package Lire::Timegroup;

use strict;

use base qw/ Lire::Aggregator /;

use Carp;
use POSIX qw/ setlocale strftime LC_TIME /;

use Lire::DataTypes qw/ check_duration daily_duration duration2sec
                        monthly_duration weekly_duration yearly_duration/;
use Lire::Utils qw/ sql_quote_name check_param /;

=pod

=head1 NAME

Lire::Timegroup - Base class for implementation of the timegroup aggregator

=head1 SYNOPSIS

    use Lire::Timegroup;

=head1 DESCRIPTION

This module is the base class for implementation of the timegroup
aggregator. This aggregator will split the DLF records based on a time
period controlled throught the period attribute. For example, using 1d
as the period value, this aggregator will group all records in the
same day period together.

=head1 CONSTRUCTOR

=head2 new( %params )

Creates a new instance of a timegroup aggregator. In addition to the
normal report operator parameters, the timegroup aggregator can take
several parameters:

=over

=item field

This optional parameter contains the DLF field which contains the time
value used to group the DLF records together. See the field() method
for more information.

=item period

This mandatory parameter should contains the period's length that will
be used to group the records. See the period() method for more
information.

=back

=cut

sub new {
    my ( $class, %params ) = @_;

    check_param( $params{'period'}, 'period' );

    my $self = bless {}, $class;
    $self->SUPER::init( %params, 'op' => "timegroup" );

    $self->field( $params{'field'} );
    $self->period( $params{'period'} );

    return $self;
}

=pod

=head1 METHODS

=head2 field( [$new_field] )

Returns the DLF field's name that is used to group the DLF records.
This should be a valid timestamp DLF field in the current schema. By
default, the default timestamp field of the DLF schema is used.

You can change the field by passing a $new_field parameter.

=cut

sub field {
    my ( $self, $field ) = @_;

    if (@_ == 2 ) {
	if ( defined $field ) {
	    croak "'$field' isn't a valid field for the specification's schemas"
		unless $self->report_spec()->has_field( $field );

	    croak "'$field' isn't a timestamp field"
	      unless $self->report_spec()->field( $field )->type()
		eq "timestamp";

	} else {
	    $field = $self->report_spec()->schema()->timestamp_field()->name();
	}
	$self->{'field'} = $field;
    }

    return $self->{'field'};
}

=pod

=head2 period( [$new_period])

Returns the period's length in which the records are grouped. This can
either be a duration value or the name of a report specification's
parameter containing a duration value.

The period's length can be changed by using the $new_period parameter.

=cut

sub period {
    my ( $self, $period ) = @_;

    if (@_ == 2 ) {
        check_param( $period, 'period' );

	if ( $period =~ /^\$/ ) {
	    my $name = substr $period, 1;
	    croak "parameter '$name' isn't defined"
	      unless $self->report_spec()->has_param( $name );

            my $type = $self->report_spec()->param( $name )->type();
	    croak "parameter '$name' isn't a 'duration' parameter: '$type'"
	      unless $type eq "duration";

	} else {
	    croak "'period' parameter isn't a valid duration: '$period'"
	      unless check_duration( $period );
	}

        my $value = $self->report_spec()->resolve_param_ref( $period );
        croak "can't use multiple with period of type 'd'"
          unless ( !daily_duration( $value ) || $value =~ m/^\s*1\s*d/ ); #1

	$self->{'period'} = $period;
    }

    return $self->{'period'};
}

# Implements Lire::ReportOperator::name
sub name {
    return "timegroup:" . $_[0]->{'field'};
}

# ------------------------------------------------------------------------
# Method create_categorical_info( $info )
#
# Implementation of the method required by Lire::Aggregator
sub create_categorical_info {
    my ( $self, $info ) = @_;

    my $dlf_field = $self->report_spec()->field( $self->field() );
    $info->create_column_info( $self->name(), 'categorical',
			       $dlf_field->type(), $self->label() );
}

# ------------------------------------------------------------------------
# Method xml_attrs( $info )
#
# Implementation of the method required by Lire::Aggregator
sub xml_attrs {
    my ( $self ) = @_;

    return "field=\"$self->{'field'}\" period=\"$self->{'period'}\"";
}

sub build_query {
    my ( $self, $query ) = @_;

    $self->SUPER::build_query( $query );

    my $period = $self->report_spec()->resolve_param_ref( $self->{'period'} );
    my ( $mult, $unit ) = $period =~ /(\d+)\s*(\w)/;
    my ($func, $param);
    if ( $unit eq 'y' ) {
        ( $func, $param ) = ('lr_timegroup_year', ",$mult" );
    } elsif ( $unit eq 'M' ) {
        ( $func, $param ) = ('lr_timegroup_month', ",$mult" );
    } elsif ( $unit eq 'w' ) {
        ( $func, $param ) = ('lr_timegroup_week', ",$mult" );
    } elsif ( $unit eq 'd' ) {
        ( $func, $param ) = ( 'lr_timegroup_day', '' );
    } else {
        $mult = duration2sec( $period );
        ( $func, $param ) = ('lr_timegroup_sec', ",$mult" );
    }

    $query->add_group_field( $self->name(),
                             sprintf( '%s(%s%s)', $func, 
                                      sql_quote_name( $self->{'field'} ),
                                      $param) );
    $query->set_sort_spec( $self->name() );

    return;
}

sub create_entry {
    my ( $self, $group, $row ) = @_;

    my $entry = $group->create_entry();
    my $value = $row->{ $self->name() };

    unless ( defined $value ) {
        $group->missing_cases( $row->{'_lr_nrecords'} );
        return undef;
    }

    my $period = $self->report_spec()->resolve_param_ref( $self->{'period'} );
    my $period_sec = duration2sec( $period );
    my ( $mult, $unit ) = $period =~ /(\d+)\s*(\w)/;

    my $fmt;
    if ( $unit eq 'y' ) {     $fmt = '%Y'; }
    elsif ( $unit eq 'M' ) {  $fmt = '%B %Y'; }
    elsif ( $unit eq 'w' ) {  $fmt = new Lire::WeekCalculator()->strformat(); }
    elsif ( $unit eq 'd' ) {  $fmt = '%Y-%m-%d'; }
    elsif ($self->_is_day_change( $group, $value ) ){ $fmt = '%Y-%m-%d %H:%M';}
    else {                    $fmt = '           %H:%M'; }

    my $old_locale = setlocale( LC_TIME, 'C' );
    $entry->add_name( strftime( $fmt, localtime $value), $value, $period_sec );
    setlocale( LC_TIME, $old_locale );

    return $entry;
}

sub _is_day_change {
    my ( $self, $group, $value ) = @_;

    my @entries = $group->entries();
    return 1 unless @entries > 1;

    # -1 is the entry currently being created
    my $name = $entries[-2]->data_by_name( $self->name() );

    my $new_day = (localtime $value)[3];
    my $old_day = (localtime $name->{'value'})[3];

    return $new_day != $old_day;
}

# Implements Lire::ReportOperator::init_merge()
sub init_merge {
    my $self = $_[0];

    $self->SUPER::init_merge();

    my $period = $self->report_spec()->resolve_param_ref( $self->period() );
    $self->{'period_sec'} = duration2sec( $period );
    my ( $multiple ) = $period =~ /^(\d+)/;

    if ( monthly_duration( $period ) ) {
        $self->{'helper'} =
          Lire::Timegroup::MonthHelper->new( $self->{'period_sec'}, $multiple);
    } elsif (weekly_duration( $period ) ) {
        $self->{'helper'} =
          Lire::Timegroup::WeekHelper->new( $self->{'period_sec'}, $multiple);
    } elsif ( yearly_duration( $period ) ) {
        $self->{'helper'} =
          Lire::Timegroup::YearHelper->new( $self->{'period_sec'}, $multiple );
    } else {
        $self->{'helper'} =
          Lire::Timegroup::SecHelper->new( $self->{'period_sec'}, $multiple );
    }

    $self->{'_merge_started'} = 0;

    return;
}

sub init_slice_data {
    my ( $self, $idx ) = @_;

    my $data = [ $self->{'helper'}->slice_start( $idx ) ];

    my $i = 1;
    foreach my $op ( @{$self->ops()} ) {
	$data->[$i++] = $op->init_group_data();
    }

    return $data;
}

# Implements Lire::Aggregator::init_aggregator_data()
sub init_aggregator_data {
    return [];
}

# Implements Lire::Aggregator::merge_aggregator_data()
sub merge_aggregator_data {
    my ( $self, $group, $timeslices ) = @_;

    # INVARIANT: entries are assumed to be sorted on timestamp and the
    # length attribute will be identical across all the entries. This
    # is respected by our create_group_entries() method
    my $first = 1;
    foreach my $e ( $group->entries() ) {
	my @names = $e->names();
	die "invalid number of names for a timegroup aggregator: ",
	  scalar @names, "\n"
	    if @names != 1;

	my $time = $names[0]{'value'};

	# Check period compatibility $self->{'start'}
	if ( $first ) {
	    my $length = $names[0]{'range'};

	    croak "incompatible merge: source period isn't compatible ",
	      "with new period: source=$length; target=$self->{'period_sec'}\n"
		if $self->{'period_sec'} < $length ||
		  $self->{'period_sec'} % $length;

	    $first = 0;
            unless ( $self->{'_merge_started'} ) {
                $self->{'helper'}->init( $time );
                $self->{'_merge_started'} = 1;
            }
	}

	my $idx = $self->{'helper'}->find_idx( $time );
        if ( $idx < 0 ) {
            unshift @$timeslices, (undef) x abs $idx;
            $self->{'helper'}->init( $time );
            $idx = 0;
        }

	my $data = $timeslices->[$idx];
	$timeslices->[$idx] = $data = $self->init_slice_data( $idx )
	  unless defined $data;

	my $i = 1;
	foreach my $op ( @{$self->ops()} ) {
	    my $value = $e->data_by_name( $op->name() );
	    my $op_data = $data->[$i++];
	    $op->merge_group_data( $value, $op_data )
	      if ( $value );
	}
    }

    return;
}

# Implements Lire::Aggregator::end_aggregator_data()
sub end_aggregator_data {
    my ( $self, $timeslices ) = @_;

    for ( my $i=0; $i < @$timeslices; $i++ ) {
        # Create empty set
        $timeslices->[$i] = $self->init_slice_data( $i )
          unless $timeslices->[$i];

        my $data = $timeslices->[$i];
        my $j = 1;
        foreach my $op ( @{$self->ops()} ) {
            $op->end_group_data( $data->[$j++] );
        }
    }
    return;
}

# Implements Lire::Aggregator::create_group_entries()
sub create_group_entries {
    my ( $self, $group, $timeslices ) = @_;

    foreach my $tslice ( @$timeslices ) {
        my $row = { $self->name() => $tslice->[0] };
	my $entry = $self->create_entry( $group, $row );

	my $i = 1;
	foreach my $op ( @{$self->ops()} ) {
	    $op->add_entry_value( $entry, $tslice->[$i++] );
	}
    }

    return;
}

package Lire::Timegroup::Helper;

sub new {
    my ( $class, $period, $multiple ) = @_;
    return bless { 'period' => $period,
                   'multiple' => $multiple,
                 }, $class;
}

package Lire::Timegroup::SecHelper;

use base qw/Lire::Timegroup::Helper/;

use Time::Timezone;
use POSIX qw/floor/;

sub init {
    my ( $self, $start ) = @_;

    $self->{'start'} = int( $start / $self->{'period'} ) * $self->{'period'};

    # The start of the period is offset by the timezone offset. We
    # need only do this once, because UTC doesn't have a standard vs.
    # daylight saving issue.
    my $offset = tz_local_offset( $self->{'start'} );
    $self->{'start'} -= $offset
      if abs($offset) < $self->{'period'};

    return;
}

sub find_idx {
    my ( $self, $time ) = @_;

    return floor( ($time - $self->{'start'}) / $self->{'period'} );
}

sub slice_start {
    my ( $self, $idx ) = @_;

    return $idx * $self->{'period'} + $self->{'start'};
}

package Lire::Timegroup::WeekHelper;

use base qw/Lire::Timegroup::Helper/;

use Lire::WeekCalculator;
use POSIX qw/floor/;

sub week_year {
    my ( $week_idx, $time ) = @_;

    my ( $month, $year ) = (localtime( $time ))[4,5];

    # ISO: Last week of December as week 01 of next year
    $year++ if $month == 11 && $week_idx == 0;

    # All: First week of january as week 52 or 53
    $year-- if $month == 0 && $week_idx > 50;

    return $year + 1900;
}

sub init {
    my ( $self, $start ) = @_;

    $self->{'week_calc'} = new Lire::WeekCalculator();
    $self->{'week_start'} = $self->{'week_calc'}->week_idx( $start );
    $self->{'year_start'} = week_year( $self->{'week_start'}, $start );

    return;
}

sub find_idx {
    my ( $self, $time ) = @_;

    my $week_idx = $self->{'week_calc'}->week_idx( $time );
    my $year = week_year( $week_idx, $time );

    my $year_diff = $year - $self->{'year_start'};
    my $idx;
    if ( $year_diff > 0 ) {
        $idx = -$self->{'week_start'};
        for ( my $i=$self->{'year_start'}; $i < $self->{'year_start'}; $i++ ) {
            $idx += $self->{'week_calc'}->last_week_of_year( $i );
        }
    } elsif ( $year_diff < 0 ) {
        $idx = -$self->{'week_start'};
        for ( my $i=$self->{'year_start'}-1; $i > $year; $i-- ) {
            $idx -= $self->{'week_calc'}->last_week_of_year( $i );
        }
        $idx -= $self->{'week_calc'}->last_week_of_year( $year ) - $week_idx;
    } elsif ( $year_diff == 0 && $week_idx < $self->{'week_start'} ) {
        $idx = - ( $self->{'week_start'} - $week_idx );
    } else {
        $idx = $week_idx - $self->{'week_start'};
    }

    return floor( $idx / $self->{'multiple'} );
}

sub slice_start {
    my ( $self, $idx ) = @_;

    my $week_idx = $idx * $self->{'multiple'};
    my $year = $self->{'year_start'};

    my $year_week = $self->{'week_calc'}->last_week_of_year( $year );
    if ( $week_idx > ( $year_week - $self->{'week_start'} ) ) {
        $week_idx -= $year_week - $self->{'week_start'};
        $year++;
        while ( $week_idx > $self->{'week_calc'}->last_week_of_year( $year ) )
        {
            $week_idx -= $self->{'week_calc'}->last_week_of_year( $year );
            $year++;
        }
    } else {
        $week_idx += $self->{'week_start'};
    }
    return $self->{'week_calc'}->week_start( $year, $week_idx + 1 );
}

package Lire::Timegroup::MonthHelper;

use base qw/Lire::Timegroup::Helper/;

use Time::Local;
use POSIX qw/floor/;

sub init {
    my ( $self, $start ) = @_;

    my ($month,$year) = (localtime( $start ))[4,5];
    $self->{'month_start'} = $month;
    $self->{'year_start'} = $year;

    return;
}

sub find_idx {
    my ( $self, $time ) = @_;

    my ($month,$year) = (localtime( $time ))[4,5];

    my $year_diff = $year - $self->{'year_start'};
    my $idx = 12 * $year_diff - $self->{'month_start'} + $month;

    return floor( $idx / $self->{'multiple'} );
}

sub slice_start {
    my ( $self, $idx ) = @_;

    my $month = $idx * $self->{'multiple'} + $self->{'month_start'};
    my $year_offset = int( $month / 12 );
    $month -= $year_offset * 12;
    return timelocal( 0, 0, 0, 1, $month,
                      $self->{'year_start'} + $year_offset );
}

package Lire::Timegroup::YearHelper;

use base qw/Lire::Timegroup::Helper/;

use Time::Local;
use POSIX qw/floor/;

sub init {
    my ( $self, $start ) = @_;

    $self->{'start'} = (localtime( $start ))[5];

    return;
}

sub slice_start {
    my ( $self, $idx ) = @_;

    my $year_off = $idx * $self->{'multiple'};
    return timelocal( 0, 0, 0, 1, 0, $self->{'start'} + $year_off );
}

sub find_idx {
    my ( $self, $time ) = @_;

    my $year = (localtime( $time ))[5];
    return floor( ($year - $self->{'start'}) / $self->{'multiple'} );
}

# keep perl happy
1;

__END__

=head1 SEE ALSO

 Lire::ReportSpec(3pm), Lire::Group(3pm), Lire::ReportOperator(3pm),
 Lire::Timeslot(3pm)

=head1 AUTHORS

  Francis J. Lacoste <flacoste@logreport.org>
  Wolfgang Sourdeau <Wolfgang.Sourdeau@Contre.COM>

=head1 VERSION

$Id: Timegroup.pm,v 1.33 2006/07/23 13:16:30 vanbaal Exp $

=head1 COPYRIGHT

Copyright (C) 2001-2004 Stichting LogReport Foundation LogReport@LogReport.org

This file is part of Lire.

Lire is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program (see COPYING); if not, check with
http://www.gnu.org/copyleft/gpl.html. 

=cut