use warnings;
use strict;

use threads;
use threads::shared;

use Time::HiRes qw(usleep);
use Try::Tiny;
use DBI;



my $succeded_count = 0;
my $no_of_retries = 0;
share($succeded_count);
share($no_of_retries);

sub transaction($$$){
    my ($sleep_milisec, $retry, $no_of_threads) = @_;

    my $dbh;
    $no_of_retries++;
    try
    {
        $dbh = DBI->connect("DBI:Pg:dbname=paralel_transaction_test;host=localhost", "transact_tester", "123", {RaiseError => 1, AutoCommit => 0}) or die $DBI::errstr;
        my $sth = $dbh->prepare(q{
            SELECT * FROM foo
        }) or die $dbh->errstr;
        $sth->execute() or die $dbh->errstr;

        usleep($sleep_milisec);

        $sth = $dbh->prepare(q{
            UPDATE foo SET name = name || ? WHERE id = ?
        }) or die $dbh->errstr;
        $sth->execute(int(rand(9)) + 1, int(rand($no_of_threads))) or die $dbh->errstr;

        usleep($sleep_milisec);

        $sth = $dbh->prepare(q{
            SELECT * FROM foo
        }) or die $dbh->errstr;
        $sth->execute() or die $dbh->errstr;
        $sth->finish;
        $dbh->commit() or die $dbh->errstr;

        $dbh->disconnect();
        $succeded_count++;
    }
    catch
    {
       # $dbh->rollback();
        print "FAILED\n";
        $no_of_retries++;
        if(defined $dbh)
        {
            $dbh->rollback();
            $dbh->disconnect();
        }
        if($retry)
        {
            transaction($sleep_milisec, $retry, $no_of_threads);
        }
    }
}

if(!defined $ARGV[0] || !defined $ARGV[1] || !defined $ARGV[2])
{
    die "Incorrect Input.
            Usage:
            perl test.pl <option> <no_of_paralel_transactions> <wait_betwean_queries_milisec>

        Options:
            -s get the number of succeeded calls without retrying
            -r get the number of retries needed to finish all transactiosns\n";
}

my $mode = $ARGV[0];
my $no_of_threads = $ARGV[1];
my $sleep_milisec = $ARGV[2];

my $retry = 0;
if($mode eq "-r")
{
    $retry = 1;
}

my @arr;
for(my $i = 0; $i < $no_of_threads; $i++)
{
    push @arr, threads->create(\&transaction, $sleep_milisec, $retry, $no_of_threads);
}

foreach my $thread (@arr)
{
    $thread->join();
}

print "succeeded: $succeded_count/$no_of_threads \n";

if($retry)
{
    print "retries needed: $no_of_retries \n";
}