#pragma once

#include <deque>
#include <string>

#include <boost/process.hpp>

struct process
{
 process(const std::string& k, const std::string& command): key{k}, child{command} {}
 std::string key;
 boost::process::child child;
};

// runs a number of processes in parallel, with an upper limit
class ProcessRunner
{
public:
 ProcessRunner();

 void spawn(const std::string& key, const std::string& command);

 bool empty(); // number of running processes is zero
 bool full(); // number of running processes equals maximum

 int wait_one(std::string& key); // returns exit code, and key via reference
 int wait_all();

 size_t running(); // number of running processes in queue
 size_t finished(); // number of finished processes in queue

private:
 int _max_number_of_processes;
 std::deque<process> _processes;
};