/*

Copyright (c) 2022, 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 "setup_transfer.hpp" // for load_file
#include "test_utils.hpp"
#include "libtorrent/session.hpp"
#include "libtorrent/create_torrent.hpp"
#include "libtorrent/flags.hpp"
#include "libtorrent/aux_/path.hpp"
#include "libtorrent/random.hpp"
#include "libtorrent/alert_types.hpp"
#include "libtorrent/bencode.hpp"

namespace {

using lt::operator""_bit;
using similar_test_t = lt::flags::bitfield_flag<std::uint32_t, struct similar_test_type_tag>;

namespace st
{
	constexpr similar_test_t no_files = 0_bit;
	constexpr similar_test_t seed_mode = 1_bit;
	constexpr similar_test_t alt_b = 2_bit;
	constexpr similar_test_t alt_a = 3_bit;
	constexpr similar_test_t magnet = 4_bit;
	constexpr similar_test_t collection = 5_bit;
}

std::array<bool, 2> test(
	 similar_test_t const sflags
	, lt::create_flags_t const cflags1
	, lt::create_flags_t const cflags2)
{
	lt::error_code ec;
	lt::create_directories("./test-torrent-1", ec);
	TORRENT_ASSERT(!ec);

	std::vector<char> A(0x8000);
	std::vector<char> B(0x5000);
	lt::aux::random_bytes(A);
	lt::aux::random_bytes(B);

	std::vector<char> A_alt(0x8000);
	lt::aux::random_bytes(A_alt);
	std::vector<char> B_alt(0x5000);
	lt::aux::random_bytes(B_alt);

	{
		ofstream f("./test-torrent-1/A");
		f.write(A.data(), int(A.size()));
	}

	{
		ofstream f("./test-torrent-1/B");
		f.write(B.data(), int(B.size()));
	}

	auto t1 = [&] {
		lt::file_storage fs;
		fs.add_file(ec, "test-torrent-1/A", std::int64_t(A.size()));
		fs.add_file(ec, "test-torrent-1/B", std::int64_t(B.size()));
		lt::create_torrent t(fs, 0, cflags1);
		lt::set_piece_hashes(t, ".");
		if (sflags & st::collection)
			t.add_collection("test collection");
		std::vector<char> torrent;
		lt::bencode(back_inserter(torrent), t.generate());
		return std::make_shared<lt::torrent_info>(torrent, lt::from_span);
	}();

	lt::create_directories("test-torrent-2", ec);
	TORRENT_ASSERT(!ec);

	if (sflags & st::alt_a)
	{
		ofstream f("test-torrent-2/A");
		f.write(A_alt.data(), int(A_alt.size()));
	}
	else
	{
		ofstream f("test-torrent-2/A");
		f.write(A.data(), int(A.size()));
	}

	if (sflags & st::alt_b)
	{
		ofstream f("test-torrent-2/B");
		f.write(B_alt.data(), int(B_alt.size()));
	}
	else
	{
		ofstream f("test-torrent-2/B");
		f.write(B.data(), int(B.size()));
	}

	auto t2 = [&] {
		lt::file_storage fs;
		fs.add_file(ec, "test-torrent-2/A", std::int64_t(A.size()));
		fs.add_file(ec, "test-torrent-2/B", std::int64_t(B.size()));
		lt::create_torrent t(fs, 0, cflags2);
		lt::set_piece_hashes(t, ".");
		if (sflags & st::collection)
			t.add_collection("test collection");
		else
			t.add_similar_torrent(t1->info_hash());
		std::vector<char> torrent;
		lt::bencode(back_inserter(torrent), t.generate());
		return std::make_shared<lt::torrent_info>(torrent, lt::from_span);
	}();

	if (sflags & st::no_files)
	{
		lt::remove_all("test-torrent-1", ec);
		TORRENT_ASSERT(!ec);
	}

	lt::remove_all("test-torrent-2", ec);
	TORRENT_ASSERT(!ec);

	lt::settings_pack pack;
	pack.set_bool(lt::settings_pack::enable_dht, false);
	pack.set_bool(lt::settings_pack::enable_lsd, false);
	pack.set_bool(lt::settings_pack::enable_natpmp, false);
	pack.set_bool(lt::settings_pack::enable_upnp, false);
	pack.set_int(lt::settings_pack::alert_mask, lt::alert::all_categories);
	lt::session ses(pack);

	lt::add_torrent_params atp;
	atp.flags &= ~lt::torrent_flags::auto_managed;
	atp.flags &= ~lt::torrent_flags::paused;

	if (sflags & st::seed_mode)
		atp.flags |= lt::torrent_flags::seed_mode;

	atp.ti = t1;
	atp.save_path = ".";
	lt::torrent_handle h1 = ses.add_torrent(atp);

	wait_for_seeding(ses, "1");

	if (sflags & st::magnet)
	{
		atp.ti.reset();
		atp.info_hashes = t2->info_hashes();
	}
	else
	{
		atp.ti = t2;
	}
	atp.flags &= ~lt::torrent_flags::seed_mode;
	lt::torrent_handle h2 = ses.add_torrent(atp);

	if (sflags & st::magnet)
	{
		h2.set_metadata(t2->info_section());
	}

	std::array<bool, 2> completed_files{{false, false}};

	// wait for torrent 2 to either start downloading or finish. While waiting,
	// record which files it completes
	auto const start_time = lt::clock_type::now();
	for (;;)
	{
		auto const done = print_alerts(ses, "2", false, false
			, [&](lt::alert const* al)
			{
				if (auto const* sc = lt::alert_cast<lt::state_changed_alert>(al))
				{
					return sc->handle == h2
						&& (sc->state == lt::torrent_status::seeding
						|| sc->state == lt::torrent_status::finished
						|| sc->state == lt::torrent_status::downloading);
				}
				if (auto const* fc = lt::alert_cast<lt::file_completed_alert>(al))
				{
					if (fc->handle == h2)
						completed_files[std::size_t(static_cast<int>(fc->index))] = true;
				}
				return false;
			}, false);
		if (done) break;

		if (lt::clock_type::now() - start_time > lt::seconds(5))
		{
			TEST_ERROR("timeout");
			break;
		}
		ses.wait_for_alert(lt::seconds(5));
	}

	return completed_files;
}

}

using bools = std::array<bool, 2>;

auto const v1 = lt::create_torrent::v1_only;
auto const v2 = lt::create_torrent::v2_only;
auto const canon = lt::create_torrent::canonical_files;

TORRENT_TEST(shared_files_v1_no_pad)
{
	// the first file will be aligned, and since its size is an even multiple of
	// the piece size, the second file will too
	TEST_CHECK(test({}, v1, v1) == bools({true, true}));
}

TORRENT_TEST(shared_files_v1)
{
	// with canonical files, all files are aligned
	TEST_CHECK(test({}, v1 | canon, v1 | canon) == bools({true, true}));
}

TORRENT_TEST(shared_files_v1_collection)
{
	TEST_CHECK(test(st::collection, v1 | canon, v1 | canon) == bools({true, true}));
}

TORRENT_TEST(shared_files_v1_magnet)
{
	TEST_CHECK(test(st::magnet, v1 | canon, v1 | canon) == bools({true, true}));
}

TORRENT_TEST(shared_files_v1_magnet_collection)
{
	TEST_CHECK(test(st::magnet | st::collection, v1 | canon, v1 | canon) == bools({true, true}));
}

TORRENT_TEST(shared_files_v2_magnet)
{
	TEST_CHECK(test(st::magnet, v2, v2) == bools({true, true}));
}

TORRENT_TEST(shared_files_v2_magnet_collection)
{
	TEST_CHECK(test(st::magnet | st::collection, v2, v2) == bools({true, true}));
}

TORRENT_TEST(shared_files_hybrid_magnet)
{
	TEST_CHECK(test(st::magnet, {}, {}) == bools({true, true}));
}

TORRENT_TEST(shared_files_v1_v2_magnet)
{
	TEST_CHECK(test(st::magnet, v1 | canon, v2) == bools({false, false}));
}

TORRENT_TEST(shared_files_seed_mode_v1)
{
	TEST_CHECK(test(st::seed_mode, v1 | canon, v1 | canon) == bools({true, true}));
}

TORRENT_TEST(shared_files_seed_mode_v1_no_files)
{
	// no files on disk, just an (incorrect) promise of being in seed mode
	// creating the hard links will fail
	TEST_CHECK(test(st::no_files | st::seed_mode, v1 | canon, v1 | canon) == bools({false, false}));
}

TORRENT_TEST(single_shared_files_v1_b)
{
	TEST_CHECK(test(st::alt_b, v1 | canon, v1 | canon) == bools({true, false}));
}

TORRENT_TEST(single_shared_files_v1_a)
{
	TEST_CHECK(test(st::alt_a, v1 | canon, v1 | canon) == bools({false, true}));
}

TORRENT_TEST(shared_files_v1_v2)
{
	// v1 piece hashes cannot be compared to the v2 merkle roots
	TEST_CHECK(test({}, v1 | canon, v2) == bools({false, false}));
}

TORRENT_TEST(shared_files_v2)
{
	TEST_CHECK(test({}, v2, v2) == bools({true, true}));
}

TORRENT_TEST(shared_files_v2_collection)
{
	TEST_CHECK(test(st::collection, v2, v2) == bools({true, true}));
}

TORRENT_TEST(shared_files_seed_mode_v2)
{
	TEST_CHECK(test(st::seed_mode, v2, v2) == bools({true, true}));
}

TORRENT_TEST(shared_files_seed_mode_v2_no_files)
{
	TEST_CHECK(test(st::no_files | st::seed_mode, v2, v2) == bools({false, false}));
}

TORRENT_TEST(single_shared_files_v2_b)
{
	TEST_CHECK(test(st::alt_b, v2, v2) == bools({true, false}));
}

TORRENT_TEST(single_shared_files_v2_a)
{
	TEST_CHECK(test(st::alt_a, v2, v2) == bools({false, true}));
}

TORRENT_TEST(shared_files_hybrid)
{
	TEST_CHECK(test({}, {}, {}) == bools({true, true}));
}

TORRENT_TEST(shared_files_hybrid_v2)
{
	TEST_CHECK(test({}, {}, v2) == bools({true, true}));
}