import argparse
import serial
import struct
import sys
import threading
import time

offset = 0x80000000
tty = '/dev/ttyUSB1'
baud = 115200
chunksize = 128


def write(s, offset, dat):
    for i in range(0, len(dat), chunksize):
        chunk = dat[i: i + chunksize]
        cmd = struct.pack('<cII', b'c', offset + i, len(chunk))

        print(f'Sending {len(chunk)} bytes @0x{offset + i:04x}')

        s.write(cmd)
        s.write(chunk)

        ack = s.read(2)
        if len(ack) < 2:
            raise RuntimeError(f'timeout waiting for full ack. got {ack}')
        if ack[0] != b'a'[0]:
            raise RuntimeError(f'expected ack, got this instead: {ack}')
        print(f'Ack! len={ack[1]}')


def jump(s, offset):
        cmd = struct.pack('<cI', b'j', offset)
        print(f'Jumping to 0x{offset:04x}')
        s.write(cmd)


def stream_logs(s):
    while True:
        dat = s.read()
        if not dat:
            continue
        sys.stdout.buffer.write(dat.replace(b'\r', b''))
        sys.stdout.buffer.flush()


def parse_args():
    parser = argparse.ArgumentParser()
    parser.add_argument("binary")
    parser.add_argument("--monitor", action="store_true",
                        help="wait for and display program serial output")
    return parser.parse_args()

def main():
    args = parse_args()

    with open(args.binary, 'rb') as f:
        dat = f.read()

    s = serial.Serial(tty, baud, timeout=1)
    write(s, offset, dat)
    jump(s, offset)

    if args.monitor:
        t = threading.Thread(target=lambda: stream_logs(s), daemon=True)
        t.start()

        try:
            while True:
                dat = input("") + '\r'
                s.write(dat.encode())
        except KeyboardInterrupt:
            print("Bye.")


if __name__ == "__main__":
    main()