#include "board.h"
#include "ymodem.h"

ymodem_cntxt_t ymodem_cntxt;

const uint16_t ccitt_table[256] = {
    0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
    0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
    0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
    0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
    0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
    0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
    0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
    0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
    0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
    0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
    0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
    0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
    0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
    0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
    0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
    0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
    0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
    0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
    0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
    0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
    0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
    0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
    0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
    0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
    0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
    0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
    0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
    0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
    0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
    0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
    0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
    0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
};

uint16_t ymodem_crc(uint8_t byte, uint16_t crc_old) {
    uint8_t index;
    uint16_t crc;

    index = (uint8_t)(byte ^ (crc_old >> 8));
    crc   = (uint16_t)(ccitt_table[index] ^ (crc_old << 8));

    return crc;
}

// call the following function within ISR
void ymodem_rx_byte(uint8_t RxByte, void *arg)
{
    ymodem_cntxt_t *p = (ymodem_cntxt_t *)arg;

    if (p->ByteIdx==0){    // wait for first byte of a block
        p->HeadByte = RxByte;
        p->CalCRC = 0x0000;

        if (RxByte==YMODEM_SOH){
            p->ByteLeft = 2 + YMODEM_SHORT_SIZE + 2;
            p->ByteIdx = 1;
        } else if (RxByte==YMODEM_STX){
            p->ByteLeft = 2 + YMODEM_LONG_SIZE + 2;
            p->ByteIdx = 1;
        } else if (RxByte==YMODEM_EOT){
            p->ByteLeft = 0;
            p->ByteIdx = 0;
            p->Flag |= YMODEM_FLAG_FILE_END;
        } else {            // unknown, maybe wrong byte order
            p->Flag |= YMODEM_FLAG_UNKNOWN;
            p->ByteIdx = 0xffff;
        }
    } else if (p->ByteIdx==0xffff){
        // nothing to do, drop all rx bytes until overtime
    } else {
        if (p->ByteIdx>=3 && p->ByteLeft>=3){       // save 128 or 1024 file bytes
            p->CalCRC = ymodem_crc(RxByte, p->CalCRC);
            p->Buf[p->WrAddr++] = RxByte;
            if (p->WrAddr>=YMODEM_BUF_DEPTH){
                p->WrAddr = 0;
            }
        } else if (p->ByteIdx==1){                  // save block index
            p->BlkSeq = RxByte;
        } else if (p->ByteLeft<=2){                 // check crc
            p->CalCRC = (p->CalCRC<<8) | ((p->CalCRC>>8) ^ RxByte);
        }

        p->ByteLeft -= 1;
        if (p->ByteLeft==0){
            p->ByteIdx = 0;
            p->Flag |= YMODEM_FLAG_BLK_END;
        } else {
            p->ByteIdx += 1;
        }
    }
}

uint16_t ymodem_wait_blk(uint16_t *Flag, uint16_t Exp)
{
    uint16_t CntOt;
    uint16_t Hit;

    Hit = 0;
    CntOt = 1500;
    while(CntOt--){
        Hit = (*Flag) & Exp;
        if (Hit){
            *Flag &= ~Hit;
            break;
        }
        us_delay(1000000*10/USART_BAUDRATE);    // time for a byte
    }
    return(Hit);
}

uint32_t ymodem_rx_fsize(uint8_t *buf)
{
    uint16_t idx;
    uint32_t fsize;

    for(idx=0; idx<128; idx++){
        if (buf[idx]=='\0'){    // file name string end
            idx++;
            break;
        }
    }

    if(idx>=127){
        return(0);
    } else {
        str2int((char *)(buf+idx), &fsize);
        return(fsize);
    }
}

// call the following function outside ISR
uint16_t ymodem_rx_file(ymodem_cntxt_t *p)
{
    uint8_t retry;
    uint8_t first_eot;
    uint16_t Flag;

    p->Flag = 0;
    p->ByteIdx = 0;

    // file name + file size
    retry = 1;
    PutChar(YMODEM_C);
    while(1){
        p->WrAddr = 0;
        p->AckAddr = 0;
        p->RdAddr = 0;

        // wait for SOH/STX untill overtime
        Flag = ymodem_wait_blk(&(p->Flag), YMODEM_FLAG_BLK_END);
        p->ByteIdx = 0;

        if ((Flag) && (p->HeadByte==YMODEM_SOH || p->HeadByte==YMODEM_STX) && p->CalCRC==YMODEM_GOOD_CRC){
            p->Fsize = ymodem_rx_fsize(p->Buf);
            p->WrAddr = 0;      // drop first block bytes
            p->AckAddr = p->WrAddr;
            PutChar(YMODEM_ACK);
            break;
        } else if (retry>=15){
            PutChar(YMODEM_CAN);
            return(0x1u);
        } else {
            retry += 1;

            if (Flag){  // wrong crc
                PutChar(YMODEM_NAK);
            } else {    // overtime
                PutChar(YMODEM_C);
            }
        }
    }

    if (p->Fsize > p->MaxSize){
        PutChar(YMODEM_CAN);
        return(0x2u);
    }
    // erase firstly
    McuFlash_Unlock();
    McuFlash_EraseSegment(p->FlashAddr, p->Fsize);

    PutChar(YMODEM_C);
    first_eot = 1;
    retry = 1;
    while(1){
        // wait for SOH/STX/EOT untill overtime
        Flag = ymodem_wait_blk(&(p->Flag), YMODEM_FLAG_BLK_END | YMODEM_FLAG_FILE_END);
        p->ByteIdx = 0;

        if ((Flag & YMODEM_FLAG_BLK_END) && p->CalCRC==YMODEM_GOOD_CRC){
            p->AckAddr = p->WrAddr;
            PutChar(YMODEM_ACK);
            retry = 1;
            p->RdAddr = FIFO_to_MCU_pp(0, p->Buf, p->AckAddr, p->RdAddr, &(p->FlashAddr));
        } else if (Flag & YMODEM_FLAG_FILE_END){
            if (first_eot==1){
                first_eot = 0;
                PutChar(YMODEM_NAK);
                p->RdAddr = FIFO_to_MCU_pp(1, p->Buf, p->AckAddr, p->RdAddr, &(p->FlashAddr));
            } else {
                PutChar(YMODEM_ACK);
                break;
            }
        } else if (retry>=10){
            PutChar(YMODEM_CAN);
            return(0x1u);
        } else {
            p->WrAddr = p->AckAddr;     // drop wrong block bytes
            PutChar(YMODEM_NAK);
            retry += 1;
        }
    }

    McuFlash_Lock();

    PutChar(YMODEM_C);

    // wait for SOH untill overtime
    Flag = ymodem_wait_blk(&(p->Flag), YMODEM_FLAG_BLK_END | YMODEM_FLAG_FILE_END);

    PutChar(YMODEM_ACK);
    if ((Flag) && (p->HeadByte==YMODEM_SOH || p->HeadByte==YMODEM_STX) && p->CalCRC==YMODEM_GOOD_CRC){
        return(0x0u);
    } else {
        return(0x1u);
    }
}

uint16_t FIFO_to_MCU_pp(uint8_t last_blk, uint8_t *buf, uint16_t waddr, uint16_t raddr, uint32_t *faddr)
{
    uint8_t *data;
    uint8_t word_pp;
    uint16_t fifo_cnt;
    union U {
        uint8_t     byte[4];
        uint32_t    word;
    } u;

    data = buf + raddr;
    fifo_cnt = (waddr>=raddr) ? (waddr - raddr) : (waddr + (YMODEM_BUF_DEPTH - raddr));

    *faddr &= ~0x3u;    // must 4 bytes aligned

    while(fifo_cnt>=4 || (last_blk==1 && fifo_cnt>0)){    // program size is 4 byte
        McuFlash_WaitBusy();

        word_pp = 0;
        while (fifo_cnt>0 && word_pp<4) {
            if (word_pp==0){
                u.byte[0] = *data;
            } else if (word_pp==1){
                u.byte[1] = *data;
            } else if (word_pp==2){
                u.byte[2] = *data;
            } else {
                u.byte[3] = *data;
            }
            data++;
            if (data>=buf+YMODEM_BUF_DEPTH){
                data = buf;
            }
            fifo_cnt--;
            word_pp++;
        }
        McuFlash_WordPP(*faddr, u.word);

        *faddr += 4;
        raddr += word_pp;
        if (raddr>=YMODEM_BUF_DEPTH){
            raddr -= YMODEM_BUF_DEPTH;
        }
    }

    return(raddr);
}