#============================================================= -*-Perl-*-
#
# Template::Plugin::Date
#
# DESCRIPTION
#
#   Plugin to generate formatted date strings.
#
# AUTHORS
#   Thierry-Michel Barral  <kktos@electron-libre.com>
#   Andy Wardley           <abw@wardley.org>
#
# COPYRIGHT
#   Copyright (C) 2000-2007 Thierry-Michel Barral, Andy Wardley.
#
#   This module is free software; you can redistribute it and/or
#   modify it under the same terms as Perl itself.
#
#============================================================================

package Template::Plugin::Date;

use strict;
use warnings;
use base 'Template::Plugin';

use POSIX ();

use Config ();

use constant HAS_SETLOCALE => $Config::Config{d_setlocale};

our $VERSION = '3.009';
our $FORMAT  = '%H:%M:%S %d-%b-%Y';    # default strftime() format
our @LOCALE_SUFFIX = qw( .ISO8859-1 .ISO_8859-15 .US-ASCII .UTF-8 );


#------------------------------------------------------------------------
# new(\%options)
#------------------------------------------------------------------------

sub new {
    my ($class, $context, $params) = @_;
    bless {
        $params ? %$params : ()
    }, $class;
}


#------------------------------------------------------------------------
# now()
# 
# Call time() to return the current system time in seconds since the epoch.
#------------------------------------------------------------------------

sub now {
    return time();
}


#------------------------------------------------------------------------
# format()                           
# format($time)
# format($time, $format)
# format($time, $format, $locale)
# format($time, $format, $locale, $gmt_flag)
# format(\%named_params);
# 
# Returns a formatted time/date string for the specified time, $time, 
# (or the current system time if unspecified) using the $format, $locale,
# and $gmt values specified as arguments or internal values set defined
# at construction time).  Specifying a Perl-true value for $gmt will
# override the local time zone and force the output to be for GMT.
# Any or all of the arguments may be specified as named parameters which 
# get passed as a hash array reference as the final argument.
# ------------------------------------------------------------------------

sub format {
    my $self   = shift;
    my $params = ref($_[$#_]) eq 'HASH' ? pop(@_) : { };

    my $time   = shift(@_);
    $time = $params->{ time } || $self->{ time } || $self->now() if !defined $time;

    my $format = @_ ? shift(@_) 
                    : ($params->{ format } || $self->{ format } || $FORMAT);
    my $locale = @_ ? shift(@_)
                    : ($params->{ locale } || $self->{ locale });
    my $gmt = @_ ? shift(@_)
            : ($params->{ gmt } || $self->{ gmt });
    my $offset = @_ ? shift(@_)
            : ( $params->{ use_offset } || $self->{ use_offset });
    my (@date, $datestr);

    if ($time =~ /^-?\d+$/) {
        # $time is now in seconds since epoch
        if ($gmt) {
            @date = (gmtime($time))[ 0 .. ( $offset ? 6 : 8 ) ];
        }
        else {
            @date = (localtime($time))[ 0 .. ( $offset ? 6 : 8 ) ];
        }
    }
    else {
        # if $time is numeric, then we assume it's seconds since the epoch
        # otherwise, we try to parse it as either a 'Y:M:D H:M:S' or a
        # 'H:M:S D:M:Y' string

        my @parts = (split(/\D/, $time));

        if (@parts >= 6) {
            if (length($parts[0]) == 4) {
                # year is first; assume 'Y:M:D H:M:S'
                @date = @parts[reverse 0..5];
            }
            else {
                # year is last; assume 'H:M:S D:M:Y'
                @date = @parts[2,1,0,3..5];
            }
        }

        if (!@date) {
            return (undef, Template::Exception->new('date',
                   "bad time/date string:  " .
                   "expects 'h:m:s d:m:y'  got: '$time'"));
        }
        $date[4] -= 1;     # correct month number 1-12 to range 0-11
        $date[5] -= 1900;  # convert absolute year to years since 1900
        $time = &POSIX::mktime(@date);

        if ($offset) {
            push @date, $gmt
                ? (gmtime($time))[6..8] : (localtime($time))[6..8];
        }
    }
    
    if ($locale) {
        # format the date in a specific locale, saving and subsequently
        # restoring the current locale.
        my $old_locale = HAS_SETLOCALE
                       ? &POSIX::setlocale(&POSIX::LC_ALL)
                       : undef;

        # some systems expect locales to have a particular suffix
        for my $suffix ('', @LOCALE_SUFFIX) {
            my $try_locale = $locale.$suffix;
            my $setlocale = HAS_SETLOCALE
                       ? &POSIX::setlocale(&POSIX::LC_ALL, $try_locale)
                       : undef;
            if (defined $setlocale && $try_locale eq $setlocale) {
                $locale = $try_locale;
                last;
            }
        }
        $datestr = &POSIX::strftime($format, @date);
        &POSIX::setlocale(&POSIX::LC_ALL, $old_locale) if HAS_SETLOCALE;
    }
    else {
        $datestr = &POSIX::strftime($format, @date);
    }

    return $datestr;
}

sub calc {
    my $self = shift;
    eval { require "Date/Calc.pm" };
    $self->throw("failed to load Date::Calc: $@") if $@;
    return Template::Plugin::Date::Calc->new('no context');
}

sub manip {
    my $self = shift;
    eval { require "Date/Manip.pm" };
    $self->throw("failed to load Date::Manip: $@") if $@;
    return Template::Plugin::Date::Manip->new('no context');
}


sub throw {
    my $self = shift;
    die (Template::Exception->new('date', join(', ', @_)));
}


package Template::Plugin::Date::Calc;
use base qw( Template::Plugin );
our $AUTOLOAD;
*throw = \&Template::Plugin::Date::throw;

sub AUTOLOAD {
    my $self = shift;
    my $method = $AUTOLOAD;

    $method =~ s/.*:://;
    return if $method eq 'DESTROY';

    my $sub = \&{"Date::Calc::$method"};
    $self->throw("no such Date::Calc method: $method")
        unless $sub;

    &$sub(@_);
}

package Template::Plugin::Date::Manip;
use base qw( Template::Plugin );
our $AUTOLOAD;
*throw = \&Template::Plugin::Date::throw;

sub AUTOLOAD {
    my $self = shift;
    my $method = $AUTOLOAD;
    
    $method =~ s/.*:://;
    return if $method eq 'DESTROY';
    
    my $sub = \&{"Date::Manip::$method"};
    $self->throw("no such Date::Manip method: $method")
        unless $sub;
    
    &$sub(@_);
}
    
    
1;

__END__

=head1 NAME

Template::Plugin::Date - Plugin to generate formatted date strings

=head1 SYNOPSIS

    [% USE date %]
    
    # use current time and default format
    [% date.format %]
    
    # specify time as seconds since epoch
    # or as a 'h:m:s d-m-y' or 'y-m-d h:m:s' string
    [% date.format(960973980) %]
    [% date.format('4:20:36 21/12/2000') %]
    [% date.format('2000/12/21 4:20:36') %]
    
    # specify format
    [% date.format(mytime, '%H:%M:%S') %]
    
    # specify locale
    [% date.format(date.now, '%a %d %b %y', 'en_GB') %]
    
    # named parameters 
    [% date.format(mytime, format = '%H:%M:%S') %]
    [% date.format(locale = 'en_GB') %]
    [% date.format(time       = date.now,
                   format     = '%H:%M:%S',
                   locale     = 'en_GB'
                   use_offset = 1) %]

    # specify default format to plugin
    [% USE date(format = '%H:%M:%S', locale = 'de_DE') %]
    
    [% date.format %]
    ...

=head1 DESCRIPTION

The C<Date> plugin provides an easy way to generate formatted time and date
strings by delegating to the C<POSIX> C<strftime()> routine.

The plugin can be loaded via the familiar USE directive.

    [% USE date %]

This creates a plugin object with the default name of 'C<date>'.  An alternate
name can be specified as such:

    [% USE myname = date %]

The plugin provides the C<format()> method which accepts a time value, a
format string and a locale name.  All of these parameters are optional
with the current system time, default format ('C<%H:%M:%S %d-%b-%Y>') and
current locale being used respectively, if undefined.  Default values
for the time, format and/or locale may be specified as named parameters 
in the C<USE> directive.

    [% USE date(format = '%a %d-%b-%Y', locale = 'fr_FR') %]

When called without any parameters, the C<format()> method returns a string
representing the current system time, formatted by C<strftime()> according 
to the default format and for the default locale (which may not be the
current one, if locale is set in the C<USE> directive).

    [% date.format %]

The plugin allows a time/date to be specified as seconds since the epoch,
as is returned by C<time()>.

    File last modified: [% date.format(filemod_time) %]

The time/date can also be specified as a string of the form C<h:m:s d/m/y>
or C<y/m/d h:m:s>.  Any of the characters : / - or space may be used to
delimit fields.

    [% USE day = date(format => '%A', locale => 'en_GB') %]
    [% day.format('4:20:00 9-13-2000') %]  

Output:

    Tuesday

A format string can also be passed to the C<format()> method, and a locale
specification may follow that.

    [% date.format(filemod, '%d-%b-%Y') %]
    [% date.format(filemod, '%d-%b-%Y', 'en_GB') %]

A fourth parameter allows you to force output in GMT, in the case of 
seconds-since-the-epoch input:

    [% date.format(filemod, '%d-%b-%Y', 'en_GB', 1) %]

Note that in this case, if the local time is not GMT, then also specifying
'C<%Z>' (time zone) in the format parameter will lead to an extremely 
misleading result.

To maintain backwards compatibility, using the C<%z> placeholder in the format
string (to output the UTC offset) currently requires the C<use_offset>
parameter to be set to a true value. This can also be passed as the fifth
parameter to format (but the former will probably be clearer).

Any or all of these parameters may be named.  Positional parameters
should always be in the order C<($time, $format, $locale)>.

    [% date.format(format => '%H:%M:%S') %]
    [% date.format(time => filemod, format => '%H:%M:%S') %]
    [% date.format(mytime, format => '%H:%M:%S') %]
    [% date.format(mytime, format => '%H:%M:%S', locale => 'fr_FR') %]
    [% date.format(mytime, format => '%H:%M:%S', gmt => 1) %]
    ...etc...

The C<now()> method returns the current system time in seconds since the 
epoch.  

    [% date.format(date.now, '%A') %]

The C<calc()> method can be used to create an interface to the C<Date::Calc>
module (if installed on your system).

    [% calc = date.calc %]
    [% calc.Monday_of_Week(22, 2001).join('/') %]

The C<manip()> method can be used to create an interface to the C<Date::Manip>
module (if installed on your system).

    [% manip = date.manip %]
    [% manip.UnixDate("Noon Yesterday","%Y %b %d %H:%M") %]

=head1 AUTHORS

Thierry-Michel Barral wrote the original plugin.

Andy Wardley provided some minor
fixups/enhancements, a test script and documentation.

Mark D. Mills cloned C<Date::Manip> from the C<Date::Calc> sub-plugin.

=head1 COPYRIGHT

Copyright (C) 2000-2007 Thierry-Michel Barral, Andy Wardley.

This module is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

=head1 SEE ALSO

L<Template::Plugin>, L<POSIX>