#
# Dispatch incoming Alexa commands to the respective lighting.
#
# EXAMPLE:
#   $ curl --json '{"Message": "280e:1"}' --header 'x-amz-sns-message-type: Notification' http://192.168.0.$ADDR/alexa
#
#   $ upnpc -d $EXTERNAL_PORT TCP
#   $ upnpc -e 'temp Alexa' -a 192.168.0.$ADDR 80 $EXTERNAL_PORT TCP
#

import asyncio
import logging

import aiohttp  # mpremote mip install aiohttp

LOGGER = logging.getLogger(__name__)

HDR_SNS_TYPE = 'x-amz-sns-message-type'
HDR_SNS_TOPIC = 'x-amz-sns-topic-arn'
SNS_TYPE_SUBSCRIBE = 'SubscriptionConfirmation'
SNS_TYPE_NOTIFY = 'Notification'


def prepare(app):
    # Create an endpoint on the APP.
    app.post('/alexa')(app.gc_cleaning(endpoint))


async def endpoint(request):
    # SNS does not set the "proper" content type. Override it.
    #LOGGER.debug(f'CONTENT-TYPE: {request.content_type}')
    request.content_type = 'application/json'

    reqtype = request.headers.get(HDR_SNS_TYPE)
    #LOGGER.debug(f'REQTYPE: {reqtype}')
    LOGGER.debug(f'BODY: {request.json}')

    if reqtype == SNS_TYPE_SUBSCRIBE:
        return await _confirm(request.json['SubscribeURL'])

    if reqtype == SNS_TYPE_NOTIFY:
        return await _notify(request.json['Message'])

    # Log an error, but don't tell (attackers?) what went wrong.
    LOGGER(f'error. unknown reqtype "{reqtype}"')
    return 'Bad request.', 400


async def _confirm(url):
    LOGGER.debug(f'Confirming: {url}')
    return
    async with aiohttp.ClientSession() as session:
        _ = await session.head(url)
    LOGGER.info(f'Subscribed to: {request.headers.get(HDR_SNS_TOPIC)}')
    return '', 204


async def _notify(msg):
    # format: xxxx:d  (x is a hex digit address; d is on/off)
    if len(msg) != 6 or msg[4] != ':' or not ('0'<=msg[5]<='1'):
        LOGGER.error(f'Message has improper format: {msg}')
        return 'Bad request.', 400

    try:
        device = int(msg[:4], 16)
    except ValueError:
        LOGGER.error(f'Device code is improper: {msg[:4]}')
        return 'Bad request.', 400

    ### bug in Lambda
    if device == 0x281e:
        device = 0x280e

    light = _find_light(device)
    LOGGER.debug(f'LIGHT: {light}')

    turn_on = msg[5] == '1'
    msg = f'Turning {"on" if turn_on else "off"}: {light["label"]}'
    LOGGER.info(msg)

    if 'shelly' in light:
        # Controlled by a Shelly. Defer to that controller.
        return await _call_shelly(light, turn_on)

    # Classic I2C device.
    ### 2025-04-04: the 110V relay boards.

    if turn_on:
        device |= 0x20  # the 'E' flag in pic/relay-board/main.asm

    ### get URL base from config
    url = f'http://192.168.0.3/i/{device:04x}'
    return await _ping_url(url)


async def _call_shelly(light, turn_on):
    ### hack. fix somehow?
    import app

    # Get the Shelly device's IP address.
    ip = app.APP.cfg['network'].get(f'SHELLY_{light["shelly"]}')

    # http://192.168.0.24/script/1/on?id=2
    url = f'http://{ip}/script/1/{"on" if turn_on else "off"}?id={light["light"]}'
    return await _ping_url(url)


async def _ping_url(url):
    LOGGER.info(f'LIGHT URL: {url}')
    async with aiohttp.ClientSession() as session:
        async with session.get(url) as response:
            # We don't care about the body. The response has read the headers,
            # and is now pending consumption of the body. There is no close()
            # function, so we're just simpy done.
            pass

    return '', 204


def _find_light(device):
    ### hack. fix somehow?
    import app

    #print(f'FIND: {device}')
    for light in app.APP.cfg['lights'].values():
        #print('CHECK:', light)
        if light.get('i2c') == device:
            return light
    return None