Jifty::DateTime - a DateTime subclass that knows about Jifty users

  use Jifty::DateTime;

  # Get the current date and time
  my $dt = Jifty::DateTime->now;

  # Print out the pretty date (i.e., today, tomorrow, yesterday, or 2007-09-11)
  Jifty->web->out( $dt->friendly_date );

  # Better date parsing
  my $dt_from_human = Jifty::DateTime->new_from_string("next Saturday");

use warnings;
use strict;

package Jifty::DateTime;

BEGIN {
    # we spent about 30% of the time in validate during 'require
    # DateTime::Locale' which isn't necessary at all
    require Params::Validate;
    no warnings 'redefine';
    local *Params::Validate::validate = sub { pop @_, return @_ };
    require DateTime::Locale;
}

use base qw(Jifty::Object DateTime);

use Jifty::DBI::Schema;
Jifty::DBI::Schema->register_types(
    timestamp => sub {
        encode_on_select is 1,
        type is 'timestamp',
        filters are qw( Jifty::Filter::DateTime Jifty::DBI::Filter::DateTime ),
    },
);

sub new {
    my $class = shift;
    my %args  = (
        current_user     => undef,
        time_zone        => undef,
        input_time_zone  => undef,
        output_time_zone => undef,
        @_,
    );

    my ($input_time_zone, $output_time_zone);
    $input_time_zone = delete($args{input_time_zone})   || $args{time_zone};
    $output_time_zone = delete($args{output_time_zone}) || $args{time_zone};

    my $current_user = delete $args{current_user};

    my $self = $class->SUPER::new(%args, time_zone => $input_time_zone);

    my $is_date = $self->hms eq '00:00:00'
               && $self->time_zone->name eq 'floating';

    # The output time_zone is the *current user's* time zone. It's okay that
    # $current_user can be undef; we'll still find and set the right current
    # user then set the time zone.
    $self->current_user($current_user);

    if ($output_time_zone) {
        $self->set_time_zone($output_time_zone);
    }
    # If we were given a date, then we need to make sure its output time zone
    # is Floating and it's set to 00:00:00.
    # This sucks when you want a timestamp (not just a datestamp) at midnight
    # in the floating time zone but we don't have any better way to make this
    # work.
    elsif ($is_date) {
        $self->set_time_zone('floating');

        # Without this check we loop infinitely, because set_hour constructs
        # a new Jifty::DateTime object.
        if ($self->hms ne '00:00:00') {
            $self->set_hour(0);
            $self->set_minute(0);
            $self->set_second(0);
        }
    }

    return $self;
}

sub now {
    my $class = shift;
    my %args  = (
        current_user => undef,
        #time_zone => undef, # DateTime doesn't like undef time_zone
        @_,
    );

    my $current_user = delete $args{current_user};
    my $self = $class->SUPER::now(%args);

    $self->current_user($current_user);

    # We set time_zone here since saying
    # "Jifty::DateTime->now(time_zone => 'UTC')" is obviously referring the
    # output time zone; the input time zone doesn't matter at all.
    $self->set_time_zone($args{time_zone}) if $args{time_zone};

    return $self;
}

sub from_epoch {
    my $class = shift;

    # from_epoch(100) should dwim
    unshift @_, 'epoch' if @_ == 1;

    my %args  = (
        current_user => undef,
        #time_zone => undef, # DateTime doesn't like undef time_zone
        @_,
    );

    my $current_user = delete $args{current_user};
    my $self = $class->SUPER::from_epoch(%args);

    $self->current_user($current_user);

    # We set time_zone here since saying
    # "Jifty::DateTime->now(time_zone => 'UTC')" is obviously referring the
    # output time zone; the input time zone doesn't matter at all.
    $self->set_time_zone($args{time_zone}) if $args{time_zone};

    return $self;
}

sub current_user {
    my $self = shift;
    return $self->SUPER::current_user unless @_;

    # $date->current_user(undef) will not remove the current user, but it will
    # calculate who the current user is for setting the time zone
    if (@_ == 1 && !defined($_[0])) {
        shift;
        $self->_get_current_user;
    }

    my $ret = $self->SUPER::current_user(@_);

    $self->set_current_user_timezone();
    return $ret;
}

sub current_user_has_timezone {
    my $self = shift;

    # make this work as Jifty::DateTime->current_user_has_timezone
    my $dt = ref($self) ? $self : $self->now;

    $dt->_get_current_user();

    # Can't continue if we have no notion of a user_object
    $dt->current_user->can('user_object') or return;

    # Can't continue unless the user object is defined
    my $user_obj = $dt->current_user->user_object or return;

    # Check for a time_zone method and then use it if it exists
    my $f = $user_obj->can('time_zone') || $user_obj->can('timezone')
        or return;

    return $f->($user_obj);
}

sub set_current_user_timezone {
    my $self    = shift;
    my $default = shift || Jifty->config->framework('Timezone') || 'UTC';
    my $tz = $self->current_user_has_timezone || $default;

    $self->set_time_zone($tz);
    return $self;
}

sub set_current_user_time_zone { shift->set_current_user_timezone(@_) }

sub new_from_string {
    my $class  = shift;
    my $string = shift;
    return unless $string;
    my %args = (
        time_zone => undef,
        @_,
    );

    my $epoch;

    # Hack to use Date::Manip to flexibly scan dates from strings
    {
        # Date::Manip interprets days of the week (eg, ''Monday'') as
        # days within the *current* week. Detect these and prepend
        # ``next''
        # XXX TODO: Find a real solution (better date-parsing library?)
        if($string =~ /^\s* (?:monday|tuesday|wednesday|thursday|friday|saturday|sunday)$/xi) {
            $string = "next $string";
        }

        my $offset = $class->get_tz_offset(
            $args{time_zone} ? (time_zone => $args{time_zone}) : (),
        );

        my $dt_now = $class->now;
        my $now = $dt_now->ymd . '-' . $dt_now->hms;

        require Date::Manip;

        # TZ sets the timezone for parsing
        # ConvTZ sets the output timezone
        # ForceDate forces the current date to be now in the user's timezone,
        #    if we don't set it then DM uses the machine's timezone
        Date::Manip::Date_Init("TZ=$offset", "ConvTZ=+0000", "ForceDate=$now");
        $epoch = Date::Manip::UnixDate( $string, "%o" );
    }

    # Stop here if Date::Manip couldn't figure it out
    return undef unless $epoch;

    # Build a DateTime object from the Date::Manip value and setup the TZ
    my $self = $class->from_epoch( epoch => $epoch, time_zone => 'UTC' );
    if (my $tz = $self->current_user_has_timezone) {
        if ($self->hms(':') ne '00:00:00') {
            $self->set_time_zone($tz);
        }
        else {
            $self->set_time_zone("floating");
        }
    }

    return $self;
}

sub friendly_date {
    my $self = shift;
    my $ymd = $self->ymd;

    # Use the current user's time zone on the date
    my $tz = $self->current_user_has_timezone || $self->time_zone;
    my $rel = DateTime->now( time_zone => $tz );

    # Is it today?
    if ($ymd eq $rel->ymd) {
        return "today";
    }

    # Is it yesterday?
    my $yesterday = $rel->clone->subtract(hours => 24);
    if ($ymd eq $yesterday->ymd) {
        return "yesterday";
    }

    # Is it tomorrow?
    my $tomorrow = $rel->clone->add(hours => 24);
    if ($ymd eq $tomorrow->ymd) {
        return "tomorrow";
    }

    # None of the above, just spit out the date
    return $ymd;
}

sub is_date {
    my $self = shift;

    # all dates are in the floating time zone
    return 0 unless $self->time_zone->name eq 'floating';

    # all dates are set to midnight
    return 0 unless $self->hms eq '00:00:00';

    return 1;
}

sub get_tz_offset {
    my $self = shift;
    my %args = (
        datetime  => DateTime->now,
        time_zone => $self->current_user_has_timezone || 'UTC',
        @_,
    );

    my $dt = $args{datetime}->clone;

    $dt->set_time_zone($args{time_zone});
    return $dt->strftime("%z");
}

sub jifty_serialize_format {
    my $dt = shift;

    # if it looks like just a date, then return just the date portion
    return $dt->ymd if $dt->is_date;

    # otherwise let stringification take care of it
    return $dt;
}

1;