#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import datetime
import io
import queue
import struct
import sys
import time
from queue import Queue
from typing import TYPE_CHECKING, Optional, cast

if TYPE_CHECKING:
    from _typeshed import ReadableBuffer, WriteableBuffer

from bluepy import btle
from libscrc import modbus

MAC = "DC:0D:30:9C:61:BA"
INTERVAL = 15

# write_service = "0000ffd0-0000-1000-8000-00805f9b34fb"
# read_service  = "0000fff0-0000-1000-8000-00805f9b34fb"
WRITE_DEVICE = "0000ffd1-0000-1000-8000-00805f9b34fb"
READ_DEVICE = "0000fff1-0000-1000-8000-00805f9b34fb"

ACTION_READ = 0x03
ACTION_WRITE = 0x03

POSSIBLE_MARKER = (0x01, 0xFD, 0xFE, 0xFF)

# get(255, 12, 2)
# "ff 03 00 0c 00 02"
CMD_GET_1 = b"\xff\x03\x00\x0c\x00\x02"
# > ff 03 04 20 20 20 20

# get(255, 12, 8)
# ff 03 00 0c 00 08
CMD_GET_MODEL = b"\xff\x03\x00\x0c\x00\x08"
# > ff 03 10 20 20 20 20 4d 4c 32 34 32 30 20 20 20 20 20 20
# Device SKU: ML2420

# get(255, 20, 4)
# ff 03 00 14 00 04
CMD_GET_VERSION = b"\xff\x03\x00\x14\x00\x04"
# > ff 03 08 00 04 02 00 02 00 00 03
#         CC ?? 11 22 33 ?? 44 55 66
# Version: 4.2.0

# get(255, 24, 3)
# ff 03 00 18 00 03
CMD_GET_SERIAL = b"\xff\x03\x00\x18\x00\x03"
# > ff 03 06 3c 13 02 67 00 01
#         CC 11 22 33 33 ?? ??
# SN: 60-19-0615

# get(255, 256, 7)
# ff 03 01 00 00 07
CMD_GET_BATTERY_STATE = b"\xff\x03\x01\x00\x00\x07"
# > ff 03 0e 00 48 00 7e 00 1d 0e 0d 00 7e 00 1c 00 03
#         CC 11 11 22 22 33 33 44 55 66 66 77 77 88 88
# 1: Battery charge: 72 %
# 2: Battery voltage: 12.6 V
# 3: Battery current: 0.29 A
# 4: Internal temperature?
# 5: External temperature probe for battery signet 8bit: 13 degC
# 6: Load voltage: 12.6 V
# 7: Load current: 0.28 A
# 8: Load power: 3 W

# get(255, 263, 4)
# ff 03 01 07 00 04
CMD_GET_PANEL_STATUS = b"\xff\x03\x01\x07\x00\x04"
# > ff 03 08 00 c8 00 14 00 04 00 01
#         CC 11 11 22 22 33 33 ?? ??
# 1: Panel voltage: 20.0 V
# 2: Panel current: 0.20 A
# 3: Panel power: 4 W
# Charging status?

# set(255, 266, 1 or 0)
# ff 06 01 0a 00 01
CMD_ENABLE_LOAD = b"\xff\x06\x01\x0a\x00\x01"
CMD_DISABLE_LOAD = b"\xff\x06\x01\x0a\x00\x00"
REG_LOAD_ENABLE = 0x010A

# get(255, 267, 21)
# ff 03 01 0b 00 15
CMD_GET_LOAD_PARAMETERS = b"\xff\x03\x01\x0b\x00\x15"
# > ff 03 2a 00 7c 00 7f 00 51 00 20 00 0a 00 03 00 00 00 00 00
# > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
# > 00 00 00 00 00

# get(255, 288, 3)
# ff 03 01 20 00 03
CMD_GET_2 = b"\xff\x03\x01\x20\x00\x03"
# > ff 03 06 80 02 00 00 00 00
#         CC 11 22 33 33 33 33
# 1: boolean flag?: 1
# 2: ?: 2
# 3: ?: 0

# get(255, 57345, 33)
# ff 03 e0 01 00 21
CMD_GET_BATTERY_PARAMETERS = b"\xff\x03\xe0\x01\x00\x21"
# > ff 03 42 07 d0 00 c8 ff 0c 00 02 00 a0 00 9b 00 92 00 90 00
# > 8a 00 84 00 7e 00 78 00 6f 00 6a 64 32 00 05 00 78 00 78 00
# > 1e 00 03 00 41 00 a3 00 4b 00 a3 00 00 00 00 00 00 00 00 00
# > 0f 00 05 00 05 00 04 01 00
# 33 * uint16

# get(1, 61440, 10)
# 01 03 f0 00 00 0a
CMD_GET_HISTORICAL_TODAY = b"\x01\x03\xf0\x00\x00\x0a"
CMD_GET_HISTORICAL_YESTERDAY = b"\x01\x03\xf0\x01\x00\x0a"
CMD_GET_HISTORICAL_D2 = b"\x01\x03\xf0\x02\x00\x0a"
CMD_GET_HISTORICAL_D3 = b"\x01\x03\xf0\x03\x00\x0a"

#             ,- battery_min_voltage
#             |     ,- battery_max_voltage
#             |     |     ,- ?1 max charge %?
#             |     |     |     ,- ?2
#             |     |     |     |     ,- charge_max_power
#             |     |     |     |     |     ,- discharge_max_power
#             |     |     |     |     |     |     ,- charge_amp_hour
#             |     |     |     |     |     |     |     ,- discharge_amp_hour
#             |     |     |     |     |     |     |     |     ,- production_power
#             |     |     |     |     |     |     |     |     |     ,- consumption_power
#            _|___ _|___ _|___ _|___ _|___ _|___ _|___ _|___ _|___ _|___
# > 01 03 14 00 7c 00 7f 00 51 00 20 00 0a 00 03 00 00 00 00 00 00 00 00
# > 01 03 14 00 7c 00 7f 00 53 00 20 00 0a 00 03 00 00 00 00 00 00 00 00
# battery_min_voltage = 12.4 V
# battery_max_voltage = 12.7 V
# ?1 = 83 % ?
# ?2 =
# charge_max_power = 10 W
# discharge_max_power = 3 W
# charge_amp_hour = 0 Ah
# discharge_amp_hour = 0 Ah
# production_power = 0 Wh
# consumption_power = 0 Wh

# ff 78 00 00 00 01
CMD_ = b"\xff\x78\x00\x00\x00\x01"

# CMD_GET_BATTERY_STATE = b'\xff\x03\x01\x00\x00\x07'
# > ff 03 0e 00 48 00 7e 00 1d 0e 0d 00 7e 00 1c 00 03
#         CC 11 11 22 22 33 33 44 55 66 66 77 77 88 88
# 1: Battery charge: 72 %
# 2: Battery voltage: 12.6 V
# 3: Battery current: 0.29 A
# 4: Internal temperature?
# 5: External temperature probe for battery signed 8bit: 13 degC
# 6: Load voltage: 12.6 V
# 7: Load current: 0.28 A
# 8: Load power: 3 W

# CMD_GET_PANEL_STATUS = b'\xff\x03\x01\x07\x00\x04'
# > ff 03 08 00 c8 00 14 00 04 00 01
#         CC 11 11 22 22 33 33 ?? ??
# > ff 03 08 00 00 00 00 00 00 00 00
# 1: Panel voltage: 20.0 V
# 2: Panel current: 0.20 A
# 3: Panel power: 4 W
# ?: load_enabled

STATUS = {}


def parsePacket(data):
    timestamp = datetime.datetime.utcnow().isoformat(" ")
    # prefix = data[0]
    operation = data[1]
    cc = data[2]
    res = None
    if operation == 3:
        if cc == 0x0E:  # GET_BATTERY_STATE
            res = dict(
                zip(
                    (
                        "battery_charge",
                        "battery_voltage",
                        "battery_current",
                        "_internal_temperature?",
                        "battery_temperature",
                        "load_voltage",
                        "load_current",
                        "load_power",
                    ),
                    struct.unpack("!xxxHHHbbHHHxx", data),
                )
            )
            res["battery_voltage"] /= 10
            res["battery_current"] /= 100
            res["load_voltage"] /= 10
            res["load_current"] /= 100
            STATUS.update(res)

        elif cc == 0x08:  # GET_PANEL_STATUS (OR version)
            res = dict(
                zip(
                    ("panel_voltage", "panel_current", "panel_power", "load_enabled"),
                    struct.unpack("!xxxHHHx?xx", data),
                )
            )
            res["panel_voltage"] /= 10
            res["panel_current"] /= 100
            STATUS.update(res)
    elif operation == 6 and cc == 1:
        res = dict(zip(("load_enabled",), struct.unpack("!xxxxx?xx", data)))
        STATUS.update(res)

    if res:
        print(timestamp, res)
        return res
    print(timestamp, data)
    sys.stdout.flush()


class Delegate(btle.DefaultDelegate):
    data = bytearray()

    def handleNotification(self, cHandle, data):
        # print(cHandle, data, dlen)

        self.data.extend(data)

        c_crc = modbus(bytes(self.data[:-2]))
        # byte order is inverted in regards to libscrc output
        d_crc = self.data[-1] << 8 | self.data[-2]
        # print(hex(c_crc), hex(d_crc))

        if c_crc == d_crc:
            parsePacket(self.data)
            self.data.clear()


class BTLEUart(io.RawIOBase):
    mac: str
    write_endpoint: str
    read_endpoint: str
    timeout: float

    device: Optional[btle.Peripheral] = None
    _write_handle: Optional[btle.Characteristic] = None
    _read_handle: Optional[btle.Characteristic] = None
    delegate: "_QueueDelegate"
    _read_buffer: bytearray

    class _QueueDelegate(btle.DefaultDelegate):
        queue: Queue
        handle: Optional[int]

        def __init__(self, queue, handle=None):
            self.queue = queue
            self.handle = handle

        def handleNotification(self, cHandle: int, data: bytes):
            # print("Notification:", cHandle, "sent data", binascii.b2a_hex(data))

            if self.handle is not None and cHandle != self.handle:
                return

            self.queue.put(data)

    def __init__(
        self,
        mac: str,
        write_endpoint: str = WRITE_DEVICE,
        read_endpoint: str = READ_DEVICE,
        timeout: float = 30,
    ):
        self.mac = mac
        self.write_endpoint = write_endpoint
        self.read_endpoint = read_endpoint
        self.timeout = timeout

        self.delegate = self._QueueDelegate(Queue())
        self._read_buffer = bytearray()

        self._connect()

    def _ensure_connected(self):
        if self.device is None:
            self._connect()

    def _poll(self, timeout: float = 0.0001):
        self._ensure_connected()
        if TYPE_CHECKING:
            self.device = cast(btle.Peripheral, self.device)

        start = time.time()
        left = timeout - (time.time() - start)
        while self.device.waitForNotifications(max(left, 0) or 0.0001):
            left = timeout - (time.time() - start)
            if left < 0:
                break

    def _connect(self):
        try:
            del self.device
        except Exception:
            pass
        self.device = btle.Peripheral(self.mac).withDelegate(self.delegate)
        self._read_handle = self.device.getCharacteristics(uuid=self.read_endpoint)[0]
        # self.delegate.handle = self._read_handle.handle
        self._write_handle = self.device.getCharacteristics(uuid=self.write_endpoint)[0]
        # print("Handles:", self._read_handle.handle, self._write_handle.handle)

    def _read(self, num: Optional[int] = None, timeout: Optional[float] = None):
        self._ensure_connected()
        if TYPE_CHECKING:
            self.device = cast(btle.Peripheral, self.device)

        if timeout is None:
            timeout = self.timeout

        if num is None:
            start = time.time()
            while not len(self._read_buffer):
                left = timeout - (time.time() - start)
                if left < 0:
                    break
                self._poll()
                try:
                    self._read_buffer.extend(self.delegate.queue.get_nowait())
                except queue.Empty:
                    pass
            try:
                while True:
                    self._poll()
                    self._read_buffer.extend(self.delegate.queue.get_nowait())

            except queue.Empty:
                pass
        else:
            start = time.time()
            while len(self._read_buffer) < num:
                left = timeout - (time.time() - start)
                if left < 0:
                    break
                self._poll()
                try:
                    self._read_buffer.extend(self.delegate.queue.get_nowait())
                except queue.Empty:
                    pass

        if num is None:
            data = bytes(self._read_buffer.copy())
            self._read_buffer.clear()
        else:
            data = bytes(self._read_buffer[:num])
            del self._read_buffer[:num]
        return data or None

    def readinto(self, buffer: "WriteableBuffer") -> Optional[int]:
        data = self._read(len(buffer))

        if data is None:
            return None

        buffer[: len(data)] = data
        return len(data)

    def readall(self) -> bytes:
        return self._read()

    def read(
        self, size: Optional[int] = None, timeout: Optional[float] = None
    ) -> Optional[bytes]:
        if timeout:
            _timeout = self.timeout
            self.timeout = timeout

        if size is None:
            res = super().read()
        else:
            res = super().read(size)

        if timeout:
            self.timeout = _timeout
        return res

    def write(self, b: "ReadableBuffer") -> Optional[int]:
        self._ensure_connected()
        if TYPE_CHECKING:
            self.device = cast(btle.Peripheral, self.device)

        if self._write_handle is None:
            raise IOError("write_handle not open")
        self._write_handle.write(b, withResponse=True)
        return len(b)

    def __enter__(self):
        return self

    def __exit__(self, type, value, traceback):
        self.device.disconnect()
        del self.device

    def seekable(self) -> bool:
        return False

    def readable(self) -> bool:
        return True

    def writable(self) -> bool:
        return True

    # dlgt = Delegate()

    # prev = time.time() - INTERVAL

    # while True:
    #    try:
    #        log("Connecting...")
    #        with btle.Peripheral(MAC).withDelegate(dlgt) as dev:
    #            wd = dev.getCharacteristics(uuid=write_device)[0]


def write(fh, data):
    bdata = bytes(data)
    crc = modbus(bdata)
    bcrc = bytes([crc & 0xFF, (crc & 0xFF00) >> 8])
    fh.write(data + bcrc)


def construct_request(address, words=1, action=ACTION_READ, marker=0xFF):
    assert marker in {POSSIBLE_MARKER}, f"marker should be one of {POSSIBLE_MARKER}"
    return struct.pack("!BBHH", marker, action, address, words)


def poll(dev: btle.Peripheral, timeout: float = 1) -> bool:
    start = time.time()
    while not dev.waitForNotifications(0.2):
        if time.time() < start + timeout:
            return False

    while dev.waitForNotifications(0.2):
        pass

    return True


def log(string: str):
    print(datetime.datetime.utcnow().isoformat(" "), string)
    sys.stdout.flush()


def parse_packet(data):
    tag, operation, size = struct.unpack_from("BBB", data)
    _unpacked = struct.unpack_from(f"<{size}BH", data, offset=3)
    crc = _unpacked[-1]
    payload = _unpacked[:-1]
    calculated_crc = modbus(bytes([tag, operation, size, *payload]))

    if crc != calculated_crc:
        e = ValueError(f"CRC missmatch: expected {crc:04X}, got {calculated_crc:04X}.")
        e.tag = tag
        e.operation = operation
        e.size = size
        e.payload = payload
        e.crc = crc
        e.calculated_crc = calculated_crc
        raise e

    return payload


if __name__ == "__main__":
    dlgt = Delegate()

    prev = time.time() - INTERVAL

    while True:
        try:
            log("Connecting...")
            with btle.Peripheral(MAC).withDelegate(dlgt) as dev:
                wd = dev.getCharacteristics(uuid=WRITE_DEVICE)[0]

                log("Connected.")

                poll(dev)

                write(wd, construct_request(0, 32))
                poll(dev)
                poll(dev)
                poll(dev)

                # Memory dump
                # for address in range(0, 0x10000, 16):
                #    log(f"Reading 0x{address:04X}...")
                #    write(wd, construct_request(address, 16))
                #    poll(dev)
                #    poll(dev)
                #    poll(dev)
                #    poll(dev)
                #    poll(dev)

                while True:
                    poll(dev)

                    now = time.time()
                    diff = now - prev
                    if diff >= INTERVAL:
                        prev += INTERVAL

                        write(wd, construct_request(0x0107, 4))  # CMD_GET_PANEL_STATUS
                        poll(dev)

                        write(wd, construct_request(0x0100, 7))  # CMD_GET_BATTERY_STATE
                        poll(dev)

                # if STATUS.get('load_enabled'):
                #    write(wd, CMD_DISABLE_LOAD)
                # else:
                #    write(wd, CMD_ENABLE_LOAD)

        except btle.BTLEDisconnectError:
            log("ERROR: Disconnected")
            time.sleep(1)
            try:
                dev.close()
            except Exception:
                pass