#!/usr/bin/env python3
'''Check if a given distro is going to be EOL soon.

   This queries the public API of https://endoflife.date to fetch EOL dates.

   ‘soon’ is defined by LEAD_DAYS, currently 30 days.'''

import datetime
import json
import sys
import urllib.request

URL_BASE = 'https://endoflife.date/api'
NOW = datetime.date.today()
LEAD_DAYS = datetime.timedelta(days=30)

DISTRO = sys.argv[1]
RELEASE = sys.argv[2]

EXIT_NOT_IMPENDING = 0
EXIT_IMPENDING = 1
EXIT_NO_DATA = 2
EXIT_FAILURE = 3

try:
    with urllib.request.urlopen(f'{ URL_BASE }/{ DISTRO }/{ RELEASE }.json') as response:
        match response.status:
            case 200:
                data = json.load(response)
            case _:
                print(
                    f'Failed to retrieve data for { DISTRO } { RELEASE } ' +
                    f'(status: { response.status }).',
                    file=sys.stderr
                )
                sys.exit(EXIT_FAILURE)
except urllib.error.HTTPError as e:
    match e.code:
        case 404:
            print(f'No data available for { DISTRO } { RELEASE }.', file=sys.stderr)
            sys.exit(EXIT_NO_DATA)
        case _:
            print(
                f'Failed to retrieve data for { DISTRO } { RELEASE } ' +
                f'(status: { e.code }).',
                file=sys.stderr
            )
            sys.exit(EXIT_FAILURE)

eol = datetime.date.fromisoformat(data['eol'])

offset = abs(eol - NOW)

if offset <= LEAD_DAYS:
    print(data['eol'])
    sys.exit(EXIT_IMPENDING)
else:
    sys.exit(EXIT_NOT_IMPENDING)