#!/usr/bin/perl

use strict;
use warnings;

use Getopt::Long;
use Pod::Usage;
use Path::Class qw(dir file);
use meon::Web::Config;
use XML::Chain qw(xc);
use DateTime;
use URI;
use URI::Escape qw(uri_escape);
use DateTime::Format::Strptime;
use HTML::Entities qw(encode_entities);
use File::MimeInfo qw(mimetype);
use 5.010;

our $MAX_FEED_ITEMS_COUNT = 20;

my $strptime_iso8601 = DateTime::Format::Strptime->new(
    pattern   => '%FT%T',
    time_zone => 'UTC',
    on_error  => 'undef',
);

exit main();

sub main {
    my $help;
    my $dst_domain;
    my $notify_email;
    my $author;
    my $title;
    GetOptions(
        'help|h'     => \$help,
        'hostname=s' => \$dst_domain,
        'title=s'    => \$title,
    ) or pod2usage;
    pod2usage if $help;
    pod2usage unless defined $dst_domain;
    pod2usage unless defined $title;

    my $hostname_folder = meon::Web::Config->hostname_to_folder($dst_domain);
    my $dst_hostname_dir =
        dir(meon::Web::SPc->srvdir, 'www', 'meon-web', $hostname_folder, 'content',);
    die 'no such hostname ' . $dst_domain unless $hostname_folder;

    my $channel =
        xc('rss', version => "2.0", 'xmlns:atom' => "http://www.w3.org/2005/Atom")->t("\n")
        ->set_io_any($dst_hostname_dir->file('rss.xml'))->c('channel')->t("\n")
        ->a('atom:link', href => 'https://'.$dst_domain.'/rss.xml', rel => 'self', type => 'application/rss+xml')->t("\n")
        ->a('title', '-' => $title)->t("\n")->a('link', '-' => 'http://' . $dst_domain . '/')
        ->t("\n")->a('description', '-' => 'news feed')->t("\n");
    my @feed_items;
    foreach my $year_dir (sort {$b cmp $a} $dst_hostname_dir->children) {
        next unless $year_dir->basename =~ m/^\d{4}$/;
        $year_dir->recurse(
            callback => sub {
                my ($file) = @_;
                return if $file->is_dir;
                return if $file !~ m/\.xml$/;
                my $rel_file = $file->stringify;
                $rel_file =~ s/(index)?\.xml$//;
                $rel_file =~ s/^$dst_hostname_dir//;
                return if $rel_file eq '/';
                return if $rel_file eq '/sitemap';

                my $content_xml = xc($file);
                $content_xml->reg_global_ns('w' => 'http://web.meon.eu/');
                my $tl_entry = $content_xml->find('/w:page/w:content//w:timeline-entry')->first;
                return unless $tl_entry->count;

                my $updated = $file->stat->mtime;
                my $created_iso8601 = $tl_entry->find('w:created')->text_content;
                my $created         = (
                    $created_iso8601
                    ? eval {$strptime_iso8601->parse_datetime($created_iso8601)->epoch}
                    : undef
                ) // $file->stat->mtime;
                warn $@.' - '.$file if $@;
                my $url =
                    URI->new('http://'
                        . $dst_domain
                        . join('/', map {uri_escape($_)} file($rel_file)->components));
                my $text = $tl_entry->find('w:text')->text_content;
                $text =~ s/^\s+//;
                $text =~ s/\s+$//;
                my $intro = $tl_entry->find('w:intro')->text_content;
                $intro =~ s/^\s+//;
                $intro =~ s/\s+$//;
                my $description = xc('div', xmlns => 'http://www.w3.org/1999/xhtml');
                my $img_thumb = $tl_entry->find('w:img-thumb')->text_content;
                my $enclosure;
                if ($img_thumb) {
                    my $thumb_abs = ($img_thumb =~ m{^/});
                    my $is_static = ($img_thumb =~ m{^/static});
                    my $is_extern = ($img_thumb =~ m{^(https?:)?//});
                    $img_thumb = 'http:'.$img_thumb
                        if $is_extern && !$1;
                    my $rel_link  = (
                          $thumb_abs
                        ? $img_thumb
                        : $rel_file . '/' . uri_escape($img_thumb)
                    );
                    if ($is_extern) {
                        $enclosure = {
                            url    => $img_thumb,
                        };
                    }
                    else {
                        my $img_file = file(
                            (     $is_static
                                ? $dst_hostname_dir->parent->subdir('www')
                                : $dst_hostname_dir
                            ),
                            ($thumb_abs ? () : $rel_file),
                            $img_thumb
                        );
                        my $mime = mimetype(file($img_thumb)->basename);
                        $enclosure = {
                            url    => 'http://' . $dst_domain . $rel_link,
                            length => $img_file->stat->size,
                            type   => $mime,
                        };
                    }
                    $description->c('div')->c('a', href => $url)->a('img', width => '32', height => '32', src=> $enclosure->{url});
                }
                $description->c('p')->c('i', '-' => $intro)
                    if $intro;
                if ($text) {
                    my @paras = split(/\n\n/, $text);
                    foreach my $para (@paras) {
                        $description->c('p', '-' => $para);
                    }
                }
                push(
                    @feed_items,
                    {   link        => $url,
                        created     => $created,
                        updated     => $updated,
                        title       => $tl_entry->find('w:title')->text_content,
                        description => $description,
                        enclosure   => $enclosure,
                    }
                );
            }
        );
        last if @feed_items >= $MAX_FEED_ITEMS_COUNT;
    }

    @feed_items = splice(@feed_items, 0, $MAX_FEED_ITEMS_COUNT);
    foreach my $feed_item (sort {$b->{created} <=> $a->{created}} @feed_items) {
        my $created = DateTime->from_epoch(epoch => $feed_item->{created});
        my $updated = DateTime->from_epoch(epoch => $feed_item->{updated});
        my $item = $channel->c('item')->t("\n");
        $item->a('title', '-' => $feed_item->{title})->t("\n")
            ->a('link', '-' => $feed_item->{link})->t("\n")->a('guid', '-' => $feed_item->{link})
            ->t("\n");
        $item->a('description', '-' => $feed_item->{description}->as_string)->t("\n")
            if $feed_item->{description};
        $item->a('enclosure', %{$feed_item->{enclosure}})->t("\n")
            if $feed_item->{enclosure};
        $item->a('pubDate',       '-' => $created->strftime('%a, %d %b %Y %H:%M:%S %z'))->t("\n");
        $channel->t("\n");
    }

    $channel->store;

    return 0;
}

=head1 NAME

meon-web-rss2-feed - generate content sitemap.xml

=head1 SYNOPSIS

    meon-web-rss2-feed --hostname domain
        --hostname domain   hostname
        --title $           title of the feed

=head1 DESCRIPTION


=cut