#include "can_comm.h"
#include "memory.h"
#include "stdlib.h"
#include "crc8.h"

/* can_comm用于保存每个实例的指针数组,用于回调函数区分实例 */
static CANCommInstance *can_comm_instance[MX_CAN_COMM_COUNT] = {NULL};
static uint8_t idx; // 配合can_comm_instance的初始化使用,标识当前初始化的是哪一个实例

/**
 * @brief 重置CAN comm的接收状态和buffer
 *
 * @param ins 需要重置的实例
 */
static void CANCommResetRx(CANCommInstance *ins)
{
    memset(ins->raw_recvbuf, 0, ins->cur_recv_len);
    ins->recv_state = 0;
    ins->cur_recv_len = 0;
}

/**
 * @brief
 *
 * @param _instance
 */
static void CANCommRxCallback(can_instance *_instance)
{
    for (size_t i = 0; i < idx; i++)
    {
        if (&can_comm_instance[i]->can_ins == _instance) // 遍历,找到对应的接收CAN COMM实例
        {
            /* 接收状态判断 */
            if (_instance->rx_buff[0] == CAN_COMM_HEADER && can_comm_instance[i]->recv_state == 0) // 尚未开始接收且新的一包里有帧头
            {
                if (_instance->rx_buff[1] == can_comm_instance[i]->recv_data_len) // 接收长度等于设定接收长度
                {
                    can_comm_instance[i]->recv_state = 1;
                }
                else
                    return; // 直接跳过即可
            }
            if (can_comm_instance[i]->recv_state) // 已经收到过帧头
            {                                     // 如果已经接收到的长度加上当前一包的长度大于总buf len,说明接收错误
                if (can_comm_instance[i]->cur_recv_len + _instance->rx_len > can_comm_instance[i]->recv_buf_len)
                {
                    CANCommResetRx(can_comm_instance[i]);
                    return; // 重置状态然后返回
                }

                // 直接拷贝到当前的接收buffer后面
                memcpy(can_comm_instance[i]->raw_recvbuf + can_comm_instance[i]->cur_recv_len, _instance->rx_buff, _instance->rx_len);
                can_comm_instance[i]->cur_recv_len += _instance->rx_len;

                // 当前已经收满
                if (can_comm_instance[i]->cur_recv_len == can_comm_instance[i]->recv_buf_len)
                { // buff里本该是tail的位置不等于CAN_COMM_TAIL
                    if (can_comm_instance[i]->raw_recvbuf[can_comm_instance[i]->recv_buf_len - 1] != CAN_COMM_TAIL)
                    {
                        CANCommResetRx(can_comm_instance[i]);
                        return; // 重置状态然后返回
                    }
                    else // tail正确, 对数据进行crc8校验
                    {
                        if (can_comm_instance[i]->raw_recvbuf[can_comm_instance[i]->recv_buf_len - 2] ==
                            crc_8(can_comm_instance[i]->raw_recvbuf + 2, can_comm_instance[i]->recv_data_len))
                        { // 通过校验,复制数据到unpack_data中
                            memcpy(can_comm_instance[i]->unpacked_recv_data,can_comm_instance[i]->raw_recvbuf + 2,  can_comm_instance[i]->recv_data_len);
                            can_comm_instance[i]->update_flag = 1; // 数据更新flag置为1
                        }
                        CANCommResetRx(can_comm_instance[i]);
                        return; // 重置状态然后返回
                    }
                }
            }
            return; // 访问完一个can comm直接退出,一次中断只会也只可能会处理一个实例的回调
        }
    }
}

CANCommInstance *CANCommInit(CANComm_Init_Config_s *comm_config)
{
    can_comm_instance[idx] = (CANCommInstance *)malloc(sizeof(CANCommInstance));
    memset(can_comm_instance[idx], 0, sizeof(CANCommInstance));
    can_comm_instance[idx]->recv_data_len = comm_config->recv_data_len;
    can_comm_instance[idx]->recv_buf_len = comm_config->recv_data_len + CAN_COMM_OFFSET_BYTES;
    can_comm_instance[idx]->send_data_len = comm_config->send_data_len;
    can_comm_instance[idx]->send_buf_len = comm_config->send_data_len + CAN_COMM_OFFSET_BYTES;
    can_comm_instance[idx]->raw_sendbuf[0] = CAN_COMM_HEADER;
    can_comm_instance[idx]->raw_sendbuf[1] = comm_config->send_data_len;
    can_comm_instance[idx]->raw_sendbuf[comm_config->send_data_len + CAN_COMM_OFFSET_BYTES - 1] = CAN_COMM_TAIL;

    comm_config->can_config.can_module_callback = CANCommRxCallback;
    CANRegister(&can_comm_instance[idx]->can_ins, &comm_config->can_config);
    return can_comm_instance[idx++];
}

void CANCommSend(CANCommInstance *instance, uint8_t *data)
{
    static uint8_t crc8;
    static uint8_t send_len;
    memcpy(instance->raw_sendbuf + 2, data, instance->send_data_len);
    crc8 = crc_8(data, instance->send_data_len);
    instance->raw_sendbuf[2 + instance->send_data_len] = crc8;

    for (size_t i = 0; i < instance->send_buf_len; i += 8)
    {   // 如果是最后一包,send len将会小于8,要修改CAN的txconf中的DLC位,调用bsp_can提供的接口即可
        send_len = instance->send_buf_len - i >= 8 ? 8 : instance->send_buf_len - i;
        CANSetDLC(&instance->can_ins, send_len);
        memcpy(instance->can_ins.tx_buff, instance->raw_sendbuf+i, send_len);
        CANTransmit(&instance->can_ins);
    }
}

void *CANCommGet(CANCommInstance *instance)
{
    instance->update_flag = 0;
    return instance->unpacked_recv_data;
}