#ifndef MODBUS_RTU_SLAVE_H
#define MODBUS_RTU_SLAVE_H

#include "stm32f4xx_hal.h"
#include <stdint.h>
#ifdef __cplusplus
extern "C"
{
#endif

/**
 * @brief Modbus 数据模型的最大地址
 *
 * 任务要求规定线圈和保持寄存器地址范围均为 0～0x270F，
 * 因此每种数据共有 10000 项
 */
#define MODBUS_MAP_LAST_ADDRESS (0x270FU) // 保持寄存器或线圈地址
#define MODBUS_MAP_ITEM_COUNT (0x2710U)   // 保持寄存器或线圈数量

#define MODBUS_SLAVE_DEFAULT_ADDRESS (1U)
#define MODBUS_CONNECTION_TIMEOUT_MS (1000U)

/* Read-only vendor diagnostics.  The request uses the same start/quantity
 * layout as function 0x03; diagnostic words are described below. */
#define MODBUS_RUNTIME_DIAGNOSTICS_FUNCTION (0x47U)
#define MODBUS_RUNTIME_DIAGNOSTICS_SIGNATURE (0x4D42U)
#define MODBUS_RUNTIME_DIAGNOSTICS_VERSION (1U)
#define MODBUS_RUNTIME_DIAGNOSTICS_WORDS (40U)

#define MODBUS_RUNTIME_FLAG_INITIALIZED (1U << 0U)
#define MODBUS_RUNTIME_FLAG_VALID_FRAME_SEEN (1U << 1U)
#define MODBUS_RUNTIME_FLAG_CONNECTED (1U << 2U)
#define MODBUS_RUNTIME_FLAG_TX_BUSY (1U << 3U)
#define MODBUS_RUNTIME_FLAG_RX_FRAME_READY (1U << 4U)
#define MODBUS_RUNTIME_FLAG_RX_ASSEMBLY_INVALID (1U << 5U)
#define MODBUS_RUNTIME_FLAG_RX_RESTART_OK (1U << 6U)

/**
 * @brief 与 TouchWin 触摸屏联调使用的演示地址
 *
 * 可以直接访问以下地址
 */
#define HMI_REG_DEVICE_ID (0U)
#define HMI_REG_UPTIME_SECONDS (1U)
#define HMI_REG_RX_FRAME_COUNT (2U)
#define D3 (3U)
#define D4 (4U)
#define D5 (5U)
#define D6 (6U)
#define D7 (7U)
#define HMI_REG_WRITE_TEST (10U)
#define HMI_COIL_WRITE_TEST (0U)

#define MODBUS_RETAINED_D_START (100U)
#define MODBUS_RETAINED_D_END (120U)
#define MODBUS_RETAINED_D_COUNT (21U)

#define MODBUS_BACKUP_MAGIC (0x44313030UL)

/**
 * @brief 掉电保持寄存器在Backup SRAM中的存储格式
 */
typedef struct
{
    uint32_t magic; ///< 掉电保持数据有效标志
    uint16_t retainedD[MODBUS_RETAINED_D_COUNT]; ///< D100～D120保持值
} MODBUS_BACKUP_DATA;
/**
 * @brief Modbus 从站通信统计信息
 */
typedef struct
{
    uint32_t rxEventCount;         ///< 串口接收事件总数
    uint32_t validFrameCount;      ///< CRC 和从站地址均有效的帧数
    uint32_t txFrameCount;         ///< 成功启动 DMA 发送的帧数
    uint32_t crcErrorCount;        ///< CRC 校验错误帧数
    uint32_t ignoredAddressCount;  ///< 因从站地址不匹配而忽略的帧数
    uint32_t illegalFunctionCount; ///< 非法功能码计数
    uint32_t illegalAddressCount;  ///< 非法数据地址计数
    uint32_t illegalValueCount;    ///< 非法数据值计数
    uint32_t droppedFrameCount;    ///< 接收槽占用或长度错误导致的丢帧数
    uint32_t uartErrorCount;       ///< HAL 串口错误计数
} MODBUS_SLAVE_STATS;

/**
 * @brief Read-only snapshot of the Modbus RTU runtime state.
 *
 * Every aligned 32-bit-or-smaller field is read without tearing on Cortex-M4.
 * The getter does not mask motion or UART interrupts, so the complete structure
 * may intentionally span adjacent UART events and is not a transaction-wide
 * atomic snapshot.
 */
typedef struct
{
    MODBUS_SLAVE_STATS statistics;
    uint32_t currentTick;
    uint32_t lastValidFrameTick;
    uint32_t lastInterFrameGapCycles;
    uint32_t receiveRestartAttemptCount;
    uint32_t receiveRestartFailureCount;
    uint32_t lastUartErrorCode;
    uint16_t rxAssemblyLength;
    uint16_t rxFrameLength;
    uint8_t lastReceiveStartStatus;
    uint8_t initialized;
    uint8_t hasReceivedValidFrame;
    uint8_t connected;
    uint8_t txBusy;
    uint8_t rxFrameReady;
    uint8_t rxAssemblyInvalid;
} MODBUS_SLAVE_RUNTIME_DIAGNOSTICS;
/** @brief Modbus 从站通信统计数据 */
extern volatile MODBUS_SLAVE_STATS ModbusSlaveStatistics;
/**
 * @brief 初始化 Modbus 从站并启动 USART DMA 空闲接收
 * @param[in] huart 已由 HAL 初始化完成的串口句柄
 * @param[in] slaveAddress 从站地址，有效范围为 1～247
 * @retval HAL_OK 初始化成功且 DMA 接收已启动
 * @retval HAL_ERROR 输入参数无效
 * @retval HAL_BUSY 串口或 DMA 当前忙
 */
HAL_StatusTypeDef ModbusSlaveInit(UART_HandleTypeDef *huart,
                                  uint8_t slaveAddress);
/**
 * @brief 校验并处理一帧待处理请求
 *
 * 本函数应在 uC/OS-II 任务中周期调用中断只负责接收数据，
 * CRC 校验、协议解析和响应发送均在任务上下文中执行
 */
void ModbusSlavePoll(void);
/**
 * @brief 处理 HAL 串口 DMA 接收事件
 * @param[in] huart 产生接收事件的串口句柄
 * @param[in] size 本次接收到的字节数
 */
void ModbusSlaveOnRxEvent(UART_HandleTypeDef *huart, uint16_t size);
/**
 * @brief 处理 HAL 串口 DMA 发送完成事件
 * @param[in] huart 完成发送的串口句柄
 */
void ModbusSlaveOnTxComplete(UART_HandleTypeDef *huart);
/**
 * @brief 处理 HAL 串口错误事件并恢复接收
 * @param[in] huart 发生错误的串口句柄
 */
void ModbusSlaveOnUartError(UART_HandleTypeDef *huart);
/**
 * @brief 写入一个保持寄存器
 * @param[in] address 保持寄存器地址
 * @param[in] value 待写入的 16 位数据
 * @retval 1 写入成功
 * @retval 0 保持寄存器地址无效
 */
uint8_t ModbusSlaveSetHoldingRegister(uint16_t address, uint16_t value);
/**
 * @brief 读取一个保持寄存器
 * @param[in] address 保持寄存器地址
 * @param[out] value 用于保存读取结果的指针
 * @retval 1 读取成功
 * @retval 0 保持寄存器地址无效或输出指针为空
 */
uint8_t ModbusSlaveGetHoldingRegister(uint16_t address, uint16_t *value);
/**
 * @brief 设置一个线圈的状态
 * @param[in] address 线圈地址
 * @param[in] state 0 表示复位，非 0 表示置位
 * @retval 1 设置成功
 * @retval 0 线圈地址无效
 */
uint8_t ModbusSlaveSetCoil(uint16_t address, uint8_t state);
/**
 * @brief 读取一个线圈的状态
 * @param[in] address 线圈地址
 * @param[out] state 用于保存线圈状态的指针，结果为 0 或 1
 * @retval 1 读取成功
 * @retval 0 线圈地址无效或输出指针为空
 */
uint8_t ModbusSlaveGetCoil(uint16_t address, uint8_t *state);
/**
 * @brief 判断指定时间内是否收到过有效请求
 * @param[in] timeoutMs 连接超时时间，单位为毫秒
 * @retval 1 从站在指定时间内收到过有效请求
 * @retval 0 尚未收到有效请求或连接已经超时
 */
uint8_t ModbusSlaveIsConnected(uint32_t timeoutMs);

/**
 * @brief Copy all RTU diagnostics with tear-free individual scalar fields.
 * @param[in] timeoutMs Age used to calculate the connected flag.
 * @param[out] diagnostics Destination for the complete snapshot.
 * @retval 1 Snapshot returned.
 * @retval 0 diagnostics is NULL.
 */
uint8_t ModbusSlaveGetRuntimeDiagnostics(
    uint32_t timeoutMs,
    MODBUS_SLAVE_RUNTIME_DIAGNOSTICS *diagnostics);
void ModbusRetainedRegistersLoad(void);
void ModbusRetainedRegistersPoll(void);

#ifdef __cplusplus
}
#endif

#endif /* MODBUS_RTU_SLAVE_H */