import serial
from serial.tools import list_ports


class ComPorts:

    com_port_exists = False
    my_port_names = []
    no_com_ports_message = "No COM ports found. Please attach a COM-port device."

    def __init__(self):
        self.parameter_changed = False
        self.port_changed = False
        self.port_open = False
        self.previous_port = serial.Serial()
        self.saved_bit_rate = 9600
        self.saved_handshake = "none"
        self.saved_port_name = ""
        self.selected_port = serial.Serial()
        self.debug_mode = False
        self.port_buffer = bytearray()
        self.user_interface_data = None

    def _emit_ui(self, action, text, color):
        if self.user_interface_data is not None:
            self.user_interface_data(action, text, color)

    @property
    def read_port_buffer(self):
        if len(self.port_buffer) <= 0:
            return b""
        data = bytes(self.port_buffer)
        del self.port_buffer[:]
        return data

    @property
    def received_data_length(self):
        return len(self.port_buffer)

    @staticmethod
    def find_com_ports():
        ComPorts.my_port_names = sorted(p.device for p in list_ports.comports())
        if len(ComPorts.my_port_names) <= 0:
            ComPorts.com_port_exists = False
        else:
            ComPorts.com_port_exists = True
        return ComPorts.my_port_names

    def _display_exception(self, module_name, ex):
        text = "Exception: {} Module: {}. Method: {}".format(ex, module_name, getattr(ex, "__class__").__name__)
        self._emit_ui("DisplayStatus", text, "red")

    def close_com_port(self, port_to_close):
        try:
            self._emit_ui("SisplayStatus", "", "black")
            if port_to_close is not None and port_to_close.is_open:
                port_to_close.close()
                self._emit_ui("DisplayCurrentSettings", "", "black")
            self.port_open = False
        except (OSError, serial.SerialException) as ex:
            self.parameter_changed = True
            self.port_changed = True
            self._display_exception("ComPorts.vb", ex)

    def data_received(self):
        try:
            if self.selected_port.in_waiting > 0:
                data = self.selected_port.read(self.selected_port.in_waiting)
                self.port_buffer.extend(data)
        except Exception as ex:
            self._display_exception("ComPorts.vb", ex)

    @staticmethod
    def error_received(event_type):
        messages = {
            "rxover": "Input buffer overflow",
            "overrun": "Character buffer overrun",
            "rxparity": "Parity error",
            "frame": "Framing error",
            "txfull": "Output buffer full",
        }
        message = messages.get(str(event_type).lower())
        if message:
            print(message)

    def open_com_port(self):
        flag = False
        try:
            if ComPorts.com_port_exists:
                if self.previous_port.is_open:
                    self.close_com_port(self.previous_port)
                if (not self.selected_port.is_open) or self.port_changed:
                    self.selected_port.open()
                    if self.selected_port.is_open:
                        self.selected_port.timeout = 5
                        self._emit_ui("DisplayCurrentSettings", "", "black")
                        self._emit_ui("DisplayStatus", "", "black")
                        flag = True
                        self.port_changed = False
        except (OSError, serial.SerialException) as ex:
            self.parameter_changed = True
            self.port_changed = True
            self._display_exception("ComPorts.vb", ex)
        self.port_open = flag
        return flag

    def write_to_com_port(self, data_to_write):
        flag = False
        try:
            if (self.selected_port is None or not self.selected_port.is_open) or self.port_changed:
                self.port_open = self.open_com_port()
            if self.selected_port.is_open:
                self.selected_port.write(data_to_write)
                flag = True
        except serial.SerialTimeoutException as ex:
            self._display_exception("ComPorts.vb", ex)
        except (OSError, serial.SerialException) as ex:
            self._display_exception("ComPorts.vb", ex)
            if isinstance(ex, PermissionError):
                self.close_com_port(self.selected_port)
            self.parameter_changed = True
            self._emit_ui("DisplayCurrentSettings", "", "black")
        return flag