#!/usr/bin/perl
#
# Copyright © 2013 Jonas Smedegaard <dr@jones.dk>
# Description: render events webpage from RDF data
#
# This program 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 3, 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.  If not, see <http://www.gnu.org/licenses/>.

use 5.010;
use strictures 1;
use utf8::all;
#use DDP alias => 'Dumper';

use DateTimeX::Easy;
use DateTime::Format::W3CDTF;
use Carp;
use Try::Tiny;
use RDF::Trine 1.006; # we need proper IRI and punycode URI support
use RDF::Query;
use RDF::TrineX::Functions qw[curie model parse];
use HTML::HTML5::Builder qw[:standard];
use HTML::HTML5::Writer;

# TODO: add options --verbose and --debug

# TODO: add override options --from, --through and --theme
#my $globalfrom = DateTimeX::Easy->new('now');
# TODO: teach DTX::Easy / DT::F::Natural DT::F::Flexible words "current" and "present" (as alternatives to this)
my $globalfrom = DateTimeX::Easy->new('first day of this month');
# TODO: teach DTX::Easy / DT::F::Natural DT::F::Flexible these:
#  last day of month three months from now
#  last day of month in three months
#  last day of (the) month three months ahead
#  ... in the future
#  ... into the future
#  ... from now
#  ... later <- this last one for changing object, not create new
#my $globalthrough = DateTimeX::Easy->new('last day of month in 3 months');
my $globalthrough = DateTimeX::Easy->new($globalfrom);
$globalthrough->add( months => 4 )->subtract( days => 1 );

# TODO: add Getopt option --preset as shortcut to --category, --from and --through

my $parser = RDF::Trine::Parser::Turtle->new;
my $model = model();

# TODO: throw sensible error if no (non-opt) args provided
while (my $data = shift @ARGV) {
	try {
		parse($data, using => $parser, into => $model);
	} catch {
		say STDERR "Failed to parse file \"$data\": $_";
		die;
	}
}

# TODO: handle multi-site events-in-events (e.g. Orødagen)

# compose query for hourspec data at least partly within a "window" of time
# (yes, comparing global dates against opposite spec dates is deliberate)
my $w3c = DateTime::Format::W3CDTF->new;
my $globalfrom_w3c = $w3c->format_datetime($globalfrom);
my $globalthrough_w3c = $w3c->format_datetime($globalthrough);
# TODO: restructure SPARQL query to only need injecting each date once
my $query = qurie( sprintf(<<'SPARQL', $globalfrom_w3c, $globalthrough_w3c, $globalfrom_w3c, $globalthrough_w3c ));
SELECT *
WHERE {
	?event
		a schema:SocialEvent ;
		schema:name ?eventname ;
		schema:location ?place ;
		schema:startDate ?start .
	?place
		a schema:Place ;
		gr:name|schema:name ?placename .
	OPTIONAL {
		?event schema:endDate ?end .
	}
	OPTIONAL {
		?event foaf:Homepage ?eventpage .
	}
	OPTIONAL {
		{ ?organizer a schema:Organization }
		UNION
		{ ?organizer a gr:BusinessEntity }
		?organizer
			gr:name|schema:name ?organizername ;
			schema:event ?event .
		OPTIONAL {
			?organizer foaf:Homepage ?organizerpage .
		}
	}
	OPTIONAL {
		{ ?host a schema:Organization }
		UNION
		{ ?host a gr:BusinessEntity }
		?host
			gr:name|schema:name ?hostname ;
			schema:location ?place .
		OPTIONAL {
			?host foaf:Homepage ?hostpage .
		}
	} .
	FILTER (
		( ! bound(?end) && ?start >= "%s"^^xsd:dateTime && ?start <= "%s"^^xsd:dateTime )
	||
		( ?start < ?end && ?end > "%s"^^xsd:dateTime && ?start <= "%s"^^xsd:dateTime )
	)
}
ORDER BY ?start ?eventname ?placename
SPARQL
#	FILTER ( ?start > "%s"^^xsd:dateTime && ?start <= "%s"^^xsd:dateTime )

my $title = 'Begivenheder';
my $intro = sprintf(
	'Begivenheder på Orø i perioden %s.',
	daterangedescribe($globalfrom, $globalthrough),
);

# TODO: make simplified html (preferred for Scribus) optional
#push my @content, "\n", h1($title), p($intro);
push my @content, "\n", h1($title), $intro;

my $iterator = $query->execute($model);
while ( my $row = $iterator->next ) {

	# TODO: iterate over potentially plural entries
	# TODO: include also foaf:page, and support multiple pages
	# TODO: handle dcterms:audience (including lack thereof)
	push @content, "\n", h2($row->{eventname}->literal_value);
	push @content, thingdescribe( 'Begivenhed', daterangedescribe( $row->{start}->datetime, $row->{end} ? $row->{end}->datetime : '' ), node2uri($row->{eventpage}) );
	push @content, objectdescribe( 'Sted', $row->{placename}, $row->{placepage} );
	push @content, objectdescribe( 'Vært', $row->{hostname}, $row->{hostpage} );
	push @content, objectdescribe( 'Arrangør', $row->{organizername}, $row->{organizerpage} );
}

my $writer = HTML::HTML5::Writer->new;
say $writer->document( html(
	-lang => 'da',
	head(
		title($title),
		Meta(-charset => 'utf-8'),
	),
	body(
		@content
	),
));

# create query object from curied SPARQL string
sub qurie {
	my $sparql = shift;
	$sparql =~ s/\b([a-z]+):([a-zA-Z]+)\b/curie("$1_$2")/eg;
	my $query = RDF::Query->new( $sparql );
	if (!$query) {
		say STDERR $sparql;
		say STDERR RDF::Query->error;
		croak "failed to prepare SPARQL query";
	}
	return $query;
}

sub daterangedescribe {
	my ($from, $through) = @_;

	return $from->format_cldr('d/M')
		unless ($through);
	return sprintf( '%s - %s',
		$from->format_cldr('d/M'),
		$through->format_cldr('d/M'),
	);
}

sub thingdescribe {
	my ($title, $thing, $uri) = @_;
	my $string;

	return undef unless ($thing);

	$string = ($uri)
		? a('-href', $uri, $thing)
		: $thing;

	return "\n", br, div( "$title: ", $string );
}

sub objectdescribe {
	my ($title, $thing, $urinode) = @_;

	return undef unless ($thing);

	return thingdescribe( $title, $thing->literal_value, node2uri($urinode) );
}

sub node2uri {
	my $node = shift;

	return ($node) ? $node->uri_value : undef;
}

1;