#ifndef __YMODEM_H_
#define __YMODEM_H_

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>

#define PACKET_SEQNO_INDEX      (1)
#define PACKET_SEQNO_COMP_INDEX (2)

#define PACKET_HEADER           (3)
#define PACKET_TRAILER          (2)
#define PACKET_OVERHEAD         (PACKET_HEADER + PACKET_TRAILER)
#define PACKET_SIZE             (128)
#define PACKET_1K_SIZE          (1024)

#define FILE_NAME_LENGTH        (256)
#define FILE_SIZE_LENGTH        (16)

#define SOH                     (0x01)  /* start of 128-byte data packet */
#define STX                     (0x02)  /* start of 1024-byte data packet */
#define EOT                     (0x04)  /* end of transmission */
#define ACK                     (0x06)  /* acknowledge */
#define NAK                     (0x15)  /* negative acknowledge */
#define CA                      (0x18)  /* two of these in succession aborts transfer */
#define WANTCRC                 (0x43)  /* 'C' == 0x43, request 16-bit CRC */
#define WANTG                   (0x47)  /* 'G' == 0x47, no crc and ack */

#define ABORT1                  (0x41)  /* 'A' == 0x41, abort by user */
#define ABORT2                  (0x61)  /* 'a' == 0x61, abort by user */

/* 1s */
#define NAK_TIMEOUT             (1000)
#define MAX_ERRORS              (10)

/* base class for ymodem user */
struct ymodem_xfer {
    /*
     * get a character from serial line with timeout millseconds.
     *
     * c: received character.
     * timeout:  wait for millseconds.
     *
     * return 0 on sucess, -1 on failure.
     */
    int (*getc)(struct ymodem_xfer *, uint8_t *c, int timeout /* in millseconds */);

    /* 
     * get more than one bytes every time.
     *
     * return `number of bytes` received, -1 on failure.
     */
    int (*read_stream)(struct ymodem_xfer *, uint8_t *, int n, int timeout);

    /*
     * send a charactor to serial line.
     *
     * return 0 on sucess, -1 on failure.
     */
    int (*putc)(struct ymodem_xfer *, uint8_t c);

    /*
     * ymodem file information.
     *
     * return < 0 abort ymodem transfer, 0 continue.
     */
    int (*on_info)(struct ymodem_xfer *, const char *name, unsigned int size);

    /*
     * ymodem file data from serial line.
     *
     * return < 0 abort ymodem transfer, 0 continue.
     */
    int (*on_data)(struct ymodem_xfer *, const void *data, unsigned int len);
};

int  ymodem_recv(struct ymodem_xfer *xfer);
int  ymodem_send(struct ymodem_xfer *xfer, uint8_t *buf, const uint8_t* sendFileName, uint32_t sizeFile);

struct serial;
int serial_ymodem_recv(struct serial *, void *user,
        int (*on_info)(void *user, const char *name, unsigned int size),
        int (*on_data)(void *user, const void *data, unsigned int len));

int stdio_ymodem_recv(void *user,
        int (*_on_info)(void *user, const char *name, unsigned int size),
        int (*_on_data)(void *user, const void *data, unsigned int len));

#ifdef __cplusplus
}
#endif
#endif  /* __YMODEM_H_ */