#ifndef MODBUS_TCP_SERVER_H
#define MODBUS_TCP_SERVER_H

#include "IYModbusTCPServer.h"
#include <functional>
#include <vector>
#include <thread>
#include <mutex>
#include <atomic>
#include <memory>
#include <unordered_map>

// libmodbus headers
extern "C" {
#include "modbus.h"
#include "modbus-tcp.h"
}

class ModbusTCPServer : public IYModbusTCPServer {
private:
    // 客户端连接结构体
    struct ClientConnection {
        int socket;
        modbus_t* modbusCtx;
        
        ClientConnection(int sock, modbus_t* ctx) : socket(sock), modbusCtx(ctx) {}
        
        ~ClientConnection() {
            if (modbusCtx) {
                modbus_free(modbusCtx);
            }
#ifdef _WIN32
            if (socket != -1) {
                closesocket(socket);
            }
#else
            if (socket != -1) {
                close(socket);
            }
#endif
        }
    };

public:
    ModbusTCPServer();
    virtual ~ModbusTCPServer() override;

    // 实现IYModbusTCPServer接口
    // 启动/停止服务器
    virtual int start(int port = 502, int maxConnections = 10) override;
    virtual void stop() override;
    bool isRunning() const { return m_isRunning.load(); }
    
    // 设置回调函数
    virtual void setWriteCoilsCallback(WriteCoilsCallback callback) override { m_writeCoilsCallback = callback; }
    virtual void setWriteRegistersCallback(WriteRegistersCallback callback) override { m_writeRegistersCallback = callback; }
    virtual void setConnectionStatusCallback(ConnectionStatusCallback callback) override { m_connectionStatusCallback = callback; }
    
    // 数据更新接口 - 线程安全
    virtual void updateCoil(uint16_t address, bool value) override;
    virtual void updateCoils(uint16_t startAddress, const std::vector<bool>& values) override;
    virtual void updateDiscreteInput(uint16_t address, bool value) override;
    virtual void updateDiscreteInputs(uint16_t startAddress, const std::vector<bool>& values) override;
    virtual void updateHoldingRegister(uint16_t address, uint16_t value) override;
    virtual void updateHoldingRegisters(uint16_t startAddress, const std::vector<uint16_t>& values) override;
    virtual void updateInputRegister(uint16_t address, uint16_t value) override;
    virtual void updateInputRegisters(uint16_t startAddress, const std::vector<uint16_t>& values) override;
    
    // 获取错误信息
    std::string getLastError() const;

private:
    // 服务器主循环
    void serverLoop();
    
    // 客户端连接管理
    void handleNewConnection();
    void handleClientData(std::shared_ptr<ClientConnection> client);
    void removeClient(int socket);
    void processModbusRequest(std::shared_ptr<ClientConnection> client, const uint8_t* query, int queryLength);
    
    // 数据读取处理器（libmodbus内部调用）
    static int readCoilsHandler(modbus_t *ctx, int function_code, int addr, int nb, uint8_t *rsp, int *rsp_length, void *user_data);
    static int readDiscreteInputsHandler(modbus_t *ctx, int function_code, int addr, int nb, uint8_t *rsp, int *rsp_length, void *user_data);
    static int readHoldingRegistersHandler(modbus_t *ctx, int function_code, int addr, int nb, uint8_t *rsp, int *rsp_length, void *user_data);
    static int readInputRegistersHandler(modbus_t *ctx, int function_code, int addr, int nb, uint8_t *rsp, int *rsp_length, void *user_data);
    
    // 数据写入函数（libmodbus内部调用）
    static int writeCoilsHandler(modbus_t *ctx, int function_code, int addr, int nb, const uint8_t *req, int req_length, void *user_data);
    static int writeRegistersHandler(modbus_t *ctx, int function_code, int addr, int nb, const uint8_t *req, int req_length, void *user_data);

private:
    // libmodbus context
    modbus_t* m_modbusCtx;
    modbus_mapping_t* m_mapping;
    
    // 服务器状态
    std::atomic<bool> m_isRunning;
    std::atomic<bool> m_shouldStop;
    std::unique_ptr<std::thread> m_serverThread;
    int m_serverSocket;
    int m_port;
    int m_maxConnections;
    
    // 客户端连接管理
    std::unordered_map<int, std::shared_ptr<ClientConnection>> m_clients;
    std::mutex m_clientsMutex;
    
    // 数据存储 - 使用libmodbus的mapping结构
    std::mutex m_dataMutex;
    
    // 回调函数
    WriteCoilsCallback m_writeCoilsCallback;
    WriteRegistersCallback m_writeRegistersCallback;
    ConnectionStatusCallback m_connectionStatusCallback;
    
    // 错误信息
    mutable std::mutex m_errorMutex;
    std::string m_lastError;
    
    // 设置错误信息
    void setLastError(const std::string& error);
};

#endif // MODBUS_TCP_SERVER_H