#!/usr/bin/env perl

use strict;
use warnings;
use autodie;

use constant SQL_STEP_INTERVAL => 1;

use IO::Select;
use POSIX qw{mkfifo};

use PM_1133400_Shared qw{:SQL};

sub _handle_death_signal {
    my $sig = shift;
    remove_fifo();
    die "\nSQL_SIM: Trapped and handled SIG$sig signal. Exiting.\n";
}

BEGIN {
    my @death_signals = qw{INT HUP};
    @SIG{@death_signals} = (\&_handle_death_signal) x @death_signals;

    remove_fifo();
    mkfifo FIFO, 0600;
}

END {
    remove_fifo();
}

my @steps = @{get_steps()};
my $step = $#steps;

{
    local $| = 1;

    if (fork) {
        open my $keep_alive_pipe_writer, '>', FIFO;
        wait;
        close $keep_alive_pipe_writer;
        exit;
    }

    open my $pipe_reader, '<', FIFO;
    my $select = IO::Select::->new();
    $select->add($pipe_reader);

    while (1) {
        while ($select->can_read(0)) {
            $step = <$pipe_reader>;
            chomp $step;
            print 'SQL_SIM: Executing web request: ';
            $steps[$step]->();
        }

        print 'SQL_SIM: Executing normal step: ';
        $step = ++$step % @steps;
        $steps[$step]->();
        sleep SQL_STEP_INTERVAL;
    }

    close $pipe_reader;
}