package dbchgk;
use DBI;
use Exporter;
use locale;
use vars qw(@ISA @EXPORT);
@ISA=qw(Exporter);

@EXPORT = qw(&getbase &closebase &getrow $z &in2out &getall &out2in &mydo
             &getequalto &forbidden &getquestion &checktable);

my $z;
my $qbase;
BEGIN {do "chgk.cnf"; 	
          $qbase = DBI -> connect ("DBI:mysql:$base",'piataev','');
      };



sub getbase
{    
        my $a=join(", ",@_);
	$z=  $qbase -> prepare("select $a FROM Questions WHERE QuestionId<=$qnumber");
	$z -> execute;
}


sub getquestion
{    
        my $a=shift;
	$z=  $qbase -> prepare("select Question, Answer, Comments FROM Questions WHERE QuestionId=$a");
	$z -> execute;
          $z -> fetchrow;
}

sub getequalto
{    
	$z=  $qbase -> prepare("select first, second FROM equalto");
	$z -> execute;
	my %h;
	while ( my  ($first, $second)=$z -> fetchrow)
        {
            $h{$first}=$second;
        }
        $z -> finish;
        %h;
}



sub closebase
{
    $z -> finish;
    $qbase -> disconnect;
}

sub getrow
{
  $z -> fetchrow
}

sub mydo
{
  $qbase -> do (shift);
}

sub getall
{
  $z -> fetchall_arrayref;
}

sub in2out
{
   $qid=shift;


   $z=  $qbase -> prepare ( "select t2.Id, t2.Number, t3.FileName 
                from Questions AS t1, Tournaments AS t2 ,  Tournaments AS t3
                where (t1.QuestionId = $qid)  && (t1.ParentId = t2.Id) && (t2.ParentId = t3.Id) ");

   $z -> execute;
  ($tourid, $tourname, $filename)= $z -> fetchrow;


   $z=  $qbase -> prepare("select QuestionId  from Questions  WHERE ParentId = $tourid");

    $z -> execute;
    my $i;
    for ($i=1;  ($q= $z->fetchrow) && $q!=$qid; $i++){};

   $_=lc $_;
   $filename=~s/\.txt$//i;
   "$filename\.$tourname\.$i";
}



sub out2in
{
   @q= split(/\./, lc shift);

   $q[0].='.txt';

# 


   $z=  $qbase -> prepare ( "select q.QuestionId  from Questions as q, 
                Tournaments as t1, Tournaments as t2
                where (t2.FileName= \"$q[0]\")  && 
                      (t1.ParentId = t2.Id) && 
                      (q.ParentId = t1.Id)  && 
                      (t1.Number=\"$q[1]\")
            ");

   $z -> execute;
#   ($tourid)=$z -> fetchrow or die "Bad identifier". join (".", @q);

#   print "--$tourid--";

#   $z=  $qbase -> prepare("select QuestionId  from questions  WHERE ParentId = $tourid");

    my $i;
    $z -> execute;
    for ($i=1;  $i <= $q[2]; $i++){@qq= $z->fetchrow};

    $z -> finish;
    $qq[0];
}

sub forbidden
{
   keys %getequalto
}

sub checktable
{
	my ($TabName) = @_;
	my ($ans);
	if (scalar(grep(/^$TabName$/, &tablelist))) {
		print "Table $TabName exists. Do you want to delete it? ";
		$ans = <STDIN>;
		if ($ans =~ /[yY]/) {
			$qbase->do("DROP TABLE $TabName");
			print "deleted table $TabName\n";
			return 0;
		} else {
			return 1
		}
	}
 0	
}

sub tablelist
{
     $qbase->func( '_ListTables' );
}

1;