# ========================================================================== #
#                                                                            #
#    KVMD - The main PiKVM daemon.                                           #
#                                                                            #
#    Copyright (C) 2018-2022  Maxim Devaev <mdevaev@gmail.com>               #
#                                                                            #
#    This program is free software: you can redistribute it and/or modify    #
#    it under the terms of the GNU General Public License as published by    #
#    the Free Software Foundation, either version 3 of the License, or       #
#    (at your option) any later version.                                     #
#                                                                            #
#    This program is distributed in the hope that it will be useful,         #
#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
#    GNU General Public License for more details.                            #
#                                                                            #
#    You should have received a copy of the GNU General Public License       #
#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
#                                                                            #
# ========================================================================== #


import asyncio

from typing import Dict
from typing import Set
from typing import Callable
from typing import Optional
from typing import Any

import gpiod

from ... import aiotools

from ...yamlconf import Option

from ...validators.os import valid_abs_path
from ...validators.hw import valid_gpio_pin

from . import UserGpioModes
from . import BaseUserGpioDriver


# =====
class Plugin(BaseUserGpioDriver):
    def __init__(
        self,
        instance_name: str,
        notifier: aiotools.AioNotifier,

        device_path: str,
    ) -> None:

        super().__init__(instance_name, notifier)

        self.__device_path = device_path

        self.__tasks: Dict[int, Optional[asyncio.Task]] = {}

        self.__chip: Optional[gpiod.Chip] = None
        self.__lines: Dict[int, gpiod.Line] = {}

    @classmethod
    def get_plugin_options(cls) -> Dict:
        return {
            "device": Option("/dev/gpiochip0", type=valid_abs_path, unpack_as="device_path"),
        }

    @classmethod
    def get_modes(cls) -> Set[str]:
        return set([UserGpioModes.OUTPUT])

    @classmethod
    def get_pin_validator(cls) -> Callable[[Any], Any]:
        return valid_gpio_pin

    def register_output(self, pin: str, initial: Optional[bool]) -> None:
        _ = initial
        self.__tasks[int(pin)] = None

    def prepare(self) -> None:
        self.__chip = gpiod.Chip(self.__device_path)
        for pin in self.__tasks:
            line = self.__chip.get_line(pin)
            line.request("kvmd::locator::outputs", gpiod.LINE_REQ_DIR_OUT, default_vals=[0])
            self.__lines[pin] = line

    async def cleanup(self) -> None:
        tasks = [
            task
            for task in self.__tasks.values()
            if task is not None
        ]
        for task in tasks:
            task.cancel()
        await asyncio.gather(*tasks, return_exceptions=True)
        if self.__chip:
            try:
                self.__chip.close()
            except Exception:
                pass

    async def read(self, pin: str) -> bool:
        return (self.__tasks[int(pin)] is not None)

    async def write(self, pin: str, state: bool) -> None:
        pin_int = int(pin)
        task = self.__tasks[pin_int]
        if state and task is None:
            self.__tasks[pin_int] = asyncio.create_task(self.__blink(pin_int))
        elif not state and task is not None:
            task.cancel()
            await task
            self.__tasks[pin_int] = None

    async def __blink(self, pin: int) -> None:
        line = self.__lines[pin]
        try:
            state = 1
            while True:
                line.set_value(state)
                state = int(not state)
                await asyncio.sleep(0.1)
        except asyncio.CancelledError:
            pass
        finally:
            line.set_value(0)

    def __str__(self) -> str:
        return f"Locator({self._instance_name})"

    __repr__ = __str__