#!/usr/bin/env python3

# © Copyright 2021-2022, Scott Gasch

"""How's the weather going to be tomorrow?"""

import datetime
import logging
import os
import urllib.request
from dataclasses import dataclass
from typing import Any

import astral  # type: ignore
import pytz
from astral.sun import sun  # type: ignore
from bs4 import BeautifulSoup  # type: ignore
from overrides import overrides

import argparse_utils
import config
import dateparse.dateparse_utils as dp
import datetime_utils
import persistent
import smart_home.thermometers as temps
import text_utils

logger = logging.getLogger(__name__)

cfg = config.add_commandline_args(
    f'Cached Weather Forecast ({__file__})',
    'Arguments controlling detailed weather rendering',
)
cfg.add_argument(
    '--weather_forecast_cachefile',
    type=str,
    default=f'{os.environ["HOME"]}/cache/.weather_forecast_cache',
    metavar='FILENAME',
    help='File in which to cache weather data',
)
cfg.add_argument(
    '--weather_forecast_stalest_acceptable',
    type=argparse_utils.valid_duration,
    default=datetime.timedelta(seconds=7200),  # 2 hours
    metavar='DURATION',
    help='Maximum acceptable age of cached data.  If zero, forces a refetch',
)


@dataclass
class WeatherForecast:
    date: datetime.date  # The date
    sunrise: datetime.datetime  # Sunrise datetime
    sunset: datetime.datetime  # Sunset datetime
    description: str  # Textual description of weather


@persistent.persistent_autoloaded_singleton()  # type: ignore
class CachedDetailedWeatherForecast(persistent.PicklingFileBasedPersistent):
    def __init__(self, forecasts=None):
        if forecasts is not None:
            self.forecasts = forecasts
            return

        now = datetime_utils.now_pacific()
        self.forecasts = {}

        # Ask the raspberry pi about the outside temperature.
        current_temp = temps.ThermometerRegistry().read_temperature(
            'house_outside', convert_to_fahrenheit=True
        )

        # Get a weather forecast for Bellevue.
        www = urllib.request.urlopen(
            "https://forecast.weather.gov/MapClick.php?lat=47.652775&lon=-122.170716"
        )
        forecast_response = www.read()
        www.close()

        soup = BeautifulSoup(forecast_response, "html.parser")
        forecast = soup.find(id='detailed-forecast-body')
        parser = dp.DateParser()

        said_temp = False
        last_dt = now
        dt = now
        for (day, txt) in zip(
            forecast.find_all('b'),
            forecast.find_all(class_='col-sm-10 forecast-text'),
        ):
            last_dt = dt
            try:
                dt = parser.parse(day.get_text())
            except Exception:
                dt = last_dt
            assert dt is not None

            # Compute sunrise/sunset times on dt.
            city = astral.LocationInfo("Bellevue", "USA", "US/Pacific", 47.653, -122.171)
            s = sun(city.observer, date=dt, tzinfo=pytz.timezone("US/Pacific"))
            sunrise = s['sunrise']
            sunset = s['sunset']

            if dt.date() == now.date() and not said_temp and current_temp is not None:
                blurb = f'{day.get_text()}: The current outside tempterature is {current_temp}. '
                blurb += txt.get_text()
                said_temp = True
            else:
                blurb = f'{day.get_text()}: {txt.get_text()}'
            blurb = text_utils.wrap_string(blurb, 80)

            if dt.date() in self.forecasts:
                self.forecasts[dt.date()].description += '\n' + blurb
            else:
                self.forecasts[dt.date()] = WeatherForecast(
                    date=dt,
                    sunrise=sunrise,
                    sunset=sunset,
                    description=blurb,
                )

    @staticmethod
    @overrides
    def get_filename() -> str:
        return config.config['weather_forecast_cachefile']

    @staticmethod
    @overrides
    def should_we_save_data(filename: str) -> bool:
        return True

    @staticmethod
    @overrides
    def should_we_load_data(filename: str) -> bool:
        return persistent.was_file_written_within_n_seconds(
            filename,
            config.config['weather_forecast_stalest_acceptable'].total_seconds(),
        )

    @overrides
    def get_persistent_data(self) -> Any:
        return self.forecasts