// SPDX-License-Identifier: Apache-2.0
// Copyright chargebyte GmbH and Contributors to EVerest
#ifndef RPCHANDLER_HPP
#define RPCHANDLER_HPP

#include <atomic>
#include <condition_variable>
#include <cstdint>
#include <deque>
#include <functional>
#include <jsonrpccxx/client.hpp>
#include <jsonrpccxx/server.hpp>
#include <memory>
#include <mutex>
#include <optional>
#include <stdexcept>
#include <string>
#include <thread>
#include <unordered_map>
#include <vector>

#include "../helpers/LimitDecimalPlaces.hpp"
#include "../server/TransportInterface.hpp"
#include "RequestHandlerInterface.hpp"
#include "methods/Api.hpp"
#include "methods/ChargePoint.hpp"
#include "methods/Evse.hpp"
#include "notifications/ChargePoint.hpp"
#include "notifications/Evse.hpp"

using namespace server;
using namespace jsonrpccxx;

namespace rpc {

static const std::chrono::seconds CLIENT_HELLO_TIMEOUT(5);

// struct to store json data, plus the transport interface
struct ClientReq {
    std::shared_ptr<server::TransportInterface> transport_interface;
    std::deque<nlohmann::json> data; // Queue of requests
};

class ClientConnector : public jsonrpccxx::IClientConnector {
public:
    explicit ClientConnector(std::vector<std::shared_ptr<TransportInterface>>& interfaces,
                             std::unordered_map<TransportInterface::ClientId, bool>& api_hello_received,
                             std::mutex& api_hello_mutex) :
        hello_received(api_hello_received), transport_interfaces(interfaces), hello_mutex(api_hello_mutex) {
    }
    std::string Send(const std::string& notification) override {
        const std::vector<uint8_t> notif_char_array{notification.begin(), notification.end()};
        std::vector<TransportInterface::ClientId> recipients;
        {
            std::lock_guard<std::mutex> lock(hello_mutex);
            recipients.reserve(hello_received.size());
            for (const auto& rec : hello_received) {
                if (rec.second) {
                    recipients.push_back(rec.first);
                }
            }
        }

        for (const auto& interface : transport_interfaces) {
            for (const auto& client_id : recipients) {
                interface->send_data(client_id, notif_char_array);
            }
        }
        return "";
    }

private:
    std::unordered_map<TransportInterface::ClientId, bool>& hello_received;
    std::vector<std::shared_ptr<TransportInterface>>& transport_interfaces;
    std::mutex& hello_mutex;
};
// Members

class JsonRpc2ServerWithClient : public JsonRpc2Server, public JsonRpcClient {
public:
    JsonRpc2ServerWithClient() = delete;
    explicit JsonRpc2ServerWithClient(ClientConnector& i) : JsonRpc2Server(), JsonRpcClient(i, version::v2){};
    // helper to be able to put data object into caller
    // which is something which json-rpc-cxx should be doing
    template <typename T> void CallNotificationWithObject(const std::string& name, const T& in, int precision = 3) {
        nlohmann::json j;
        nlohmann::to_json(j, in);
        helpers::round_floats_in_json(j, precision);
        CallNotificationNamed(name, j);
    }
};

class RpcHandler {
public:
    // Constructor and Destructor
    RpcHandler() = delete;
    // RpcHandler just needs a transport interface array
    RpcHandler(std::vector<std::shared_ptr<server::TransportInterface>> transport_interfaces, DataStoreCharger& dataobj,
               std::unique_ptr<request_interface::RequestHandlerInterface> request_handler, int precision = 3);

    ~RpcHandler() = default;

    // Methods
    void start_server();
    void stop_server();

private:
    void init_rpc_api();
    void init_transport_interfaces();
    void client_connected(const std::shared_ptr<server::TransportInterface>& transport_interfaces,
                          const TransportInterface::ClientId& client_id, const TransportInterface::Address& address);
    void client_disconnected(const std::shared_ptr<server::TransportInterface>& transport_interfaces,
                             const server::TransportInterface::ClientId& client_id);
    void data_available(const std::shared_ptr<server::TransportInterface>& transport_interfaces,
                        const TransportInterface::ClientId& client_id, const TransportInterface::Data& data);
    inline bool is_api_hello_req(const TransportInterface::ClientId& client_id, const nlohmann::json& request) {
        // Check if the request is a hello request
        if (request.contains("method") && request["method"] == methods::METHOD_API_HELLO) {
            // If it's a API.Hello request, we set the api_hello_received flag to true
            // and notify the condition variable to unblock the waiting thread
            m_api_hello_received[client_id] = true;
            return true;
        }
        return false;
    }
    void process_client_requests();

    std::vector<std::shared_ptr<TransportInterface>> m_transport_interfaces;
    DataStoreCharger& m_data_store;
    std::mutex m_mtx;
    std::condition_variable m_cv_api_hello;
    std::condition_variable m_cv_data_available;
    std::unordered_map<TransportInterface::ClientId, bool> m_api_hello_received;
    std::shared_ptr<JsonRpc2ServerWithClient> m_rpc_server;
    std::unordered_map<TransportInterface::ClientId, ClientReq> messages;
    std::chrono::steady_clock::time_point m_last_req_notification; // Last tick time
    std::thread m_rpc_recv_thread;
    std::atomic<bool> m_is_running{false};

    methods::Api m_methods_api;
    methods::ChargePoint m_methods_chargepoint;
    methods::Evse m_methods_evse;
    ClientConnector m_conn;
    std::unique_ptr<notifications::ChargePoint> m_notifications_chargepoint;
    std::unique_ptr<notifications::Evse> m_notifications_evse;
    int m_precision = 3;
};
} // namespace rpc

#endif // RPCHANDLER_HPP