/*

Copyright (c) 2013-2022, Arvid Norberg
Copyright (c) 2016, 2018, 2021, Alden Torres
Copyright (c) 2018, Steven Siloti
All rights reserved.

You may use, distribute and modify this code under the terms of the BSD license,
see LICENSE file.
*/

#include "test.hpp"
#include "setup_transfer.hpp"
#include "dht_server.hpp"
#include "peer_server.hpp"
#include "udp_tracker.hpp"
#include "test_utils.hpp"
#include "settings.hpp"

#include "libtorrent/alert.hpp"
#include "libtorrent/aux_/random.hpp"
#include "libtorrent/alert_types.hpp"
#include "libtorrent/torrent_info.hpp"
#include "libtorrent/aux_/path.hpp"
#include "libtorrent/flags.hpp"
#include "libtorrent/session_params.hpp"

#include <fstream>

using namespace lt;

namespace {

char const* proxy_name[] = {
	"none",
	"socks4",
	"socks5",
	"socks5_pw",
	"http",
	"http_pw",
	"i2p_proxy"
};

using flags_t = flags::bitfield_flag<std::uint32_t, struct test_proxy_tag>;

constexpr flags_t expect_http_connection = 1_bit;
constexpr flags_t expect_udp_connection = 2_bit;
//constexpr flags_t expect_http_reject = 3_bit;
//constexpr flags_t expect_udp_reject = 4_bit;
constexpr flags_t expect_dht_msg = 5_bit;
constexpr flags_t expect_peer_connection = 6_bit;

constexpr flags_t dont_proxy_peers = 10_bit;
constexpr flags_t dont_proxy_trackers = 11_bit;

session_proxy test_proxy(settings_pack::proxy_type_t proxy_type, flags_t flags)
{
#ifdef TORRENT_DISABLE_DHT
	// if DHT is disabled, we won't get any requests to it
	flags &= ~expect_dht_msg;
#endif
	std::printf("\n=== TEST == proxy: %s \n\n", proxy_name[proxy_type]);
	int const http_port = start_web_server();
	int const udp_port = start_udp_tracker();
	int const dht_port = start_dht();
	int const peer_port = start_peer();

	int const prev_udp_announces = num_udp_announces();

	settings_pack sett = settings();
	sett.set_int(settings_pack::stop_tracker_timeout, 2);
	sett.set_int(settings_pack::tracker_completion_timeout, 2);
	sett.set_int(settings_pack::tracker_receive_timeout, 2);
	sett.set_bool(settings_pack::announce_to_all_trackers, true);
	sett.set_bool(settings_pack::announce_to_all_tiers, true);
	sett.set_bool(settings_pack::enable_upnp, false);
	sett.set_bool(settings_pack::enable_natpmp, false);
	sett.set_bool(settings_pack::enable_lsd, false);
	sett.set_bool(settings_pack::enable_dht, true);

	// since multiple sessions may exist simultaneously (because of the
	// pipelining of the tests) they actually need to use different ports
	static int listen_port = 10000 + int(aux::random(50000));
	char iface[200];
	std::snprintf(iface, sizeof(iface), "127.0.0.1:%d", listen_port);
	listen_port += aux::random(10) + 1;
	sett.set_str(settings_pack::listen_interfaces, iface);

	// if we don't do this, the peer connection test
	// will be delayed by several seconds, by first
	// trying uTP
	sett.set_bool(settings_pack::enable_outgoing_utp, false);

	// in non-anonymous mode we circumvent/ignore the proxy if it fails
	// whereas in anonymous mode, we just fail
	sett.set_str(settings_pack::proxy_hostname, "non-existing.com");
	sett.set_int(settings_pack::proxy_type, proxy_type);
	sett.set_bool(settings_pack::proxy_peer_connections, !(flags & dont_proxy_peers));
	sett.set_bool(settings_pack::proxy_tracker_connections, !(flags & dont_proxy_trackers));
	sett.set_int(settings_pack::proxy_port, 4444);

	auto s = std::make_unique<lt::session>(sett);

	error_code ec;
	remove_all("tmp1_privacy", ec);
	create_directory("tmp1_privacy", ec);
	std::ofstream file(combine_path("tmp1_privacy", "temporary").c_str());
	add_torrent_params addp = ::create_torrent(&file, "temporary", 16 * 1024, 13, false);
	file.close();

	char http_tracker_url[200];
	std::snprintf(http_tracker_url, sizeof(http_tracker_url)
		, "http://127.0.0.1:%d/announce", http_port);
	addp.trackers.push_back(http_tracker_url);
	addp.tracker_tiers.push_back(0);
	std::printf("http tracker: %s\n", http_tracker_url);

	char udp_tracker_url[200];
	std::snprintf(udp_tracker_url, sizeof(udp_tracker_url)
		, "udp://127.0.0.1:%d/announce", udp_port);
	addp.trackers.push_back(udp_tracker_url);
	addp.tracker_tiers.push_back(1);
	std::printf("udp tracker: %s\n", udp_tracker_url);

	addp.flags &= ~torrent_flags::paused;
	addp.flags &= ~torrent_flags::auto_managed;

	// we don't want to waste time checking the torrent, just go straight into
	// seeding it, announcing to trackers and connecting to peers
	addp.flags |= torrent_flags::seed_mode;

	addp.save_path = "tmp1_privacy";
	addp.dht_nodes.push_back(std::pair<std::string, int>("127.0.0.1", dht_port));
	torrent_handle h = s->add_torrent(addp);

	std::printf("connect_peer: 127.0.0.1:%d\n", peer_port);
	h.connect_peer({make_address_v4("127.0.0.1"), std::uint16_t(peer_port)});

	std::vector<std::string> accepted_trackers;

	// all outcomes (success or proxy-blocked failure) resolve well under
	// 1.5s in practice, so 15 iterations is plenty of margin
	int const timeout = 15;
	std::size_t const expected_trackers
		= ((flags & expect_http_connection) ? 2 : 0)
		+ ((flags & expect_udp_connection) ? 2 : 0);

	// most sub-tests expect only a subset of {tracker, peer} connections to
	// succeed; the rest are meant to be blocked by the proxy, and there's no
	// alert to wait for to prove a connection did *not* happen. Once the
	// expected subset has been observed, keep waiting out this floor of
	// iterations so a proxy bypass on the unexpected side still has a chance
	// to show up before the checks below run (observed worst case for a
	// blocked connection to resolve is ~0.5s, this leaves ample margin).
	int const settle_iterations = 8;
	bool const all_connections_expected =
		bool(flags & expect_udp_connection) && bool(flags & expect_peer_connection);

	for (int i = 0; i < timeout; ++i)
	{
		print_alerts(*s, "s", false, false
			, [&](lt::alert const* a)
			{
				if (auto const* ta = alert_cast<tracker_reply_alert>(a))
				{
					std::printf("accepted tracker: %s\n", ta->tracker_url());
					accepted_trackers.push_back(ta->tracker_url());
				}
				return false;
			});
		std::this_thread::sleep_for(lt::milliseconds(100));

		bool const udp_done =
			!(flags & expect_udp_connection) || num_udp_announces() >= prev_udp_announces + 1;
		bool const peer_done = !(flags & expect_peer_connection) || num_peer_hits() > 0;
		bool const trackers_done = accepted_trackers.size() >= expected_trackers;

		if (udp_done && peer_done && trackers_done
			&& (all_connections_expected || i >= settle_iterations))
		{
			break;
		}
	}

	// we should have announced to the tracker by now
	TEST_EQUAL(num_udp_announces(), prev_udp_announces
		+ ((flags & expect_udp_connection) ? 2 : 0));

	if (flags & expect_dht_msg)
	{
		TEST_CHECK(num_dht_hits() > 0);
	}
	else
	{
		TEST_EQUAL(num_dht_hits(), 0);
	}

	if (flags & expect_peer_connection)
	{
		TEST_CHECK(num_peer_hits() > 0);
	}
	else
	{
		TEST_EQUAL(num_peer_hits(), 0);
	}

	if (flags & expect_http_connection)
	{
		std::printf("expecting: %s\n", http_tracker_url);
		TEST_CHECK(std::find(accepted_trackers.begin(), accepted_trackers.end()
			, http_tracker_url) != accepted_trackers.end());
	}
	else
	{
		std::printf("NOT expecting: %s\n", http_tracker_url);
		TEST_CHECK(std::find(accepted_trackers.begin(), accepted_trackers.end()
			, http_tracker_url) == accepted_trackers.end());
	}

	if (flags & expect_udp_connection)
	{
		std::printf("expecting: %s\n", udp_tracker_url);
		TEST_CHECK(std::find(accepted_trackers.begin(), accepted_trackers.end()
			, udp_tracker_url) != accepted_trackers.end());
	}
	else
	{
		std::printf("NOT expecting: %s\n", udp_tracker_url);
		TEST_CHECK(std::find(accepted_trackers.begin(), accepted_trackers.end()
			, udp_tracker_url) == accepted_trackers.end());
	}

	std::printf("%s: ~session\n", time_now_string().c_str());
	session_proxy pr = s->abort();
	s.reset();

	stop_peer();
	stop_dht();
	stop_udp_tracker();
	stop_web_server();
	return pr;
}

} // anonymous namespace

// not using anonymous mode
// UDP fails open if we can't connect to the proxy
// or if the proxy doesn't support UDP

TORRENT_TEST(no_proxy)
{
	test_proxy(settings_pack::none, expect_udp_connection
		| expect_http_connection | expect_dht_msg | expect_peer_connection);
}

// since we don't actually have a proxy in this test, make sure libtorrent
// doesn't send any outgoing packets to either tracker or the peer
TORRENT_TEST(socks4)
{
	test_proxy(settings_pack::socks4, {});
}

TORRENT_TEST(socks5)
{
	test_proxy(settings_pack::socks5, {});
}

TORRENT_TEST(socks5_pw)
{
	test_proxy(settings_pack::socks5_pw, {});
}

TORRENT_TEST(http)
{
	test_proxy(settings_pack::http, {});
}

TORRENT_TEST(http_pw)
{
	test_proxy(settings_pack::http_pw, {});
}

// if we configure trackers to not be proxied, they should be let through
TORRENT_TEST(socks4_tracker)
{
	test_proxy(settings_pack::socks4, dont_proxy_trackers | expect_http_connection | expect_udp_connection);
}

TORRENT_TEST(socks5_tracker)
{
	test_proxy(settings_pack::socks5, dont_proxy_trackers | expect_http_connection | expect_udp_connection);
}

TORRENT_TEST(socks5_pw_tracker)
{
	test_proxy(settings_pack::socks5_pw, dont_proxy_trackers | expect_http_connection | expect_udp_connection);
}

TORRENT_TEST(http_tracker)
{
	test_proxy(settings_pack::http, dont_proxy_trackers | expect_http_connection | expect_udp_connection);
}

TORRENT_TEST(http_pw_tracker)
{
	test_proxy(settings_pack::http_pw, dont_proxy_trackers | expect_http_connection | expect_udp_connection);
}

// if we configure peers to not be proxied, they should be let through
TORRENT_TEST(socks4_peer)
{
	test_proxy(settings_pack::socks4, dont_proxy_peers | expect_peer_connection);
}

TORRENT_TEST(socks5_peer)
{
	test_proxy(settings_pack::socks5, dont_proxy_peers | expect_peer_connection);
}

TORRENT_TEST(socks5_pw_peer)
{
	test_proxy(settings_pack::socks5_pw, dont_proxy_peers | expect_peer_connection);
}

TORRENT_TEST(http_peer)
{
	test_proxy(settings_pack::http, dont_proxy_peers | expect_peer_connection);
}

TORRENT_TEST(http_pw_peer)
{
	test_proxy(settings_pack::http_pw, dont_proxy_peers | expect_peer_connection);
}
