import re

class MockJDS6600Device:
    class ChannelState:
        def __init__(self):
            self.on = False
            self.frequency = None
            self.amplitude = None
            self.function = None

    def __init__(self):
        self._channels = [MockJDS6600Device.ChannelState() for i in [1, 2]]
        self._injectedFailureCounter = 0

    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(",")

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

        # channel frequency
        elif function == 23 or function == 24:
            ch = function - 23
            if opcode == "w":
                # Actual device takes a second argument for scaling, here we ignore it and always use 0 (Hz)
                frequency = float(args[0]) / 100.0

                if self._injectedFailureCounter > 0:
                    self._channels[ch].frequency = 0.0
                    self._injectedFailureCounter -= 1
                else:
                    self._channels[ch].frequency = frequency
                return ":ok\r\n"
            elif opcode == "r":
                frequency = self._channels[ch].frequency
                return f":r{function}={int(frequency)},0.\r\n"

        # channel amplitude
        elif function == 25 or function == 26:
            if opcode == "w":
                ch = function - 25
                amplitude = float(args[0]) / 1000.0
                self._channels[ch].amplitude = amplitude
                return ":ok\r\n"

        # channel function shape
        elif function == 21 or function == 22:
            if opcode == "w":
                ch = function - 21
                shape = int(args[0])
                self._channels[ch].function = shape
                return ":ok\r\n"

        # Unknown request format, no response
        return None

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

    def getFrequency(self, ch: int) -> float:
        return self._channels[ch - 1].frequency

    def getAmplitude(self, ch: int) -> float:
        return self._channels[ch - 1].amplitude

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

    def injectFailures(self, count: int) -> None:
        self._injectedFailureCounter += count