/*
 * cdc.c
 *
 *  Created on: Nov 6, 2024
 *      Author: true
 */

#include "cdc.h"

#include "usb_lib.h"

#include "../../usblib/config/usb_desc.h"
#include "../../usblib/config/usb_prop.h"



#define USB_TIM         TIM4
#define USB_TIM_IRQn    TIM4_IRQn



/*******************************************************************************/
/* Variable Definition */
/* Global */

/* The following are serial port transmit and receive related variables and buffers */
volatile CDC_CTL Cdc;

__attribute__((aligned(4))) uint8_t cdc_from[DEF_CDC_FROM_HOST_BUF_LEN];  /* Serial port 2 transmit data buffer */
__attribute__((aligned(4))) uint8_t cdc_send[DEF_CDC_SEND_HOST_BUF_LEN];  /* Serial port 2 receive data buffer */

extern uint8_t USBD_Endp3_Busy;


/*********************************************************************
 * @fn      USB_TIM_Init
 *
 * @brief   100us Timer
 *          144 * 100 * 13.8888 -----> 100uS
 *          todo: document why we need this counter.
 *
 * @return  none
 */
void USB_TIM_Init( void )
{
    TIM_TimeBaseInitTypeDef tim = {0};

    TIM_DeInit(USB_TIM);

    /* Time base configuration */
    tim.TIM_Period        = 100 - 1;
    tim.TIM_Prescaler     = SystemCoreClock / 1000000 - 1;
    tim.TIM_ClockDivision = 0;
    tim.TIM_CounterMode   = TIM_CounterMode_Up;
    TIM_TimeBaseInit(USB_TIM, &tim);

    /* Clear USB_TIM update pending flag */
    TIM_ClearFlag(USB_TIM, TIM_FLAG_Update);

    /* TIM IT enable */
    TIM_ITConfig(USB_TIM, TIM_IT_Update, ENABLE);

    /* Enable Interrupt */
    NVIC_EnableIRQ(USB_TIM_IRQn);

    /* USB_TIM enable counter */
    TIM_Cmd(USB_TIM, ENABLE);
}

/*********************************************************************
 * @fn      CDC_ParaInit
 *
 * @brief   UART parameters initialization
 *          mode = 0 : Used in usb modify initialization
 *          mode = 1 : Used in default initializations
 * @return  none
 */
void CDC_ParaInit(uint8_t mode)
{
    // uint8_t i;

    /*
    Cdc.Rx_LoadPtr = 0x00;
    Cdc.Rx_DealPtr = 0x00;
    Cdc.Rx_RemainLen = 0x00;
    Cdc.Rx_TimeOut = 0x00;
    Cdc.Rx_TimeOutMax = 30;

    Cdc.Tx_LoadNum = 0x00;
    Cdc.Tx_DealNum = 0x00;
    Cdc.Tx_RemainNum = 0x00;

    for(i = 0; i < DEF_CDC_FROM_HOST_NUM_MAX; i++) {
        Cdc.Tx_PackLen[ i ] = 0x00;
    }

    Cdc.Tx_Flag = 0x00;
    Cdc.Tx_CurPackLen = 0x00;
    Cdc.Tx_CurPackPtr = 0x00;

    Cdc.USB_Up_IngFlag = 0x00;
    Cdc.USB_Up_TimeOut = 0x00;
    Cdc.USB_Up_Pack0_Flag = 0x00;
    Cdc.USB_Down_StopFlag = 0x00;
    */

    Cdc.send_host_ptr = 0;
    Cdc.send_host_idx = 0;
    Cdc.send_host_count = 0;

    if (mode) {
        Cdc.cdc_cfg[ 0 ] = (uint8_t)( DEF_CDC_BAUDRATE );
        Cdc.cdc_cfg[ 1 ] = (uint8_t)( DEF_CDC_BAUDRATE >> 8 );
        Cdc.cdc_cfg[ 2 ] = (uint8_t)( DEF_CDC_BAUDRATE >> 16 );
        Cdc.cdc_cfg[ 3 ] = (uint8_t)( DEF_CDC_BAUDRATE >> 24 );
        Cdc.cdc_cfg[ 4 ] = DEF_CDC_STOPBIT;
        Cdc.cdc_cfg[ 5 ] = DEF_CDC_PARITY;
        Cdc.cdc_cfg[ 6 ] = DEF_CDC_DATABIT;
    }
}

/*********************************************************************
 * @fn      CDC_USB_Init
 *
 * @brief   CDC initialization in usb interrupt
 *
 * @return  none
 */
void CDC_USB_Init(void)
{
    uint32_t baudrate;
    uint8_t  stopbits __attribute__((unused));
    uint8_t  parity __attribute__((unused));

    baudrate = ( uint32_t )( Cdc.cdc_cfg[ 3 ] << 24 ) + ( uint32_t )( Cdc.cdc_cfg[ 2 ] << 16 );
    baudrate += ( uint32_t )( Cdc.cdc_cfg[ 1 ] << 8 ) + ( uint32_t )( Cdc.cdc_cfg[ 0 ] );
    stopbits = Cdc.cdc_cfg[ 4 ];
    parity = Cdc.cdc_cfg[ 5 ];

    // this is the point where you would apply these settings.
    // since we are virtual only with no real UART, there is nothing to do here.
    // UART2_Init( 0, baudrate, stopbits, parity );
}

/*********************************************************************
 * @fn      UART2_DataTx_Process
 *
 * @brief   Cdc2 data transmission processing
 *
 * @return  none
 */
void cdc_from_host_process(void)
{
    // uint16_t  count;

    if(Cdc.from_host_flag) {
        // process incoming data from the host.

        /*
        // Query whether the DMA transmission of the serial port is completed
        if( USART2->STATR & USART_FLAG_TC )
        {
            USART2->STATR = (uint16_t)( ~USART_FLAG_TC );
            USART2->CTLR3 &= ( ~USART_DMAReq_Tx );

            Cdc.Tx_Flag = 0x00;

            NVIC_DisableIRQ( USB_LP_CAN1_RX0_IRQn );
            NVIC_DisableIRQ( USB_HP_CAN1_TX_IRQn );

            // Calculate the variables of last data
            count = Cdc.Tx_CurPackLen - DEF_UART2_TX_DMA_CH->CNTR;
            Cdc.Tx_CurPackLen -= count;
            Cdc.Tx_CurPackPtr += count;
            if( Cdc.Tx_CurPackLen == 0x00 )
            {
                Cdc.Tx_PackLen[ Cdc.Tx_DealNum ] = 0x0000;
                Cdc.Tx_DealNum++;
                if( Cdc.Tx_DealNum >= DEF_CDC_FROM_HOST_NUM_MAX )
                {
                    Cdc.Tx_DealNum = 0x00;
                }
                Cdc.Tx_RemainNum--;
            }

            // If the current serial port has suspended the downlink, restart the driver downlink
            if( ( Cdc.USB_Down_StopFlag == 0x01 ) && ( Cdc.Tx_RemainNum < 2 ) )
            {
                SetEPRxValid( ENDP2 );
                Cdc.USB_Down_StopFlag = 0x00;
            }
            */

            NVIC_EnableIRQ(USB_LP_CAN1_RX0_IRQn);
            NVIC_EnableIRQ(USB_HP_CAN1_TX_IRQn);
        //}
    } else {
        /*
        // Load data from the serial port send buffer to send
        if(Cdc.Tx_RemainNum) {
            // Determine whether to load from the last unsent buffer or from a new buffer
            if( Cdc.Tx_CurPackLen == 0x00 ) {
                Cdc.Tx_CurPackLen = Cdc.Tx_PackLen[ Cdc.Tx_DealNum ];
                Cdc.Tx_CurPackPtr = ( Cdc.Tx_DealNum * DEF_USB_FS_PACKET_LEN );
            }

            // Configure DMA and send
            USART_ClearFlag( USART2, USART_FLAG_TC );
            DMA_Cmd( DEF_UART2_TX_DMA_CH, DISABLE );
            DEF_UART2_TX_DMA_CH->MADDR = (uint32_t)&UART2_Tx_Buf[ Cdc.Tx_CurPackPtr ];
            DEF_UART2_TX_DMA_CH->CNTR = Cdc.Tx_CurPackLen;
            DMA_Cmd( DEF_UART2_TX_DMA_CH, ENABLE );
            USART2->CTLR3 |= USART_DMAReq_Tx;
            Cdc.from_host_flag = 0x01;
        }
        */
    }
}

/*********************************************************************
 * @fn      UART2_DataRx_Deal
 *
 * @brief   Cdc2 data receiving processing
 *
 * @return  none
 */
void cdc_send_host_process(void)
{
    uint16_t remain;
    uint16_t len;

    // process sending data over USB to the host.
    if (Cdc.send_host_count) {
        if (!Cdc.usb_send_flag) {
            // Calculate the length of this transmission
            remain = Cdc.send_host_count;
            if (remain >= DEF_USBD_MAX_PACK_SIZE ) {
                len = DEF_USBD_MAX_PACK_SIZE;
            } else {
                len = remain;
            }

            // only send end of buffer if we need to loop it
            if (len > (DEF_CDC_SEND_HOST_BUF_LEN - Cdc.send_host_idx)) {
                len = (DEF_CDC_SEND_HOST_BUF_LEN - Cdc.send_host_idx);
            }

            // send data via usb
            if (len) {
                Cdc.usb_send_flag = 1;

                // disable interrupts while configuring
                NVIC_DisableIRQ(USB_LP_CAN1_RX0_IRQn);
                NVIC_DisableIRQ(USB_HP_CAN1_TX_IRQn);

                USBD_ENDPx_DataUp(ENDP3, &cdc_send[Cdc.send_host_idx], len);

                // calculate new pointer locations
                Cdc.send_host_count -= len;
                Cdc.send_host_idx += len;

                // reset send pointer to beginning of buffer on overflow
                if (Cdc.send_host_idx >= DEF_CDC_SEND_HOST_BUF_LEN) {
                    Cdc.send_host_idx = 0;
                }

                // re-enable interrupts
                NVIC_EnableIRQ(USB_LP_CAN1_RX0_IRQn);
                NVIC_EnableIRQ(USB_HP_CAN1_TX_IRQn);
            }
        }
        else {
            // this is where we could handle a timeout and reset, but ...
        }
    }

    /*****************************************************************/
    /* Determine if a 0-length packet needs to be uploaded (required for CDC mode)
     * todo: figure out wtf this is about */
    /*
    if( Cdc.USB_Up_Pack0_Flag ) {
        if( Cdc.USB_Up_IngFlag == 0 ) {
            if( Cdc.USB_Up_TimeOut >= ( DEF_CDC_RX_TIMEOUT * 20 ) ) {
                NVIC_DisableIRQ( USB_LP_CAN1_RX0_IRQn );
                NVIC_DisableIRQ( USB_HP_CAN1_TX_IRQn );
                Cdc.USB_Up_IngFlag = 0x01;
                Cdc.USB_Up_TimeOut = 0x00;

                USBD_ENDPx_DataUp( ENDP3, &CDC_Rx_Buf[ Cdc.Rx_DealPtr], 0);

                Cdc.USB_Up_IngFlag = 0;
                Cdc.USB_Up_Pack0_Flag = 0x00;
                NVIC_EnableIRQ( USB_LP_CAN1_RX0_IRQn );
                NVIC_EnableIRQ( USB_HP_CAN1_TX_IRQn );
            }
        }
    }
    */
}

int usb_cdc_puts(char *buf, int cnt)
{
    int remain;

    // no overflowing the buffer
    // note: you can overflow on consecutive writes, be careful...
    if (cnt > DEF_CDC_SEND_HOST_BUF_LEN) {
        return 0;
    }

    remain = cnt;

    if (cnt >= DEF_CDC_SEND_HOST_BUF_LEN - Cdc.send_host_ptr) {
        // if we've got too much data, then copy what will fit to end of buffer
        remain = DEF_CDC_SEND_HOST_BUF_LEN - Cdc.send_host_ptr;
        memcpy(cdc_send + Cdc.send_host_ptr, buf, remain);

        // set pointers
        Cdc.send_host_ptr = 0;

        buf += remain;
        remain = cnt - remain;
    }

    // fill the buffer
    memcpy(cdc_send + Cdc.send_host_ptr, buf, remain);

    return cnt;
}

int usb_cdc_gets(char *buf, int cnt)
{
    uint16_t idx = Cdc.from_host_idx;
    uint16_t len = 0;

    // can only get data if a length is requested
    if (!cnt) {
        return 0;
    }

    // there is no data to actually get
    if (idx == Cdc.from_host_ptr) {
        return 0;
    }

    for (len = 0; len < cnt; len++) {
        *buf = cdc_from[idx];
        buf++;
        idx++;
        if (idx >= DEF_CDC_FROM_HOST_BUF_LEN) {
            idx = 0;
        }
        if (idx == Cdc.from_host_ptr) {
            break;
        }
    }

    Cdc.from_host_idx = idx;
    return len;
}


__attribute__((interrupt("WCH-Interrupt-fast")))
void TIM4_IRQHandler(void)
{
    // uart timeout counts
    //Cdc.Rx_TimeOut++;
    //Cdc.USB_Up_TimeOut++;

    // clear status
    TIM4->INTFR = (uint16_t)~TIM_IT_Update;
}