"""
An example of a 'noun' class, able to serve as the basis for PWM control of an
LED attached to a suitable GPIO pin

Overview
--------

This is a reasonably minimal example of a 'noun' class, which inherits from
`urest.api.base.APIBase`. It also requires the `Pin` library from MicroPython:
but should be able to be adapted to other GPIO libraries which provide a similar
interface.

In contrast to the `urest.examples.simpleled.SimpleLED` class, the
`urest.examples.pwmled.PWMLED` class shows the use of the `ayncio`
`create_tasks()` hook within a `urest.api.base.APIBase` 'noun' to set off slow
running tasks. This allows the state update to be returned to the network client
via the API 'immediately' (at least subject to the other tasks outstanding and
network conditions); without waiting for the _actual_ internal state to
complete. This is a much more realistic scenario for use in the control of
external devices: especially devices such as motors which may take seconds (or
longer) to obtain the correct state.

API
---

The 'noun' will return two objects in the JSON state, in response to `get_state`
requests

  * `actual` : The _current_ state of the output, which will be `0` for fully off
and `1` for fully on
  * `desired`: The _next_ state, if any, that the output is
currently transitioning to; either `0` for fully off and `1` for fully on

This gives a full state table as follows

| Actual State | Desired State | Description                                                  |
|--------------|---------------|--------------------------------------------------------------|
| 0            | 0             | Output fully `off`                                           |
| 0            | 1             | Output commanded `on`; currently turning from `off` to `on`  |
| 1            | 0             | Output commanded `off`; currently turning from `on` to `off` |
| 1            | 1             | Output fully `on`                                            |



Tested Implementations
----------------------

This version is written for MicroPython 3.4, and has been tested on:

  * Raspberry Pi Pico W

Licence
-------

This class, and all included code, is made available under the terms of the MIT Licence

> Copyright (c) 2023 David Love

> Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:

> The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""

# Import the Asynchronous IO Library, preferring the MicroPython library if
# available
try:
    from machine import Pin, PWM
    import uasyncio as asyncio
except ImportError:
    print("Ignoring MicroPython include: machine")

from ..api.base import APIBase

PWM_STEP = 6550
""" Determines the increment (or decrement) for each step in the PWM 'on' or 'off' movement"""


class PWMLED(APIBase):
    def __init__(self, pin: int):
        self._gpio = PWM(Pin(pin))
        self._gpio.duty_u16(0)
        self._gpio.freq(100)
        self._gpio_lock = asyncio.Lock()

        self._duty = 0

        self._state_attributes = dict(desired=0, current=0)

    async def _slow_on(self):
        # Wait for the GPIO lock if we need to
        await self._gpio_lock.acquire()

        # Increase the duty cycle from 0 to near the
        # maximum in steps lasting 1s. We will also
        # allow other co-routines to run whilst we
        # are waiting for the next step to take place

        self._duty = 0

        while self._duty < (65000):
            print(f"duty on: {self._duty}")

            self._duty += PWM_STEP
            self._gpio.duty_u16(self._duty)

            await asyncio.sleep_ms(1000)
        else:
            self._state_attributes["current"] = 1

        # Set the duty cycle to maximum before we leave,
        # and release the GPIO lock
        self._duty = 2 ** 16
        self._gpio.duty_u16(self._duty)

        self._gpio_lock.release()

    async def _slow_off(self):
        # Wait for the GPIO lock if we need to
        await self._gpio_lock.acquire()

        # Decrease the duty cycle from the maximum to
        # near 0 in steps lasting 1s. We will also
        # allow other co-routines to run whilst we
        # are waiting for the next step to take place

        self._duty = 2 ** 16

        while self._duty > 6000:
            print(f"duty off: {self._duty}")

            self._duty -= PWM_STEP
            self._gpio.duty_u16(self._duty)

            await asyncio.sleep_ms(1000)
        else:
            self._state_attributes["current"] = 0

        # Set the duty cycle to 0 before we leave,
        # and release the GPIO lock
        self._duty = 0
        self._gpio.duty_u16(self._duty)

        self._gpio_lock.release()

    def set_state(self, state_attributes: dict):
        try:
            loop = asyncio.get_event_loop()

            self._state_attributes["desired"] = state_attributes["desired"]

            if self._state_attributes["desired"] == 0:
                self._state_attributes["current"] = 1

                loop.create_task(self._slow_off())
            else:
                self._state_attributes["current"] = 0

                loop.create_task(self._slow_on())

        except KeyError:
            # On exception try to return to a known good
            # state
            self._gpio.duty_u16(0)
            self._duty = 0

            self._state_attributes["desired"] = 0
            self._state_attributes["current"] = 0

    def get_state(self) -> dict:
        return self._state_attributes

    def delete_state(self):
        self._gpio.duty_u16(0)
        self._gpio.freq(100)
        self._duty = 0

        self._state_attributes["desired"] = 0
        self._state_attributes["current"] = 0

    def update_state(self, state_attributes: dict):
        loop = asyncio.get_event_loop()

        if self._state_attributes["desired"] == 0:
            self._state_attributes["desired"] = 1
            self._state_attributes["current"] = 0

            loop.create_task(self._slow_on())
        else:
            self._state_attributes["desired"] = 0
            self._state_attributes["current"] = 1

            loop.create_task(self._slow_off())
