ernad_ns,'item');
    my $polet=&Ernad::Lenu::code($count_text+1);
    $item_element->setAttribute('polet',$polet);
    my $paper=$papers_elements[$count_text];
    my $ref=$paper->getAttribute('ref') // '';
    if(not $ref) {
      die "no ref= attribute on paper number $count_text (from 0)";
    }
    $item_element->setAttribute('ref',$ref);
    my $weight;
    if(ref $weights eq 'HASH') {
      ## has to be here for coherene with array case
      $count_text++;
      $weight=$weights->{$ref};
      if(not defined($weight)) {
        confess "I must have a weight for $ref defined.";
      }
    }
    elsif(ref $weights eq 'ARRAY') {
      $weight=$weights->[$count_text++] // 0;
    }
    else {
      confess "I have no clue what to do with $weights.";
    }
    $item_element->setAttribute('weight',$weight);
    $sort_element->appendChild($item_element);
    ## print out the first item to check
    if(not $printed) {
      # print "weight is $weight, ref is $ref\n";
      $printed=1;
    }
  }
  my $e=$main::e // confess 'I need an erimp here.';
  my $xpc=$e->{'xpc'} // confess 'I need an xpc here.';
  my $collection_element=$xpc->findnodes('/amf:amf/amf:collection[1]',$doc)->get_node(1);
  if(not defined($collection_element)) {
    print $doc;
    confess "I need a collection_element defined here.";
  }
  ## delete old sort, if it exists
  my $sort_xp='/amf:amf/amf:collection[1]/ernad:sort[@criterion=\''.$criterion.'\']';
  my @old_sort_elements=$xpc->findnodes($sort_xp,$doc)->get_nodelist;
  #open(F,"> /tmp/sort.log");
  foreach my $old_sort_element (@old_sort_elements) {
    my $result=$old_sort_element->parentNode->removeChild($old_sort_element);
    #print F "removed ", $old_sort_element->toString, "\n";
  }
  #close F;
  if(not defined($sort_element)) {
    confess "I need a sort_element defined here.";
  }
  $collection_element->appendChild($sort_element);
  $doc=$e->{'x'}->polet($doc);
  return $doc;
}


## are all weights zero
sub are_all_weights_zero {
  my $weights=shift;
  foreach my $weight (@{$weights}) {
    if($weight != 0) {
      return 0;
    }
  }
  return 1;
}

## set all weights to zero to allow for repeat sorting
sub set_all_weights_zero {
  my $weights=shift;
  my $count_weights=0;
  foreach my $weight (@{$weights}) {
    $weights->[$count_weights++]=0;
  }
  return $weights;
}

## sort by a criterion in the sort element
sub sort_by_criterion {
  my $doc=shift;
  my $criterion=shift // '';
  if(not $criterion) {
    confess "I need a criterion here.";
  }
  my $direction=shift // '';
  if($direction ne 'a' and $direction ne 'd') {
    confess "My direction must 'a' or 'd'.";
  }
  my $type=shift // 'numeric';
  ## 2018-11-14 moved truncated to Rif::Truncate
  # my $truncate_param=shift // '';
  # ## this may indicate a default truncation. Fixme:
  # my $max_papers=0;
  # my $max_percent=0;
  # if($truncate_param) {
  #   if($truncate_param=~m|^\d+$|) {
  #     $max_papers=$truncate_param;
  #     if($max_percent<100) {
  #       warn "You want to truncate to $max_papers less than 100, did you mean $max_papers%?";
  #     }
  #   }
  #   elsif($truncate_param=~m|^(\d+)%$|) {
  #     $max_percent=$1;
  #     if($max_percent>100) {
  #       confess "My percentage can not be larger than 100.";
  #     }
  #   }
  #   else {
  #     confess "You truncate parameter '$truncate_param' is neither a number nor percentage.";
  #   }
  # }
  my $sort_xp='/amf:amf/amf:collection[1]/ernad:sort[@criterion=\''.$criterion.'\']';
  my $e=$main::e // confess 'I need an erimp here.';
  my $xpc=$e->{'xpc'} // confess 'I need an xpc here.';
  my $sort_element=$xpc->findnodes($sort_xp,$doc)->get_node(1) // '';
  if(not $sort_element) {
    print $doc->toString;
    die "I can not find a sort element for criterion $criterion";
  }
  my $out=&get_rump_doc($doc,$xpc);
  my $item_xp="ernad:item";
  my @items=$xpc->findnodes($item_xp,$sort_element)->get_nodelist() or
    confess "I don't see any item element in '$sort_element'.\n";
  my $weights;
  my $item_elements;
  foreach my $item (@items) {
    #print $item->toString;
    my $ref=$item->getAttribute('ref') or die;
    my $weight=$item->getAttribute('weight');
    $weights->{$ref}=$weight;
    $item_elements->{$ref}=$item->cloneNode(1);
  }
  my $haspart_xp='/amf:amf/amf:collection[1]/amf:haspart';
  my @hasparts=$xpc->findnodes($haspart_xp,$doc)->get_nodelist();
  # my $total_hasparts=scalar @hasparts;
  # if(not $max_papers and $max_percent) {
  #   $max_papers=int($total_hasparts * $max_percent / 100);
  # }
  my $papers;
  my $refs;
  my $count_papers=0;
  foreach my $haspart_element (@hasparts) {
    my $ref=$xpc->findvalue('amf:text/@ref',$haspart_element) or die "no ref";
    my $paper=$haspart_element->cloneNode(1);
    my $item_xp='ernad:item[@criterion=\''.$criterion.'\']';
    my @old_item_elements=$xpc->findnodes($item_xp,$paper);
    ## remove the old item element
    foreach my $old_item_element (@old_item_elements) {
      #print "old item element removed\n";
      $old_item_element->parentNode->removeChild($old_item_element);
    }
    ## append item
    my $my_item=$item_elements->{$ref} or die;
    $my_item->setAttribute('criterion',$criterion);
    $my_item->removeAttribute('ref');
    # $count_papers++;
    #  if($max_papers and $count_papers > $max_papers) {
    #    last;
    #  }
    $paper->appendChild($my_item);
    $papers->{$ref}=$paper;
  }
  my $coll_xp='/amf:amf/amf:collection[1]';
  my $collection=$xpc->findnodes($coll_xp,$out)->get_node(1);
  my @sorted;
  if($type eq 'numeric') {
    if($direction eq 'd') {
      @sorted=sort {$weights->{$b} <=> $weights->{$a}} keys %$papers;
    }
    elsif($direction eq 'a') {
      @sorted=sort {$weights->{$a} <=> $weights->{$b}} keys %$papers;
    }
  }
  elsif($type eq 'string') {
    if($direction eq 'd') {
      @sorted=sort {$weights->{$b} cmp $weights->{$a}} keys %$papers;
    }
    elsif($direction eq 'a') {
      @sorted=sort {$weights->{$a} cmp $weights->{$b}} keys %$papers;
    }
  }
  else {
    confess "I need a sorting type 'numeric' or 'string', you gave me '$type'.";
  }
  $count_papers=0;
  foreach my $ref (@sorted) {
    $count_papers++;
    # if($max_papers and $count_papers > $max_papers) {
    #  last;
    # }
    $collection->appendChild($papers->{$ref});
  }
  ## delete the existing sort element
  $sort_element=$xpc->findnodes($sort_xp,$out)->get_node(1) // '';
  if($sort_element) {
    $sort_element->parentNode->removeChild($sort_element);
  }
  return $out;
}


## removes papers from a rix. This should be in Ernad::Rix, but then it needs an erimp.
sub get_rump_doc {
  my $doc=shift;
  my $xpc=shift;
  if (not ref $doc eq 'XML::LibXML::Document') {
    die 'no document for get_rump';
  }
  my $out=$doc->cloneNode(1);
  my $texts_xp='/amf:amf/amf:collection[1]/amf:haspart';
  my @hasparts=$xpc->findnodes($texts_xp,$out)->get_nodelist();
  foreach my $haspart (@hasparts) {
    $haspart->parentNode->removeChild($haspart);
  }
  return $out;
}




# ## injects an hash of weights
# sub inject_sort_by_hash {
#   my $doc=shift;
#   my $weights=shift;
#   die ref $weights;
#   my $criterion=shift // '';
#   if(not $criterion) {
#     die "no criterion name";
#   }
#   my @papers_elements=$doc->getElementsByTagNameNS($amf_ns,'text')->get_nodelist();
#   my $papers_count=$doc->getElementsByTagNameNS($amf_ns,'text')->size();
#   my $count_text=0;
#   my $sort_element=$doc->createElementNS($ernad_ns,'sort');
#   $sort_element->setAttribute('criterion',$criterion);
#   while($count_text < $papers_count) {
#     my $item_element=$doc->createElementNS($ernad_ns,'item');
#     my $paper=$papers_elements[$count_text];
#     my $ref=$paper->getAttribute('ref') // '';
#     if(not $ref) {
#       die "no ref= attribute on paper number $count_text (from 0)";
#     }
#     $item_element->setAttribute('ref',$ref);
#     my $weight=$weights->{$ref};
#     if(not defined($weight)) {
#       confess "I must have a weight fro $ref defined.";
#     }
#     $item_element->setAttribute('weight',$weight);
#     $sort_element->appendChild($item_element);
#   }
#   my $collection_element=$xpc->findnodes('/amf:amf/amf:collection[1]',$doc)->get_node(1);
#   ## delete old sort, if it exists
#   my $sort_xp='/amf:amf/amf:collection[1]/ernad:sort[@criterion=\''.$criterion.'\']';
#   my @old_sort_elements=$xpc->findnodes($sort_xp,$doc)->get_nodelist;
#   foreach my $old_sort_element (@old_sort_elements) {
#     open(F,"> /tmp/sort.log");
#     my $result=$old_sort_element->parentNode->removeChild($old_sort_element);
#     print F "removed ", $old_sort_element->toString, "\n";
#     close F;
#   }
#   $collection_element->appendChild($sort_element);
#   return $doc;
# }

1;