#!/usr/bin/env python3
# Part of JoeyLib, Copyright (c) 2026 Scott Duensing, under the MIT License.
# See LICENSE.md for license information.
# SPDX-License-Identifier: MIT

"""mameNullModemCfg.py - a MAME cfg file that sets a null_modem's line.

MAME's null_modem clocks the wire itself, at 9600 8 N 1 unless its
configuration says otherwise, so a guest whose UART runs at any other rate
sees garbage. The line is a CONFIG input port on the device, which MAME
reads back from cfg/SYSTEM.cfg in its -cfg_directory.

    mameNullModemCfg.py SYSTEM TAG BAUD [DATABITS PARITY STOPBITS]

SYSTEM is the driver (x68000, apple2gs, apple2gsr1), TAG the null_modem's
device tag (":rs232c:null_modem", ":modem:null_modem"). The line may also
come as one quoted argument ("4800 7 E 1"). DATABITS PARITY STOPBITS
default to 8 N 1. Prints the cfg; exit 2 for a line MAME cannot set.
"""

import sys

# MAME's RS232_* enum values (src/devices/bus/rs232/rs232.h).
BAUD = {"50": 14, "75": 15, "110": 0, "150": 1, "200": 17, "300": 2, "600": 3,
        "1200": 4, "1800": 18, "2000": 19, "2400": 5, "3600": 20, "4800": 6,
        "7200": 21, "9600": 7, "14400": 8, "19200": 9, "28800": 10,
        "38400": 11, "57600": 12, "115200": 13}
DATA = {"5": 0, "6": 1, "7": 2, "8": 3}
PARITY = {"N": 0, "O": 1, "E": 2}
STOP = {"1": 1, "2": 3}
DEFAULT_FORMAT = ["8", "N", "1"]
# The null_modem's own defaults (src/devices/bus/rs232/null_modem.cpp).
BAUD_DEFAULT = 7
DATA_DEFAULT = 3
PARITY_DEFAULT = 0
STOP_DEFAULT = 1


def main(argv):
    if len(argv) < 4:
        sys.stderr.write(__doc__)
        return 2
    system = argv[1]
    tag = argv[2]
    line = " ".join(argv[3:]).split()
    if len(line) == 1:
        line += DEFAULT_FORMAT
    if len(line) != 4:
        sys.stderr.write("mameNullModemCfg.py: the line is BAUD [DATABITS PARITY STOPBITS]\n")
        return 2
    baud, data, parity, stop = line
    parity = parity.upper()
    for value, table, what in ((baud, BAUD, "baud rate"), (data, DATA, "data bits"),
                               (parity, PARITY, "parity"), (stop, STOP, "stop bits")):
        if value not in table:
            sys.stderr.write("mameNullModemCfg.py: MAME's null_modem has no %s %s (it takes %s)\n"
                             % (what, value, " ".join(table)))
            return 2
    ports = [("RS232_TXBAUD", BAUD_DEFAULT, BAUD[baud]), ("RS232_RXBAUD", BAUD_DEFAULT, BAUD[baud]),
             ("RS232_DATABITS", DATA_DEFAULT, DATA[data]), ("RS232_PARITY", PARITY_DEFAULT, PARITY[parity]),
             ("RS232_STOPBITS", STOP_DEFAULT, STOP[stop])]
    print('<?xml version="1.0"?>\n<mameconfig version="10">\n    <system name="%s">\n        <input>' % system)
    for name, default, value in ports:
        print(f'            <port tag="{tag}:{name}" type="CONFIG" mask="255" defvalue="{default}" value="{value}" />')
    print('        </input>\n    </system>\n</mameconfig>')
    return 0


if __name__ == "__main__":
    sys.exit(main(sys.argv))