/*

Copyright (c) 2010, Arvid Norberg
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in
      the documentation and/or other materials provided with the distribution.
    * Neither the name of the author nor the names of its
      contributors may be used to endorse or promote products derived
      from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.

*/

#include "test.hpp"
#include "settings.hpp"
#include "setup_swarm.hpp"
#include "simulator/simulator.hpp"
#include "simulator/http_server.hpp"
#include "simulator/utils.hpp"
#include "libtorrent/alert_types.hpp"
#include "libtorrent/announce_entry.hpp"
#include "libtorrent/session.hpp"
#include "libtorrent/create_torrent.hpp"
#include "libtorrent/file_storage.hpp"
#include "libtorrent/torrent_info.hpp"

using namespace lt;
using namespace sim;

using chrono::duration_cast;

// seconds
const int duration = 10000;

template <typename Tp1, typename Tp2>
bool eq(Tp1 const lhs, Tp2 const rhs)
{
	return std::abs(lt::duration_cast<seconds>(lhs - rhs).count()) <= 1;
}

void test_interval(int interval)
{
	using sim::asio::ip::address_v4;
	sim::default_config network_cfg;
	sim::simulation sim{network_cfg};

	lt::time_point start = lt::clock_type::now();
	bool ran_to_completion = false;

	sim::asio::io_service web_server(sim, address_v4::from_string("2.2.2.2"));
	// listen on port 8080
	sim::http_server http(web_server, 8080);

	// the timestamps of all announces
	std::vector<lt::time_point> announces;

	http.register_handler("/announce"
		, [&announces,interval,start,&ran_to_completion](std::string /* method */
			, std::string /* req */
		, std::map<std::string, std::string>&)
	{
		// don't collect events once we're done. We're not interested in the
		// tracker stopped announce for instance
		if (!ran_to_completion)
			announces.push_back(lt::clock_type::now());

		char response[500];
		int const size = std::snprintf(response, sizeof(response), "d8:intervali%de5:peers0:e", interval);
		return sim::send_response(200, "OK", size) + response;
	});

	std::vector<lt::time_point> announce_alerts;

	lt::settings_pack default_settings = settings();
	// since the test tracker is only listening on IPv4 we need to configure the
	// client to do the same so that the number of tracker_announce_alerts matches
	// the number of announces seen by the tracker
	default_settings.set_str(settings_pack::listen_interfaces, "0.0.0.0:6881");
	lt::add_torrent_params default_add_torrent;

	setup_swarm(1, swarm_test::upload, sim, default_settings, default_add_torrent
		// add session
		, [](lt::settings_pack&) {}
		// add torrent
		, [](lt::add_torrent_params& params) {
			params.trackers.push_back("http://2.2.2.2:8080/announce");
		}
		// on alert
		, [&](lt::alert const* a, lt::session&) {

			if (ran_to_completion) return;
			if (lt::alert_cast<lt::tracker_announce_alert>(a))
			{
				announce_alerts.push_back(a->timestamp());
			}
		}
		// terminate
		, [&](int const ticks, lt::session& ses) -> bool {
			if (ticks > duration + 1)
			{
				ran_to_completion = true;
				return true;
			}
			return false;
		});

	TEST_CHECK(ran_to_completion);
	TEST_EQUAL(announce_alerts.size(), announces.size());

	lt::time_point last_announce = announces[0];
	lt::time_point last_alert = announce_alerts[0];
	for (int i = 1; i < int(announces.size()); ++i)
	{
		// make sure the interval is within 1 second of what it's supposed to be
		// (this accounts for network latencies, and the second-granularity
		// timestamps)
		TEST_CHECK(eq(duration_cast<lt::seconds>(announces[i] - last_announce), lt::seconds(interval)));
		last_announce = announces[i];

		TEST_CHECK(eq(duration_cast<lt::milliseconds>(announce_alerts[i] - last_alert), lt::seconds(interval)));
		last_alert = announce_alerts[i];
	}
}

TORRENT_TEST(event_completed)
{
	using sim::asio::ip::address_v4;
	sim::default_config network_cfg;
	sim::simulation sim{network_cfg};

	sim::asio::io_service web_server(sim, address_v4::from_string("2.2.2.2"));
	// listen on port 8080
	sim::http_server http(web_server, 8080);

	// the request strings of all announces
	std::vector<std::pair<int, std::string>> announces;

	const int interval = 500;
	lt::time_point start = lt::clock_type::now();

	http.register_handler("/announce"
	, [&](std::string method, std::string req
		, std::map<std::string, std::string>&)
	{
		TEST_EQUAL(method, "GET");
		int const timestamp = int(chrono::duration_cast<lt::seconds>(
			lt::clock_type::now() - start).count());
		announces.push_back({timestamp, req});

		char response[500];
		int const size = std::snprintf(response, sizeof(response), "d8:intervali%de5:peers0:e", interval);
		return sim::send_response(200, "OK", size) + response;
	});

	lt::settings_pack default_settings = settings();
	lt::add_torrent_params default_add_torrent;

	int completion = -1;

	setup_swarm(2, swarm_test::download, sim, default_settings, default_add_torrent
		// add session
		, [](lt::settings_pack&) { }
		// add torrent
		, [](lt::add_torrent_params& params) {
			params.trackers.push_back("http://2.2.2.2:8080/announce");
		}
		// on alert
		, [&](lt::alert const*, lt::session&) {}
		// terminate
		, [&](int const ticks, lt::session& ses) -> bool
		{
			if (completion == -1 && is_seed(ses))
			{
				completion = int(chrono::duration_cast<lt::seconds>(
					lt::clock_type::now() - start).count());
			}

			return ticks > duration;
		});

	// the first announce should be event=started, the second should be
	// event=completed, then all but the last should have no event and the last
	// be event=stopped.
	for (int i = 0; i < int(announces.size()); ++i)
	{
		std::string const& str = announces[i].second;
		int timestamp = announces[i].first;

		const bool has_start = str.find("&event=started")
			!= std::string::npos;
		const bool has_completed = str.find("&event=completed")
			!= std::string::npos;
		const bool has_stopped = str.find("&event=stopped")
			!= std::string::npos;

		// we there can only be one event
		const bool has_event = str.find("&event=") != std::string::npos;

		std::printf("- %s\n", str.c_str());

		// there is exactly 0 or 1 events.
		TEST_EQUAL(int(has_start) + int(has_completed) + int(has_stopped)
			, int(has_event));

		switch (i)
		{
			case 0:
				TEST_CHECK(has_start);
				break;
			case 1:
			{
				// the announce should have come approximately the same time we
				// completed
				TEST_CHECK(std::abs(completion - timestamp) <= 1);
				TEST_CHECK(has_completed);
				break;
			}
			default:
				if (i == int(announces.size()) - 1)
				{
					TEST_CHECK(has_stopped);
				}
				else
				{
					TEST_CHECK(!has_event);
				}
				break;
		}
	}
}

TORRENT_TEST(announce_interval_440)
{
	test_interval(440);
}

TORRENT_TEST(announce_interval_1800)
{
	test_interval(1800);
}

TORRENT_TEST(announce_interval_1200)
{
	test_interval(3600);
}

struct sim_config : sim::default_config
{
	explicit sim_config(bool ipv6 = true) : ipv6(ipv6) {}

	chrono::high_resolution_clock::duration hostname_lookup(
		asio::ip::address const& requestor
		, std::string hostname
		, std::vector<asio::ip::address>& result
		, boost::system::error_code& ec) override
	{
		if (hostname == "tracker.com")
		{
			result.push_back(address_v4::from_string("10.0.0.2"));
			if (ipv6)
				result.push_back(address_v6::from_string("ff::dead:beef"));
			return duration_cast<chrono::high_resolution_clock::duration>(chrono::milliseconds(100));
		}

		return default_config::hostname_lookup(requestor, hostname, result, ec);
	}

	bool ipv6;
};

void on_alert_notify(lt::session* ses)
{
	ses->get_io_service().post([ses] {
		std::vector<lt::alert*> alerts;
		ses->pop_alerts(&alerts);

		for (lt::alert* a : alerts)
		{
			lt::time_duration d = a->timestamp().time_since_epoch();
			std::uint32_t const millis = std::uint32_t(
				lt::duration_cast<lt::milliseconds>(d).count());
			std::printf("%4d.%03d: %s\n", millis / 1000, millis % 1000,
				a->message().c_str());
		}
	});
}

static const int num_interfaces = 3;

void test_ipv6_support(char const* listen_interfaces
	, int const expect_v4, int const expect_v6)
{
	using sim::asio::ip::address_v4;
	sim_config network_cfg;
	sim::simulation sim{network_cfg};

	sim::asio::io_service web_server_v4(sim, address_v4::from_string("10.0.0.2"));
	sim::asio::io_service web_server_v6(sim, address_v6::from_string("ff::dead:beef"));

	// listen on port 8080
	sim::http_server http_v4(web_server_v4, 8080);
	sim::http_server http_v6(web_server_v6, 8080);

	int v4_announces = 0;
	int v6_announces = 0;

	http_v4.register_handler("/announce"
	, [&v4_announces](std::string method, std::string req
		, std::map<std::string, std::string>&)
	{
		++v4_announces;
		TEST_EQUAL(method, "GET");

		char response[500];
		int const size = std::snprintf(response, sizeof(response), "d8:intervali1800e5:peers0:e");
		return sim::send_response(200, "OK", size) + response;
	});

	http_v6.register_handler("/announce"
	, [&v6_announces](std::string method, std::string req
		, std::map<std::string, std::string>&)
	{
		++v6_announces;
		TEST_EQUAL(method, "GET");

		char response[500];
		int const size = std::snprintf(response, sizeof(response), "d8:intervali1800e5:peers0:e");
		return sim::send_response(200, "OK", size) + response;
	});

	{
		lt::session_proxy zombie;

		std::vector<asio::ip::address> ips;

		for (int i = 0; i < num_interfaces; i++)
		{
			char ep[30];
			std::snprintf(ep, sizeof(ep), "10.0.0.%d", i + 1);
			ips.push_back(address::from_string(ep));
			std::snprintf(ep, sizeof(ep), "ffff::1337:%d", i + 1);
			ips.push_back(address::from_string(ep));
		}

		asio::io_service ios(sim, ips);
		lt::settings_pack sett = settings();
		if (listen_interfaces)
		{
			sett.set_str(settings_pack::listen_interfaces, listen_interfaces);
		}
		std::unique_ptr<lt::session> ses(new lt::session(sett, ios));

		ses->set_alert_notify(std::bind(&on_alert_notify, ses.get()));

		lt::add_torrent_params p;
		p.name = "test-torrent";
		p.save_path = ".";
		p.info_hash.assign("abababababababababab");

//TODO: parameterize http vs. udp here
		p.trackers.push_back("http://tracker.com:8080/announce");
		ses->async_add_torrent(p);

		// stop the torrent 5 seconds in
		sim::timer t1(sim, lt::seconds(5)
			, [&ses](boost::system::error_code const&)
		{
			std::vector<lt::torrent_handle> torrents = ses->get_torrents();
			for (auto const& t : torrents)
			{
				t.pause();
			}
		});

		// then shut down 10 seconds in
		sim::timer t2(sim, lt::seconds(10)
			, [&ses,&zombie](boost::system::error_code const&)
		{
			zombie = ses->abort();
			ses.reset();
		});

		sim.run();
	}

	TEST_EQUAL(v4_announces, expect_v4);
	TEST_EQUAL(v6_announces, expect_v6);
}

// this test makes sure that a tracker whose host name resolves to both IPv6 and
// IPv4 addresses will be announced to twice, once for each address family
TORRENT_TEST(ipv6_support)
{
	// null means default
	test_ipv6_support(nullptr, 2, num_interfaces * 2);
}

TORRENT_TEST(ipv6_support_bind_v4_v6_any)
{
	// 2 because there's one announce on startup and one when shutting down
	// IPv6 will send announces for each interface
	test_ipv6_support("0.0.0.0:6881,[::0]:6881", 2, num_interfaces * 2);
}

TORRENT_TEST(ipv6_support_bind_v6_any)
{
	test_ipv6_support("[::0]:6881", 0, num_interfaces * 2);
}

TORRENT_TEST(ipv6_support_bind_v4)
{
	test_ipv6_support("10.0.0.3:6881", 2, 0);
}

TORRENT_TEST(ipv6_support_bind_v6)
{
	test_ipv6_support("[ffff::1337:1]:6881", 0, 2);
}

TORRENT_TEST(ipv6_support_bind_v6_3interfaces)
{
	test_ipv6_support("[ffff::1337:1]:6881,[ffff::1337:2]:6881,[ffff::1337:3]:6881", 0, 3 * 2);
}

TORRENT_TEST(ipv6_support_bind_v4_v6)
{
	test_ipv6_support("10.0.0.3:6881,[ffff::1337:1]:6881", 2, 2);
}

TORRENT_TEST(ipv6_support_bind_v6_v4)
{
	test_ipv6_support("[ffff::1337:1]:6881,10.0.0.3:6881", 2, 2);
}

// this runs a simulation of a torrent with tracker(s), making sure the request
// received by the tracker matches the expectation.
// The Setup function is run first, giving the test an opportunity to add
// trackers to the torrent. It's expected to return the number of seconds to
// wait until test2 is called.
// The Announce function is called on http requests. Test1 is run on the session
// 5 seconds after startup. The tracker is running at 10.0.0.2 (or tracker.com)
// port 8080.
template <typename Setup, typename Announce, typename Test1, typename Test2>
void tracker_test(Setup setup, Announce a, Test1 test1, Test2 test2
	, char const* url_path = "/announce")
{
	using sim::asio::ip::address_v4;
	sim_config network_cfg;
	sim::simulation sim{network_cfg};

	sim::asio::io_service tracker_ios(sim, address_v4::from_string("10.0.0.2"));
	sim::asio::io_service tracker_ios6(sim, address_v6::from_string("ff::dead:beef"));

	// listen on port 8080
	sim::http_server http(tracker_ios, 8080);
	sim::http_server http6(tracker_ios6, 8080);

	http.register_handler(url_path, a);
	http6.register_handler(url_path, a);

	lt::session_proxy zombie;

	asio::io_service ios(sim, { address_v4::from_string("10.0.0.3")
		, address_v6::from_string("ffff::1337") });
	lt::settings_pack sett = settings();
	std::unique_ptr<lt::session> ses(new lt::session(sett, ios));

	ses->set_alert_notify(std::bind(&on_alert_notify, ses.get()));

	lt::add_torrent_params p;
	p.name = "test-torrent";
	p.save_path = ".";
	p.info_hash.assign("abababababababababab");
	int const delay = setup(p, *ses);
	ses->async_add_torrent(p);

	// run the test 5 seconds in
	sim::timer t1(sim, lt::seconds(5)
		, [&ses,&test1](boost::system::error_code const&)
	{
		std::vector<lt::torrent_handle> torrents = ses->get_torrents();
		TEST_EQUAL(torrents.size(), 1);
		torrent_handle h = torrents.front();
		test1(h);
	});

	sim::timer t2(sim, lt::seconds(5 + delay)
		, [&ses,&test2](boost::system::error_code const&)
	{
		std::vector<lt::torrent_handle> torrents = ses->get_torrents();
		TEST_EQUAL(torrents.size(), 1);
		torrent_handle h = torrents.front();
		test2(h);
	});

	// then shut down 10 seconds in
	sim::timer t3(sim, lt::seconds(10 + delay)
		, [&ses,&zombie](boost::system::error_code const&)
	{
		zombie = ses->abort();
		ses.reset();
	});

	sim.run();
}

template <typename Announce, typename Test1, typename Test2>
void tracker_test(Announce a, Test1 test1, Test2 test2, char const* url_path = "/announce")
{
	tracker_test([](lt::add_torrent_params& p, lt::session&) {
		p.trackers.push_back("http://tracker.com:8080/announce");
		return 5;
	},
	a, test1, test2, url_path);
}

template <typename Announce, typename Test>
void announce_entry_test(Announce a, Test t, char const* url_path = "/announce")
{
	tracker_test(a
		, [&t] (torrent_handle h) {
			std::vector<announce_entry> tr = h.trackers();

			TEST_EQUAL(tr.size(), 1);
			announce_entry const& ae = tr[0];
			t(ae);
		}
		, [](torrent_handle){}
		, url_path);
}

TORRENT_TEST(test_error)
{
	announce_entry_test(
		[](std::string method, std::string req
			, std::map<std::string, std::string>&)
		{
			TEST_EQUAL(method, "GET");

			char response[500];
			int const size = std::snprintf(response, sizeof(response), "d14:failure reason4:teste");
			return sim::send_response(200, "OK", size) + response;
		}
		, [](announce_entry const& ae)
		{
			TEST_EQUAL(ae.url, "http://tracker.com:8080/announce");
			TEST_EQUAL(ae.endpoints.size(), 2);
			for (auto const& aep : ae.endpoints)
			{
				TEST_EQUAL(aep.is_working(), false);
				TEST_EQUAL(aep.message, "test");
				TEST_EQUAL(aep.last_error, error_code(errors::tracker_failure));
				TEST_EQUAL(aep.fails, 1);
			}
		});
}

TORRENT_TEST(test_warning)
{
	announce_entry_test(
		[](std::string method, std::string req
			, std::map<std::string, std::string>&)
		{
			TEST_EQUAL(method, "GET");

			char response[500];
			int const size = std::snprintf(response, sizeof(response), "d5:peers6:aaaaaa15:warning message5:test2e");
			return sim::send_response(200, "OK", size) + response;
		}
		, [](announce_entry const& ae)
		{
			TEST_EQUAL(ae.url, "http://tracker.com:8080/announce");
			TEST_EQUAL(ae.endpoints.size(), 2);
			for (auto const& aep : ae.endpoints)
			{
				TEST_EQUAL(aep.is_working(), true);
				TEST_EQUAL(aep.message, "test2");
				TEST_EQUAL(aep.last_error, error_code());
				TEST_EQUAL(aep.fails, 0);
			}
		});
}

TORRENT_TEST(test_scrape_data_in_announce)
{
	announce_entry_test(
		[](std::string method, std::string req
			, std::map<std::string, std::string>&)
		{
			TEST_EQUAL(method, "GET");

			char response[500];
			int const size = std::snprintf(response, sizeof(response),
				"d5:peers6:aaaaaa8:completei1e10:incompletei2e10:downloadedi3e11:downloadersi4ee");
			return sim::send_response(200, "OK", size) + response;
		}
		, [](announce_entry const& ae)
		{
			TEST_EQUAL(ae.url, "http://tracker.com:8080/announce");
			TEST_EQUAL(ae.endpoints.size(), 2);
			for (auto const& aep : ae.endpoints)
			{
				TEST_EQUAL(aep.is_working(), true);
				TEST_EQUAL(aep.message, "");
				TEST_EQUAL(aep.last_error, error_code());
				TEST_EQUAL(aep.fails, 0);
				TEST_EQUAL(aep.scrape_complete, 1);
				TEST_EQUAL(aep.scrape_incomplete, 2);
				TEST_EQUAL(aep.scrape_downloaded, 3);
			}
		});
}

TORRENT_TEST(test_scrape)
{
	tracker_test(
		[](std::string method, std::string req
			, std::map<std::string, std::string>&)
		{
			TEST_EQUAL(method, "GET");

			char response[500];
			int const size = std::snprintf(response, sizeof(response),
				"d5:filesd20:ababababababababababd8:completei1e10:downloadedi3e10:incompletei2eeee");
			return sim::send_response(200, "OK", size) + response;
		}
		, [](torrent_handle h)
		{
			h.scrape_tracker();
		}
		, [](torrent_handle h)
		{
			std::vector<announce_entry> tr = h.trackers();

			TEST_EQUAL(tr.size(), 1);
			announce_entry const& ae = tr[0];
			TEST_EQUAL(ae.endpoints.size(), 2);
			for (auto const& aep : ae.endpoints)
			{
				TEST_EQUAL(aep.scrape_incomplete, 2);
				TEST_EQUAL(aep.scrape_complete, 1);
				TEST_EQUAL(aep.scrape_downloaded, 3);
			}
		}
		, "/scrape");
}

TORRENT_TEST(test_http_status)
{
	announce_entry_test(
		[](std::string method, std::string req
			, std::map<std::string, std::string>&)
		{
			TEST_EQUAL(method, "GET");
			return sim::send_response(410, "Not A Tracker", 0);
		}
		, [](announce_entry const& ae)
		{
			TEST_EQUAL(ae.url, "http://tracker.com:8080/announce");
			TEST_EQUAL(ae.endpoints.size(), 2);
			for (auto const& aep : ae.endpoints)
			{
				TEST_EQUAL(aep.is_working(), false);
				TEST_EQUAL(aep.message, "Not A Tracker");
				TEST_EQUAL(aep.last_error, error_code(410, http_category()));
				TEST_EQUAL(aep.fails, 1);
			}
		});
}

TORRENT_TEST(test_interval)
{
	announce_entry_test(
		[](std::string method, std::string req
			, std::map<std::string, std::string>&)
		{
			TEST_EQUAL(method, "GET");
			char response[500];
			int const size = std::snprintf(response, sizeof(response)
				, "d10:tracker id8:testteste");
			return sim::send_response(200, "OK", size) + response;
		}
		, [](announce_entry const& ae)
		{
			TEST_EQUAL(ae.url, "http://tracker.com:8080/announce");
			TEST_EQUAL(ae.endpoints.size(), 2);
			for (auto const& aep : ae.endpoints)
			{
				TEST_EQUAL(aep.is_working(), true);
				TEST_EQUAL(aep.message, "");
				TEST_EQUAL(aep.last_error, error_code());
				TEST_EQUAL(aep.fails, 0);
			}

			TEST_EQUAL(ae.trackerid, "testtest");
		});
}

TORRENT_TEST(test_invalid_bencoding)
{
	announce_entry_test(
		[](std::string method, std::string req
			, std::map<std::string, std::string>&)
		{
			TEST_EQUAL(method, "GET");
			char response[500];
			int const size = std::snprintf(response, sizeof(response)
				, "d10:tracer idteste");
			return sim::send_response(200, "OK", size) + response;
		}
		, [](announce_entry const& ae)
		{
			TEST_EQUAL(ae.url, "http://tracker.com:8080/announce");
			TEST_EQUAL(ae.endpoints.size(), 2);
			for (auto const& aep : ae.endpoints)
			{
				TEST_EQUAL(aep.is_working(), false);
				TEST_EQUAL(aep.message, "");
				TEST_EQUAL(aep.last_error, error_code(bdecode_errors::expected_value
					, bdecode_category()));
				TEST_EQUAL(aep.fails, 1);
			}
		});
}

TORRENT_TEST(try_next)
{
// test that we move on to try the next tier if the first one fails

	bool got_announce = false;
	tracker_test(
		[](lt::add_torrent_params& p, lt::session&)
		{
		// TODO: 3 use tracker_tiers here to put the trackers in different tiers
			p.trackers.push_back("udp://failing-tracker.com/announce");
			p.trackers.push_back("http://failing-tracker.com/announce");

			// this is the working tracker
			p.trackers.push_back("http://tracker.com:8080/announce");
			return 60;
		},
		[&](std::string method, std::string req
			, std::map<std::string, std::string>&)
		{
			got_announce = true;
			TEST_EQUAL(method, "GET");

			char response[500];
			// respond with an empty peer list
			int const size = std::snprintf(response, sizeof(response), "d5:peers0:e");
			return sim::send_response(200, "OK", size) + response;
		}
		, [](torrent_handle h) {}
		, [](torrent_handle h)
		{
			torrent_status st = h.status();
			TEST_EQUAL(st.current_tracker, "http://tracker.com:8080/announce");

			std::vector<announce_entry> tr = h.trackers();

			TEST_EQUAL(tr.size(), 3);

			for (int i = 0; i < int(tr.size()); ++i)
			{
				std::printf("tracker \"%s\"\n", tr[i].url.c_str());
				if (tr[i].url == "http://tracker.com:8080/announce")
				{
					for (auto const& aep : tr[i].endpoints)
					{
						TEST_EQUAL(aep.fails, 0);
					}
					TEST_EQUAL(tr[i].verified, true);
				}
				else if (tr[i].url == "http://failing-tracker.com/announce")
				{
					for (auto const& aep : tr[i].endpoints)
					{
						TEST_CHECK(aep.fails >= 1);
						TEST_EQUAL(aep.last_error
							, error_code(boost::asio::error::host_not_found));
					}
					TEST_EQUAL(tr[i].verified, false);
				}
				else if (tr[i].url == "udp://failing-tracker.com/announce")
				{
					TEST_EQUAL(tr[i].verified, false);
					for (auto const& aep : tr[i].endpoints)
					{
						TEST_CHECK(aep.fails >= 1);
						TEST_EQUAL(aep.last_error
							, error_code(boost::asio::error::host_not_found));
					}
				}
				else
				{
					TEST_ERROR(("unexpected tracker URL: " + tr[i].url).c_str());
				}
			}
		});
	TEST_EQUAL(got_announce, true);
}

std::shared_ptr<torrent_info> make_torrent(bool priv)
{
	file_storage fs;
	fs.add_file("foobar", 13241);
	create_torrent ct(fs);

	ct.add_tracker("http://tracker.com:8080/announce");

	for (piece_index_t i(0); i < piece_index_t(ct.num_pieces()); ++i)
		ct.set_hash(i, sha1_hash(nullptr));

	ct.set_priv(priv);

	entry e = ct.generate();
	std::vector<char> buf;
	bencode(std::back_inserter(buf), e);
	return std::make_shared<torrent_info>(buf, from_span);
}

// make sure we _do_ send our IPv6 address to trackers for private torrents
TORRENT_TEST(tracker_ipv6_argument)
{
	bool got_announce = false;
	bool got_ipv6 = false;
	tracker_test(
		[](lt::add_torrent_params& p, lt::session& ses)
		{
			settings_pack pack;
			pack.set_bool(settings_pack::anonymous_mode, false);
			ses.apply_settings(pack);
			p.ti = make_torrent(true);
			return 60;
		},
		[&](std::string method, std::string req
			, std::map<std::string, std::string>&)
		{
			got_announce = true;
			bool const stop_event = req.find("&event=stopped") != std::string::npos;
			// stop events don't need to advertise the IPv6 address
			std::string::size_type pos = req.find("&ipv6=");
			TEST_CHECK(pos != std::string::npos || stop_event);
			got_ipv6 |= pos != std::string::npos;
			// make sure the IPv6 argument is url encoded
			TEST_CHECK(req.substr(pos + 6, req.substr(pos + 6).find_first_of('&'))
				== "ffff%3a%3a1337");
			return sim::send_response(200, "OK", 11) + "d5:peers0:e";
		}
		, [](torrent_handle) {}
		, [](torrent_handle) {});
	TEST_EQUAL(got_announce, true);
	TEST_EQUAL(got_ipv6, true);
}

// make sure we do _not_ send our IPv6 address to trackers for non-private
// torrents
TORRENT_TEST(tracker_ipv6_argument_non_private)
{
	bool got_announce = false;
	bool got_ipv6 = false;
	tracker_test(
		[](lt::add_torrent_params& p, lt::session& ses)
		{
			settings_pack pack;
			pack.set_bool(settings_pack::anonymous_mode, false);
			ses.apply_settings(pack);
			p.ti = make_torrent(false);
			return 60;
		},
		[&](std::string method, std::string req
			, std::map<std::string, std::string>&)
		{
			got_announce = true;
			std::string::size_type pos = req.find("&ipv6=");
			TEST_CHECK(pos == std::string::npos);
			got_ipv6 |= pos != std::string::npos;
			return sim::send_response(200, "OK", 11) + "d5:peers0:e";
		}
		, [](torrent_handle) {}
		, [](torrent_handle) {});
	TEST_EQUAL(got_announce, true);
	TEST_EQUAL(got_ipv6, false);
}

TORRENT_TEST(tracker_ipv6_argument_privacy_mode)
{
	bool got_announce = false;
	bool got_ipv6 = false;
	tracker_test(
		[](lt::add_torrent_params& p, lt::session& ses)
		{
			settings_pack pack;
			pack.set_bool(settings_pack::anonymous_mode, true);
			ses.apply_settings(pack);
			p.ti = make_torrent(true);
			return 60;
		},
		[&](std::string method, std::string req
			, std::map<std::string, std::string>&)
		{
			got_announce = true;
			std::string::size_type pos = req.find("&ipv6=");
			TEST_CHECK(pos == std::string::npos);
			got_ipv6 |= pos != std::string::npos;
			return sim::send_response(200, "OK", 11) + "d5:peers0:e";
		}
		, [](torrent_handle) {}
		, [](torrent_handle) {});
	TEST_EQUAL(got_announce, true);
	TEST_EQUAL(got_ipv6, false);
}

TORRENT_TEST(tracker_user_agent_privacy_mode_public_torrent)
{
	bool got_announce = false;
	tracker_test(
		[](lt::add_torrent_params& p, lt::session& ses)
		{
			settings_pack pack;
			pack.set_bool(settings_pack::anonymous_mode, true);
			pack.set_str(settings_pack::user_agent, "test_agent/1.2.3");
			ses.apply_settings(pack);
			p.ti = make_torrent(false);
			return 60;
		},
		[&](std::string method, std::string req
			, std::map<std::string, std::string>& headers)
		{
			got_announce = true;

			// in anonymous mode we should not send a user agent
			TEST_CHECK(headers["user-agent"] == "");
			return sim::send_response(200, "OK", 11) + "d5:peers0:e";
		}
		, [](torrent_handle h) {}
		, [](torrent_handle h) {});
	TEST_EQUAL(got_announce, true);
}

TORRENT_TEST(tracker_user_agent_privacy_mode_private_torrent)
{
	bool got_announce = false;
	tracker_test(
		[](lt::add_torrent_params& p, lt::session& ses)
		{
			settings_pack pack;
			pack.set_bool(settings_pack::anonymous_mode, true);
			pack.set_str(settings_pack::user_agent, "test_agent/1.2.3");
			ses.apply_settings(pack);
			p.ti = make_torrent(true);
			return 60;
		},
		[&](std::string method, std::string req
			, std::map<std::string, std::string>& headers)
		{
			got_announce = true;

			// in anonymous mode we should still send the user agent for private
			// torrents (since private trackers sometimes require it)
			TEST_CHECK(headers["user-agent"] == "test_agent/1.2.3");
			return sim::send_response(200, "OK", 11) + "d5:peers0:e";
		}
		, [](torrent_handle h) {}
		, [](torrent_handle h) {});
	TEST_EQUAL(got_announce, true);
}

// TODO: test external IP
// TODO: test with different queuing settings
// TODO: test when a torrent transitions from downloading to finished and
// finished to seeding
// TODO: test that left, downloaded and uploaded are reported correctly

// TODO: test scrape