package PubMed::Record;

use strict;
use warnings;
use utf8;

use Data::Dumper;
use Carp qw(confess);

use PubMed::Dates;

my $date_paths;
$date_paths->[0]='/MedlineCitation/Article/ArticleDate';
$date_paths->[1]='/MedlineCitation/Article/Journal/JournalIssue/PubDate';
my $pmid_path='/MedlineCitation/PMID';

## a counter to see how sucessful the paths are
our $count_paths;
foreach my $date_path (@$date_paths) {
  $count_paths->{$date_path}=0;
}

my $month_number=$PubMed::Dates::month_number;
my $seasons_date=$PubMed::Dates::seasons_date;

sub get_pmid {
  my $txt=shift;
  my $doc=shift;
  my $xpc = XML::LibXML::XPathContext->new($doc);
  my @nodes=$xpc->find($pmid_path)->get_nodelist;
  if(not scalar @nodes) {
    confess "I found no pmid in \n$txt.";
  }
  if(@nodes) {
    if(scalar(@nodes) > 1) {
      confess "I found several years in \n$txt;";
    }
  }
  my $pmid=$nodes[0]->textContent;
  if(not $pmid=~m|^\d+$|) {
    confess "This '$pmid' is not a pmid";
  }
  return $pmid;
}

sub get_date_part {
  my $txt=shift;
  my $doc=shift;
  my $type=shift;
  my $xpc = XML::LibXML::XPathContext->new($doc);
  my $year=0;
  my $part='';
  foreach my $path (@{$date_paths}) {
    $part=&try_to_find_part($xpc,$path.'/'.$type,$txt) or next;
    if($part) {
      $count_paths->{$part}->{$path}++;
      last;
    }
  }
  if(not $part and $main::test) {
    print "no $part in\n$txt\n";
    exit;
  }
  return $part;
}
  

sub find_date {
  my $txt=shift;
  my $doc=shift;
  my $year=&get_date_part($txt,$doc,'Year');
  if(not $year=~m|^\d{4}$|) {
    return 0;
  }
  ## check the seasons
  my $season=&get_date_part($txt,$doc,'Season') // '';
  if($season) {
    if($seasons_date->{$season}) {
      return "$year-".$seasons_date->{$season};
    }
    confess "I don't know about the season '$season'.";
  }    
  my $month=&get_date_part($txt,$doc,'Month');
  if(not $month) {
    ## report the PubDate;
    my $pubdate_ele=$doc->getElementsByTagName('PubDate')->[0]; 
    open(M,">> /tmp/monthless");
    print M $pubdate_ele->toString(),"\n";
    close M;
    return "$year-01-01";
  }
  if($month=~m|^\d$|) {
    $month="0$month";
  }  
  if($month_number->{$month}) {
    $month=$month_number->{$month};
  }
  if(not $month=~m|\d{2}|) {
    confess "month is $month in $txt";
    return 0;
  }  
  my $day=&get_date_part($txt,$doc,'Day');
  if($day=~m|^\d$|) {
    $day="0$day";
  }
  if(not $day) {
    $day='01';
  }  
  if(not $day=~m|\d{2}|) {
    return 0;
  }
  return "$year-$month-$day";
}


sub find_medline_date {
  my $txt=shift;
  my $doc=shift;
  my $xpc = XML::LibXML::XPathContext->new($doc);
  my $medline_date_xp='/MedlineCitation/Article/Journal/JournalIssue/PubDate/MedlineDate';
  my @nodes=$xpc->find($medline_date_xp)->get_nodelist;
  if(@nodes) {
    if(scalar(@nodes) > 1) {
      confess "I found several years in \n$txt;";
    }
    my $to_parse=$nodes[0]->textContent;
    my $text=&parse_medline_date($to_parse);
    if(not $text) {
      print "My parse_medline_date could not parse '$to_parse'.\n";
    }
    return $text;
  }
  return 0;
}

sub parse_medline_date {
  my $in=shift;
  my $year;
  my $month;
  my $day;
  if($in=~m|^(\d{4})$|) {
    my $year=$1;
    return "$year-01-01";
  }
  if($in=~m|^(\d{4})-(\d{4})|) {
    my $year=$1;
    return "$year-01-01";
  }
  if($in=~s|^(\d{4})\s+||) {
    $year=$1;
  }
  elsif($in=~m|^(\d{4})-(\d{4})$|) {
    return "$1-01-01";
  }
  elsif($in=~m|^(\d{4})-(\d{4}) Winter$|) {
    return "$1-12-21";
  }
  elsif($in=~m|^(\d{4}), (\d{4})|) {
    return "$1-01-01";
  }
  elsif($in=~m|^(\d{4}), reçu|) {
    return "$1-01-01";
  }
  elsif($in=~m|^(\d{4})-00 Winter$|) {
    return "$1-01-01";
  }
  elsif($in=~m|^(\d{3})(\d)-(\d)$|) {
    my $year="$1$2";
    if($2+1 == $3) {
      return "year-01-01";
    }
    return '';
  }
  elsif($in=~m|^(\d{4})-\d{2}$|) {
    return "$1-01-01";
  } 
  elsif($in=~m|^(\D+) (\d{4})$|) {
    my $year=$2;
    my $may_be_season=$1;
    if($seasons_date->{$may_be_season}) {
      return "$year-".$seasons_date->{$may_be_season};
    }
  }
  elsif($in=~m|^(\d{2})(\d{2})-(\d{2})|) {
    $year="$1$2"; 
    if($2 eq $3) {
      ## remove the redundant part
      $in=~s|\d{4}-(\d{2}) ||;
    }
  }  
  else {
    warn "I warn you. I can't parse '$in'\n";
    return '';
  }
  ## scan after the year
  ## year repeat in two-digits
  $in=~s|;$||;
  $in=~s|Early\s*||;
  $in=~s|Contd\s+||;
  $in=~s|\s*\(II\)\s*||;
  if($in=~m|^1st Quart|) {
    return "$year-01-01";
  }
  if($in=~m|^2n?d Quart|) {
    return "$year-04-01";
  }
  if($in=~m|^Second Quarter|) {
    return "$year-04-01";
  }
  if($in=~m|^3r?d Quart|) {
    return "$year-06-01";
  }
  if($in=~m|^Third Quart|) {
    return "$year-06-01";
  }
  if($in=~m|^4th Quart|) {
    return "$year-09-01";
  }
  if($in=~m|^1st Trimest|) {
    return "$year-01-01";
  }
  if($in=~m|^2n?d Trimest|) {
    return "$year-04-01";
  }
  if($in=~m|^3r?d Trimest|) {
    return "$year-06-01";
  }
  if($in=~m|^4th Trimest|) {
    return "$year-09-01";
  }
  if($in=~m|^EASTER|i) {
    return "$year-04-07";
  }
  if($in=~m|^Christmas|i) {
    return "$year-12-25";
  }
  ## parts, we can't make a guess
  if($in=~m|^p \d+|i) {
    return "$year-01-01";
  }
  if($in=~m| p |i) {
    return "$year-01-01";
  }
  if($in=~m|Part|i) {
    return "$year-01-01";
  }
  if($in=~m|Suppl|i) {
    return "$year-01-01";
  }
  if($in=~m|^p \d+|i) {
    return "$year-01-01";
  }
  if($in=~m|^1/2|i) {
    return "$year-01-01";
  }
  if($in=~m|^1-2|i) {
    return "$year-02-01";
  }
  if($in=~m|^Summber|i) {
    return "$year-06-22";
  }
  if($in=~m|^Summer/Fall|i) {
    return "$year-06-22";
  }
  if($in=~m|^3/4|i) {
    return "$year-06-01";
  }
  my $start=substr($in,0,3);
  if($month_number->{$start}) {
    return "$year-".$month_number->{$start}."-01";
  }
  if($in=~m|^(\d)$|) {
    return "$year-0$1-01";
  }
  ## year + two digits
  if($in=~m|^(\d+)$|) {
    my $may_be_month=$1;
    if($may_be_month<13) {
      return "$year-$may_be_month-01";
    }
    return "$year-01-01";
  }
  ## year + (date enacted)
  if($in=~m|\(date enacted\)|) {
    return "$year-01-01";
  }
  ## year + (date approved)
  if($in=~m|\(date approved\)|) {
    return "$year-01-01";
  }
  ## year + semester
  if($in=~m|1st Semest|) {
    return "$year-01-01";
  }
  if($in=~m|2rd Semest|) {
    return "$year-06-01";
  }  
  ## year season
  if($seasons_date->{$in}) {
    return "$year-".$seasons_date->{$in};
  }
  ## year season
  if($month_number->{$in}) {
    return "$year-".$month_number->{$in}.'-01';
  }
  if($in=~m|^(\d{1,2})th (\w{3})$|) {
    my $may_be_day=$1;
    my $may_be_month=$2;
    if($may_be_day>32) {
      return '';
    }
    my $month=$month_number->{$may_be_month} // return '';
    if($may_be_day<10) {
      return $year.'-'.$month.'-0'.$may_be_day;
    }
    else {
      return $year.'-'.$month.'-'.$may_be_day;
    }
  }
  if($in=~m|^(\d{1,2}) (\w{3})$|) {
    my $may_be_day=$1;
    my $may_be_month=$2;
    if($may_be_day>32) {
      return '';
    }
    my $month=$month_number->{$may_be_month} // return '';
    if($may_be_day<10) {
      return $year.'-'.$month.'-0'.$may_be_day;
    }
    else {
      return $year.'-'.$month.'-'.$may_be_day;
    }
  }
  ## big numbers, don't know what to do
  if($in=~m|S?\d{2,}-S?\d{2,}|) {
    return $year.'-01-01';
  }
  ## just a guess
  if($in=~m|^9-10$|) {
    return $year.'-09-01';
  }
  ## year + season + season
  if($in=~m|^([A-Z][a-z]+)-([A-Z][a-z]+)$|) {
    my $may_be_season_1=$1;
    my $may_be_season_2=$2;
    if($seasons_date->{$may_be_season_1} and $seasons_date->{$may_be_season_2}) {
      return "$year-".$seasons_date->{$may_be_season_1};
    }    
  }
  ## year + season and season
  if($in=~m|^([A-Z][a-z]+) and ([A-Z][a-z]+)$|) {
    my $may_be_season_1=$1;
    my $may_be_season_2=$2;
    if($seasons_date->{$may_be_season_1} and $seasons_date->{$may_be_season_2}) {
      return "$year-".$seasons_date->{$may_be_season_1};
    }    
  }    
  ## year + season - year, usually followed by a season, so not anchored at the end
  if($in=~m|^([A-Z][a-z]+)[- ]+(\d{4})|) {
    my $may_be_season=$1;
    if($seasons_date->{$may_be_season}) {
      return "$year-".$seasons_date->{$may_be_season};
    }    
  }
  ## ' 5th Jan 2017'
  if($in=~m|^\s*(\d+)th\s+(\S{3})\s+(\d{4})\s*$|) {
    my $day=$1;
    my $month_short_name=$2;
    my $month=&month_short_name_to_number($month_short_name);
    my $year=$3;
    my $result="$year-$month-$day";
    return $result;
  }
  ## month1-month2
  if($in=~m|^\s*([A-Z][a-z][a-z])-[A-Z][a-z][a-z]\s*$|) {
    my $month_short_name=$1;
    my $month=&month_short_name_to_number($month_short_name);
    my $result="$year-$month-01";
    return $result;
  }
  if($in eq 'Dev') {
    my $result="$year-12-01";
    return $result;
  }
  if($in eq 'Desember') {
    my $result="$year-12-01";
    return $result;
  }
  if($in eq 'Dic') {
    my $result="$year-12-01";
    return $result;
  }
  if($in eq '"Apr') {
    my $result="$year-04-01";
    return $result;
  }
  ## I give up.
  my $return="$year-01-01";
  warn "I warn you. I return the default $return for '$in'.";  
  return $return;
}

sub month_short_name_to_number {
  my $in=shift;
  if($in eq 'Jan') {
    return '01';
  }
  if($in eq 'Feb') {
    return '02';
  }
  if($in eq 'Mar') {
    return '03';
  }
  if($in eq 'Apr') {
    return '04';
  }
  if($in eq 'May') {
    return '05';
  }
  if($in eq 'Jun') {
    return '06';
  }
  if($in eq 'Jul') {
    return '07';
  }
  if($in eq 'Aug') {
    return '08';
  }
  if($in eq 'Sep') {
    return '09';
  }
  if($in eq 'Oct') {
    return '10';
  }
  if($in eq 'Nov') {
    return '11';
  }
  if($in eq 'Dec') {
    return '12';
  }
}
  
sub try_to_find_part {
  my $xpc=shift;
  my $path=shift;
  my $txt=shift;
  my @nodes=$xpc->find($path)->get_nodelist;
  if(@nodes) {
    if(scalar(@nodes) > 1) {
      confess "I found several years in \n$txt;";
    }
    my $text=$nodes[0]->textContent;
    return $text;
  }
  return '';
}

1;