import hashlib
import json
import re

from requests_futures.sessions import FuturesSession


BASE_URL = 'https://www.instagram.com'
QUERY_HASH = '42323d64886122307be10013ad2dcc44'
SHARED_DATA = re.compile(r'window\._sharedData = (\{.*\});</script>')


class Instagram(object):
    def __init__(self, username):
        self.username = username
        shared_data = self._get_shared_data()
        try:
            graphql = shared_data['entry_data']['ProfilePage'][0]['graphql']
            self.user = {k: v for k, v in graphql['user'].items() if not k.startswith('edge')}
            self.rhx_gis = shared_data['rhx_gis']
        except (IndexError, KeyError, TypeError):
            self.user = {}
            self.rhx_gis = None

    def _get_shared_data(self):
        session = FuturesSession()
        r = session.get('{0}/{1}'.format(BASE_URL, self.username)).result()
        if not r.ok:
            return None
        m = SHARED_DATA.search(r.text)
        if m:
            return json.loads(m.group(1))
        return None

    def fetch_media(self):
        session = FuturesSession()
        def get_media(count, cursor):
            variables = json.dumps(dict(
                id=self.user.get('id'),
                first=count,
                after=cursor))
            gis = '{0}:{1}'.format(self.rhx_gis, variables)
            gis = hashlib.md5(gis.encode('UTF-8')).hexdigest()
            url = '{0}/graphql/query'.format(BASE_URL)
            params = dict(
                query_hash=QUERY_HASH,
                variables=variables)
            return session.get(url, params=params, headers={'X-Instagram-GIS': gis})
        result = []
        count = 50
        cursor = ''
        while True:
            request = get_media(count, cursor)
            r = request.result()
            if not r.ok:
                return []
            data = r.json()
            try:
                data = data['data']['user']['edge_owner_to_timeline_media']
            except KeyError:
                return []
            for edge in data.get('edges', []):
                node = edge.get('node', {})
                node['owner'].update(self.user)
                result.append(node)
            cursor = data['page_info']['end_cursor']
            if not cursor:
                break
        return result