#!/usr/bin/perl

# Parameters:
#
# mark=id
#     mark item id as read
#
# redir=id
#    redirect to url of item id and mark item as read
#
# fls=(all|unread)
#    "feed list show": Show all feeds or only feeds with unread items in feed list
#
# fis= comma separated list of feed ids
#    show only listed feeds
#    BUG: fis is only effective if sr is non-zero!
#
# sr=n
#    show last n read items. Note: Currently these are the n read items with the 
#    highest ids, which may not be the last items which have been read. Need to
#    store the read date for that.
#
# so=1
#    also show old items.
#
# sl=1
#    show items marked as "later".


use strict;
use warnings;
use v5.14;
use utf8;
use experimental 'smartmatch'; # for given/when
use experimental 'autoderef';

use CGI;
use Cache::Memcached;
use DBI;
use Data::Dumper;
use Encode qw(encode_utf8 decode_utf8);
use POSIX qw(strftime);
use Rss2Html::Scrubber;
use Time::HiRes qw(time);

$| = 1;

my $start = time();

my $q = CGI->new();
binmode STDOUT, ":encoding(UTF-8)";
my $mcd = Cache::Memcached->new(servers => ['127.0.0.1:11211']);

if ($q->param('mark')) {
    mark();
} elsif ($q->param('redir')) {
    redirect();
} else {
    list();
}

sub redirect {
    my $dbh = DBI->connect("dbi:SQLite:dbname=rss2html.sqlite", "", "",
                           {
                            sqlite_use_immediate_transaction => 1,
                           });
    $dbh->{sqlite_unicode} = 1;
    my $item_id = $q->param('redir');
    my $item = $dbh->selectrow_hashref("select * from items where id=?", {}, $item_id);
    if ($item) {
	print "Status: 302\n";
	print "Location: $item->{link}\n";
	print "\n";
	$dbh->do("insert into read(user, item_id) values(?, ?)", {}, $q->remote_user, $item_id);
        $mcd->delete(item_info_key($q->remote_user, $item->{feed_id}));
	exit(0);
    }
    print "Status: 404\n";
    print "Content-Type: text/html; charset=utf-8\n";
    print "\n";
    print "not found\n";

}

sub mark {
    print_log("mark start");
    my $dbh = DBI->connect("dbi:SQLite:dbname=rss2html.sqlite", "", "");
    $dbh->{sqlite_unicode} = 1;
    my $item_id = $q->param('mark');
    my $item = $dbh->selectrow_hashref("select * from items where id=?", {}, $item_id);
    if ($item) {
        my $q1 = CGI->new($q);
        $q1->delete('mark');
	print "Status: 302\n";
	print "Location: ", $q1->self_url, "\n";
	print "\n";
	$dbh->do("insert into read(user, item_id) values(?, ?)", {}, $q->remote_user, $item_id);
        $mcd->delete(item_info_key($q->remote_user, $item->{feed_id}));
        print_log("mark done");
	exit(0);
    }
    print "Status: 404\n";
    print "Content-Type: text/html; charset=utf-8\n";
    print "\n";
    print "not found\n";
    print_log("mark failed");

}

sub list {

    my $feed_list_show = $q->param('fls') // "all";
    my $feed_item_show = $q->param('fis') // '';
    my $show_read = $q->param('sr');
    my $show_old = $q->param('so');
    my $show_later = $q->param('sl');
    my %feed_item_show = map(($_+0 => 1), split(/,/, $feed_item_show));


    print "Content-Type: text/html; charset=utf-8\n";
    print "Refresh: 600\n";
    print "\n";

    print "<meta name='viewport' content='width=device-width, initial-scale=1' />\n";
    print "<link rel='stylesheet' type='text/css' href='rss2html.css'/>\n";
    print "<h1>RSS 2 HTML</h1>\n";
    print "<div class='lastupdate'>", strftime("%Y-%m-%d %H:%M:%S%z", localtime()), "</div>\n";

    my $dbh = DBI->connect("dbi:SQLite:dbname=rss2html.sqlite", "", "");
    $dbh->{sqlite_unicode} = 1;

    print_log("list_feeds start");
    list_feeds($dbh, $feed_list_show, $show_old);
    print_log("list_feeds done");

    my $items;
    if ($show_read) {
        my $fields = "feeds.id as feed_id, feeds.title as feed_title, allow_img, link, items.title as item_title, content, items.id as item_id, issued, user, lang";
        my $tables = "items
		join feeds on items.feed_id=feeds.id
		left outer join read on (items.id=read.item_id and user=?)";
        my @where;
        if (%feed_item_show) {
            push @where, "feeds.id in (" . join(',', keys %feed_item_show) . ")";
        }
        if (!$show_old) {
            push @where, "(items.old is null or items.old == 0)"
        }

        my $where = "where " . join(" and ", @where);

        my $cmd = "select $fields from $tables $where order by issued";
        print_log("$cmd");
        my $items1 = $dbh->selectall_arrayref($cmd, { Slice => {} }, $q->remote_user);
        my $nrd = 0;
        while (@$items1) {
            my $item = pop @$items1;
            {
                no warnings 'uninitialized';
                print_log("id=$item->{item_id}, user=$item->{user}");
            }
            if (!$item->{user}) {
                print_log("id=$item->{item_id}: unread");
                unshift @$items, $item;
            } elsif ($nrd < $show_read) {
                print_log("id=$item->{item_id}: $nrd < $show_read");
                unshift @$items, $item;
                $nrd++;
            }
        }

    } else {
        my @where = ("user is null");

        if (!$show_old) {
            push @where, "(items.old is null or items.old == 0)"
        }

        my $where = "where " . join(" and ", @where);


	$items = $dbh->selectall_arrayref(
	    "select feeds.id as feed_id, feeds.title as feed_title, allow_img, link, items.title as item_title, content, items.id as item_id, issued, lang
	     from items
		join feeds on items.feed_id=feeds.id
		left outer join read on (items.id=read.item_id and user=?)
	     $where
	     order by issued",
	    { Slice => {} }, $q->remote_user);
    }
    my $feeds = $dbh->selectall_arrayref(
                        "select id, title from feeds where update_frequency is not null order by id",
                        { Slice => {} }
                      );
    for my $f (@$feeds) {
        $f->{selected} = 1 if $feed_item_show{$f->{id}};
    }
    print_itemlist($items, $feeds);
    print_log("list done");
}

sub print_itemlist {
    my ($items, $feeds) = @_;
    print "<div class='itemlist'>\n";
    print "<form action='./'>\n";
    print "<select name='fis'>\n";
    print "<option value=''>\n";
    for my $f (@$feeds) {
        print "<option value='" . $q->escapeHTML($f->{id}) . "' " . ($f->{selected} ? "selected='selected'" : "") .">" . $q->escapeHTML($f->{title}) . "</option>\n";
    }
    print "</select>\n";
    my $fls = $q->param('fls');
    print "<input type='hidden' name='fls' value='" . $q->escapeHTML($fls) . "'>\n" if defined $fls;
    print "<input type='hidden' name='sr' value='10'>\n";
    print "<input type='submit' value='»'>\n";
    print "</form>\n";
    my $n_items = 0;
    my $n_html_mcd = 0;
    my $n_scrub_mcd = 0;
    my $n_scrub = 0;
    print_log("print_itemlist: \$q=" . $q->self_url);
    my $q1 = CGI->new($q);
    print_log("print_itemlist: \$q1=" . $q1->self_url . " (before loop)");
    print_log(scalar @$items . " before remix");
    $items = remix($items);
    print_log(scalar @$items . " after remix");
    for my $item (@$items) {
        $n_items++;
        my $is_read = defined($item->{user});
        my $scrubbed_content = $mcd->get(scrubbed_content_key($item->{item_id}));
        if ($scrubbed_content) {
            $scrubbed_content = decode_utf8($scrubbed_content);
            $n_scrub_mcd++;
        } else {
            my $scrubber = Rss2Html::Scrubber->new(allow_img => $item->{allow_img});
            $scrubbed_content = $scrubber->scrub($item->{content});
            $mcd->set(scrubbed_content_key($item->{item_id}), encode_utf8($scrubbed_content), 3600);
            $n_scrub++;
        }
        $q1->param('mark', $item->{item_id});
        my $item_class = 'item' . ($is_read ? ' read' : '');
        my $langattr = defined $item->{lang} ? "lang='$item->{lang}'" : "";
        my $html = "";
        $html .= "<div class='$item_class' $langattr>\n";
        $html .= "<span class='itemno'>" . $item->{item_id} . "</span>\n";
        $html .= "<span class='issued'>" . strftime('%Y-%m-%d %H:%M:%S', localtime($item->{issued})) . "</span>\n";
        unless ($is_read) {
            print_log("print_itemlist: \$q1=" . $q1->self_url . " (in loop)");
            $html .= "<div class='op'><a href='" . $q->escapeHTML($q1->self_url) . "'>Mark read</a></div>\n";
        }
        $html .= "<div class='feed'>" . $q->escapeHTML($item->{feed_title}) . "</div>\n";
        $html .= "<h2><a href='./?redir=" . $q->escapeHTML($item->{item_id}) . "'>" . $q->escapeHTML($item->{item_title}) . "</a></h2>\n";
        $html .= "<div class='content'>" . $scrubbed_content . "</div>\n";
        unless ($is_read) {
            $html .= "<div class='op'><a href='" . $q->escapeHTML($q1->self_url) . "'>Mark read</a></div>\n";
        }
        $html .= "<div class='end'></div>\n";
        $html .= "</div\n>";
        print $html;

    }
    print "</div>\n";
    print_log("itemlist: $n_items items ($n_html_mcd html cached, $n_scrub_mcd scrubbed content cached, $n_scrub scrubbed)");
}

sub remix {
    my ($items) = @_;

    my $queues = {};
    for my $item (@$items) {
        if (!defined $item->{feed_id}) {
            local $Data::Dumper::Indent = 0;
            print_log("item w/o feed_id: " . Dumper($item));
        }
        $queues->{$item->{feed_id}} //= [];
        push $queues->{$item->{feed_id}}, $item;
    }
    my @ordered_feeds = sort { $queues->{$a}[0]{issued} <=> $queues->{$b}[0]{issued} } keys $queues;
    my $new_items = [];
    my $found;
    do {
        $found = 0;
        for my $feed (@ordered_feeds) {
            my $item = shift $queues->{$feed};
            if ($item) {
                push $new_items, $item;
                $found++;
                print_log("found an item in feed $feed. " . scalar(@{$queues->{$feed}}) . " items left")
            }
        }
    } while ($found);

    return $new_items;
}

sub list_feeds {
    my ($dbh, $feed_list_show, $show_old) = @_;

    no autovivification qw(fetch);

    my $q1 = CGI->new($q);
    my $other = $feed_list_show eq 'all' ? 'unread' : 'all';
    $q1->param('fls', $other);
    print "<div><a href='", $q->escapeHTML($q1->self_url), "'>$other</a></div>\n";
    print "<div class='feedlist'>\n";
    $dbh->begin_work;

    my $feeds = $dbh->selectall_arrayref("select * from feeds where update_frequency is not null", { Slice => {} });
    my $seconds_per_week = 86400 * 7;
    for my $feed (@$feeds) {
        $feed->{title} //= "-";
        print_item_info($dbh, $feed, $feed_list_show, $show_old);

    }
    $dbh->commit;

    print "</div>\n";
}


sub print_item_info {
    my ($dbh, $feed, $feed_list_show, $show_old) = @_;

    my $item_info_key = item_info_key($q->remote_user, $feed->{id});
    my $item_info = $mcd->get($item_info_key);
    my $cmd
        = "select count(i.id) as nr_items, max(i.issued) as last_issued, max(i.seen) as last_seen, count(r.item_id) as nr_read
           from items i left outer join (select item_id from read where user=?) r on i.id=r.item_id
           where i.feed_id=?";
    unless ($show_old) {
        $cmd .= " and (old is null or old = 0)";
    }
    unless ($item_info) {
        $item_info
            = $dbh->selectrow_hashref(
                $cmd,
                {},
                $q->remote_user, $feed->{id}
              );
        $mcd->set($item_info_key, $item_info, 3600);
    }
    my $now = time();
    my $unread = $item_info->{nr_items} - $item_info->{nr_read};
    print_log("print_item_info: feed $feed->{id}, nr_items=$item_info->{nr_items}, read=$item_info->{nr_read}, unread=$unread");
    return unless ($unread || $feed_list_show eq 'all');

    my $q1 = CGI->new($q);
    $q1->param('fis', $feed->{id});
    $q1->param('sr', 10);
    print "<span class='feed_info'>\n";
    print "<span class='feed_id'>", $q->escapeHTML($feed->{id}), "</span>\n";
    print "<span class='feed_title'>",
            "<a href='", $q1->escapeHTML($q1->self_url), "'>",
                $q->escapeHTML($feed->{title}),
            "</a>",
          "</span>\n";
    print "<span class='feed_items'>", $item_info->{nr_items}, "</span>\n";
    print "<span class='feed_unread'>", $unread, "</span>\n";
    print "<span class='feed_lastissued'>", delta_t($item_info->{last_issued}, $now), "</span>\n";
    print "<span class='feed_lastseen'>", delta_t($item_info->{last_seen}, $now), "</span>\n";
    print "</span>\n";
}


sub print_log {
    my $msg = "@_";
    my $now = time();
    printf STDERR "%s: %s.%06d %f: %s\n", $0, strftime("%H:%M:%S", localtime($now)), ($now - int($now)) * 1E6, $now - $start, $msg;
}

sub delta_t {
    my ($t1, $t2) = @_;
    return "N/A" unless defined $t1 && defined $t2;
    my $dt = $t2 - $t1;
    my $s = "";
    if ($dt < 0) {
	$s .= "-";
	$dt = -$dt;
    }
    given ($dt) {
	when ($_ >= 86400 * 10) {
	    $s .= sprintf("%.0fd", $_ / 86400);
	}
	when ($_ >= 86400) {
	    $s .= sprintf("%.1fd", $_ / 86400);
	}
	when ($_ >= 3600 * 10) {
	    $s .= sprintf("%.0fh", $_ / 3600);
	}
	when ($_ >= 3600) {
	    $s .= sprintf("%.1fh", $_ / 3600);
	}
	when ($_ >= 60 * 10) {
	    $s .= sprintf("%.0fm", $_ / 60);
	}
	when ($_ >= 60) {
	    $s .= sprintf("%.1fm", $_ / 60);
	}
	when ($_ >= 10) {
	    $s .= sprintf("%.0fs", $_);
	}
	default {
	    $s .= sprintf("%.1fs", $_);
	}
    }
}


sub item_info_key {
    my ($user, $feed_id) = @_;
    return "rss2html/item_info/$user/$feed_id";
}


sub scrubbed_content_key {
    my ($item_id) = @_;
    return "rss2html/scrubbed_content/$item_id";
}

sub item_html_key {
    my ($item_id, $is_read) = @_;
    return "rss2html/item_html/$item_id/$is_read";
}


# vim: tw=132 expandtab