"""Uart module."""

import asyncio
import binascii
import logging
from typing import Callable, Dict

import zigpy.config
import zigpy.serial

LOGGER = logging.getLogger(__name__)

# fmt: off
crc16_le_table = [
    0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf, 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,  # noqa: E501
    0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e, 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,  # noqa: E501
    0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd, 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,  # noqa: E501
    0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c, 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,  # noqa: E501
    0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb, 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,  # noqa: E501
    0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a, 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,  # noqa: E501
    0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9, 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,  # noqa: E501
    0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738, 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,  # noqa: E501

    0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7, 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,  # noqa: E501
    0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036, 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,  # noqa: E501
    0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5, 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,  # noqa: E501
    0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134, 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,  # noqa: E501
    0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3, 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,  # noqa: E501
    0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232, 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,  # noqa: E501
    0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1, 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,  # noqa: E501
    0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330, 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78  # noqa: E501
]
# fmt: on


class Gateway(asyncio.Protocol):
    END = b"\xC0"
    ESC = b"\xDB"
    ESC_END = b"\xDC"
    ESC_ESC = b"\xDD"

    def __init__(self, api, connected_future=None):
        """Initialize instance of the UART gateway."""

        self._api = api
        self._buffer = b""
        self._connected_future = connected_future
        self._transport = None

    def connection_lost(self, exc) -> None:
        """Port was closed expectedly or unexpectedly."""

        if exc is not None:
            LOGGER.warning("Lost connection: %r", exc, exc_info=exc)

        self._api.connection_lost(exc)

    def connection_made(self, transport):
        """Call this when the uart connection is established."""

        LOGGER.debug("Connection made")
        self._transport = transport
        if self._connected_future and not self._connected_future.done():
            self._connected_future.set_result(True)

    def close(self):
        self._transport.close()

    def send(self, data):
        """Send data, taking care of escaping and framing."""
        LOGGER.debug("Send: %s", binascii.hexlify(data).decode())
        checksum = bytes(self._checksum(data))
        frame = self._escape(data + checksum)
        self._transport.write(self.END + frame + self.END)

    def data_received(self, data):
        """Handle data received from the uart."""
        self._buffer += data
        while self._buffer:
            end = self._buffer.find(self.END)
            if end < 0:
                return None

            frame = self._buffer[:end]
            self._buffer = self._buffer[(end + 1) :]
            frame = self._unescape(frame)

            if len(frame) < 4:
                continue

            checksum = frame[-2:]
            frame = frame[:-2]
            if self._checksum(frame) != checksum:
                LOGGER.warning(
                    "Invalid checksum: 0x%s, data: 0x%s",
                    binascii.hexlify(checksum).decode(),
                    binascii.hexlify(frame).decode(),
                )
                continue

            LOGGER.debug("Frame received: 0x%s", binascii.hexlify(frame).decode())
            try:
                self._api.data_received(frame)
            except Exception as exc:
                LOGGER.error("Unexpected error handling the frame", exc_info=exc)

    def _unescape(self, data):
        ret = []
        idx = 0
        while idx < len(data):
            b = data[idx]
            if b == self.ESC[0]:
                idx += 1
                if idx >= len(data):
                    return None
                elif data[idx] == self.ESC_END[0]:
                    b = self.END[0]
                elif data[idx] == self.ESC_ESC[0]:
                    b = self.ESC[0]
            ret.append(b)
            idx += 1

        return bytes(ret)

    def _escape(self, data):
        ret = []
        for b in data:
            if b == self.END[0]:
                ret.append(self.ESC[0])
                ret.append(self.ESC_END[0])
            elif b == self.ESC[0]:
                ret.append(self.ESC[0])
                ret.append(self.ESC_ESC[0])
            else:
                ret.append(b)
        return bytes(ret)

    def _checksum(self, data):
        ret = []

        idx = 0
        crc = 0
        while idx < len(data):
            crc = crc16_le_table[(crc ^ data[idx]) & 0xFF] ^ (crc >> 8)
            idx += 1
        crc = ~crc

        ret.append(crc % 0x100)
        ret.append((crc >> 8) % 0x100)
        return bytes(ret)


async def connect(config: Dict[str, any], api: Callable) -> Gateway:
    loop = asyncio.get_running_loop()
    connected_future = loop.create_future()
    protocol = Gateway(api, connected_future)

    LOGGER.debug("Connecting to %s", config[zigpy.config.CONF_DEVICE_PATH])

    _, protocol = await zigpy.serial.create_serial_connection(
        loop=loop,
        protocol_factory=lambda: protocol,
        url=config[zigpy.config.CONF_DEVICE_PATH],
        baudrate=config[zigpy.config.CONF_DEVICE_BAUDRATE],
        xonxoff=False,
    )

    await connected_future

    LOGGER.debug("Connected to %s", config[zigpy.config.CONF_DEVICE_PATH])

    return protocol
