#include "modbus_rec_send.h"
#include "hardware.h"

MODBUS_RX_STATE ModbusRxState = MODBUS_RX_RECEIVING;


/*USART接收空闲中断*/
void USART1_IRQHandler(void)
{
    uint32_t temp;
    uint16_t rxLenRemain;

    OSIntEnter();   /*进入中断*/
    if(USART_GetITStatus(USART1, USART_IT_IDLE) == SET)
    {
        /*清除IDLE中断标志位*/
        temp = USART1->SR;
        temp = USART1->DR;
        (void)temp;

        /*判断是否接收到帧，触发TIM计时*/
        rxLenRemain = DMA_GetCurrDataCounter(DMA2_Stream2);
        ModbusRxLen = MODBUS_RX_BUF_SIZE - rxLenRemain;

        if(ModbusRxLen != 0)
        {
            switch (ModbusRxState)
            {
                /*正常接收数据*/
                case MODBUS_RX_RECEIVING:
                    ModbusRxState = MODBUS_RX_CHECK_T15;
                    TimRestart(MODBUS_IDLE_TO_T15_US);
                    break;

                /*在t1.5定时还未到达时又接收到了数据*/
                case MODBUS_RX_CHECK_T15:
                    ModbusRxState = MODBUS_RX_CHECK_T15;
                    TimRestart(MODBUS_IDLE_TO_T15_US);
                    break;

                /*在判断t1.5～t3.5是否出现字符时，t3.5定时中断还未触发，又接收到了数据*/
                case MODBUS_RX_CHECK_T35:
                    ModbusRxState = MODBUS_RX_DISCARD_CHECK_T35;    /*判断为错误帧*/
                    TimRestart(MODBUS_IDLE_TO_T35_US);              /*等待3.5字符该帧结束之后丢失该帧*/
                    break;
                
                /*在t1.5～t3.5中出现字符，随后又接收到数据*/
                case MODBUS_RX_DISCARD:
                    ModbusRxState = MODBUS_RX_DISCARD_CHECK_T35;    /*判断为错误帧*/
                    TimRestart(MODBUS_IDLE_TO_T35_US);              /*等待3.5字符该帧结束之后丢失该帧*/
                    break;  
                
                /*在等待3.5字符该帧结束期间又接收到数据*/
                case MODBUS_RX_DISCARD_CHECK_T35:
                    ModbusRxState = MODBUS_RX_DISCARD_CHECK_T35;
                    TimRestart(MODBUS_IDLE_TO_T35_US);              /*再等待3.5字符该帧结束之后丢失该帧*/
                    break;
            }
        }
    }
    OSIntExit();    /*退出中断*/
}

/*TIM定时器中断*/
void TIM5_IRQHandler(void)
{
    uint16_t rxLenRemain;

    OSIntEnter();

    rxLenRemain = DMA_GetCurrDataCounter(DMA2_Stream2);

    if (TIM_GetITStatus(TIM5, TIM_IT_Update) != RESET)
    {
        switch (ModbusRxState)
        {
            /*检查在t1-t1.5期间是否接收到数据*/
            case MODBUS_RX_CHECK_T15:
                /*在t1-t1.5期间接收到了数据，正常继续接收*/
                if (MODBUS_RX_BUF_SIZE - rxLenRemain != ModbusRxLen)
                {
                    ModbusRxState = MODBUS_RX_RECEIVING;
                    TimOff();
                }
                /*在t1-t1.5期间没收到，开始检查t1.5-t3.5期间是否接收到数据*/
                else
                {
                    ModbusRxState = MODBUS_RX_CHECK_T35;
                    TimRestart(MODBUS_T15_TO_T35_US);
                }
                break;

            /*检查在t1.5-t3.5期间是否接收到数据*/
            case MODBUS_RX_CHECK_T35:
                /*在t1.5-t3.5期间接收到了数据，判断为错误帧，等待串口空闲中断开启3.5字符等待定时器计时*/
                if (MODBUS_RX_BUF_SIZE - rxLenRemain != ModbusRxLen)
                {
                    ModbusRxState = MODBUS_RX_DISCARD;
                    TimOff();
                }
                /*在t1.5-t3.5之间都没接收到数据，该帧结束，开始帧解析*/
                else
                {
                    ModbusRxState = MODBUS_RX_RECEIVING;
                    ModbusParseWakeUp();
                }
                break;
            
            /*接收到错误帧，等待3.5字符之后丢弃该帧*/    
            case MODBUS_RX_DISCARD_CHECK_T35:
                /*在等待3.5字符期间又接收到了数据，等待串口空闲中断重新开启3.5字符等待定时器计时*/
                if (MODBUS_RX_BUF_SIZE - rxLenRemain != ModbusRxLen)
                {
                    ModbusRxState = MODBUS_RX_DISCARD_CHECK_T35;
                    TimOff();
                }
                /*在等待3.5字符期间没接收到数据，该错误帧结束，丢弃该帧，准备开始下一帧的接收*/
                else
                {
                    ModbusRxState = MODBUS_RX_RECEIVING;
                    ModbusDmaRestart();
                }
                break;
        }
    }
    OSIntExit();
}

void TimRestart(uint32_t timArr)
{
    /*启动TIM计时*/
    TIM_Cmd(TIM5, DISABLE);
    TIM_SetCounter(TIM5, 0);        /*清除计数值*/
    TIM_SetAutoreload(TIM5, timArr);
    TIM_ClearITPendingBit(TIM5, TIM_IT_Update);     /*清除中断标志位*/
    TIM_Cmd(TIM5, ENABLE);
}

void TimOff(void)
{
    TIM_Cmd(TIM5, DISABLE);
    TIM_SetCounter(TIM5, 0);        /*清除计数值*/
    TIM_ClearITPendingBit(TIM5, TIM_IT_Update);     /*清除中断标志位*/
}

void ModbusParseWakeUp(void)
{
    uint16_t rxLenRemain;

    TimOff();

    /*关闭DMA*/
    DMA_Cmd(DMA2_Stream2, DISABLE);
    /*清除传输已经完成TCIF2、传输已经完成一半HTIF2标志位*/
    DMA_ClearFlag(DMA2_Stream2, DMA_FLAG_TCIF2 | DMA_FLAG_HTIF2);

    /*计算数据长度*/
    rxLenRemain = DMA_GetCurrDataCounter(DMA2_Stream2);
    ModbusRxLen = MODBUS_RX_BUF_SIZE - rxLenRemain;

    /*释放接收到数据帧信号量，唤醒帧解析任务*/
    if(ModbusRxLen >= 4)    /*4字节（1字节地址、1字节功能、2字节CRC）*/
    {
        OSSemPost(ModbusReceived);
    }

    /*重新指定接收地址*/
    DMA_MemoryTargetConfig(DMA2_Stream2, (uint32_t)ModbusRxBuf, DMA_Memory_0);
    /*重启DMA*/
    DMA_SetCurrDataCounter(DMA2_Stream2, MODBUS_RX_BUF_SIZE);
    DMA_Cmd(DMA2_Stream2, ENABLE);
}

void ModbusDmaRestart(void)
{
    TimOff();

    /*关闭DMA*/
    DMA_Cmd(DMA2_Stream2, DISABLE);
    /*清除传输已经完成TCIF2、传输已经完成一半HTIF2标志位*/
    DMA_ClearFlag(DMA2_Stream2, DMA_FLAG_TCIF2 | DMA_FLAG_HTIF2);
    /*重新指定接收地址*/
    DMA_MemoryTargetConfig(DMA2_Stream2, (uint32_t)ModbusRxBuf, DMA_Memory_0);
    /*重启DMA*/
    DMA_SetCurrDataCounter(DMA2_Stream2, MODBUS_RX_BUF_SIZE);
    DMA_Cmd(DMA2_Stream2, ENABLE);
}

/*modbus响应帧发送*/
void ModbusSend(uint8_t *txBuf, uint16_t len)
{
    if(DMA_GetCmdStatus(DMA2_Stream7) == ENABLE)
    {
        /*等待DMA发送完成*/
        while(DMA_GetFlagStatus(DMA2_Stream7, DMA_FLAG_TCIF7) == RESET);
    }

    /*先关闭DMA发送通道*/
    DMA_Cmd(DMA2_Stream7, DISABLE);

    /*等待DMA关闭*/
    while (DMA_GetCmdStatus(DMA2_Stream7) != DISABLE); 

    /*清除传输已经完成TCIF7、传输已经完成一半HTIF7、FIFO错误FEIF7标志位*/
    DMA_ClearFlag(DMA2_Stream7, DMA_FLAG_FEIF7 | DMA_FLAG_HTIF7 | DMA_FLAG_TCIF7);
    
    /*配置发送地址和长度*/
    DMA_MemoryTargetConfig(DMA2_Stream7, (uint32_t)txBuf, DMA_Memory_0);     
    DMA_SetCurrDataCounter(DMA2_Stream7, len);

    /*等待串口发送完成*/
    while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET);
    
    /*启动 DMA 发送*/
    DMA_Cmd(DMA2_Stream7, ENABLE);
}

/*crc16校验*/
uint16_t Crc16(const uint8_t *data, uint16_t length)
{
    uint16_t crc;
    uint16_t byteInd;
    uint8_t bitInd;
    
    crc = 0xFFFFu;
    for (byteInd = 0u; byteInd < length; byteInd++)
    {
        crc ^= (uint16_t)data[byteInd];
        for (bitInd = 0u; bitInd < 8u; bitInd++)
        {
            if ((crc & 0x0001u) != 0u)
            {
                crc >>= 1;
                crc ^= 0xA001u;
            }
            else
            {
                crc >>= 1;
            }
        }
    }
    return crc;
}

/*crc16检查*/
int8_t ChcekCrc16(uint16_t recCrc16, uint8_t *data, uint16_t length)
{
    uint16_t crc16 = Crc16(data, (length - 2));

    if(recCrc16 == crc16)
    {
        return 0;
    }
    else
    {
        return -1;
    }
}

void AddCrc16(uint8_t *data, uint16_t length)
{
    uint8_t *dataT = data;
    uint16_t crc16 = Crc16(data, length);

    /*低前高后*/
    dataT[length] = (uint8_t)(crc16 & 0x00FF);
    dataT[length + 1] = (uint8_t)(crc16 >> 8);
}