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

# doco is at https://www.weather.gov/documentation/services-web-api
# openAPI spec is at https://api.weather.gov/openapi.json

base_url = 'https://api.weather.gov'
headers = {
    'user-agent': 'meteor.py/0.1 (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()

    # this title was cooler when we requested only one zone
    # e.g. it would end with "for Holmes County (MSC051) MS"
    # but now it's just "current watches, warnings, and advisories"
    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")}')
        # TODO description can be quite long
        # short desc appears to be available as parameters.NWSheadline[0]
        # and follow up with instruction when it exists
        print('--------------------')

        # many more cool fields available.
        # verious datetimes: sent, effective, onset, expires, ends
        # severity: Minor, Moderate, Severe, Extreme, Unknown
        # certainty: Possible, Likely, Observed, Unknown
        # urgency: 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):
    # TODO pick up gridId AFC (AER/ALU), AFG, AJK, BOX< CAE, DLH, FSD, HGX, HNX, LIX, LWX, MAF, MFR, MLB, MRX, MTR, PIH and reduce gridX and gridY by 1 - known issue

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

    try: 
        print(cache.read(cache_key))
    except fs.CacheMiss:
        forecast_url = point.get('forecast')
        forecast = requests.get(forecast_url, headers=headers).json()
        # TODO retry on 500 - known issue
        # TODO query param units=si

        # TODO replace the whole thing with /gridpoints/{point.gridId}/{gridX},{gridY} and create our own forecast
        # there is lots more information there that would be useful
        # probabilityOfPrecipitation is the neatest one that's not in .../forecast or .../forecast/hourly
        # but there's also relativeHumidity, apparentTemperature (and, separately, windChill), skyCover, windGust
        # downside, it appears to always convert the F/mph measurements into C/kph for no reason. e.g. all temps are measured in 9ths of C
    
        # TODO pick out location name from somewhere.
        # city and state hide in point.relativeLocation.properties.city (and state)
        # getting the county or zone's `name (id) state` is good too

        buffer = f'{term.BOLD}forecast'
        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:]:
            # TODO parse isDaytime true/false to squish a day together
            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)
        print(buffer)

def main():
    args = handle_args()
    global cache
    cache = fs.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())