#include "ymodem.h"
#include "ring_buf.h"
#include "../swapi/subjects/serial/serial.h"

static unsigned short crc16(const unsigned char *buf, unsigned long count)
{
  unsigned short crc = 0;
  while(count--) {
    crc = crc ^ *buf++ << 8;
    for(int i = 0; i < 8; i++) {
      if(crc & 0x8000) crc = crc << 1 ^ 0x1021;
      else crc = crc << 1;
    }
  }
  return crc;
}

static const char *u32_to_str(unsigned int val)
{
  static char num_str[11]; int pos = 10; num_str[10] = 0;

  if(val == 0) return "0"; // If already zero then just return zero

  while((val != 0) && (pos > 0)) {
    num_str[--pos] = (val % 10) + '0';
    val /= 10;
  }

  return &num_str[pos];
}

static unsigned long str_to_u32(char *str)
{
  const char *s = str; unsigned long acc; int c;

  do {
    c = *s++;
  } while(c == ' ');

  for(acc = 0; (c >= '0') && (c <= '9'); c = *s++) {
    c -= '0'; acc *= 10; acc += c;
  }

  return acc;
}

typedef struct
{
  void *h; RingBuf rx_buf;
  RingBufElement rx_buf_storage[2*(PACKET_1K_SIZE+PACKET_OVERHEAD)]; // 最大缓存2包数据
} SYmodemUart;

static SYmodemUart s_myUart;

static int uart_getchar(int timeout_ms)
{
  RingBufElement val; unsigned long stime, now;
  if(timeout_ms >= 0) xgettickcount(&stime);
  while(1) {
    if(RingBuf_get(&s_myUart.rx_buf, &val)) return (int)val;
    if(timeout_ms >= 0) {
      xgettickcount(&now);
      if((now - stime) >= (unsigned long)timeout_ms) return -1; // timeout
    }
    sw_thrd_delay(THRDWAIT_DELAY);
  }
}

static void uart_putchar(int c)
{
  unsigned char ch = (unsigned char)c;
  serial_send_data(s_myUart.h, &ch, 1);
}

/* returns 0 on success, 1 on corrupt packet, -1 on error (timeout): */
static int receive_packet(unsigned char *data, int *length)
{
  int i, c; unsigned int packet_size;
  unsigned short received_crc;

  *length = 0;

  c = uart_getchar(PACKET_TIMEOUT);
  if(c < 0) return -1;

  switch(c) {
  case SOH:
    packet_size = PACKET_SIZE;
    break;
  case STX:
    packet_size = PACKET_1K_SIZE;
    break;
  case EOT:
    return 0;
  case CAN:
    c = uart_getchar(PACKET_TIMEOUT);
    if(c == CAN) { *length = -1; return 0; }
  default:
    *length = -1;
    return 0;
  }

  *data = (char)c;

  for(i = 1; i < (packet_size + PACKET_OVERHEAD); ++i) {
    c = uart_getchar(PACKET_TIMEOUT);
    if(c < 0) return -1;
    data[i] = (char)c;
  }

  if(data[PACKET_SEQNO_INDEX] != ((data[PACKET_SEQNO_COMP_INDEX] ^ 0xff) & 0xff)) return 1;

  received_crc = (data[PACKET_HEADER + packet_size] << 8) | data[PACKET_HEADER + packet_size + 1];
  if(crc16(data + PACKET_HEADER, packet_size) != received_crc) return 1;

  *length = packet_size;
  return 0;
}

static int comio_data_recv_proc(unsigned long wParam/*传递打开的串口句柄*/, unsigned long lParam/*保留暂未使用*/)
{
  SYmodemUart *pComIO = &s_myUart; void *pSerial = pComIO->h;
  const unsigned char *pRecvBuf = serial_get_recv_buffer(pSerial); int nRecvBytes = serial_get_recv_buffer_bytes(pSerial);
  const char *send_log_prefix = serial_get_log_prefix(pSerial); RingBufElement val = pRecvBuf[nRecvBytes - 1]; // 取出1字节数据
  if(!RingBuf_put(&pComIO->rx_buf, val)) {
    uart_putchar(CAN); uart_putchar(CAN);
    sw_log_error("%s: sorry,ring buffer full, failed to put!!", send_log_prefix);
    return -1;
  }
  serial_clear_recv_buffer(pSerial);
  return 1;
}

int ymodem_recv_files(const char *dir)
{
  unsigned char packet_data[PACKET_1K_SIZE + PACKET_OVERHEAD];
  int packet_length, i, file_done, session_done, ret;
  unsigned int packets_received, errors, first_try, files_num;
  char file_name[FILE_NAME_LENGTH], file_size[FILE_SIZE_LENGTH], *file_ptr;
  unsigned char block[PACKET_1K_SIZE]; unsigned int file_size_val = 0; char path[MAX_PATH_CHARS];

  RingBuf_ctor(&s_myUart.rx_buf, s_myUart.rx_buf_storage, sizeof(s_myUart.rx_buf_storage)/sizeof(RingBufElement));
  s_myUart.h = serial_open(UART_DEVICE_NAME, UART_BAUD_RATE, UART_PARITY_CHECK, \
                           comio_data_recv_proc, NULL, NULL);
  if(!s_myUart.h) return -1;

  file_name[0] = '\0'; first_try = 1; ret = files_num = 0;
  for(session_done = 0, errors = 0; serial_recvThrd_isAlive(s_myUart.h); )
  { // receive files
    if(!first_try) uart_putchar(CRC);
    first_try = 0;

    for(packets_received = 0, file_done = 0; serial_recvThrd_isAlive(s_myUart.h); )
    { // receive packets
      switch(receive_packet(packet_data, &packet_length))
      {
      case  0: // receive success
        if(errors != 0) errors = 0;
        switch(packet_length)
        {
        case -1: { uart_putchar(ACK); ret = -2; goto ret_p; } // abort
        case  0: { uart_putchar(ACK); file_done = 1; ++files_num; break; } // end of file
        default: // normal data packet
          if((packet_data[PACKET_SEQNO_INDEX] & 0xff) != (packets_received & 0xff)) { uart_putchar(NAK); break; } // sequence number error
          if(packets_received == 0)
          {
            if(packet_data[PACKET_HEADER] != 0x00)
            { // filename packet has data
              for(file_ptr = (char *)packet_data + PACKET_HEADER, i = 0; *file_ptr && i < FILE_NAME_LENGTH; ) file_name[i++] = *file_ptr++;
              file_name[i++] = '\0'; // 接收的文件名称
              for(++file_ptr, i = 0; *file_ptr != ' ' && i < FILE_SIZE_LENGTH; ) file_size[i++] = *file_ptr++;
              file_size[i++] = '\0'; // 接收的文件大小
              file_size_val = str_to_u32(file_size);

              uart_putchar(ACK); uart_putchar(CRC);

              sw_log_debug("[%s] <文件: %s, 大小: %u字节> 开始接收...", UART_MODULE_NAME, file_name, file_size_val);
              snprintf(path, sizeof(path), "%s/%s", dir, file_name);
              if(sw_file_exists(path)) sw_file_delete(path);
            }
            else
            { // filename packet is empty(空包文件); end of session
              uart_putchar(ACK); file_done = 1; session_done = 1; break;
            }
          }
          else
          {
            for(i = 0; i < packet_length; i++) { block[i] = packet_data[PACKET_HEADER+i]; }
            uart_putchar(ACK);
            sw_log_debug("[%s] <文件: %s, 大小: %u字节> 收到第%u包数据, 数据包大小: %u字节", \
              UART_MODULE_NAME, file_name, file_size_val, packets_received, packet_length);

            if(!sw_dir_exists(dir)) sw_dir_create(dir);
            ret = sw_file_update(path, "ab", (char *)block, packet_length);
            if(ret != packet_length) { uart_putchar(CAN); uart_putchar(CAN); ret = -3; goto ret_p; }
          }
          ++packets_received; // 累加已接收包数
        }
        break;
      default: // receive error
        if(packets_received != 0) { if(++errors >= MAX_ERRORS/* too many errors */) { uart_putchar(CAN); uart_putchar(CAN); ret = -4; goto ret_p; } }
        uart_putchar(CRC);
      }

      if(file_done)  { if(!session_done) sw_log_debug("[%s] 文件: %s 接收完成, 实际接收文件大小: %u字节", UART_MODULE_NAME, file_name, sw_file_getSize(path)); break; } // 文件接收完成
    }

    if(session_done) { ret = files_num; break; } // 传输会话结束
  }

ret_p:
  if(s_myUart.h) serial_close(s_myUart.h, WAITTHRD_SAFEEXIT_TIMEOUT);
  return ret;
}

static void send_packet(unsigned char *data, int block_no)
{
  int count, packet_size; unsigned short crc;

  if(block_no == 0) packet_size = PACKET_SIZE;
  else packet_size = PACKET_1K_SIZE;

  crc = crc16(data, packet_size);
  uart_putchar((block_no == 0) ? SOH : STX);
  uart_putchar(block_no & 0xFF);
  uart_putchar(~block_no & 0xFF);

  for(count = 0; count < packet_size; count++) uart_putchar(data[count]);
  uart_putchar((crc >> 8) & 0xFF);
  uart_putchar(crc & 0xFF);
}

/* Send block 0 (the filename block). filename might be truncated to fit. */
static char send_log_prefix[MAX_LINE_CHARS];
static void send_packet0(char *filename, unsigned long size)
{
  unsigned long count = 0; unsigned char block[PACKET_SIZE];
  const char *num; const char *str = (filename ? filename : "null");

  if(filename) {
    while(*filename && (count < PACKET_SIZE-FILE_SIZE_LENGTH-2)) block[count++] = *filename++;
    block[count++] = 0;

    num = u32_to_str(size);
    while(*num) block[count++] = *num++;
  }

  while(count < PACKET_SIZE) block[count++] = 0;

  send_packet(block, 0);
  snprintf(send_log_prefix, sizeof(send_log_prefix), "<文件: %s, 大小: %lu字节>", str, size);
  sw_log_debug("[%s] %s 开始发送...", UART_MODULE_NAME, send_log_prefix);
}

static long send_data_packets(unsigned char *data, unsigned long size)
{
  int blockno = 1; unsigned long send_size; int ch, retry = 0;
  unsigned long total_sent = 0;

  while(size > 0)
  {
    if(size > PACKET_1K_SIZE) send_size = PACKET_1K_SIZE;
    else send_size = size;

    send_packet(data, blockno);
    sw_log_debug("[%s] %s 已发送第%u包数据, 数据包大小: %lu字节", UART_MODULE_NAME, send_log_prefix, blockno, send_size);
    ch = uart_getchar(PACKET_TIMEOUT);
    if(ch == ACK)
    {
      blockno++; retry = 0;
      data += send_size;
      size -= send_size;
      total_sent += send_size; // 累加已发送的字节数
    }
    else if(ch == NAK || ch == -1)
    {
      retry++;
      if(retry >= MAX_ERRORS) return -1; // give up after MAX_ERRORS retries
    }
    else if(ch == CAN)
    {
      uart_putchar(CAN);
      uart_putchar(CAN);
      return -2;
    }
  }

  retry = 0; do {
    uart_putchar(EOT);
    sw_log_debug("[%s] %s 文件发送已完成, 实际发送字节数: %lu字节", UART_MODULE_NAME, send_log_prefix, total_sent);
    ch = uart_getchar(PACKET_TIMEOUT);
  } while((ch != ACK) && (ch != -1) && (++retry < MAX_ERRORS));

  if(ch != ACK) return -3;

  // 最后发送一个空包文件, 结束文件接收
  ch = uart_getchar(PACKET_TIMEOUT);
  if(ch == CRC)
  {
    retry = 0; do {
    send_packet0(0, 0);
    sw_log_debug("[%s] %s 已发送空包文件, 等待传输会话结束", UART_MODULE_NAME, send_log_prefix);
    ch = uart_getchar(PACKET_TIMEOUT);
    } while((ch != ACK) && (ch != -1) && (++retry < MAX_ERRORS));

    if(ch != ACK) return -4;
  }

  return (long)total_sent;
}

int ymodem_send_file(const char *path)
{
  char file_name[FILE_NAME_LENGTH], *file_buf = NULL;
  int file_size, ch, crc_nak = 1, retry, ret = 0;

  if(!sw_file_exists(path)) return -1;
  snprintf(file_name, sizeof(file_name), "%s", xGetPathFileName(path));
  file_size = sw_file_getSize(path);
  if(file_size <= 0) return -2;

  file_buf = (char*)malloc(file_size);
  if(!file_buf) return -3;

  if(sw_file_load(path, "rb", file_buf, file_size) != file_size) { ret = -4; goto ret_p; }

  RingBuf_ctor(&s_myUart.rx_buf, s_myUart.rx_buf_storage, sizeof(s_myUart.rx_buf_storage)/sizeof(RingBufElement));
  s_myUart.h = serial_open(UART_DEVICE_NAME, UART_BAUD_RATE, UART_PARITY_CHECK, \
                           comio_data_recv_proc, NULL, NULL);
  if(!s_myUart.h) { ret = -5; goto ret_p; }

  retry = 0; do { ch = uart_getchar(PACKET_TIMEOUT); } while(ch != CRC && ++retry < 30); // 等待接收CRC, 而后才开始发送文件
  if(ch != CRC) { uart_putchar(CAN); uart_putchar(CAN); ret = -6; goto ret_p; }

  retry = 0; do
  {
    send_packet0(file_name, (unsigned long)file_size);
    ch = uart_getchar(PACKET_TIMEOUT);
    if(ch == ACK)
    {
      ch = uart_getchar(PACKET_TIMEOUT);
      if(ch == CRC) { ret = send_data_packets((unsigned char *)file_buf, file_size); if(ret < 0) { ret += -7; } break; }
    }
    else if((ch == CRC) && (crc_nak)) { crc_nak = 0; continue; } // 接收到CRC, 重发一次0包
    else if((ch != NAK) || (crc_nak)) { sw_log_error("[%s] %s 接收到错误应答: 0x%02X", UART_MODULE_NAME, send_log_prefix, ch); break; } // 接收到NAK, 需要重发一次0包
  } while(++retry < MAX_ERRORS && serial_recvThrd_isAlive(s_myUart.h));

ret_p:
  if(file_buf) free(file_buf);
  if(s_myUart.h) serial_close(s_myUart.h, WAITTHRD_SAFEEXIT_TIMEOUT);
  return ret;
}