#!/usr/bin/env python3
from argparse import ArgumentParser
import requests
import fscache

base_url = 'https://api.weather.gov'
headers = {
    'user-agent': 'meteor.py/0.2 (us@starfall.systems)',
    'accept': 'application/ld+json'
}

# SGR decorations / ANSI escape colors
class term:
    RESET = '\033[0m'
    BOLD = '\033[1m'

def handle_args():
    parser = ArgumentParser()
    parser.add_argument('lat', help='latitude')
    parser.add_argument('lon', help='longitude')
    return parser.parse_args()

def print_alerts(county, zone): 
    # in some areas, alerts are not published for the zone but only for the county
    # you can request both like this rather than making two requestsfork
    alerts = requests.get(base_url + f'/alerts/active?zone={county},{zone}',
                          headers=headers).json()

    print(f'{term.BOLD}{alerts.get("title")}')
    print(f'===================={term.RESET}')
    for alert in alerts.get('@graph'):
        print(f'{alert.get("headline")}')
        print(f'  {alert.get("severity")} - {alert.get("certainty")} - {alert.get("urgency")}')
        print(f'  Until: {alert.get("expires")}')
        print(f'{alert.get("description")}')
        print('--------------------')

        # many more cool fields available.
        # verious datetimes: sent, effective, onset, expires, ends
        # severity: Minor, Moderate, Severe, Extreme, Unknown
        # certainty: Unlikely, Possible, Likely, Observed, Unknown
        # urgency: Past, Future, Expected, Immediate, Unknown
        # messageType: Alert, Update
                
        # can construct the headline ourseves as f'{event} issued {sent} [until {end}] by {senderName}'
    print()

def print_forecast(point):
    cache_key = f'{point.get("gridId")}-{point.get("gridX")},{point.get("gridY")}'

    try: 
        print(cache.read(cache_key))
    except fscache.CacheMiss:
        response = requests.get(point.get('forecast'), headers=headers)
        # ugly cache_control parsing honestly, break out later
        ttl = int(response.headers['cache-control'].split('max-age=')[-1].split(',')[0])
        forecast = response.json()

        buffer = f'{term.BOLD}forecast for {point.get("relativeLocation").get("city")}, {point.get("relativeLocation").get("state")} ({cache_key})'
        buffer += '\n' + f'===================={term.RESET}'
        periods = forecast.get('periods')
        # print today and tonight in long format
        for period in periods[:2]:
            buffer += '\n' + f'{term.BOLD}{period.get("name")}{term.RESET}:'
            buffer += '\n' + f'  {period.get("temperature")}°{period.get("temperatureUnit")}, wind {period.get("windSpeed")} {period.get("windDirection")}'
            buffer += '\n' + f'  {period.get("detailedForecast")}'
        # print further forecasted periods in short format
        for period in periods[2:]:
            buffer += '\n' + f'{term.BOLD}{period.get("name").ljust(15)}{term.RESET}: {period.get("shortForecast")} - {period.get("temperature")}°{period.get("temperatureUnit")}, {period.get("windSpeed")} {period.get("windDirection")}'

        cache.write(cache_key, buffer, ttl)
        print(buffer)

def main():
    args = handle_args()
    global cache
    cache = fscache.Cache('meteor.py')

    point = requests.get(base_url + f'/points/{args.lat},{args.lon}',
                         headers=headers).json()

    county = point.get('county').split('/')[-1]
    zone = point.get('forecastZone').split('/')[-1]
    print_alerts(county, zone)

    # TODO can hazardous weather outlook be gotten programatically?

    print_forecast(point)

if __name__ == '__main__':
    import sys
    sys.exit(main())