package DateTime::Calendar::FrenchRevolutionary;

use strict;

use vars qw($VERSION);

$VERSION = '0.07';

use Params::Validate qw(validate SCALAR BOOLEAN OBJECT);
use Roman;
use DateTime;
use DateTime::Calendar::FrenchRevolutionary::Locale;

my $BasicValidate =
    { year   => { type => SCALAR },
      month  => { type => SCALAR, default => 1,
                  callbacks =>
                  { 'is between 1 and 13' =>
                    sub { $_[0] >= 1 && $_[0] <= 13 }
                  },
                },
      day    => { type => SCALAR, default => 1,
                  callbacks =>
                  { 'is between 1 and 30' =>
                    sub { $_[0] >= 1 && $_[0] <= 30 },
                  },
                },
      hour   => { type => SCALAR, default => 0,
                  callbacks =>
                  { 'is between 0 and 9' =>
                    sub { $_[0] >= 0 && $_[0] <= 9 },
                  },
                },
      minute => { type => SCALAR, default => 0,
                  callbacks =>
                  { 'is between 0 and 99' =>
                    sub { $_[0] >= 0 && $_[0] <= 99 },
                  },
                },
      second => { type => SCALAR, default => 0,
                  callbacks =>
                  { 'is between 0 and 99' =>
                    sub { $_[0] >= 0 && $_[0] <= 99 },
                  },
                },
      abt_hour   => { type => SCALAR, default => 0,
                  callbacks =>
                  { 'is between 0 and 23' =>
                    sub { $_[0] >= 0 && $_[0] <= 23 },
                  },
                },
      abt_minute => { type => SCALAR, default => 0,
                  callbacks =>
                  { 'is between 0 and 59' =>
                    sub { $_[0] >= 0 && $_[0] <= 59 },
                  },
                },
      abt_second => { type => SCALAR, default => 0,
                  callbacks =>
                  { 'is between 0 and 61' =>
                    sub { $_[0] >= 0 && $_[0] <= 61 },
                  },
                },
      nanosecond => { type => SCALAR, default => 0,
                      callbacks =>
                      { 'cannot be negative' =>
                        sub { $_[0] >= 0 },
                      }
                    },
      locale    => { type => SCALAR | OBJECT,
                      callbacks =>
                      { "only 'fr' and 'en' possible" =>
                        sub { ($_[0] eq 'fr') or ($_[0] eq 'en') or ref($_[0]) =~ /(?:en|fr)$/ },
                      },
                     default => 'fr' },
    };

my $NewValidate =
    { %$BasicValidate,
      time_zone => { type => SCALAR | OBJECT,
                      callbacks =>
                      { "only 'floating' possible" =>
                        sub { ($_[0] eq 'floating') or ref($_[0]) and $_[0]->is_floating },
                      },
                     default => 'floating' },
    };
my $Lastday_validate = { %$BasicValidate };
delete $Lastday_validate->{day};

# Constructors
sub new {
    my $class = shift;
    my %args = validate( @_, $NewValidate );

    my $self = {};

    $self->{tz} = DateTime::TimeZone->new(name => 'floating');
    $args{locale} = delete $args{language} if exists $args{language};
    $args{locale} = $class->DefaultLocale unless defined $args{locale};
    if ( ref $args{locale} )
      { $self->{locale} = $args{locale} }
    else
      { $self->{locale} = DateTime::Calendar::FrenchRevolutionary::Locale->load( $args{locale} ) }

    $self->{local_rd_days} = $class->_ymd2rd(@args{qw(year month day)});
    my $abtsecs = $class->_time_as_abt_seconds(@args{qw(abt_hour abt_minute abt_second)});
    my $decsecs = $class->_time_as_seconds(@args{qw(hour minute second)});
    warn("You cannot specify both 24x60x60 time and 10x100x100 time when initializing a date")
        if $^W && $abtsecs && $decsecs;
    # We prefer decimal time over Anglo-Babylonian time when initializing a date
    $self->{local_rd_secs} = $decsecs ? $decsecs : $abtsecs;
    $self->{rd_nano} =  $args{nanosecond};

    bless $self, $class;
    $self->_calc_local_components;
    $self->_calc_utc_rd;

    return $self;
}

sub from_epoch {
  my $class = shift;
  my %args = validate( @_,
                         { epoch => { type => SCALAR },
                          locale => { type => SCALAR | OBJECT,
                                      default => $class->DefaultLocale },

                         }
                       );

  my $date = DateTime->from_epoch(%args);
  return $class->from_object(object => $date);
}

# use scalar time in case someone's loaded Time::Piece
sub now { shift->from_epoch(epoch => (scalar time), @_) }

sub from_object {
  my $class = shift;
  my %args = validate(@_,
                         { object => { type => OBJECT,
                                       can => 'utc_rd_values',
                                     },
                           locale => { type => SCALAR | OBJECT,
                                      default => $class->DefaultLocale },
                         },
                       );

  my $object = delete $args{object};
  $object = $object->clone->set_time_zone('floating')
      if $object->can('set_time_zone');

  my ($rd_days, $rd_secs, $rd_nano) = $object->utc_rd_values;

  my %p;
  @p{ qw(year  month   day) }     = $class->_rd2ymd($rd_days);
  # ABT seconds preferred over decimal seconds, because of precision loss
  @p{ qw(abt_hour  abt_minute  abt_second) }  = $class->_abt_seconds_as_components($rd_secs);
  # nanoseconds are copied, never converted ABT to decimal or reverse
  $p{nanosecond} = $rd_nano || 0;
  #@p{ qw(hour minute second) } = $class->_seconds_as_components($rd_secs);

  my $new = $class->new(%p, %args, time_zone => 'floating');

  return $new;
}

sub last_day_of_month {
    my $class = shift;
    my %p = validate( @_, $Lastday_validate);
    my $day = $p{month} <= 12 ? 30 : $class->_is_leap_year($p{year}) ? 6 : 5;
    return $class->new(%p, day => $day);
}

sub clone { bless { %{ $_[0] } }, ref $_[0] }

# Many of the same parameters as new() but all of them are optional,
# and there are no defaults.
my $SetValidate =
    { map { my %copy = %{ $BasicValidate->{$_} };
            delete $copy{default};
            $copy{optional} = 1;
            $_ => \%copy }
      keys %$BasicValidate };
sub set
{
    my $self = shift;
    my %p = validate( @_, $SetValidate );

    my %old_p =
        ( map { $_ => $self->$_() }
          qw( year month day hour minute second nanosecond locale )
        );

    my $new_dt = (ref $self)->new( %old_p, %p );

    %$self = %$new_dt;

    return $self;
}

sub set_time_zone { } # do nothing, only 'floating' allowed

# Internal functions
use constant REV_BEGINNING => 654415; # RD value for 1 Vendémiaire I in the Revolutionary calendar
use constant NORMAL_YEAR    => 365;
use constant LEAP_YEAR      => 366;
use constant FOUR_YEARS     =>  4 * NORMAL_YEAR + 1; # one leap year every four years
use constant CENTURY        => 25 * FOUR_YEARS - 1;  # centuries aren't leap years...
use constant FOUR_CENTURIES =>  4 * CENTURY + 1;     # ...except every four centuries that are.
use constant FOUR_MILLENIA  => 10 * FOUR_CENTURIES - 1; # ...except every four millenia that are not.

# number of days between the start of the revolutionary calendar, and the
# beginning of year n - 1 as long as the equinox rule is in effect
my @YEARS_BEGINS=    (0, 365, 730, 1096, 1461, 1826, 2191, 2557, 2922, 3287, 3652,
		   4018, 4383, 4748, 5113, 5479, 5844);
sub _is_leap_year {
    my ($self, $year) = @_;

    # Autumn equinox from I to XIX
    return 1 if ($year == 3) or ($year == 7) or ($year == 11) or ($year == 15);
    return 0 if ($year < 20);

    # Romme rule from XX on
    return 0 if $year %    4; # not a multiple of 4 -> normal year
    return 1 if $year %  100; # a multiple of 4 but not of 100 is a leap year
    return 0 if $year %  400; # a multiple of 100 but not of 400 is a normal year
    return 1 if $year % 4000; # a multiple of 400 but not of 4000 is leap
    return 0; # a multiple of 4000 is a normal year
}

sub _calc_utc_rd {
  my $self = shift;

  delete $self->{utc_c};

  if ($self->{tz}->is_utc)
    {
      $self->{utc_rd_days} = $self->{local_rd_days};
      $self->{utc_rd_secs} = $self->{local_rd_secs};
      return;
    }

  $self->{utc_rd_days} = $self->{local_rd_days};
  $self->{utc_rd_secs} = $self->{local_rd_secs} - $self->_offset_from_local_time;
  _normalize_seconds($self->{utc_rd_days}, $self->{utc_rd_secs}, $self->{rd_nano});
}

sub _calc_local_rd {
  my $self = shift;

  delete $self->{local_c};

  # We must short circuit for UTC times or else we could end up with
  # loops between DateTime.pm and DateTime::TimeZone
  if ($self->{tz}->is_utc)
    {
      $self->{local_rd_days} = $self->{utc_rd_days};
      $self->{local_rd_secs} = $self->{utc_rd_secs};
    }
   else
    {
      $self->{local_rd_days} = $self->{utc_rd_days};
      $self->{local_rd_secs} = $self->{utc_rd_secs} + $self->offset;
      _normalize_seconds($self->{local_rd_days}, $self->{local_rd_secs});
    }

    $self->_calc_local_components;
}

sub _normalize_seconds {
  my ($d, $s) = @_;
  my $adj;
  if ($s < 0)
    { $adj = int(($s - 86399) / 86400) }
  else
    { $adj = int($s / 86400) }
  $_[0] += $adj;
  $_[1] -= $adj * 86400;
}

sub _calc_local_components {
  my $self = shift;
  @{ $self->{local_c} }{ qw(year month day day_of_decade day_of_year) } 
        = $self->_rd2ymd($self->{local_rd_days}, 1);
  @{ $self->{local_c} }{ qw(abt_hour abt_minute abt_second) }
        = $self->_abt_seconds_as_components($self->{local_rd_secs});
  @{ $self->{local_c} }{ qw(hour minute second) }
        = $self->_seconds_as_components($self->{local_rd_secs});
}

sub _calc_utc_components {
  my $self = shift;
  @{ $self->{utc_c} }{ qw(year month day) } = $self->_rd2ymd($self->{utc_rd_days});
  @{ $self->{utc_c} }{ qw(abt_hour abt_minute abt_second) }
          = $self->_abt_seconds_as_components($self->{utc_rd_secs});
  @{ $self->{utc_c} }{ qw(hour minute second) } 
          = $self->_seconds_as_components($self->{utc_rd_secs});
}

sub _ymd2rd {
    my ($self, $y, $m, $d) = @_;
    my $rd = REV_BEGINNING - 1; # minus 1 for the zeroth Vendémiaire
    $y --;  #get years *before* this year.  Makes math easier.  :)
    # first, convert year into days. . .
    if ($y < 0 || $y >= 16) # Romme rule in effect, or nearly so
      {
        my $x = int($y/4000);
        --$x if $y <= 0;
	$rd += $x * FOUR_MILLENIA;
	$y  %= 4000;
	$rd += int($y/400)* FOUR_CENTURIES;
	$y  %= 400;
	$rd += int($y/100)* CENTURY;
	$y  %= 100;
	$rd += int($y/4)* FOUR_YEARS;
	$y  %= 4;
	$rd += $y * NORMAL_YEAR;
      }
    else # table look-up for the programmer-hostile equinox rule
      {	$rd += $YEARS_BEGINS[$y] }

    # now, month into days.
    $rd += 30 * ($m - 1) + $d;
    return $rd;
}

sub _rd2ymd {
    my ($self, $rd, $extra) = @_;

    my $doy;
    my $y;
    # note:  years and days are initially days *before* today, rather than
    # today's date.  This is because of fenceposts.  :)
    $doy =  $rd - REV_BEGINNING;
    if ($doy >= 0 && $doy < $YEARS_BEGINS[16])
      {
       	$y = scalar grep { $_ <= $doy } @YEARS_BEGINS;
	$doy -= $YEARS_BEGINS[$y - 1];
	$doy++;
      }
    else
      {
	#$doy --;
	my $x;
	$x    = int ($doy / FOUR_MILLENIA);
        --$x  if $doy < 0; # So pre-1792 dates will give something that look about right
        $y   += $x * 4000;
	$doy -= $x * FOUR_MILLENIA;

	$x    = int ($doy / FOUR_CENTURIES);
        $y   += $x * 400;
	$doy -= $x * FOUR_CENTURIES;

	$x    = int ($doy / CENTURY);
        $x    = 3 if $x == 4; # last day of the 400-year period; see comment below
        $y   += $x * 100;
	$doy -= $x * CENTURY;

	$x    = int ($doy / FOUR_YEARS);
        $y   += $x * 4;
	$doy -= $x * FOUR_YEARS;

	$x    = int ($doy / NORMAL_YEAR);
        # The division above divides the 4-year period, 1461 days,
        # into 5 parts: 365, 365, 365, 365 and 1. This mathematically sound operation
        # is wrong with respect to the calendar, which needs to divide
        # into 4 parts: 365, 365, 365 and 366. Therefore the adjustment below.
        $x    = 3 if $x == 4; # last day of the 4-year period
        $y   += $x;
	$doy -= $x * NORMAL_YEAR;

        ++$y; # because of 0-based mathematics vs 1-based chronology
        ++$doy;
      }
    my $d  = $doy % 30 || 30;
    my $m = ($doy - $d) / 30 + 1;
    if ($extra)
      {
        # day_of_decade, day_of_year
        my $dod = ($d % 10) || 10;
        return $y, $m, $d, $dod, $doy;
      }
    return $y, $m, $d;
}

# Aliases provided for compatibility with DateTime; if DateTime switches
# over to _ymd2rd and _rd2ymd, these will be removed eventually.
*_greg2rd = \&_ymd2rd;
*_rd2greg = \&_rd2ymd;

#
# Accessors
#
sub year    { $_[0]->{local_c}{year} }

sub month   { $_[0]->{local_c}{month} }
*mon = \&month;

sub month_0 { $_[0]->{local_c}{month} - 1 };
*mon_0 = \&month_0;

sub month_name {
    my $self = shift;
    return $self->{locale}->month_name($self);
    #return $months[$self->month_0]
}

sub month_abbr {
    my $self = shift;
    return $self->{locale}->month_abbreviation($self);
    #return $months_short[$self->month_0]
}

sub day_of_month { $_[0]->{local_c}{day} }
*day  = \&day_of_month;
*mday = \&day_of_month;

sub day_of_month_0 { $_[0]->{local_c}{day} - 1 }
*day_0  = \&day_of_month_0;
*mday_0 = \&day_of_month_0;

sub day_of_decade { $_[0]->{local_c}{day} % 10 || 10 }
*dod         = \&day_of_decade;
*dow         = \&day_of_decade;
*wday        = \&day_of_decade;
*day_of_week = \&day_of_decade;

sub day_of_decade_0 { ($_[0]->{local_c}{day} - 1) % 10 }
*dod_0         = \&day_of_decade_0;
*dow_0         = \&day_of_decade_0;
*wday_0        = \&day_of_decade_0;
*day_of_week_0 = \&day_of_decade_0;

sub day_name {
    my $self = shift;
    return $self->{locale}->day_name($self);
    #return $decade_days[$self->day_of_decade_0];
}

sub day_abbr {
    my $self = shift;
    return $self->{locale}->day_abbreviation($self);
    #return $decade_days_short[$self->day_of_decade_0];
}

sub day_of_year { $_[0]->{local_c}{day_of_year} }
*doy = \&day_of_year;

sub day_of_year_0 { $_[0]->{local_c}{day_of_year} - 1 }
*doy_0 = \&day_of_year_0;

sub feast_short {
  my ($dt) = @_;
  return $dt->{locale}->feast_short($dt);
}
*feast = \&feast_short;

sub _raw_feast {
  my ($dt) = @_;
  return $dt->{locale}->_raw_feast($dt);
}

sub feast_long {
  my ($dt) = @_;
  return $dt->{locale}->feast_long($dt);
}

sub feast_caps {
  my ($dt) = @_;
  return $dt->{locale}->feast_caps($dt);
}

sub ymd {
    my ($self, $sep) = @_;
    $sep = '-' unless defined $sep;
    return sprintf("%0.4d%s%0.2d%s%0.2d",
                   $self->year, $sep,
                   $self->{local_c}{month}, $sep,
                   $self->{local_c}{day});
}
*date = \&ymd;

sub mdy {
    my ($self, $sep) = @_;
    $sep = '-' unless defined $sep;
    return sprintf("%0.2d%s%0.2d%s%0.4d",
                   $self->{local_c}{month}, $sep,
                   $self->{local_c}{day},   $sep,
                   $self->year);
}

sub dmy {
  my ($self, $sep) = @_;
  $sep = '-' unless defined $sep;
  return sprintf("%0.2d%s%0.2d%s%0.4d",
                 $self->{local_c}{day},   $sep,
                 $self->{local_c}{month}, $sep,
                 $self->year);
}

# Anglo-Babylonian (or sexagesimal) time
sub abt_hour   { $_[0]->{local_c}{abt_hour} }
sub abt_minute { $_[0]->{local_c}{abt_minute} } *abt_min = \&abt_minute;
sub abt_second { $_[0]->{local_c}{abt_second} } *abt_sec = \&abt_second;
sub abt_hms {
  my ($self, $sep) = @_;
  $sep = ':' unless defined $sep;
  return sprintf("%0.2d%s%0.2d%s%0.2d",
                    $self->{local_c}{abt_hour},   $sep,
                    $self->{local_c}{abt_minute}, $sep,
                    $self->{local_c}{abt_second});
}

sub nanosecond { $_[0]->{rd_nano} }

# Decimal time
sub hour   { $_[0]->{local_c}{hour} }
sub minute { $_[0]->{local_c}{minute} } *min = \&minute;
sub second { $_[0]->{local_c}{second} } *sec = \&second;

sub hms {
    my ($self, $sep) = @_;
    $sep = ':' unless defined $sep;
    return sprintf("%0.1d%s%0.2d%s%0.2d",
                    $self->{local_c}{hour},   $sep,
                    $self->{local_c}{minute}, $sep,
                    $self->{local_c}{second} );
}
# don't want to override CORE::time()
*DateTime::Calendar::FrenchRevolutionary::time = \&hms;

sub iso8601 {
  my $self = shift;
  return join 'T', $self->ymd, $self->hms(':');
}
*datetime = \&iso8601;

sub is_leap_year { $_[0]->_is_leap_year($_[0]->year) }

sub decade_number {
  my $self = shift;
  return 3 * $self->month + int(($self->day - 1) / 10) - 2;
}
*week_number = \&decade_number;

sub decade {
  my $self = shift;
  return ($self->year, $self->decade_number);
}
*week = \&decade;

#sub time_zone { $_[0]->{tz} }

sub offset { $_[0]->{tz}->offset_for_datetime($_[0]) }
sub _offset_from_local_time { $_[0]->{tz}->offset_for_local_datetime($_[0]) }

#sub is_dst { $_[0]->{tz}->is_dst_for_datetime($_[0]) }

#sub time_zone_short_name { $_[0]->{tz}->short_name_for_datetime($_[0]) }

sub locale { $_[0]->{locale} }

sub utc_rd_values { @{ $_[0] }{ 'utc_rd_days', 'utc_rd_secs', 'rd_nano' } }

# Anglo-Babylonian time
sub   utc_rd_as_abt_seconds    { ($_[0]->{utc_rd_days}   * 86400) + $_[0]->{utc_rd_secs} }
sub local_rd_as_abt_seconds    { ($_[0]->{local_rd_days} * 86400) + $_[0]->{local_rd_secs} }
sub    _time_as_abt_seconds    { $_[1] * 3600 + $_[2] * 60 + $_[3] }
sub _abt_seconds_as_components { int($_[1] / 3600), int($_[1] % 3600 / 60), $_[1] % 60 }

# Decimal time
sub _time_as_seconds { .864 * ($_[1] * 10000 + $_[2] * 100 + $_[3]) }
sub _seconds_as_components { 
  my $sec = $_[1] / .864; 
  int($sec / 10000), int($sec % 10000 / 100), $sec % 100 
}

# RD 1 is JD 1,721,424.5 - a simple offset
sub jd {
  my $self = shift;
  my $jd = $self->{utc_rd_days} + 1_721_424.5;
  return $jd + ($self->{utc_rd_secs} / 86400);
}

sub mjd { $_[0]->jd - 2_400_000.5 }

my %formats = (
        'a' => sub { $_[0]->day_abbr }
      , 'A' => sub { $_[0]->day_name }
      , 'b' => sub { $_[0]->month_abbr }
      , 'B' => sub { $_[0]->month_name }
      , 'c' => sub { $_[0]->strftime( $_[0]->{locale}->default_datetime_format ) }
      , 'C' => sub { int($_[0]->year / 100) }
      , 'd' => sub { sprintf '%02d', $_[0]->day_of_month }
      , 'D' => sub { $_[0]->strftime('%m/%d/%y') }
      , 'e' => sub { sprintf('%2d', $_[0]->day_of_month) }
      , 'f' => sub { sprintf('%2d', $_[0]->month) }
      , 'F' => sub { $_[0]->ymd('-') }
      , 'g' => sub { substr($_[0]->year, -2) }
      , 'G' => sub { sprintf '%04d', $_[0]->year }
      , 'h' => sub { $_[0]->month_abbr }
      , 'H' => sub { sprintf('%d', $_[0]->hour) }
      , 'I' => sub { my $h = $_[0]->hour || 10; sprintf('%d', $h) }
      , 'j' => sub { sprintf '%03d', $_[0]->day_of_year }
      , 'k' => sub { sprintf('%2d', $_[0]->hour) }
      , 'l' => sub { my $h = $_[0]->hour || 10; sprintf('%2d', $h) }
      , 'L' => sub { sprintf '%04d', $_[0]->year }
      , 'm' => sub { sprintf '%02d', $_[0]->month }
      , 'M' => sub { sprintf '%02d', $_[0]->minute }
      , 'n' => sub { "\n" } # should this be OS-sensitive?
      , 'p' => sub {    $_[0]->{locale}->am_pm($_[0]) }
      , 'P' => sub { lc $_[0]->{locale}->am_pm($_[0]) }
#      , 'p' => sub { $_[0]->hour < 5 ? 'AM' : 'PM' }
#      , 'P' => sub { $_[0]->hour < 5 ? 'am' : 'pm' }
      , 'r' => sub { $_[0]->strftime('%I:%M:%S %p') }
      , 'R' => sub { $_[0]->strftime('%H:%M') }
      , 's' => sub { $_[0]->epoch }
      , 'S' => sub { sprintf('%02d', $_[0]->second) }
      , 't' => sub { "\t" }
      , 'T' => sub { $_[0]->strftime('%H:%M:%S') }
      , 'u' => sub { sprintf '%2d', $_[0]->day_of_decade },
      , 'U' => sub { $_[0]->decade_number }
      , 'V' => sub { $_[0]->decade_number }
      , 'w' => sub { $_[0]->day_of_decade % 10 }
      , 'W' => sub { $_[0]->decade_number }
      , 'y' => sub { sprintf('%02d', substr( $_[0]->year, -2 )) }
      , 'Y' => sub { sprintf '%04d', $_[0]->year }
      , 'z' => sub { DateTime::TimeZone::offset_as_string( $_[0]->offset ) }
      , 'Z' => sub { $_[0]->{tz}->short_name_for_datetime($_[0]) }
      , '+' => sub { '+' }
      , '%' => sub { '%' }
      , 'EY' => sub { Roman $_[0]->year }
      , 'Ey' => sub { roman $_[0]->year }
      , 'Ej' => sub { $_[0]->feast_long }
      , 'EJ' => sub { $_[0]->feast_caps }
      , 'Oj' => sub { $_[0]->feast_short }

    );

$formats{h} = $formats{b};

sub strftime {
  my $self = shift;
  # make a copy or caller's scalars get munged
  my @formats = @_;

  my @r;
  foreach my $f (@formats)
    {
      # regex from DateTime from Date::Format - thanks Graham and Dave!
      # but there is a twist: 3-char format specifiers such as '%Ey' are
      # allowed. All 3-char specifiers begin with a '%E' or '%O' prefix.
      # At the same time, if the user wants %Em or %Om, which do not exist, it defaults to %m
      # And if the user asks for %E!,
      # it defaults to E! because neither %E! nor %! exist.
      $f =~ s/
	        %([EO]?([%a-zA-Z]))
              | %{(\w+)}
             /
              $3 ? ($self->can($3) ? $self->$3() : "\%{$3}")
                 : ($formats{$1} ? $formats{$1}->($self)
                             : $formats{$2} ? $formats{$2}->($self) : $1)
             /sgex;
      return $f unless wantarray;
      push @r, $f;
    }
  return @r;
}

sub epoch {
  my $self = shift;
  my $greg = DateTime->from_object(object => $self);
  return $greg->epoch;
}

sub DefaultLocale {
  'fr'
}

#my %events = ();
sub on_date {
  my ($dt, $lan) = @_;
  my $locale;

  if (defined $lan)
    { $locale = DateTime::Calendar::FrenchRevolutionary::Locale->load( $lan )}
  else
    { $locale = $dt->{locale} }
  return $locale->on_date($dt);

}

# A module must return a true value. Traditionally, a module returns 1.
# But this module is a revolutionary one, so it discards all old traditions.
"Liberté, égalité, fraternité
ou la mort !";

__END__

=head1 NAME

DateTime::Calendar::FrenchRevolutionary - Dates in the French Revolutionary Calendar

=head1 SYNOPSIS

  use DateTime::Calendar::FrenchRevolutionary;

  $dt = DateTime::Calendar::FrenchRevolutionary->new( year  => 8,
                                         month =>  2,
                                         day   => 18,
                                       );

  # convert FrenchRevolutionary->Gregorian...

  $dtgreg = DateTime->from_object( object => $dt );

  # ... and back again

  $dtrev = DateTime::Calendar::FrenchRevolutionary->from_object( object => $dtgreg );

=head1 DESCRIPTION

DateTime::Calendar::FrenchRevolutionary implements the French Revolutionary
Calendar.  This module implements most methods of DateTime; see the
DateTime(3) manpage for all methods.

=head1 HISTORICAL NOTES

The Revolutionary calendar was in  use in France from 24 November 1793
(4 Frimaire  II) to 31  December 1805 (10  Nivôse XIV). An  attempt to
apply  the  decimal rule  (the  basis of  the  metric  system) to  the
calendar. Therefore, the week  disappeared, replaced by the décade (10
days, totally different from the  English word "decade", 10 years). In
addition, all months have exactly 3 decades, no more, no less.

At first,  the year was  beginning on the  equinox of autumn,  for two
reasons.  First, the  republic had  been established  on  22 September
1792, which  happened to be the  equinox, and second,  the equinox was
the symbol of equality, the day and the night lasting exactly 12 hours
each. It  was therefore  in tune with  the republic's  motto "Liberty,
Equality, Fraternity". But  it was not practical, so  Romme proposed a
leap year rule similar to the Gregorian calendar rule.

In his book I<The French Revolution>, the XIXth century writer Thomas
Carlyle proposes these translations for the month names:

=over 4

=item Vendémiaire -> Vintagearious

=item Brumaire -> Fogarious

=item Frimaire -> Frostarious

=item Nivôse -> Snowous

=item Pluviôse -> Rainous

=item Ventôse -> Windous

=item Germinal -> Buddal

=item Floréal -> Floweral

=item Prairial -> Meadowal

=item Messidor -> Reapidor

=item Thermidor -> Heatidor

=item Fructidor -> Fruitidor

=back

There was also an attempt to decimalize the day's subunits, with 1 day
= 10 hours, 1 hour = 100 minutes and 1 minute = 100 seconds.  But this
reform was put on hold after two years or so and it never reappeared.

=head1 METHODS

Since  the week  has been  replaced by  the décade,  the corresponding
method  names  still   are  C<decade_number>,  C<day_of_decade>,  etc.
English  speakers, please  note that  this has  nothing to  do  with a
10-year period.

The module supports both  Anglo-Babylonian time and decimal time.  The
accessors  for ABT are  C<abt_hour>, C<abt_minute>,  C<abt_second> and
C<abt_hms>,  the accessors  for decimal  time are  C<hour>, C<minute>,
C<second> and C<hms>. The  C<strftime> and C<iso8601> methods use only
decimal  time.  The  ABT  accessors are  provided  to be  historically
correct, since  the decimal time reform  was never put  in force. Yet,
emphasis is  on decimal time because  it is more  fun than sexagesimal
time,  which  anyhow  can  be  obtained with  the  standard  Gregorian
C<DateTime.pm> module.

=head2 Constructors

=over 4

=item * new(...)

Creates a new date object. This class accepts the following parameters:

=over 4

=item * C<year>

Year number, mandatory. Year 1 corresponds to Gregorian years late 1792 
and early 1793.

=item * C<month>

Month number, in the range 1..12, plus number 13 to designate the end-of-year
additional days.

=item * C<day>

Day number, in the range 1..30. In the case of additional days, the range
is 1..5 or 1..6 depending on the year (leap year or normal).

=item * C<hour>, C<minute>, C<second>

Decimal hour number, decimal minute number and decimal second number.
The hour is in the 0..9 range, both other parameters are in the 0..99
range. These parameters cannot be specified with the sexagesimal time
parameters C<abt_>I<xxx> (see below).

=item * C<abt_hour>, C<abt_minute>, C<abt_second>

Sexagesimal hour number, sexagesimal minute number and sexagesimal second number.
The hour is in the 0..23 range, both other parameters are in the 0..59
range. These parameters cannot be specified with the decimal time
parameters (see above).

=item * C<locale>

Only the values C<fr> (French) and C<en> (English) are allowed. Default
is French. No other values are possible, even territory variants such
as C<fr_BE> or C<en_US>.

=back

=item * from_epoch( epoch => $epoch )

Creates a date object from a timestamp value. This timestamp is the number of
seconds since the computer epoch, not the calendar epoch.

=item * now( )

Creates a date object that corresponds to the precise instant the 
method is called.

=item * from_object( object => $object, ... )

Creates a date object by converting another object from the DateTime suite.
The preferred way for calendar to calendar conversion.

=item * last_day_of_month( ... )

Same as new, except that the C<day> parameter is forbidden and
is automatically set to the end of the month. If the C<month>
paramter is 13 for the additional days, the day is set to the
end of the year, either the 5th or the 6th additional day.

=item * clone

Creates a replica of the original date object.

=item * set( .. )

This method can be used to change the local components of a date time,
or its locale.  This method accepts any parameter allowed by the
C<new()> method.

This method performs parameters validation just as is done in the
C<new()> method.

=back

=head2 Accessors

=over 4

=item * year

Returns the year

=item * month

Returns the month in the 1..12 range. If the date is an additional day
at the end of the year, returns 13, which is not really a month number.

=item * month_0

Returns the month in the 0..11 range. If the date is an additional day
at the end of the year, returns 12, which is not really a month number.

=item * month_name

Returns the  French name of the  month or its  English translation. No
other language is  supported yet.  For the additional  days at the end
of  the  year,  returns  "jour  complémentaire",  the  translation  of
"additional day".

Note: The  English translations for  the month names come  from Thomas
Carlyle's book.

=item * month_abbr

Returns  a 3-letter abbreviation of the month name. For the additional
days at the end of the year, returns "S-C", because these additional days
were also known as the I<Sans-culottides>.

=item * day_of_month, day, mday

Returns the day of the month, from 1..30.

=item * day_of_decade, dod, day_of_week, dow, wday

Returns the day of the decade, from 1..10. The C<dow>, C<wday> and C<day_of_week>
names are there for compatibility's sake with C<DateTime>, even if the word
"week" is improper.

=item * day_name

Returns the name of the current day of the I<décade>.

=item * day_abbr

Returns the abbreviated name of the current day of the I<décade>.

=item * day_of_year, doy

Returns the day of the year.

=item * feast, feast_short, feast_long, feast_caps

Returns the plant, animal, mineral or tool associated with the day.
The default format is C<short>. If requested, you can ask for 
the C<long> format, with a C<jour de...> prefix, or the C<caps>
format, with the first letter of the prefix and feast capitalized.
Example: for 11 Vendémiaire, we have:

   feast, feast_short  pomme de terre
   feast_long          jour de la pomme de terre
   feast_caps          Jour de la Pomme de terre

Note: the  English translation for  the feasts comes mainly  from Alan
Taylor's website "Preserving the French Republican Calendar".

=item * ymd, dmy, mdy

Returns the date in the corresponding composite format. An optional
parameter allows you to choose the separator between the date elements.

=item * abt_hour, abt_minute, abt_min, abt_second, abt_sec

Return the corresponding time elements, using a sexagesimal scale.
This is also known as the I<Anglo-Babylonian Time>.

=item * hour, minute, min, second, sec

Return the corresponding time elements, using a decimal scale,
with 10 hours per day, 100 minutes per hour and 100 seconds per minute.

=item * abt_hms

Returns a composite string with the three time elements. Uses the
I<Anglo-Babylonian Time>.  An optional parameter allows you to choose
the separator (C<:> by default).

=item * hms

Returns a composite string with the three time elements. Uses the
decimal time.  An optional parameter allows you to choose the
separator (C<:> by default).

=item * iso8601

Returns the date and time is a format similar to what ISO-8601 has
specified for the Gregorian calendar.

=item * is_leap_year

Returns a true value if the year is a leap year, false else.

=item * decade_number, week_number

Returns the I<décade> number.

=item * decade, week

Returns a 2-element list, with the year number and the decade number.
Since the I<décade> is always aligned with a month and then with a 
year, the year element is always the same as the date's year.
Anyhow, this is done for compatibility with DateTime's C<week> method.

=item * utc_rd_values

Returns the  current UTC Rata Die  days, seconds and  nanoseconds as a
3-element list.  This exists primarily to allow other calendar modules
to create objects based on the values provided by this object.

=item * jd, mjd

These return the Julian Day and Modified Julian Day, respectively.
The value returned is a floating point number.  The fractional portion
of the number represents the time portion of the datetime.

=item * utc_rd_as_seconds

Returns the current UTC Rata Die days and seconds purely as seconds.
This is useful when you need a single number to represent a date.

=item * local_rd_as_seconds

Returns the current local Rata Die days and seconds purely as seconds.

=item * strftime( $format, ... )

This method implements functionality similar to the C<strftime()>
method in C.  However, if given multiple format strings, then it will
return multiple elements, one for each format string.

See the L<strftime Specifiers|/strftime Specifiers> section for a list
of all possible format specifiers.

=item * epoch

Return the UTC epoch value  for the datetime object.  Internally, this
is  implemented  C<expoch>  from  C<DateTime>,  which  in  turn  calls
C<Time::Local>,  which uses  the Unix  epoch even  on machines  with a
different epoch (such  as Mac OS).  Datetimes before  the start of the
epoch will be returned as a negative number.

Since epoch times cannot represent many dates on most platforms, this
method may simply return undef in some cases.

Using your system's epoch time may be error-prone, since epoch times
have such a limited range on 32-bit machines.  Additionally, the fact
that different operating systems have different epoch beginnings is
another source of bugs.

=item * on_date

Gives  a  few historical  events  that took  place  on  the same  date
(day+month, irrespective of the  year).  These events occur during the
period of use  of the calendar, that is, no  later than Gregorian year
1805. The  related  events either  were  located  in  France, or  were
battles in which a French army was involved.

This  method accepts  one  optional argument,  the  language. For  the
moment, only  "en" for English and  "fr" for French  are available. If
not given, the method will use the date object's current locale.

Not all eligible events are portrayed there. The events database will
be expanded in future versions.

Most military events are extracted from I<Calendrier Militaire>, a book
written by an anonymous author in VII (1798) or so. I guess there is 
no longer any copyright attached. Please note that this is a propaganda
book, which therefore gives a very biased view of the events.

=back

=head2 strftime Specifiers

The following specifiers are allowed in the format string given to the
C<strftime()> method:

=over 4

=item * %a

The abbreviated day of decade name.

=item * %A

The full day of decade name.

=item * %b

The abbreviated month name, or 'S-C' for additional days (abbreviation
of I<Sans-culottide>, another name for these days).

=item * %B

The full month name.

=item * %C

The century number (year/100) as a 2-digit integer.

=item * %d

The day of the month as a decimal number (range 01 to 30).

=item * %D

Equivalent to %m/%d/%y.  This is not a good standard format if you
have want both Americans and Europeans to understand the date!

=item * %e

Like %d, the day of the month as a decimal number, but a leading zero
is replaced by a space.

=item * %F

Equivalent to %Y-%m-%d (the ISO 8601 date format)

=item * %G

Strictly similar to C<%Y>, since I<décades> are aligned with 
the beginning of the year in this calendar.

=item * %g

Strictly similar to C<%y>, since I<décades> are aligned with 
the beginning of the year in this calendar.

=item * %h

Equivalent to %b.

=item * %H

The hour as a decimal number using a 10-hour clock (range 0 to 9).
The result is a single-char string.

=item * %I

The hour as a decimal number using the numbers on a clockface, that
is, range 1 to 10. The result is a single-char string, except for 10.

=item * %j

The day of the year as a decimal number (range 001 to 366).

=item * %k

The hour (10-hour clock) as a decimal number (range 0 to 9); 
the result is a 2-char string, the digit is preceded by a blank. (See also %H.)

=item * %l

The hour as read from a clockface (range 1 to 10). The result is
a  2-char string, the digit is preceded by a blank, except of course
for 10. (See also %I.)

=item * %m

The month as a decimal number (range 01 to 13).

=item * %M

The minute as a decimal number (range 00 to 99).

=item * %n

A newline character.

=item * %p

Either `AM' or `PM' according to the given time value, or the
corresponding strings for the current locale.  Noon is treated as `pm'
and midnight as `am'.

=item * %P

Like %p but in lowercase: `am' or `pm' or a corresponding string for
the current locale.

=item * %r

The decimal time in a.m.  or p.m. notation.  In the POSIX locale this is
equivalent to `%I:%M:%S %p'.

=item * %R

The decimal time in 10-hour notation (%H:%M). (SU) For a version including the
seconds, see %T below.

=item * %s

The number of seconds since the epoch.

=item * %S

The second as a decimal number (range 00 to 99).

=item * %t

A tab character.

=item * %T

The decimal time in 10-hour notation (%H:%M:%S).

=item * %u

The day of the I<décade> as a decimal, range 1 to 10, Primidi being 1.  See
also %w.

=item * %U

The I<décade> number of the current year as a decimal number, range 00
to 37.

=item * %V

The decade number (French Revolutionary equivalent to
the ISO 8601:1988 week number) of the current year as a decimal number,
range 01 to 37. Identical to %U, since décades are aligned with the
beginning of the year.

=item * %w

The day of the I<décade> as a decimal, range 0 to 9, Décadi being 0.  See
also %u.

=item * %W

The I<décade> number of the current year as a decimal number, range 00
to 37.

=item * %y

The year as a decimal number without a century (range 00 to 99).

=item * %Y

The year as a decimal number including the century.

=item * %Ey

The year as a lowercase Roman number.

=item * %EY

The year as a uppercase Roman number, which is the traditional way
to write years when using the French Revolutionary calendar.

=item * %z

The time-zone as hour offset from UTC.  Required to emit
RFC822-conformant dates (using "%a, %d %b %Y %H:%M:%S %z").
Since the module does not support time zones, this gives
silly results and you cannot be RFC822-conformant.
Anyway, RFC822 requires the Gregorian calendar, doesn't it?

=item * %Z

The time zone or name or abbreviation, should the module have supported them.

=item * %%

A literal `%' character.

=back

=head1 REMARKS

=head2 Time Zones

Only the I<floating> time zone is supported.  Time zones were created
in the late XIXth century, at a time when instant communication
(electric telegraph) made it necessary.  But at this time, the French
Revolutionary calendar was no longer in use.

=head2 Leap Seconds

They are not supported.

=head2 I18N

For the moment, only French and English are available. For the English
translation, I have  used Thomas Carlyle's book and  Alan Taylor's web
site at kokogiak.com (see below).

Some feast names are not translated, other's translations are doubtful
(they are flagged with a question mark).  Remarks are welcome.

=head1 SUPPORT

Support for this module is provided via the datetime@perl.org email
list. See L<http://lists.perl.org/> for more details.

Please enter bug reports at L<http://rt.cpan.org/>

=head1 AUTHOR

Jean Forget <JFORGET@cpan.org>

based on Dave Rolsky's DateTime module,  Eugene van der Pijll's 
DateTime::Calendar::Pataphysical module and my prior Date::Convert::French_Rev module.

The development of this module is hosted by I<Les Mongueurs de Perl>,
L<http://www.mongueurs.net/>.

=head1 SEE ALSO

=head2 Software

date(1), perl(1), DateTime(3), DateTime::Calendar::Pataphysical(3), Date::Convert::French_Rev

calendar/cal-french.el in emacs-21.2 or xemacs 21.1.8

=head2 Books

Quid 2001, M and D Frémy, publ. Robert Laffont

Agenda Républicain 197 (1988/89), publ. Syros Alternatives

Any French schoolbook about the French Revolution

The French Revolution, Thomas Carlyle, Oxford University Press

Calendrier Militaire, anonymous

=head2 Internet

http://datetime.perl.org/

http://www.faqs.org/faqs/calendars/faq/part3/

http://zapatopi.net/metrictime.html

http://www.kokogiak.com/frc/default.asp

=head1 LICENSE STUFF

Copyright (c) 2003--2004 Jean Forget. All rights reserved. This program is
free software. You can distribute, modify, and otherwise mangle
DateTime::Calendar::FrenchRevolutionary under the same terms as perl.

=cut