# This is part of Kaylee
# -- this code is licensed GPLv3
# Copyright 2015-2017 Clayton G. Hobbs
# Portions Copyright 2013 Jezra

"""Dark Sky weather plugin for Kaylee

This plugin provides weather information `powered by Dark Sky
<https://darksky.net/poweredby/>`__.  The user must provide a key for
the Dark Sky API, as well as decimal latitude and longitude::

    ".darksky": {
        "api_key": "USER_API_KEY",
        "latitude": USER_LATITUDE,
        "longitude": USER_LONGITUDE
    }

Weather information is cached for up to ``cache_max_age`` seconds
(default 1800, half an hour).  To conserve API calls, the cache is not
updated until the first time the user requests weather information
after the cache becomes stale.

Temperatures are read to the nearest ``temp_precision`` decimal places
(default 0).
"""

import json
import os
import time

import requests

from .pluginbase import PluginBase


class Plugin(PluginBase):
    """Main class for the Dark Sky weather plugin"""

    def __init__(self, config, name):
        """Initialize the Dark Sky weather plugin"""
        super().__init__(config, name)

        self._cache_filename = os.path.join(config.cache_dir, 'darksky.json')
        self._weather_url = 'https://api.darksky.net/forecast/{}/{},{}'.format(
            self.options['api_key'],
            self.options['latitude'],
            self.options['longitude']
        )
        try:
            self._cache_max_age = self.options['cache_max_age']
        except KeyError:
            self._cache_max_age = 1800
        try:
            self._temp_precision = self.options['temp_precision']
        except KeyError:
            self._temp_precision = 0

        self.commands = {
            'whats the temperature': self._temperature,
            'whats todays low': self._todays_low,
            'whats todays high': self._todays_high,
            'whats tomorrows high': self._tomorrows_high,
            'whats the humidity': self._relative_humidity,
            'whats the weather': self._current_conditions,
            'whens sunset': self._sunset_time,
            'hoos your weather provider': self._provider_credits
        }

        self.corpus_strings.update(self.commands)

    def _format_temperature(self, temperature, unit='Fahrenheit'):
        """Format a temperature for the TTS system"""
        return '{:.{prec}f} degrees {}'.format(temperature, unit,
                prec=self._temp_precision)

    def _temperature(self):
        return self._format_temperature(self.cache['currently']['temperature'])

    def _todays_low(self):
        return self._format_temperature(
            self.cache['daily']['data'][0]['temperatureMin'])

    def _todays_high(self):
        return self._format_temperature(
            self.cache['daily']['data'][0]['temperatureMax'])

    def _tomorrows_high(self):
        return self._format_temperature(
            self.cache['daily']['data'][1]['temperatureMax'])

    def _relative_humidity(self):
        return '{:.0f} percent'.format(
            100 * self.cache['currently']['humidity'])

    def _current_conditions(self):
        return '{}, {}, relative humidity {}'.format(
            self.cache['currently']['summary'],
            self._temperature(),
            self._relative_humidity())

    def _sunset_time(self):
        # Get the time in a more useful structure
        t = time.localtime(self.cache['daily']['data'][0]['sunsetTime'])

        # Format each part of the time to be pronounced nicely
        hour = time.strftime('%I', t)
        if hour[0] == '0':
            hour = hour[1]

        minute = time.strftime('%M', t)
        if minute[0] == '0':
            if minute[1] == '0':
                minute = "o'clock"
            else:
                minute = 'O' + minute[1]

        ante_post = time.strftime('%p', t)
        if ante_post[0] == 'A':
            ante_post = 'AE ' + ante_post[1]

        # Put the parts together
        return '{} {} {}'.format(hour, minute, ante_post)

    def _provider_credits(self):
        return 'Powered by Dark Sky, https://darksky.net/poweredby/.'

    def _update_cache_if_stale(self):
        try:
            st = os.stat(self._cache_filename)
        except FileNotFoundError:
            # If there's no cache file, we need to get one
            self._update_cache()
        else:
            if time.time() - st.st_mtime > self._cache_max_age:
                self._update_cache()

    def _update_cache(self):
        r = requests.get(self._weather_url, stream=True)
        if r.status_code == 200:
            with open(self._cache_filename, 'wb') as f:
                for chunk in r:
                    f.write(chunk)

    def _read_cache(self):
        with open(self._cache_filename, 'r') as f:
            return json.load(f)

    def confidence(self, text):
        """Return whether or not the command can be handled"""
        return 1 if text in self.corpus_strings else 0

    def handle(self, text):
        """Speak reasonably up-to-date weather information"""
        # Is there a matching command?
        if self.confidence(text):
            self._update_cache_if_stale()
            self.cache = self._read_cache()
            self.emit('tts', self.commands[text]())
            return True
        else:
            return False