#ifndef ALSK_ALSK_CONTEXT_CONTEXT_H
#define ALSK_ALSK_CONTEXT_CONTEXT_H

#include <functional>
#include <tuple>
#include <vector>

#include <random>

#include "../skeleton/link/args/placeholders.h"

namespace alsk {

template<typename RNG>
class Context {
public:
	using Id    = std::size_t;

	using Args  = std::tuple<Id, RNG&>;

	using Seed  = decltype(+RNG::default_seed);

private:
	Id _idCount;

	std::vector<RNG> _rng;
	std::vector<Args> _args;

public:
	Seed seed;

public:
	constexpr Context(): _idCount{0}, seed{RNG::default_seed} {}

	void setup(Id idCount = 30) {
		if(idCount <= _idCount) return;
		Id baseId = _idCount;
		_idCount = idCount;

		RNG seeder{seed};

		_rng.reserve(idCount);
		for(Id id = baseId; id < idCount; ++id)
			_rng.emplace_back(seeder());

		_args.reserve(idCount);
		for(Id id = baseId; id < idCount; ++id)
			_args.emplace_back(id, std::ref(_rng[id]));
	}

	void reset() {
		RNG seeder{seed};

		_rng.clear();
		for(Id id = 0; id < _idCount; ++id)
			_rng.emplace_back(seeder());

		_args.clear();
		for(Id id = 0; id < _idCount; ++id)
			_args.emplace_back(id, std::ref(_rng[id]));
	}

	constexpr Id maxId() const noexcept { return _idCount; }

	Args& args(Id const& id) { return _args[id]; }

	~Context() noexcept {}
};

using DefaultContext = Context<std::mt19937>;

namespace arg {

/**
 * CtxId
 * to get own's context identifier
 */
using CtxId = C<0>;

/**
 * RNG
 * for random number generator
 */
using RNG = C<1>;

}

}

#endif