package Ernad::Dates;

use strict;
use warnings;

use Carp qw(cluck longmess shortmess croak confess);
use Cwd 'abs_path';
use Data::Dumper;
use Date::Calc qw(Add_Delta_Days);
use Date::Format;
use File::Basename;

use Krichel::Shoti;
use Ernad::Constant;

my $seconds_in_a_day=24*60*60;
my $format='%Y-%m-%d';
my $time_format="%Y\x{2012}%m\x{2012}%d %H:%M:%S";

sub mtime {
  my $file=shift // confess "I need a file here.";
  if(not -f $file) {
    confess "I can't see the file '$file'.";
  }
  my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
      $atime,$mtime,$ctime,$blksize,$blocks)
    = stat($file);
  return $mtime;
}

sub lmtime {
  my $file=shift // confess "I need a file here.";
  if(not -l $file) {
    confess "I can't see the link '$file'.";
  }
  my $target=abs_path($file) or confess "The link $file is broken";
  my $mtime=&mtime($target);
  return $mtime;
}

sub mshoti {
  my $file=shift // confess "I need a file here.";
  my $time=&mtime($file);
  my $shoti=&Krichel::Shoti::make($time);
  return $shoti;
}

sub mdate {
  my $file=shift // confess "I need a file here.";
  my $time=&mtime($file);
  my $date=time2str($format,$time);
  return $date;
}

sub mtime_string {
  my $file=shift // confess "I need a file here.";
  my $time=&mtime($file);
  my $date=time2str($time_format,$time);
  return $date;
}

sub get_shift {
  my $date=shift //  confess "I need a date here.";
  my $shift=shift // confess "I need a number  here.";
  if(not $shift=~m|^-*\d+$|) {
    confess "Your shift argument needs to be an integer, $shift does not qualily.";
  }
  $date=~m|^(\d{4})-(\d{2})-(\d{2})$| or confess "I need a better date than '$date'";
  my $year=$1;
  my $month=$2;
  my $day=$3;
  my @dated=&Add_Delta_Days($year,$month,$day,$shift);
  $year=$dated[0];
  $month=$dated[1];
  if(length($month)<2) {
    $month="0$month";
  }
  $day=$dated[2];
  if(length($day)<2) {
    $day="0$day";
  }
  $date="$year-$month-$day";
  return $date;
}

sub numeric {
  my $date=shift;
  $date=~m|^(\d{4})-(\d{2})-(\d{2})$| or confess "I need a better date than '$date'";
  $date=~s|-||g;
  return $date;
}

## $in has dates as keys
sub ge_earliest_date_from_hash {
  my $in=shift;
  my @dates=sort (keys %{$in});
  return $dates[0];
}

sub pretty_date {
  my $date=shift or confess "I need a date here.";
  my $pretty_date=$date;
  $pretty_date=~s|-|\x{2012}|g;
  return $pretty_date;
}

sub date_to_dadi {
  my $date=shift or confess "I need a date here.";
  my $dadi=substr($date,0,4)."/$date";
  return $dadi;
}

sub dadi_to_dati {
  my $dadi=shift or confess "I need a date here.";
  my $date=substr($dadi,5);
  return $date;
}

## $in has dates as keys
sub get_latest_date_from_hash {
  my $in=shift;
  my @dates=sort (keys %{$in});
  return $dates[$#dates];
}

## $in has dates as keys
sub calculate_date_weights {
  my $in=shift;
  my $earliest=&get_earliest_date_from_hash($in);
  my $latest=&get_latest_date_from_hash($in);
  my $span=diff_dates($earliest,$latest);
  my $diffs={};
  my $total=0;
  foreach my $date (keys %{$in}) {
    if(not defined($in->{$date})) {
      next;
    }
    my $diff=&diff_dates($date,$earliest);
    $total+=$diff;
    $diffs->{$date}=$diff;
  }
  my $weights={};
  foreach my $date (keys %{$in}) {
    $weights->{$date}=$diffs->{$date}/$total;
  }
  return $weights;
}

## $in has dates as keys
sub average_by_date {
  my $in=shift;
  my $weights=&calculate_date_weights($in);
  my $average=0;
  foreach my $date (keys %{$in}) {
    $average+=$weights->{$date} * $in->{$date};
  }
  return $average;
}

sub pretty_today {
  my $time=shift // time;
  my $date=time2str("%Y\x{2012}%m\x{2012}%d", $time);
  return $date;
}

sub pretty_time {
  my $time=shift // time;
  my $date=time2str("%Y\x{2012}%m\x{2012}%d %H:%M:%S", $time);
  return $date;
}

sub get_past_dates_from_number {
  my $number=shift // '';
  my $start_date=shift // '';
  if(not $number=~m|^\d+$|) {
    confess "The first argument must be an integer.";
  }
  if($start_date) {
    if(not  $start_date=~m|^\d{4}-\d{2}-\d{2}$|) {
      confess "The argument must be a date, not '$start_date'.";
    }
  }
  else {
    $start_date=&today();
  }
  my $dates=[];
  if(not $number=~m|^\d+|) {
    confess "I need a different number than '$number'.";
  }
  ## we never look at today's date
  if(not $number > 0) {
    return $dates;
  }
  my $start=0;
  if($start_date) {
    $start=&get_time_on_date($start_date);
    ## to start from the given day
    $start+=$seconds_in_a_day;
  }
  else {
    $start=time();
  }
  my $count=0;
  while($number>0) {
    my $time=$start - $number * $seconds_in_a_day;
    $dates->[$count++]=time2str($format,$time);
    $number--;
  }
  return $dates;
}


##########################################################################
## from Common

sub today {
  my $date=time2str("%Y-%m-%d", time);
  return $date;
}

sub get_up_date {
  my $date=time2str("%Y\x{2012}%m\x{2012}%d", time);
  return $date;
}

sub get_update {
  my $date=time2str('%Y-%m-%d', time);
  return $date;
}

## FixMe: change to compare
sub compare_dates {
  my $early=shift // confess "I need an early date here.";
  my $late=shift // confess "I need a late date here.";
  $early=~m|^(\d{4})-(\d{2})-(\d{2})$| or confess "You gave me a bad date '$early'";
  my $early_time="$1$2$3";
  $late=~m|^(\d{4})-(\d{2})-(\d{2})$| or confess "You gave me bad date '$late'";
  my $late_time="$1$2$3";
  if($late_time > $early_time) {
    return 1;
  }
  if($late_time < $early_time) {
    return -1;
  }
  return 0;
}

## FIXED FixMe: change to compare
sub compare {
  my $early=shift // confess "I need an early date here.";
  my $late=shift // confess "I need a late date here.";
  $early=~m|^(\d{4})-(\d{2})-(\d{2})$| or confess "You gave me a bad date '$early'";
  my $early_time="$1$2$3";
  $late=~m|^(\d{4})-(\d{2})-(\d{2})$| or confess "You gave me bad date '$late'";
  my $late_time="$1$2$3";
  if($late_time > $early_time) {
    return 1;
  }
  if($late_time < $early_time) {
    return -1;
  }
  return 0;
}

## later date come second
sub diff_dates {
  my $d1=shift;
  my $d2=shift;
  ## construct containing the parsed dates
  my $d;
  my $count=0;
  foreach my $in ($d1,$d2) {
    $in=~m|^(\d{4})-(\d{2})-(\d{2})| or confess "bad date '$in'.";
    $d->[$count]->[0]=$1;
    $d->[$count]->[1]=$2;
    $d->[$count]->[2]=$3;
    $count++;
  }
  if(not &Date::Calc::check_date(@{$d->[0]})) {
    # confess "The date is not $d1 is not valid.";
    return undef;
  }
  if(not &Date::Calc::check_date(@{$d->[1]})) {
    # confess "The date is not $d1 is not valid.";
    return undef;
  }
  my $delta=Date::Calc::Delta_Days(@{$d->[0]},@{$d->[1]});
  return $delta;
}

sub stretch_paper_date {
  my $in=shift // return '';
  if($in=~m|^\d{4}$|) {
    return "$in"."-01-01";
  }
  if($in=~m|^\d{4}-\d{2}$|) {
    return "$in"."-01";
  }
  if($in=~m|^\d{4}-\d{2}-\d{2}$|) {
    return "$in";
  }
  return '';
}

sub is {
  my $in=shift // confess "I need the input defined.";
  if($in=~m/^[0-9]{4}-(((0[13578]|(10|12))-(0[1-9]|[1-2][0-9]|3[0-1]))|(02-(0[1-9]|[1-2][0-9]))|((0[469]|11)-(0[1-9]|[1-2][0-9]|30)))$/) {
    return 1;
  }
  return 0;
}

sub paper_age {
  my $in=shift // return '';
  my $verbose=shift // '';
  $in=&stretch_paper_date($in) // return '';
  if($verbose) {
    print "The stretch date is $in\n";
  }
  return diff_dates($in,&today());
}

sub oldest_paper_age {
  my $text_ele=shift // confess "I need a text element here.";
  my $default=shift // confess "I need a default element here";
  my $verbose=shift // '';
  my $amf_ns=$Ernad::Constant::c->{'amf_ns'} // die "I need amf_ns defined here.";
  ## take the earliest dates
  my @date_eles=$text_ele->getElementsByTagNameNS($amf_ns,'date')->get_nodelist();
  if(not scalar(@date_eles)) {
    if($verbose) {
      print "I have no date elements\n";
    }
    return $default;
  }
  else {
    my $oldest_age=0;
    foreach my $date_ele (@date_eles) {
      my $date=$date_ele->textContent;
      if($verbose) {
        print "I found a date $date\n";
      }
      my $age=&Ernad::Dates::paper_age($date,$verbose);
      ## if an invalid date was supplied, make it extremely old
      if(not defined($age)) {
        return 99999999999999999999;
      }
      if(not $age) {
        $age=0;
      }
      if($age>$oldest_age) {
        $oldest_age=$age;
      }
    }
    if(not $oldest_age) {
      return $default;
    }
    else {
      return $oldest_age;
    }
  }
  ##
  confess "I should not be reaching this line";
}

#############################################################################
## old stuff that needs clearing

#compares two dates, returns 1 if they're equal and 0 otherwise
sub DCEqual {
    my ( $d1, $d2 ) = @_;
    my $i;

    for( $i = 0; $i < scalar( @$d1 ); $i++ ) {
	if( @$d1[$i] != @$d2[$i] ) {
	    return 0;
	}
    }

    return 1;
}

#compares two dates, returns 1 if first is greater and 0 otherwise
sub DCGreater {
    my ( $d1, $d2 ) = @_;
    my $i;

    for( $i = 0; $i < scalar( @$d1 ); $i++ ) {
	if( $$d1[$i] < $$d2[$i] ) {
	    return 0;
	}
	if( $$d1[$i] > $$d2[$i] ) {
	    return 1;
	}
    }

    return 0;
}

#lower
sub DCLower {
    my ( $d1, $d2 ) = @_;
    my $i;

    for( $i = 0; $i < scalar( @$d1 ); $i++ ) {
	if( @$d1[$i] < @$d2[$i] ) {
	    return 1;
	}
	if( @$d1[$i] > @$d2[$i] ) {
	    return 0;
	}
    }

    return 0;
}

sub DoZero {
    my	$n = $_[0];

    if( $n < 10 ) {
	return "0$n";
    }

    return $n;
}

#returns string with current date/time
sub CurrentAsString {
#    my ( $sec, $min, $hour, $mday, $mon, $year, $wday, $yday, $isdst );
    my	@data;

    $#data	=	9;

    @data	=	localtime( time );

    $data[4]++;
    $data[5]	+=	1900;

    my	$sz = 6;

    $sz = $_[0] if( scalar( @_ ) >= 1 );

    my	$result = "";

    for( my $i = 0; $i < $sz; $i++ ) {
	$result	=	$result.DoZero( $data[5 - $i] );
	$result	=	$result."-" if( $i < $sz - 1 );
    }

    return $result;
}

1;