use Modern::Perl;

return {
    bug_number => 30571,
    description => "Table z3950servers: three cols NOT NULL",
    up => sub {
        my ($args) = @_;
        my ($dbh, $out) = @$args{qw(dbh out)};

        # Preliminary data checks
        my $sql = "SELECT COUNT(*) FROM z3950servers WHERE host IS NULL";
        my ($cnt) = $dbh->selectrow_array($sql);
        if( $cnt ) { # No host is really bad data! Remove it.
            $dbh->do( "DELETE FROM z3950servers WHERE host IS NULL" );
            say $out "Found bad data in table z3950servers: removed $cnt records with host undefined";
        }
        $sql = "SELECT host FROM z3950servers WHERE syntax IS NULL OR encoding IS NULL";
        my $hosts = $dbh->selectcol_arrayref($sql);
        if( @$hosts ) { # This is bad data too. We choose a default here.
            $dbh->do( q|UPDATE z3950servers SET syntax = COALESCE(syntax, 'USMARC'), encoding = COALESCE(encoding, 'utf8')
                WHERE syntax IS NULL OR encoding IS NULL| );
            say $out "Corrected empty syntax or encoding for the following hosts. Please check after upgrade.";
            say $out "Updated hosts: ". (join ',', @$hosts);
        }

        # Actual dbrev
        $dbh->do(q{
alter table z3950servers
    change column `host` `host` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL COMMENT 'target''s host name',
    change column `syntax` `syntax` varchar(80) COLLATE utf8mb4_unicode_ci NOT NULL COMMENT 'MARC format provided by this target',
    change column `encoding` `encoding` mediumtext COLLATE utf8mb4_unicode_ci NOT NULL COMMENT 'characters encoding provided by this target';
        });
    },
};