#!/usr/bin/perl
#
# import-scheduler
#
# This module is responsible for scheduling import jobs.  This takes care of
# the hairy logic and dependencies so we don't have to do that in TheSchwartz.
#
# Authors:
#      Mark Smith <mark@dreamwidth.org>
#
# Copyright (c) 2009 by Dreamwidth Studios, LLC.
#
# This program is free software; you may redistribute it and/or modify it under
# the same terms as Perl itself. For a copy of the license, please reference
# 'perldoc perlartistic' or 'perldoc perlgpl'.
#

use strict;
BEGIN {
    require "$ENV{LJHOME}/cgi-bin/ljlib.pl";
}

use Time::HiRes qw/ gettimeofday tv_interval /;
use Getopt::Long;

$| = 1;  # Line buffered.
my $DEBUG = 0;
sub _log {
    my $txt = "[$$] " . sprintf( shift() . "\n", @_ );

    if ( $DEBUG ) {
        print $txt;
    } else {
        open FILE, ">>$ENV{LJHOME}/logs/import-scheduler.log" or die;
        print FILE $txt;
        close FILE;
    }

    return undef;
}

sub worker_helper {
    eval { worker(); };
    if ( my $msg = $@ ) {
        $msg =~ s/\r?\n/ /g;
        _log( "worker died: %s", $msg );
        exit 1;
    }
}

sub worker {
    LJ::start_request();

    my $dbh = LJ::get_db_writer()
        or die "no global master database handle available";

    my ( $userid, $impid ) = $dbh->selectrow_array(
        q{SELECT userid, import_data_id FROM import_items WHERE status = 'ready'
          ORDER BY priority DESC
          LIMIT 1}
    );
    die $dbh->errstr . "\n" if $dbh->err;

    return _log( "nothing to do" )
        unless $userid;

    my $u = LJ::load_userid( $userid )
        or die "userid $userid doesn't exist\n";
    _log( 'user %s(%d) has stuff to import', $u->user, $u->id );

    # now load up and ensure this is their most recent import group
    my $maxid = $dbh->selectrow_array(
        q{SELECT MAX(import_data_id) FROM import_items WHERE userid = ?},
        undef, $userid
    );
    if ( $maxid > $impid ) {
        _log( 'user %s(%d) had stuff to import but it was aborted', $u->user, $u->id );
        $dbh->do( q{UPDATE import_items SET status = 'aborted'
                    WHERE userid = ? AND import_data_id = ? AND status = 'ready'},
                  undef, $userid, $impid );
        return;
    }

    my $statusrows = $dbh->selectall_arrayref(
        q{SELECT item, status, created, import_data_id, priority
          FROM import_items WHERE userid=?},
        undef, $u->id
    );
    die $dbh->errstr . "\n" if $dbh->err;
    die "user had no status rows!\n" unless @{ $statusrows || [] };

    my @status = (
        map {
            {
                item => $_->[0],
                status => $_->[1],
                created => $_->[2],
                impid => $_->[3],
                priority => $_->[4]
            }
        } @$statusrows
    );

# FIXME: handle the case where the user already has an import_job going and it's
# different from the current import_data_id that we are trying to import for.
# if we don't handle this case, we're going to get pretty confused about what
# to update later...

    # now find the ready jobs, dispatch them
    foreach my $item ( @status ) {

        next if $item->{status} ne 'ready';

        _log( 'scheduling %d:%s', $item->{impid}, $item->{item} );

        my $class = {
            lj_bio => 'DW::Worker::ContentImporter::LiveJournal::Bio',
            lj_tags => 'DW::Worker::ContentImporter::LiveJournal::Tags',
            lj_entries => 'DW::Worker::ContentImporter::LiveJournal::Entries',
            lj_comments => 'DW::Worker::ContentImporter::LiveJournal::Comments',
            lj_userpics => 'DW::Worker::ContentImporter::LiveJournal::Userpics',
            lj_friends => 'DW::Worker::ContentImporter::LiveJournal::Friends',
            lj_friendgroups => 'DW::Worker::ContentImporter::LiveJournal::FriendGroups',
            lj_verify => 'DW::Worker::ContentImporter::LiveJournal::Verify',
        }->{ $item->{item} } || die 'unknown item ';

        my $sh = LJ::theschwartz()
            or die "no schwartz client\n";

        my $job = TheSchwartz::Job->new(
            funcname => $class,
            uniqkey => join( '-', ( $item->{item}, $u->id ) ),
            arg => {
                userid         => $u->id,
                import_data_id => $item->{impid},
            }
        ) or die "can't create job\n";

        my $h = $sh->insert( $job );
        unless ( $h ) {
            # best guess is that this is a dupe, so abort it
            _log( 'looks like they already have %s queued, aborting this one', $item->{item} );
            $dbh->do( q{UPDATE import_items SET status = 'aborted'
                      WHERE userid = ? AND import_data_id = ? AND item = ? AND status = 'ready'},
                      undef, $u->id, $item->{impid}, $item->{item} );
            return;
        }

        $u->set_prop( import_job => $item->{impid} );

        $dbh->do( "UPDATE import_items SET status = 'queued', last_touch = UNIX_TIMESTAMP() " .
                  "WHERE userid = ? AND item = ? AND import_data_id = ?",
                  undef, $u->id, $item->{item}, $item->{impid} );
        die $dbh->errstr . "\n" if $dbh->err;
    }
}

# run the job in a loop
while ( 1 ) {
    my $once = 0;
    GetOptions( 'verbose' => \$DEBUG, 'once' => \$once );

    worker_helper();
    last if $once;

    sleep 1;
}