/*

Copyright (c) 2014-2021, Arvid Norberg
Copyright (c) 2016, Andrei Kurushin
Copyright (c) 2016, Eugene Shalygin
Copyright (c) 2017, Steven Siloti
Copyright (c) 2018, 2020-2021, Alden Torres
All rights reserved.

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

#include "libtorrent/session.hpp"
#include "libtorrent/session_settings.hpp"
#include "libtorrent/alert_types.hpp"
#include "libtorrent/time.hpp"
#include "libtorrent/aux_/random.hpp"
#include "libtorrent/session_params.hpp"
#include "libtorrent/aux_/path.hpp"
#include <iostream>
#include <tuple>

#include "test.hpp"
#include "test_utils.hpp"
#include "setup_transfer.hpp"
#include "settings.hpp"
#include "swarm_suite.hpp"

#ifdef _MSC_VER
#pragma warning(push)
// warning C4706: assignment within conditional expression
#pragma warning( disable : 4706 )
#endif

void test_swarm(test_flags_t const flags)
{
	using namespace lt;

	std::printf("\n\n ==== TEST SWARM === %s%s%s%s%s%s%s ===\n\n\n"
		, (flags & test_flags::super_seeding) ? "super-seeding ": ""
		, (flags & test_flags::strict_super_seeding) ? "strict-super-seeding ": ""
		, (flags & test_flags::seed_mode) ? "seed-mode ": ""
		, (flags & test_flags::time_critical) ? "time-critical ": ""
		, (flags & test_flags::suggest) ? "suggest ": ""
		, (flags & test_flags::v1_meta) ? "v1-meta ": ""
		, (flags & test_flags::v2_meta) ? "v2-meta ": ""
		);

	// in case the previous run was terminated
	error_code ec;
	remove_all("tmp1_swarm", ec);
	remove_all("tmp2_swarm", ec);
	remove_all("tmp3_swarm", ec);

	// these are declared before the session objects
	// so that they are destructed last. This enables
	// the sessions to destruct in parallel
	session_proxy p1;
	session_proxy p2;
	session_proxy p3;

	settings_pack pack = settings();
	pack.set_bool(settings_pack::allow_multiple_connections_per_ip, true);

#if TORRENT_ABI_VERSION == 1
	if (flags & test_flags::strict_super_seeding)
		pack.set_bool(settings_pack::strict_super_seeding, true);
#endif

	if (flags & test_flags::suggest)
		pack.set_int(settings_pack::suggest_mode, settings_pack::suggest_read_cache);

	// this is to avoid everything finish from a single peer
	// immediately. To make the swarm actually connect all
	// three peers before finishing.
	float const rate_limit = 100000;

	pack.set_int(settings_pack::upload_rate_limit, int(rate_limit));
	pack.set_str(settings_pack::listen_interfaces, test_listen_interface());
	pack.set_int(settings_pack::max_retry_port_bind, 1000);

	pack.set_int(settings_pack::out_enc_policy, settings_pack::pe_forced);
	pack.set_int(settings_pack::in_enc_policy, settings_pack::pe_forced);

	lt::session ses1(pack);

	pack.set_str(settings_pack::listen_interfaces, test_listen_interface());
	pack.set_int(settings_pack::download_rate_limit, int(rate_limit / 2));
	pack.set_int(settings_pack::upload_rate_limit, int(rate_limit));
	lt::session ses2(pack);

	pack.set_str(settings_pack::listen_interfaces, test_listen_interface());
	lt::session ses3(pack);

	add_torrent_params p;
	p.flags &= ~torrent_flags::paused;
	p.flags &= ~torrent_flags::auto_managed;
	if (flags & test_flags::seed_mode) p.flags |= torrent_flags::seed_mode;
	// test v1 metadata using piece sizes smaller than 16kB
	int const piece_size = (flags & test_flags::v1_meta) ? 8 * 1024 : 16 * 1024;
	auto const [tor1, tor2, tor3] = setup_transfer(&ses1, &ses2, &ses3, true
		, false, true, "_swarm", piece_size, &p, bool(flags & test_flags::super_seeding)
		, true, false, nullptr
		, (flags & test_flags::v1_meta) ? create_torrent::v1_only
		: (flags & test_flags::v2_meta) ? create_torrent::v2_only
		: create_flags_t{});

	if (flags & test_flags::time_critical)
	{
		tor2.set_piece_deadline(2_piece, 0);
		tor2.set_piece_deadline(5_piece, 1000);
		tor2.set_piece_deadline(8_piece, 2000);
	}

	float sum_dl_rate2 = 0.f;
	float sum_dl_rate3 = 0.f;
	int count_dl_rates2 = 0;
	int count_dl_rates3 = 0;

	// none of this suite's scenarios ever hand out intentionally corrupt
	// data, so a hash check failure anywhere in the swarm (including a
	// seed-mode piece failing its lazy verification) is always a bug, not
	// a condition to silently tolerate via the fall-back recheck.
	auto const fail_on_hash_failure = [](lt::alert const* a) {
		if (auto const* hf = alert_cast<hash_failed_alert>(a))
		{
			std::printf("unexpected hash failure: piece %d\n", static_cast<int>(hf->piece_index));
			TEST_CHECK(false);
		}
		return false;
	};

	auto const start_time = lt::clock_type::now();
	for (int i = 0; i < 80; ++i)
	{
		print_alerts(ses1, "ses1", false, false, fail_on_hash_failure);
		print_alerts(ses2, "ses2", false, false, fail_on_hash_failure);
		print_alerts(ses3, "ses3", false, false, fail_on_hash_failure);

		torrent_status st1 = tor1.status();
		torrent_status st2 = tor2.status();
		torrent_status st3 = tor3.status();

		if (flags & test_flags::super_seeding)
		{
			TEST_CHECK(st1.is_seeding);
			TEST_CHECK(tor1.flags() & torrent_flags::super_seeding);
		}

		if (st2.progress < 1.f && st2.progress > 0.5f)
		{
			sum_dl_rate2 += float(st2.download_payload_rate);
			++count_dl_rates2;
		}
		if (st3.progress < 1.f && st3.progress > 0.5f)
		{
			sum_dl_rate3 += float(st3.download_rate);
			++count_dl_rates3;
		}

		print_ses_rate(start_time, &st1, &st2, &st3);

		if (st2.is_seeding && st3.is_seeding) break;
		std::this_thread::sleep_for(lt::milliseconds(1000));
	}

	TEST_CHECK(tor2.status().is_seeding);
	TEST_CHECK(tor3.status().is_seeding);

	float average2 = count_dl_rates2 > 0 ? sum_dl_rate2 / float(count_dl_rates2) : -1;
	float average3 = count_dl_rates3 > 0 ? sum_dl_rate3 / float(count_dl_rates3) : -1;

	std::cout << "average rate: " << (average2 / 1000.f) << "kB/s - "
		<< (average3 / 1000.f) << "kB/s" << std::endl;

	if (tor2.status().is_seeding && tor3.status().is_seeding) std::cout << "done\n";

	// make sure the files are deleted
	ses1.remove_torrent(tor1, lt::session::delete_files);
	ses2.remove_torrent(tor2, lt::session::delete_files);
	ses3.remove_torrent(tor3, lt::session::delete_files);

	alert const* a = wait_for_alert(ses1, torrent_deleted_alert::alert_type, "swarm_suite");

	TEST_CHECK(alert_cast<torrent_deleted_alert>(a) != nullptr);

	// there shouldn't be any alerts generated from now on
	// make sure that the timer in wait_for_alert() works
	// this should time out (ret == 0) and it should take
	// about 2 seconds
	time_point start = clock_type::now();
	while (ses1.wait_for_alert(seconds(2)))
	{
		std::printf("wait returned: %d ms\n"
			, int(total_milliseconds(clock_type::now() - start)));
		std::vector<alert*> alerts;
		ses1.pop_alerts(&alerts);
		for (auto ap : alerts)
		{
			std::printf("%s\n", ap->message().c_str());
		}
		start = clock_type::now();
	}

	std::printf("loop returned: %d ms\n"
		, int(total_milliseconds(clock_type::now() - start)));

	// this allows shutting down the sessions in parallel
	p1 = ses1.abort();
	p2 = ses2.abort();
	p3 = ses3.abort();

	time_point const end = clock_type::now();

	std::printf("time: %d ms\n", int(total_milliseconds(end - start)));
	TEST_CHECK(end - start < milliseconds(3000));
	TEST_CHECK(end - start > milliseconds(1900));

	TEST_CHECK(!exists("tmp1_swarm/temporary"));
	TEST_CHECK(!exists("tmp2_swarm/temporary"));
	TEST_CHECK(!exists("tmp3_swarm/temporary"));

	remove_all("tmp1_swarm", ec);
	remove_all("tmp2_swarm", ec);
	remove_all("tmp3_swarm", ec);
}

#ifdef _MSC_VER
#pragma warning(pop)
#endif
