#include <boost/test/unit_test.hpp>

#include <boost/asio/any_completion_handler.hpp>

#include <async_mqtt5/mqtt_client.hpp>

#include "test_common/message_exchange.hpp"
#include "test_common/test_service.hpp"
#include "test_common/test_stream.hpp"

using namespace async_mqtt5;

BOOST_AUTO_TEST_SUITE(read_message/*, *boost::unit_test::disabled()*/)

using test::after;
using namespace std::chrono;

void test_receive_malformed_packet(
	std::string malformed_packet, std::string reason_string
) {
	// packets
	auto connect = encoders::encode_connect(
		"", std::nullopt, std::nullopt, 60, false, {}, std::nullopt
	);
	connack_props co_props;
	co_props[prop::maximum_packet_size] = 2000;
	auto connack = encoders::encode_connack(false, reason_codes::success.value(), co_props);

	disconnect_props dc_props;
	dc_props[prop::reason_string] = reason_string;
	auto disconnect = encoders::encode_disconnect(
		reason_codes::malformed_packet.value(), dc_props
	);

	error_code success {};
	test::msg_exchange broker_side;
	broker_side
		.expect(connect)
			.complete_with(success, after(0ms))
			.reply_with(connack, after(0ms))
		.send(malformed_packet, after(5ms))
		.expect(disconnect)
			.complete_with(success, after(0ms))
		.expect(connect)
			.complete_with(success, after(0ms))
			.reply_with(connack, after(0ms));


	asio::io_context ioc;
	auto executor = ioc.get_executor();
	auto& broker = asio::make_service<test::test_broker>(
		ioc, executor, std::move(broker_side)
	);

	using client_type = mqtt_client<test::test_stream>;
	client_type c(executor);
	c.brokers("127.0.0.1,127.0.0.1") // to avoid reconnect backoff
		.async_run(asio::detached);

	asio::steady_timer timer(c.get_executor());
	timer.expires_after(100ms);
	timer.async_wait([&c](error_code) { c.cancel(); });

	ioc.run();
	BOOST_TEST(broker.received_all_expected());
}

BOOST_AUTO_TEST_CASE(forbidden_packet_type) {
	test_receive_malformed_packet(
		std::string({ 0x00 }),
		"Malformed Packet received from the Server"
	);
}

BOOST_AUTO_TEST_CASE(malformed_varint) {
	test_receive_malformed_packet(
		std::string({ 0x10, -1 /* 0xFF */, -1, -1, -1 }),
		"Malformed Packet received from the Server"
	);
}

BOOST_AUTO_TEST_CASE(malformed_fixed_header) {
	test_receive_malformed_packet(
		std::string({ 0x60, 1, 0 }),
		"Malformed Packet received from the Server"
	);
}

BOOST_AUTO_TEST_CASE(packet_larger_than_allowed) {
	test_receive_malformed_packet(
		std::string({ 0x10, -1, -1, -1, 0 }),
		"Malformed Packet received from the Server"
	);
}

BOOST_AUTO_TEST_CASE(receive_malformed_publish) {
	test_receive_malformed_packet(
		std::string({ 0x30, 1, -1 }),
		"Malformed PUBLISH received: cannot decode"
	);
}

struct shared_test_data {
	error_code success{};
	error_code fail = asio::error::not_connected;

	const std::string topic = "topic";
	const std::string payload = "payload";

	const std::string connect = encoders::encode_connect(
		"", std::nullopt, std::nullopt, 60, false, {}, std::nullopt
	);
	const std::string connack = encoders::encode_connack(false, uint8_t(0x00), {});

	const std::string publish = encoders::encode_publish(
		0, topic, payload, qos_e::at_most_once, retain_e::no, dup_e::no, {}
	);

	std::string encode_disconnect_with_rs(std::string_view reason_string) {
		disconnect_props dc_props;
		dc_props[prop::reason_string] = reason_string;
		return encoders::encode_disconnect(
			reason_codes::malformed_packet.value(), dc_props
		);
	}
};

BOOST_FIXTURE_TEST_CASE(receive_disconnect, shared_test_data) {
	// packets
	auto disconnect = encoders::encode_disconnect(0x00, {});

	test::msg_exchange broker_side;
	broker_side
		.expect(connect)
			.complete_with(success, after(0ms))
			.reply_with(connack, after(0ms))
		.send(disconnect, after(5ms))
		.expect(connect)
			.complete_with(success, after(0ms))
			.reply_with(connack, after(0ms));

	asio::io_context ioc;
	auto executor = ioc.get_executor();
	auto& broker = asio::make_service<test::test_broker>(
		ioc, executor, std::move(broker_side)
	);

	using client_type = mqtt_client<test::test_stream>;
	client_type c(executor);
	c.brokers("127.0.0.1,127.0.0.1") // to avoid reconnect backoff
		.async_run(asio::detached);

	asio::steady_timer timer(c.get_executor());
	timer.expires_after(100ms);
	timer.async_wait([&c](error_code) { c.cancel(); });

	ioc.run();
	BOOST_TEST(broker.received_all_expected());
}

template <typename VerifyFun>
void run_receive_test(
	test::msg_exchange broker_side, int num_of_receives,
	VerifyFun&& verify_fun
) {
	const int expected_handlers_called = num_of_receives;
	int handlers_called = 0;

	asio::io_context ioc;
	auto executor = ioc.get_executor();
	auto& broker = asio::make_service<test::test_broker>(
		ioc, executor, std::move(broker_side)
	);

	using client_type = mqtt_client<test::test_stream>;
	client_type c(executor);
	c.brokers("127.0.0.1,127.0.0.1") // to avoid reconnect backoff
		.async_run(asio::detached);

	for (int i = 0; i < num_of_receives; ++i)
		c.async_receive([&](
			error_code ec,
			std::string topic, std::string payload, publish_props props
		) {
			handlers_called++;
			verify_fun(ec, topic, payload, props);

			if (handlers_called == expected_handlers_called)
				c.cancel();
		});

	ioc.run();
	BOOST_TEST(handlers_called == expected_handlers_called);
	BOOST_TEST(broker.received_all_expected());
}

BOOST_FIXTURE_TEST_CASE(receive_byte_by_byte, shared_test_data) {
	test::msg_exchange broker_side;
	broker_side
		.expect(connect)
			.complete_with(success, after(0ms))
			.reply_with(connack, after(0ms));

	for (size_t i = 0; i < publish.size(); i++)
		broker_side.send(
			std::string { publish[i] }, after(std::chrono::milliseconds(i + 7))
		);

	auto verify_fun = [&](
		error_code ec, std::string topic_, std::string payload_, publish_props
	) {
		BOOST_TEST(!ec);
		BOOST_TEST(topic == topic_);
		BOOST_TEST(payload == payload_);
	};

	run_receive_test(std::move(broker_side), 1, std::move(verify_fun));
}

BOOST_FIXTURE_TEST_CASE(receive_multiple_packets_at_once, shared_test_data) {
	test::msg_exchange broker_side;
	broker_side
		.expect(connect)
			.complete_with(success, after(1ms))
			.reply_with(connack, after(2ms))
		.send(publish, publish, publish, publish, publish, after(100ms));

	auto verify_fun = [&](
		error_code ec, std::string topic_, std::string payload_, publish_props
		) {
			BOOST_TEST(!ec);
			BOOST_TEST(topic == topic_);
			BOOST_TEST(payload == payload_);
		};

	run_receive_test(std::move(broker_side), 5, std::move(verify_fun));
}

BOOST_FIXTURE_TEST_CASE(receive_multiple_packets_with_malformed, shared_test_data) {
	// packets
	// ghost publishes need to be cleared once the client reads the malformed packet
	auto ghost_publish = encoders::encode_publish(
		0, topic, "should not be received!", qos_e::at_most_once, retain_e::no, dup_e::no, {}
	);

	test::msg_exchange broker_side;
	broker_side
		.expect(connect)
			.complete_with(success, after(1ms))
			.reply_with(connack, after(2ms))
		.send(
			publish, publish, std::string({ 0x00 }) /* malformed */,
			ghost_publish, ghost_publish, after(100ms)
		)
		.expect(encode_disconnect_with_rs("Malformed Packet received from the Server"))
		.expect(connect)
			.complete_with(success, after(1ms))
			.reply_with(connack, after(2ms))
		.send(publish, after(300ms));

	auto verify_fun = [&](
		error_code ec, std::string topic_, std::string payload_, publish_props
	) {
		BOOST_TEST(!ec);
		BOOST_TEST(topic == topic_);
		BOOST_TEST(payload == payload_);
	};

	run_receive_test(std::move(broker_side), 3, std::move(verify_fun));
}

BOOST_AUTO_TEST_SUITE_END();