import serial
import re

class DeviceInterface:
    """
    Helper class for interfacing the device running flexPTP.
    """

    def __init__(self, url: str, options: dict = {}) -> None:
        """
        Initialize the interface.

        :param str url: url of the device (tty, socket etc.)
        :param dict options: collection of several options (baudrate, bytesize, parity, stopbits etc.)
        :rtype: None
        """

        self.device = serial.serial_for_url(url, timeout=0.05) # open remote device

        # set serial port options if applicable
        if "baudrate" in options:
            self.device.baudrate = options["baudrate"]
        if "bytesize" in options:
            self.device.bytesize = options["bytesize"]
        if "parity" in options:
            self.device.parity = options["parity"]
        if "stopbits" in options:
            self.device.stopbits = options["stopbits"]

    def read_until(self, expected: bytes = serial.LF) -> bytes:
        """
        Read from the device until a specific sequence is found.

        :param bytes expected: delimiter sequence
        :return: bytes read
        :rtype: bytes
        """

        return self.device.read_until(expected=expected)
    

    def write(self, data: bytes) -> None:
        """
        Write data onto the device

        :param bytes data: data to transfer
        """

        self.device.write(data)


    def execute_command(self, cmd: str, expect_results: bool = True, separate_results: bool = False) -> str | dict[str, str] | None:
        """
        Execute command on the device

        :param str cmd: command to launch
        :param bool expect_results: is there any return values expected and awaited?
        :param bool separate_results: if True a key-value separation attempted on the results
        :return: results (if requested)
        :rtype: str | None
        """

        self.device.write((cmd.strip("\r\n") + "\r\n").encode()) # sanitize commands
        self.device.read_until(cmd.encode()) # flush echo
        if expect_results: # store results if required
            timeout = False
            results = ""
            while not timeout: # store continuous chunks
                data = self.device.read(32)
                if len(data) > 0:
                    results += data.decode()
                else:
                    timeout = True
            
            if separate_results: # separation requested
                records = re.findall("^[ ]*([^:]+)[ ]*:[ ]*(.+)[ ]*$", results.strip(), flags=re.MULTILINE)
                results = dict[str, str]()
                for rec in records:
                    results[rec[0]] = rec[1].strip()
                return results
            else:
                return results
        else:
            return None