"""Apple Artist Model."""
import datetime
import jwt
import requests

from artist.config import secrets_manager_client
from artist.constants import apple, errors
from artist.response import create_error_response
from artist.response import Response

MUSIC_KIT_SECRET = '\n'.join([
    '-----BEGIN PRIVATE KEY-----',
    secrets_manager_client.get_cred('MUSIC_KIT_PRIVATE_KEY') or '',
    '-----END PRIVATE KEY-----'])
MUSIC_KIT_KEY_ID = secrets_manager_client.get_cred('MUSIC_KIT_KEY_ID')
APPLE_MUSIC_TEAM_ID = secrets_manager_client.get_cred('APPLE_MUSIC_TEAM_ID')


def get_auth_token():
    """Generate an encrypted token using JWT specification.

    Required for all Apple Music API calls.

    Returns:
        str: Apple Music developer token.
    """
    alg = apple.DSA

    time_now = datetime.datetime.now()
    time_expired = datetime.datetime.now() + datetime.timedelta(seconds=60)

    headers = {
        'alg': alg,
        'kid': MUSIC_KIT_KEY_ID
    }

    payload = {
        'iss': APPLE_MUSIC_TEAM_ID,
        'exp': int(time_expired.strftime('%s')),
        'iat': int(time_now.strftime('%s'))
    }

    token = jwt.encode(payload, MUSIC_KIT_SECRET, algorithm=alg, headers=headers)
    return token.decode()


def search(query, storefront, limit=None, offset=None):
    """Fetch a list of artists from Apple Music."""
    auth_token = get_auth_token()

    response = requests.get(
        'https://api.music.apple.com/v1/catalog/{}/search'.format(storefront),
        headers={'Authorization': 'Bearer {}'.format(auth_token)},
        params={
            'term': query,
            'types': 'artists',
            'limit': limit,
            'offset': offset
        }
    )

    if response.status_code == 401:
        return create_error_response(
            code=errors.VALIDATION_ERROR,
            status=401,
            message='Failed to authenticate with Apple Music.'
        )

    # Rate limited.
    if response.status_code == 429:
        return response

    response_json = response.json()
    results = response_json['results'] or []
    if results:
        results = results['artists']['data']

    return Response(message={'items': results})