/******************************************************************************
 * 2016 ideasX (Tyler Berezowsky)
 *
 * FileName: uart.c
 *
 * Description: Two UART mode configration and interrupt handler.
 *              Check your hardware connection while use this mode.
 *              Future Work: Modify ISR to handle UART timeout and Errors
 *
 * Modification history:
 *     2014/3/12, v1.0 create this file.
*******************************************************************************/

#include "driver/uart.h"
// UartDev is defined and initialized in rom code.
extern UartDevice UartDev;


static void uart0_rx_intr_handler(void *para);

/******************************************************************************
 * FunctionName : uart_config
 * Description  : Internal used function
 *                UART0 used for data TX/RX, RX buffer size is 0x100, interrupt enabled
 *                UART1 just used for debug output
 * Parameters   : uart_no, use UART0 or UART1 defined ahead
 * Returns      : NONE
*******************************************************************************/
static void ICACHE_FLASH_ATTR
uart_config(uint8 uart_no)
{
    if (uart_no == UART1) {
        PIN_FUNC_SELECT(PERIPHS_IO_MUX_GPIO2_U, FUNC_U1TXD_BK);                 // setup gpio2 for UART1
    }
    else {
        ETS_UART_INTR_ATTACH(uart0_rx_intr_handler,  &(UartDev.rcv_buff));      // attach uart0_rx_intr_handler ISR
        PIN_PULLUP_DIS(PERIPHS_IO_MUX_U0TXD_U);                                 // disable pullup on TX pin
        PIN_FUNC_SELECT(PERIPHS_IO_MUX_U0TXD_U, FUNC_U0TXD);                    // setup gpio TX pin
    /* setup hardware flow control */
    #if UART_HW_RTS
        PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTDO_U, FUNC_U0RTS);   //SETUP HW FLOW CONTROL RTS PIN
        #endif
    #if UART_HW_CTS
        PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTCK_U, FUNC_U0CTS);   //SETUP HW FLOW CONTROL CTS PIN
        #endif
    }

    uart_div_modify(uart_no, UART_CLK_FREQ / (UartDev.baut_rate));  // setup baudrate

    WRITE_PERI_REG(UART_CONF0(uart_no), ((UartDev.exist_parity & UART_PARITY_EN_M)  <<  UART_PARITY_EN_S)   // setup parity
                    | ((UartDev.parity & UART_PARITY_M)  <<UART_PARITY_S )
                    | ((UartDev.stop_bits & UART_STOP_BIT_NUM) << UART_STOP_BIT_NUM_S)                      // setup stop bits
                    | ((UartDev.data_bits & UART_BIT_NUM) << UART_BIT_NUM_S));                              // setup data bits


    //clear rx and tx fifo,not ready
    SET_PERI_REG_MASK(UART_CONF0(uart_no), UART_RXFIFO_RST | UART_TXFIFO_RST);      // set clear RX FIFO bits
    CLEAR_PERI_REG_MASK(UART_CONF0(uart_no), UART_RXFIFO_RST | UART_TXFIFO_RST);    // clear clear RX FIFO bits


    if (uart_no == UART0){
        WRITE_PERI_REG(UART_CONF1(uart_no),
        ((1 & UART_RXFIFO_FULL_THRHD) << UART_RXFIFO_FULL_THRHD_S) |        // set UART0 full interrupt to 1 bytes
        #if UART_HW_RTS
            ((110 & UART_RX_FLOW_THRHD) << UART_RX_FLOW_THRHD_S) |          // set hardware flow control threshold
            UART_RX_FLOW_EN |                                               // set enable hardware flow control flag
        #endif
        (0x02 & UART_RX_TOUT_THRHD) << UART_RX_TOUT_THRHD_S |               // setup timeout interrupt
        UART_RX_TOUT_EN|                                                    // setup enable timeout flag
        ((0x10 & UART_TXFIFO_EMPTY_THRHD)<<UART_TXFIFO_EMPTY_THRHD_S));     // setup UART0 empty interrupt threshold to 16 bytes

        #if UART_HW_CTS
            SET_PERI_REG_MASK( UART_CONF0(uart_no),UART_TX_FLOW_EN);        //add this sentense to add a tx flow control via MTCK( CTS )
        #endif
        //SET_PERI_REG_MASK(UART_INT_ENA(uart_no), UARben affleck in batman suitT_RXFIFO_TOUT_INT_ENA |UART_FRM_ERR_INT_ENA);     // enable interrupts for timeout and byte error
    }
    else{
        WRITE_PERI_REG(UART_CONF1(uart_no),((UartDev.rcv_buff.TrigLvl & UART_RXFIFO_FULL_THRHD) << UART_RXFIFO_FULL_THRHD_S));//TrigLvl default val == 1
    }

    WRITE_PERI_REG(UART_INT_CLR(uart_no), 0xffff);                          //clear all interrupts
    SET_PERI_REG_MASK(UART_INT_ENA(uart_no), UART_RXFIFO_FULL_INT_ENA);     // enable full RX FIFO interrupt
}

/******************************************************************************
 * FunctionName : uart1_tx_one_char
 * Description  : Internal used function
 *                Use uart1 interface to transfer one char
 * Parameters   : uint8 TxChar - character to tx
 * Returns      : OK
*******************************************************************************/
static STATUS ICACHE_FLASH_ATTR
uart1_tx_one_char(uint8 TxChar)
{
    while (true)    // dump FIFO until empty
	{
		uint32 fifo_cnt = READ_PERI_REG(UART_STATUS(UART1)) & (UART_TXFIFO_CNT<<UART_TXFIFO_CNT_S);
		if ((fifo_cnt >> UART_TXFIFO_CNT_S & UART_TXFIFO_CNT) < 126) {
			break;
		}
	}
	WRITE_PERI_REG(UART_FIFO(UART1) , TxChar); // add character to FIFO
	return OK;
}

/******************************************************************************
 * FunctionName : uart1_write_char
 * Description  : Internal used function
 *                Do some special deal while tx char is '\r' or '\n'
 * Parameters   : char c - character to tx
 * Returns      : NONE
*******************************************************************************/
static void ICACHE_FLASH_ATTR
uart1_write_char(char c)
{
    if (c == '\n') {
        uart1_tx_one_char('\r');
        uart1_tx_one_char('\n');
    } else if (c == '\r') {
    } else {
        uart1_tx_one_char(c);
    }
}

/******************************************************************************
 * FunctionName : uart0_rx_intr_handler
 * Description  : Internal used function
 *                UART0 interrupt handler, add self handle code inside
 * Parameters   : void *para - point to ETS_UART_INTR_ATTACH's arg
 * Returns      : NONE
*******************************************************************************/
extern void process_command(char* str);
static void uart0_rx_intr_handler(void *para)
{
    /* uart0 and uart1 intr combine togther, when interrupt occur, see reg 0x3ff20020, bit2, bit0 represents
     * uart1 and uart0 respectively
     */
    RcvMsgBuff *pRxBuff = (RcvMsgBuff *)para;
    uint8 RcvChar;

    // if uart0 fifo isn't full return
    if (UART_RXFIFO_FULL_INT_ST == (READ_PERI_REG(UART_INT_ST(UART0)) & UART_RXFIFO_FULL_INT_ST)){

    WRITE_PERI_REG(UART_INT_CLR(UART0), UART_RXFIFO_FULL_INT_CLR); // clear full FIFO flag

        while (READ_PERI_REG(UART_STATUS(UART0)) & (UART_RXFIFO_CNT << UART_RXFIFO_CNT_S)) {
            RcvChar = READ_PERI_REG(UART_FIFO(UART0)) & 0xFF;

            /* you can add your handle code below.*/

    		uart_tx_one_char(RcvChar);    // echo recieved character
            // NOTE: Lets modify the \r\n sequence to something more american.
            // NOTE: Add hook for backspace character...I need to learn the ASCII code
            // NOTE: Backspace character should also remove the last two stored characters
            // in the buffer. This might be possible by moving the pWritePos back 2 characters?

            // if "\r\n" recieved dump UART buffer into str
            if (RcvChar == '\r') continue;
    		if (RcvChar == '\n') {

    			int len;
    			char *str;
    			len = pRxBuff->pWritePos - pRxBuff->pReadPos;
    			if (len == 0) continue;
    			if (len < 0) len += RX_BUFF_SIZE;
    			str = (char*)os_zalloc(len+1);
    			if (str) {
    				uint8 loop;
    				for (loop = 0; loop < len; loop++) str[loop] = uart0_rx_one_char();
    				str[len] = '\0';
    				process_command(str);
    				os_free(str);
    			}

            }
            // otherwise add character to buffer
            else {
    			*(pRxBuff->pWritePos) = RcvChar;
    			pRxBuff->pWritePos++;
    		}
            // if we hit the end of the buffer, loop back to the beginning
            if (pRxBuff->pWritePos == (pRxBuff->pRcvMsgBuff + RX_BUFF_SIZE)) {
                // overflow ...we may need more error handle here.
                pRxBuff->pWritePos = pRxBuff->pRcvMsgBuff ;
            }
        }
    }
}

ICACHE_FLASH_ATTR int uart0_rx_one_char() {
  if(UartDev.rcv_buff.pReadPos == UartDev.rcv_buff.pWritePos) return -1;
  int ret = *UartDev.rcv_buff.pReadPos;
  UartDev.rcv_buff.pReadPos++;
  if(UartDev.rcv_buff.pReadPos == (UartDev.rcv_buff.pRcvMsgBuff + RX_BUFF_SIZE)) {
    UartDev.rcv_buff.pReadPos = UartDev.rcv_buff.pRcvMsgBuff;
  }

  return ret;
}

/******************************************************************************
 * FunctionName : uart0_tx_buffer
 * Description  : use uart0 to transfer buffer
 * Parameters   : uint8 *buf - point to send buffer
 *                uint16 len - buffer len
 * Returns      :
*******************************************************************************/
// void ICACHE_FLASH_ATTR uart0_tx_buffer(uint8 *buf, uint16 len)
// {
//     uint16 i;
//
//     for (i = 0; i < len; i++) {
//         uart_tx_one_char(buf[i]);
//     }
// }

void ICACHE_FLASH_ATTR uart0_send(const char *str) {
	uint8 i = 0;
	while (str[i]) {
        uart_tx_one_char(str[i]);
		i++;
    }
}

/******************************************************************************
 * FunctionName : uart_init
 * Description  : user interface for init uart
 * Parameters   : UartBautRate uart0_br - uart0 bautrate
 *                UartBautRate uart1_br - uart1 bautrate
 * Returns      : NONE
*******************************************************************************/
void ICACHE_FLASH_ATTR
uart_init(UartBautRate uart0_br, UartBautRate uart1_br, bool enable_uart1) {
    // rom use 74880 baut_rate, here reinitialize
    UartDev.baut_rate = uart0_br;
    uart_config(UART0);

    if (enable_uart1) {
        UartDev.baut_rate = uart1_br;
        uart_config(UART1);
    }

    ETS_UART_INTR_ENABLE();
}