import os
import pty
import termios
import threading
import re

class MockJDS6600Device():
    def __init__(self):
        self._master, self._slave = pty.openpty()
        self._masterFile = os.fdopen(self._master, mode="r+b", closefd=False, buffering=0)

        self._portName = os.ttyname(self._slave)
        self._channels = [False, False]
        
        self._mainThread = threading.Thread(target=self._mainLoop)
        self._mainThread.start()

    def _mainLoop(self) -> None:
        while True:
            try:
                request = self._masterFile.readline().decode().strip()
                response = self._handleRequest(request)
                
                if response is not None:
                    self._masterFile.write(response.encode())
            except OSError as e:
                break

    def _handleRequest(self, request: str) -> str:
        pattern = r":(?P<opcode>[wrab])(?P<function>\d+)=(?P<args>.*)\."
        m = re.search(pattern, request)
        
        if not m:
            return None

        opcode = m.group("opcode")
        function = int(m.group("function"))
        args = m.group("args").split(",")

        if opcode == "w":
            if function == 20:
                self._channels[0] = args[0] == "1"
                self._channels[1] = args[1] == "1"
        elif opcode == "r":
            if function == 20:
                return f":r20={int(self._channels[0])},{int(self._channels[1])}.\r\n"

        return ":ok\r\n"

    def stop(self) -> None:
        self._masterFile.close()
        os.close(self._master)
        os.close(self._slave)
        self._mainThread.join()

    def checkPortConfiguration(self) -> None:
        iflag, oflag, cflag, lflag, ispeed, ospeed, cc = termios.tcgetattr(self._slave)

        # JDS6600 configuration taken from manual
        assert ispeed == termios.B115200
        assert ospeed == termios.B115200
        assert (cflag & termios.CSIZE) == termios.CS8
        assert (cflag & termios.CSTOPB) == 0
        assert (cflag & (termios.PARENB | termios.PARODD)) == 0

    def getPortName(self) -> str:
        return self._portName

    def isOn(self, ch: int) -> bool:
        return self._channels[ch - 1]