"""Quick AT command terminal - minicom but less hostile.

Usage:
    python at_terminal.py [port]

Default port: /dev/ttyUSB2 (SIM7600 AT command interface)
"""

import sys
import serial
import threading

PORT = sys.argv[1] if len(sys.argv) > 1 else "/dev/ttyUSB2"
BAUD = 115200


def reader(ser):
    """Background thread: print everything the modem sends."""
    while True:
        try:
            data = ser.read(ser.in_waiting or 1)
            if data:
                sys.stdout.write(data.decode("utf-8", errors="replace"))
                sys.stdout.flush()
        except Exception:
            break


def main():
    print(f"Opening {PORT} @ {BAUD} baud")
    print("Type AT commands. Ctrl+C to quit.\n")

    ser = serial.Serial(PORT, BAUD, timeout=0.1)

    t = threading.Thread(target=reader, args=(ser,), daemon=True)
    t.start()

    try:
        while True:
            line = input()
            ser.write((line + "\r\n").encode())
    except (KeyboardInterrupt, EOFError):
        print("\nBye.")
    finally:
        ser.close()


if __name__ == "__main__":
    main()