#include "WebsocketGameClient.h"
#include "NetworkProtocol.h"
#include <boost/asio.hpp>
#include <boost/beast.hpp>
#include <atomic>
#include <iostream>
#include <mutex>
#include <thread>
#include <utility>
#include <vector>

namespace FRG {
namespace {

namespace asio = boost::asio;
namespace beast = boost::beast;
namespace websocket = beast::websocket;
using tcp = asio::ip::tcp;

} // namespace

class WebsocketGameClient::Impl {
public:
	Impl(std::string host, std::string port, std::string path)
		: resolver_(io_)
		, socket_(io_)
		, host_(std::move(host))
		, port_(std::move(port))
		, path_(std::move(path))
	{
		resolve();
		thread_ = std::thread([this]() { io_.run(); });
	}

	~Impl()
	{
		io_.stop();
		if (thread_.joinable()) thread_.join();
	}

	std::vector<std::string> takeMessages()
	{
		std::lock_guard<std::mutex> lock(messagesMutex_);
		std::vector<std::string> result;
		result.swap(messages_);
		return result;
	}

	bool connected() const { return connected_.load(); }

private:
	void resolve()
	{
		resolver_.async_resolve(
			host_, port_,
			[this](beast::error_code error, tcp::resolver::results_type results) {
				if (error) return fail("resolve", error);
				asio::async_connect(
					socket_.next_layer(), results,
					[this](beast::error_code connectError,
						const tcp::endpoint&) {
						if (connectError) return fail("connect", connectError);
						socket_.set_option(
							websocket::stream_base::timeout::suggested(
								beast::role_type::client));
						socket_.async_handshake(
							host_, path_,
							[this](beast::error_code handshakeError) {
								if (handshakeError)
									return fail("handshake", handshakeError);
								connected_.store(true);
								std::cout
									<< "[network] Connected to ws://"
									<< host_ << ':' << port_ << path_ << '\n';
								read();
							});
					});
			});
	}

	void read()
	{
		socket_.async_read(
			buffer_,
			[this](beast::error_code error, std::size_t) {
				if (error) {
					connected_.store(false);
					if (error != websocket::error::closed) fail("read", error);
					return;
				}
				std::string message = beast::buffers_to_string(buffer_.data());
				buffer_.consume(buffer_.size());
				{
					std::lock_guard<std::mutex> lock(messagesMutex_);
					messages_.push_back(std::move(message));
				}
				read();
			});
	}

	void fail(const char* operation, beast::error_code error)
	{
		connected_.store(false);
		std::cerr << "[network] WebSocket " << operation << " failed: "
			<< error.message() << '\n';
	}

	asio::io_context io_;
	tcp::resolver resolver_;
	websocket::stream<tcp::socket> socket_;
	beast::flat_buffer buffer_;
	std::thread thread_;
	std::string host_;
	std::string port_;
	std::string path_;
	std::atomic_bool connected_{false};
	std::mutex messagesMutex_;
	std::vector<std::string> messages_;
};

WebsocketGameClient::WebsocketGameClient(
	std::string host, std::string port, std::string path)
	: impl_(std::make_unique<Impl>(
		std::move(host), std::move(port), std::move(path)))
{
}

WebsocketGameClient::~WebsocketGameClient() = default;

std::shared_ptr<const GameSnapshot> WebsocketGameClient::snapshot() const
{
	return replica_.snapshot();
}

const std::string& WebsocketGameClient::localPlayerId() const
{
	return replica_.localPlayerId();
}

void WebsocketGameClient::submit(const GameCommand&)
{
	// Commands intentionally remain local no-ops in the first iteration.
}

std::vector<GameServerEvent> WebsocketGameClient::drainEvents()
{
	return {};
}

void WebsocketGameClient::update(std::int64_t)
{
	std::vector<std::string> messages = impl_->takeMessages();
	if (messages.empty()) return;

	// State messages are complete snapshots; only the newest queued one matters.
	for (auto it = messages.rbegin(); it != messages.rend(); ++it) {
		nlohmann::json state;
		std::string error;
		if (!parseStateMessage(*it, state, error)) {
			std::cerr << "[network] Ignoring WebSocket message: "
				<< error << '\n';
			continue;
		}
		try {
			replica_.load(state);
		} catch (const std::exception& exception) {
			std::cerr << "[network] Ignoring invalid game state: "
				<< exception.what() << '\n';
		}
		break;
	}
}

void WebsocketGameClient::save(nlohmann::json&) const
{
	// Persistence remains server-side.
}

void WebsocketGameClient::load(const nlohmann::json&)
{
	// Persistence remains server-side.
}

bool WebsocketGameClient::connected() const
{
	return impl_->connected();
}

} // namespace FRG