#ifndef BLE_NUS_H__
#define BLE_NUS_H__

#include <stdint.h>
#include <stdbool.h>
#include "sdk_config.h"
#include "ble.h"
#include "ble_srv_common.h"
#include "nrf_sdh_ble.h"

#ifdef __cplusplus
extern "C" {
#endif

//定义串口透传服务实例，该实例完成2件事情
//1：定义了static类型串口透传服务结构体变量，为串口透传服务结构体分配了内存
//2：注册了BLE事件监视者，这使得串口透传程序模块可以接收BLE协议栈的事件，从而可以在ble_uarts_on_ble_evt()事件回调函数中处理自己感兴趣的事件
#define BLE_NUS_DEF(_name)                                        \
    static ble_nus_t _name;                                                            \
    NRF_SDH_BLE_OBSERVER(_name ## _obs,                           \
                         BLE_NUS_BLE_OBSERVER_PRIO,               \
                         ble_nus_on_ble_evt,                      \
                         &_name)

//定义串口透传服务128位UUID基数
#define NUS_BASE_UUID        {{0xfb, 0x34, 0x9b, 0x5f, 0x80, 0x00, 0x00, 0x80, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}} 
//定义串口透传服务16位UUID
#define BLE_UUID_NUS_SERVICE           0x1000 //串口透传服务16位UUID
#define BLE_UUID_NUS_TX_CHARACTERISTIC 0x1002 //TX特征16位UUID
#define BLE_UUID_NUS_RX_CHARACTERISTIC 0x1001 //RX特征16位UUID

//定义操作码长度
#define OPCODE_LENGTH        1
//定义句柄长度
#define HANDLE_LENGTH        2

//定义最大传输数据长度（字节数）
#if defined(NRF_SDH_BLE_GATT_MAX_MTU_SIZE) && (NRF_SDH_BLE_GATT_MAX_MTU_SIZE != 0)
    #define BLE_NUS_MAX_DATA_LEN (NRF_SDH_BLE_GATT_MAX_MTU_SIZE - OPCODE_LENGTH - HANDLE_LENGTH)
#else
    #define BLE_NUS_MAX_DATA_LEN (BLE_GATT_MTU_SIZE_DEFAULT - OPCODE_LENGTH - HANDLE_LENGTH)
    #warning NRF_SDH_BLE_GATT_MAX_MTU_SIZE is not defined.
#endif


//定义串口透传事件类型，这是用户自己定义的，供应用程序使用
typedef enum
{
    BLE_NUS_EVT_RX_DATA,      //接收到新的数据
    BLE_NUS_EVT_TX_RDY,       //准备就绪，可以发送新数据
    BLE_NUS_EVT_COMM_STARTED, /**< Notification has been enabled. */
    BLE_NUS_EVT_COMM_STOPPED, /**< Notification has been disabled. */
} ble_nus_evt_type_t;


/* Forward declaration of the ble_nus_t type. */
typedef struct ble_nus_s ble_nus_t;


//串口透传服务BLE_NUS_EVT_RX_DATA事件数据结构体，该结构体用于当BLE_NUS_EVT_RX_DATA产生时将接收的数据信息传递给处理函数
typedef struct
{
    uint8_t const * p_data; //指向存放接收数据的缓存
    uint16_t        length; //接收的数据长度
} ble_nus_evt_rx_data_t;


/**@brief Nordic UART Service client context structure.
 *
 * @details This structure contains state context related to hosts.
 */
typedef struct
{
    bool is_notification_enabled; /**< Variable to indicate if the peer has enabled notification of the RX characteristic.*/
} ble_nus_client_context_t;


//串口透传服务事件结构体
typedef struct
{
    ble_nus_evt_type_t         type;        //事件类型
    ble_nus_t                * p_nus;       //指向串口透传实例的指针
    uint16_t                   conn_handle; //连接句柄
//  ble_nus_client_context_t * p_link_ctx;  /**< A pointer to the link context. */
    union
    {
        ble_nus_evt_rx_data_t rx_data; //BLE_NUS_EVT_RX_DATA事件数据
    } params;
} ble_nus_evt_t;


//定义函数指针类型ble_uarts_data_handler_t
typedef void (* ble_nus_data_handler_t) (ble_nus_evt_t * p_evt);


//串口服务初始化结构体
typedef struct
{
    ble_nus_data_handler_t data_handler; //处理接收数据的事件句柄 
} ble_nus_init_t;


//串口透传服务结构体，包含所需要的信息
struct ble_nus_s
{
    uint8_t                         uuid_type;          //UUID类型
    uint16_t                        service_handle;     //串口透传服务句柄（由协议栈提供）
    ble_gatts_char_handles_t        tx_handles;         //TX特征句柄
    ble_gatts_char_handles_t        rx_handles;         //RX特征句柄
//  blcm_link_ctx_storage_t * const p_link_ctx_storage; /**< Pointer to link context storage with handles of all current connections and its context. */
    ble_nus_data_handler_t          data_handler;       //处理接收数据的事件句柄
};


/**@brief   Function for initializing the Nordic UART Service.
 *
 * @param[out] p_nus      Nordic UART Service structure. This structure must be supplied
 *                        by the application. It is initialized by this function and will
 *                        later be used to identify this particular service instance.
 * @param[in] p_nus_init  Information needed to initialize the service.
 *
 * @retval NRF_SUCCESS If the service was successfully initialized. Otherwise, an error code is returned.
 * @retval NRF_ERROR_NULL If either of the pointers p_nus or p_nus_init is NULL.
 */
uint32_t ble_nus_init(ble_nus_t * p_nus, ble_nus_init_t const * p_nus_init);


/**@brief   Function for handling the Nordic UART Service's BLE events.
 *
 * @details The Nordic UART Service expects the application to call this function each time an
 * event is received from the SoftDevice. This function processes the event if it
 * is relevant and calls the Nordic UART Service event handler of the
 * application if necessary.
 *
 * @param[in] p_ble_evt     Event received from the SoftDevice.
 * @param[in] p_context     Nordic UART Service structure.
 */
void ble_nus_on_ble_evt(ble_evt_t const * p_ble_evt, void * p_context);


/**@brief   Function for sending a data to the peer.
 *
 * @details This function sends the input string as an RX characteristic notification to the
 *          peer.
 *
 * @param[in]     p_nus       Pointer to the Nordic UART Service structure.
 * @param[in]     p_data      String to be sent.
 * @param[in,out] p_length    Pointer Length of the string. Amount of sent bytes.
 * @param[in]     conn_handle Connection Handle of the destination client.
 *
 * @retval NRF_SUCCESS If the string was sent successfully. Otherwise, an error code is returned.
 */
uint32_t ble_nus_data_send(ble_nus_t * p_nus,
                           uint8_t   * p_data,
                           uint16_t  * p_length,
                           uint16_t    conn_handle);


#ifdef __cplusplus
}
#endif

#endif // BLE_NUS_H__

/** @} */
