#include "test.hpp"

#include "libtorrent/bandwidth_manager.hpp"
#include "libtorrent/bandwidth_queue_entry.hpp"
#include "libtorrent/bandwidth_limit.hpp"
#include "libtorrent/socket.hpp"
#include "libtorrent/stat.hpp"
#include "libtorrent/time.hpp"
#include "libtorrent/intrusive_ptr_base.hpp"

#include <boost/lexical_cast.hpp>

struct torrent;
struct peer_connection;

using namespace libtorrent;

const float sample_time = 6.f; // seconds

//#define VERBOSE_LOGGING


struct peer_connection: intrusive_ptr_base<peer_connection>
{
	typedef torrent torrent_type;

	peer_connection(io_service& ios, boost::shared_ptr<torrent> const& t
		, int prio, bool ignore_limits, std::string name);

	bool ignore_bandwidth_limits() { return m_ignore_limits; }
	int max_assignable_bandwidth(int channel) const
	{ return m_bandwidth_limit[channel].max_assignable(); }
	boost::weak_ptr<torrent> associated_torrent() const
	{ return m_torrent; }
	bool is_disconnecting() const { return m_abort; }
	void assign_bandwidth(int channel, int amount);
	void on_transfer(int channel, int amount);
	void start();
	void stop() { m_abort = true; }
	void expire_bandwidth(int channel, int amount);
	void tick();

	int bandwidth_throttle(int channel) const
	{ return m_bandwidth_limit[channel].throttle(); }

	void throttle(int limit) { m_bandwidth_limit[0].throttle(limit); }

	bandwidth_limit m_bandwidth_limit[1];
	boost::weak_ptr<torrent> m_torrent;
	int m_priority;
	bool m_ignore_limits;
	bool m_abort;
	libtorrent::stat m_stats;
	io_service& m_ios;
	std::string m_name;
	bool m_writing;
};

struct torrent
{
	torrent(bandwidth_manager<peer_connection, torrent>& m)
		: m_bandwidth_manager(m)
	{}

	void assign_bandwidth(int channel, int amount, int max_block_size)
	{
#ifdef VERBOSE_LOGGING
		std::cerr << time_now_string()
			<< ": assign bandwidth, " << amount << " blk: " << max_block_size << std::endl;
#endif
		TEST_CHECK(amount > 0);
		TEST_CHECK(amount <= max_block_size);
		if (amount < max_block_size)
			expire_bandwidth(channel, max_block_size - amount);
	}

	int bandwidth_throttle(int channel) const
	{ return m_bandwidth_limit[channel].throttle(); }

	int max_assignable_bandwidth(int channel) const
	{ return m_bandwidth_limit[channel].max_assignable(); }

	void request_bandwidth(int channel
		, boost::intrusive_ptr<peer_connection> const& p
		, int max_block_size
		, int priority)
	{
		TORRENT_ASSERT(max_block_size > 0);
		TORRENT_ASSERT(m_bandwidth_limit[channel].throttle() > 0);
		int block_size = (std::min)(m_bandwidth_limit[channel].throttle() / 10
			, max_block_size);
		if (block_size <= 0) block_size = 1;

		if (m_bandwidth_limit[channel].max_assignable() > 0)
		{
#ifdef VERBOSE_LOGGING
			std::cerr << time_now_string()
				<< ": request bandwidth " << block_size << std::endl;
#endif
			perform_bandwidth_request(channel, p, block_size, priority);
		}
		else
		{
#ifdef VERBOSE_LOGGING
			std::cerr << time_now_string()
				<< ": queue bandwidth request" << block_size << std::endl;
#endif
			// skip forward in the queue until we find a prioritized peer
			// or hit the front of it.
			queue_t::reverse_iterator i = m_bandwidth_queue[channel].rbegin();
			while (i != m_bandwidth_queue[channel].rend() && priority > i->priority)
			{
				++i->priority;
				++i;
			}
			m_bandwidth_queue[channel].insert(i.base(), bw_queue_entry<peer_connection, torrent>(
				p, block_size, priority));
		}
	}

	void expire_bandwidth(int channel, int amount);

	void perform_bandwidth_request(int channel
		, boost::intrusive_ptr<peer_connection> const& p
		, int block_size
		, int priority)
	{
		m_bandwidth_manager.request_bandwidth(p
			, block_size, priority);
		m_bandwidth_limit[channel].assign(block_size);
	}
	bandwidth_limit m_bandwidth_limit[1];
	typedef std::deque<bw_queue_entry<peer_connection, torrent> > queue_t;
	queue_t m_bandwidth_queue[1];
	bandwidth_manager<peer_connection, torrent>& m_bandwidth_manager;
};

peer_connection::peer_connection(io_service& ios, boost::shared_ptr<torrent> const& t
	, int prio, bool ignore_limits, std::string name)
	: m_torrent(t)
	, m_priority(prio)
	, m_ignore_limits(ignore_limits)
	, m_abort(false)
	, m_ios(ios)
	, m_name(name)
	, m_writing(false)
{}

void peer_connection::assign_bandwidth(int channel, int amount)
{
	TEST_CHECK(m_writing);
#ifdef VERBOSE_LOGGING
	std::cerr << time_now_string() << ": [" << m_name
		<< "] assign bandwidth, " << amount << std::endl;
#endif
	TEST_CHECK(amount > 0);
	m_bandwidth_limit[channel].assign(amount);
	m_ios.post(boost::bind(&peer_connection::on_transfer, self(), channel, amount));
}

void peer_connection::on_transfer(int channel, int amount)
{
	TEST_CHECK(m_writing);
	m_writing = false;
	m_stats.sent_bytes(amount, 0);

	boost::shared_ptr<torrent> t = m_torrent.lock();
	if (!t) return;
	if (m_bandwidth_limit[channel].max_assignable() > 0)
	{
		m_writing = true;
		t->request_bandwidth(0, this, 32 * 1024, m_priority);
	}
}

void peer_connection::start()
{
	boost::shared_ptr<torrent> t = m_torrent.lock();
	if (!t) return;
	m_writing = true;
	t->request_bandwidth(0, this, 32 * 1024, m_priority);
}

void peer_connection::expire_bandwidth(int channel, int amount)
{
	TEST_CHECK(amount > 0);
#ifdef VERBOSE_LOGGING
	std::cerr << time_now_string() << ": [" << m_name
		<< "] expire bandwidth, " << amount << std::endl;
#endif
	m_bandwidth_limit[channel].expire(amount);

	if (!m_writing && m_bandwidth_limit[channel].max_assignable() > 0)
	{
		boost::shared_ptr<torrent> t = m_torrent.lock();
		if (!t) return;
		m_writing = true;
		t->request_bandwidth(0, this, 32 * 1024, m_priority);
	}
}

void peer_connection::tick()
{
#ifdef VERBOSE_LOGGING
	std::cerr << time_now_string() << ": [" << m_name
		<< "] tick, rate: " << m_stats.upload_rate() << std::endl;
#endif
	m_stats.second_tick(1.f);
}


void torrent::expire_bandwidth(int channel, int amount)
{
#ifdef VERBOSE_LOGGING
	std::cerr << time_now_string()
		<< ": expire bandwidth, " << amount << std::endl;
#endif
	TEST_CHECK(amount > 0);
	m_bandwidth_limit[channel].expire(amount);
	queue_t tmp;
	while (!m_bandwidth_queue[channel].empty())
	{
		bw_queue_entry<peer_connection, torrent> qe = m_bandwidth_queue[channel].front();
		if (m_bandwidth_limit[channel].max_assignable() == 0)
			break;
		m_bandwidth_queue[channel].pop_front();
		if (qe.peer->max_assignable_bandwidth(channel) <= 0)
		{
			if (!qe.peer->is_disconnecting()) tmp.push_back(qe);
			continue;
		}
		perform_bandwidth_request(channel, qe.peer
			, qe.max_block_size, qe.priority);
	}
	m_bandwidth_queue[channel].insert(m_bandwidth_queue[channel].begin(), tmp.begin(), tmp.end());
}

typedef std::vector<boost::intrusive_ptr<peer_connection> > connections_t;

bool abort_tick = false;

void do_tick(asio::error_code const&e, deadline_timer& tick, connections_t& v)
{
	if (e || abort_tick)
	{
		std::cerr << " tick aborted" << std::endl;
		return;
	}
	std::for_each(v.begin(), v.end()
		, boost::bind(&peer_connection::tick, _1));
	tick.expires_from_now(seconds(1));
	tick.async_wait(boost::bind(&do_tick, _1, boost::ref(tick), boost::ref(v)));
}

void do_stop(deadline_timer& tick, connections_t& v)
{
	abort_tick = true;
	tick.cancel();
	std::for_each(v.begin(), v.end()
		, boost::bind(&peer_connection::stop, _1));
	std::cerr << " stopping..." << std::endl;
}

void do_change_rate(asio::error_code const&e, deadline_timer& tick
	, boost::shared_ptr<torrent> t1
	, boost::shared_ptr<torrent> t2
	, int limit
	, int counter)
{
	TEST_CHECK(!e);
	if (e) return;

	if (counter == 0)
	{
		t1->m_bandwidth_limit[0].throttle(limit);
		t2->m_bandwidth_limit[0].throttle(limit);
		return;
	}

	t1->m_bandwidth_limit[0].throttle(limit + limit / 2 * ((counter & 1)?-1:1));
	t2->m_bandwidth_limit[0].throttle(limit + limit / 2 * ((counter & 1)?1:-1));

	tick.expires_from_now(milliseconds(1600));
	tick.async_wait(boost::bind(&do_change_rate, _1, boost::ref(tick), t1, t2, limit, counter-1));
}

void do_change_peer_rate(asio::error_code const&e, deadline_timer& tick
	, connections_t& v
	, int limit
	, int counter)
{
	TEST_CHECK(!e);
	if (e) return;

	if (counter == 0)
	{
		std::for_each(v.begin(), v.end()
			, boost::bind(&peer_connection::throttle, _1, limit));
		return;
	}

	int c = counter;
	for (connections_t::iterator i = v.begin(); i != v.end(); ++i, ++c)
		i->get()->throttle(limit + limit / 2 * ((c & 1)?-1:1));

	tick.expires_from_now(milliseconds(1100));
	tick.async_wait(boost::bind(&do_change_peer_rate, _1, boost::ref(tick), boost::ref(v), limit, counter-1));
}

void run_test(io_service& ios, connections_t& v)
{
	abort_tick = false;
	std::cerr << "-------------" << std::endl;
	deadline_timer tick(ios);
	tick.expires_from_now(seconds(1));
	tick.async_wait(boost::bind(&do_tick, _1, boost::ref(tick), boost::ref(v)));

	deadline_timer complete(ios);
	complete.expires_from_now(milliseconds(int(sample_time * 1000)));
	complete.async_wait(boost::bind(&do_stop, boost::ref(tick), boost::ref(v)));

	std::for_each(v.begin(), v.end()
		, boost::bind(&peer_connection::start, _1));

	ios.run();
}

bool close_to(float val, float comp, float err)
{
	return fabs(val - comp) <= err;
}

void spawn_connections(connections_t& v, io_service& ios
	, boost::shared_ptr<torrent> t, int num, char const* prefix)
{
	for (int i = 0; i < num; ++i)
	{
		v.push_back(new peer_connection(ios, t, 200, false
			, prefix + boost::lexical_cast<std::string>(i)));
	}
}

void test_equal_connections(int num, int limit)
{
	std::cerr << "\ntest equal connections " << num << " " << limit << std::endl;
	io_service ios;
	bandwidth_manager<peer_connection, torrent> manager(ios, 0);
	manager.throttle(limit);

	boost::shared_ptr<torrent> t1(new torrent(manager));

	connections_t v;
	spawn_connections(v, ios, t1, num, "p");
	run_test(ios, v);

	float sum = 0.f;
	float err = (std::max)(limit / num * 0.3f, 1000.f);
	for (connections_t::iterator i = v.begin()
		, end(v.end()); i != end; ++i)
	{
		sum += (*i)->m_stats.total_payload_upload();

		std::cerr << (*i)->m_stats.total_payload_upload() / sample_time
			<< " target: " << (limit / num) << " eps: " << err << std::endl;
		TEST_CHECK(close_to((*i)->m_stats.total_payload_upload() / sample_time, limit / num, err));
	}
	sum /= sample_time;
	std::cerr << "sum: " << sum << " target: " << limit << std::endl;
	TEST_CHECK(sum > 0);
	TEST_CHECK(close_to(sum, limit, 50));
}

void test_connections_variable_rate(int num, int limit, int torrent_limit)
{
	std::cerr << "\ntest connections variable rate" << num
		<< " l: " << limit
		<< " t: " << torrent_limit
		<< std::endl;
	io_service ios;
	bandwidth_manager<peer_connection, torrent> manager(ios, 0);

	boost::shared_ptr<torrent> t1(new torrent(manager));
	if (torrent_limit)
		t1->m_bandwidth_limit[0].throttle(torrent_limit);

	connections_t v;
	spawn_connections(v, ios, t1, num, "p");
	std::for_each(v.begin(), v.end()
		, boost::bind(&peer_connection::throttle, _1, limit));

	deadline_timer change_rate(ios);
	change_rate.expires_from_now(milliseconds(1600));
	change_rate.async_wait(boost::bind(&do_change_peer_rate, _1, boost::ref(change_rate)
		, boost::ref(v), limit, 9));
	run_test(ios, v);

	if (torrent_limit > 0 && limit * num > torrent_limit)
		limit = torrent_limit / num;
	
	float sum = 0.f;
	float err = limit * 0.3f;
	for (connections_t::iterator i = v.begin()
		, end(v.end()); i != end; ++i)
	{
		sum += (*i)->m_stats.total_payload_upload();

		std::cerr << (*i)->m_stats.total_payload_upload() / sample_time
			<< " target: " << limit << " eps: " << err << std::endl;
		TEST_CHECK(close_to((*i)->m_stats.total_payload_upload() / sample_time, limit, err));
	}
	sum /= sample_time;
	std::cerr << "sum: " << sum << " target: " << (limit * num) << std::endl;
	TEST_CHECK(sum > 0);
	TEST_CHECK(close_to(sum, limit * num, limit * 0.3f * num));
}

void test_single_peer(int limit, bool torrent_limit)
{
	std::cerr << "\ntest single peer " << limit << " " << torrent_limit << std::endl;
	io_service ios;
	bandwidth_manager<peer_connection, torrent> manager(ios, 0);
	boost::shared_ptr<torrent> t1(new torrent(manager));

	if (torrent_limit)
		t1->m_bandwidth_limit[0].throttle(limit);
	else
		manager.throttle(limit);

	connections_t v;
	spawn_connections(v, ios, t1, 1, "p");
	run_test(ios, v);

	float sum = 0.f;
	for (connections_t::iterator i = v.begin()
		, end(v.end()); i != end; ++i)
	{
		sum += (*i)->m_stats.total_payload_upload();
	}
	sum /= sample_time;
	std::cerr << sum << " target: " << limit << std::endl;
	TEST_CHECK(sum > 0);
	TEST_CHECK(close_to(sum, limit, 1000));
}

void test_torrents(int num, int limit1, int limit2, int global_limit)
{
	std::cerr << "\ntest equal torrents " << num
		<< " l1: " << limit1
		<< " l2: " << limit2
		<< " g: " << global_limit << std::endl;
	io_service ios;
	bandwidth_manager<peer_connection, torrent> manager(ios, 0);
	if (global_limit > 0)
		manager.throttle(global_limit);

	boost::shared_ptr<torrent> t1(new torrent(manager));
	boost::shared_ptr<torrent> t2(new torrent(manager));

	t1->m_bandwidth_limit[0].throttle(limit1);
	t2->m_bandwidth_limit[0].throttle(limit2);

	connections_t v1;
	spawn_connections(v1, ios, t1, num, "t1p");
	connections_t v2;
	spawn_connections(v2, ios, t2, num, "t2p");
	connections_t v;
	std::copy(v1.begin(), v1.end(), std::back_inserter(v));
	std::copy(v2.begin(), v2.end(), std::back_inserter(v));
	run_test(ios, v);

	if (global_limit > 0 && global_limit < limit1 + limit2)
	{
		limit1 = (std::min)(limit1, global_limit / 2);
		limit2 = global_limit - limit1;
	}
	float sum = 0.f;
	for (connections_t::iterator i = v1.begin()
		, end(v1.end()); i != end; ++i)
	{
		sum += (*i)->m_stats.total_payload_upload();
	}
	sum /= sample_time;
	std::cerr << sum << " target: " << limit1 << std::endl;
	TEST_CHECK(sum > 0);
	TEST_CHECK(close_to(sum, limit1, 1000));

	sum = 0.f;
	for (connections_t::iterator i = v2.begin()
		, end(v2.end()); i != end; ++i)
	{
		sum += (*i)->m_stats.total_payload_upload();
	}
	sum /= sample_time;
	std::cerr << sum << " target: " << limit2 << std::endl;
	TEST_CHECK(sum > 0);
	TEST_CHECK(close_to(sum, limit2, 1000));
}

void test_torrents_variable_rate(int num, int limit, int global_limit)
{
	std::cerr << "\ntest torrents variable rate" << num
		<< " l: " << limit
		<< " g: " << global_limit << std::endl;
	io_service ios;
	bandwidth_manager<peer_connection, torrent> manager(ios, 0);
	if (global_limit > 0)
		manager.throttle(global_limit);

	boost::shared_ptr<torrent> t1(new torrent(manager));
	boost::shared_ptr<torrent> t2(new torrent(manager));

	t1->m_bandwidth_limit[0].throttle(limit);
	t2->m_bandwidth_limit[0].throttle(limit);

	connections_t v1;
	spawn_connections(v1, ios, t1, num, "t1p");
	connections_t v2;
	spawn_connections(v2, ios, t2, num, "t2p");
	connections_t v;
	std::copy(v1.begin(), v1.end(), std::back_inserter(v));
	std::copy(v2.begin(), v2.end(), std::back_inserter(v));

	deadline_timer change_rate(ios);
	change_rate.expires_from_now(milliseconds(1100));
	change_rate.async_wait(boost::bind(&do_change_rate, _1, boost::ref(change_rate), t1, t2, limit, 9));
	
	run_test(ios, v);

	if (global_limit > 0 && global_limit < 2 * limit)
		limit = global_limit / 2;

	float sum = 0.f;
	for (connections_t::iterator i = v1.begin()
		, end(v1.end()); i != end; ++i)
	{
		sum += (*i)->m_stats.total_payload_upload();
	}
	sum /= sample_time;
	std::cerr << sum << " target: " << limit << std::endl;
	TEST_CHECK(sum > 0);
	TEST_CHECK(close_to(sum, limit, 1000));

	sum = 0.f;
	for (connections_t::iterator i = v2.begin()
		, end(v2.end()); i != end; ++i)
	{
		sum += (*i)->m_stats.total_payload_upload();
	}
	sum /= sample_time;
	std::cerr << sum << " target: " << limit << std::endl;
	TEST_CHECK(sum > 0);
	TEST_CHECK(close_to(sum, limit, 1000));
}

void test_peer_priority(int limit, bool torrent_limit)
{
	std::cerr << "\ntest peer priority " << limit << " " << torrent_limit << std::endl;
	io_service ios;
	bandwidth_manager<peer_connection, torrent> manager(ios, 0);
	boost::shared_ptr<torrent> t1(new torrent(manager));

	if (torrent_limit)
		t1->m_bandwidth_limit[0].throttle(limit);
	else
		manager.throttle(limit);

	connections_t v1;
	spawn_connections(v1, ios, t1, 10, "p");
	connections_t v;
	std::copy(v1.begin(), v1.end(), std::back_inserter(v));
	boost::intrusive_ptr<peer_connection> p(
		new peer_connection(ios, t1, 0, false, "no-priority"));
	v.push_back(p);
	run_test(ios, v);

	float sum = 0.f;
	for (connections_t::iterator i = v1.begin()
		, end(v1.end()); i != end; ++i)
	{
		sum += (*i)->m_stats.total_payload_upload();
	}
	sum /= sample_time;
	std::cerr << sum << " target: " << limit << std::endl;
	TEST_CHECK(sum > 0);
	TEST_CHECK(close_to(sum, limit, 50));

	std::cerr << "non-prioritized rate: " << p->m_stats.total_payload_upload() / sample_time << std::endl;
	TEST_CHECK(p->m_stats.total_payload_upload() / sample_time < 10);
}

void test_no_starvation(int limit)
{
	std::cerr << "\ntest no starvation " << limit << std::endl;
	io_service ios;
	bandwidth_manager<peer_connection, torrent> manager(ios, 0);
	boost::shared_ptr<torrent> t1(new torrent(manager));
	boost::shared_ptr<torrent> t2(new torrent(manager));

	manager.throttle(limit);

	const int num_peers = 20;

	connections_t v1;
	spawn_connections(v1, ios, t1, num_peers, "p");
	connections_t v;
	std::copy(v1.begin(), v1.end(), std::back_inserter(v));
	boost::intrusive_ptr<peer_connection> p(
		new peer_connection(ios, t2, 0, false, "no-priority"));
	v.push_back(p);
	run_test(ios, v);

	float sum = 0.f;
	for (connections_t::iterator i = v.begin()
		, end(v.end()); i != end; ++i)
	{
		sum += (*i)->m_stats.total_payload_upload();
	}
	sum /= sample_time;
	std::cerr << sum << " target: " << limit << std::endl;
	TEST_CHECK(sum > 0);
	TEST_CHECK(close_to(sum, limit, 50));

	std::cerr << "non-prioritized rate: " << p->m_stats.total_payload_upload() / sample_time << std::endl;
	TEST_CHECK(close_to(p->m_stats.total_payload_upload() / sample_time, limit / (num_peers + 1), 1000));
}

int test_main()
{
	using namespace libtorrent;

	test_equal_connections(2, 20);
	test_equal_connections(2, 2000);
	test_equal_connections(2, 20000);
	test_equal_connections(3, 20000);
	test_equal_connections(5, 20000);
	test_equal_connections(7, 20000);
	test_equal_connections(33, 60000);
	test_equal_connections(33, 500000);
	test_connections_variable_rate(2, 20, 0);
	test_connections_variable_rate(5, 20000, 0);
	test_connections_variable_rate(3, 2000, 6000);
	test_connections_variable_rate(5, 2000, 30000);
	test_connections_variable_rate(33, 500000, 0);
	test_torrents(2, 400, 400, 0);
	test_torrents(2, 100, 500, 0);
	test_torrents(2, 3000, 3000, 6000);
	test_torrents(1, 40000, 40000, 0);
	test_torrents(24, 50000, 50000, 0);
	test_torrents(5, 6000, 6000, 3000);
	test_torrents(5, 6000, 5000, 4000);
	test_torrents(5, 20000, 20000, 30000);
	test_torrents_variable_rate(5, 6000, 3000);
	test_torrents_variable_rate(5, 20000, 30000);
	test_single_peer(40000, true);
	test_single_peer(40000, false);
	test_peer_priority(40000, false);
	test_peer_priority(40000, true);
	test_no_starvation(40000);

	return 0;
}