#!/usr/bin/perl

# Calculates the age of a paper citation.
# Author: Ian Hickman

use strict;

use Time::Local;

my %months=( "Jan", 0, "Feb", 1, "Mar", 2, "Apr", 3, "May", 4, "Jun", 5, "Jul", 6, "Aug", 7, "Sep", 8,
"Oct", 9, "Nov", 10, "Dec", 11 );

my (%table, %subtimes );
my ($day, $month, $monthtext, $year);
my ($paper, @field);
my ($hittime, $subtime, $diff);
my $line=0;

print STDERR "opening paper dates\n";
openpapers();
print STDERR "doing the rest\n";
while( <STDIN> ){
  
  @field=split;

  # get the date the paper was first submitted (nearest day)
  if( exists($subtimes{$field[0]}) ){
    if( exists($subtimes{$field[1]}) ){
      print"$field[0] $subtimes{$field[0]} $field[1] $subtimes{$field[1]}\n";
    } else {
      print STDERR "target paper $field[1] not in d_firstsubmit\n";
    }
  } else {
    print STDERR "paper $field[0] not in d_firstsubmit\n";
  }
}

my $time;
foreach $time ( keys ( %table ) ){
  print"$time\t$table{$time}\n";
}

sub openpapers{

  my ( $time, $day, $month, $year );
  open( PAPERLIST, "../d_firstsubmit" ) || die"Cant open paperlist: $!";

  # loop through all the papers
  while( defined( $_ = <PAPERLIST> )){

    # loop through list of papers getting date and paperid
    my @field;
    @field=split;
    $_=$field[0];
    ($year, $month, $day)=/(....)(..)(..)/;
    if( $month>0 ){
      $time=timelocal( 0, 0, 0, $day, $month-1, $year );
      if( !(exists ($subtimes{$field[2]})) ){
        $time/=(24*3600);
        if( int($time) ne $time ){
          if( int($time) > ($time-0.5) ){
            $time=int($time);
          } elsif( int($time) <= ($time-0.5) ){
            $time=int($time)+1;
          }
        }
        $subtimes{$field[2]}=$time;
      } else {
        print"clash\n";
      }
    }
  }
  close( PAPERLIST ) || die"Cant close paper list: $!";
}