import re
import requests


class FbAuthenticationError(Exception):
    pass


class FacebookAPI(object):

    def __init__(self, email, password):
        """Create a new Facebook interface."""

        self._email = email
        self._password = password

        self._session = None

        self._login()


    def _build_login_params(self, content):
        """Parse HTML code to get POST login parameters."""

        params = {}

        # Get the form parameters

        input_exp = re.compile('<input[^>]*>')

        type_exp = re.compile('type="hidden"')
        id_exp = re.compile('id="([^"]*)"')
        name_exp = re.compile('name="([^"]*)"')
        value_exp = re.compile('value="([^"]*)"')

        form = re.compile('<form.*</form>').search(content).group()

        for inp in input_exp.findall(form):

            match = type_exp.search(inp)

            if match is None:
                continue

            name = name_exp.search(inp)

            if name is None:
                continue
            else:
                name = name.group(1)

            value = value_exp.search(inp)

            if value is None:
                value = ''
            else:
                value = value.group(1)

            params[name] = value

        # Extend with user login

        params["email"] = self._email
        params["pass"] = self._password
        params["login"] = "1"

        return params


    def _login(self):
        """Log into Facebook services."""

        headers = {
            "Host": "www.facebook.com",
            "User-agent": "Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0",
            "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
            "Accept-Language": "en-US,en;q=0.5",
            "Accept-Encoding": "gzip, deflate",
            "DNT": "1",
            "Connection": "keep-alive",
            "Cache-Control": "max-age=0",
        }

        self._session = requests.Session()
        self._session.headers.update(headers)

        response = self._session.post('https://www.facebook.com/login.php', data={})

        params = self._build_login_params(str(response.content))

        response = self._session.post('https://www.facebook.com/login.php', data=params)

        #print('headers', response.headers)
        #print('cookies', requests.utils.dict_from_cookiejar(self._session.cookies))

        # If c_user cookie is present, login was successful

        if not('c_user' in self._session.cookies):
            raise FbAuthenticationError()


    def get_user_id(self):
        """Get the identifier for the registered user."""

        if not('c_user' in self._session.cookies):
            raise FbAuthenticationError()

        return self._session.cookies['c_user']


    def _build_access_params(self, content):
        """Parse HTML code to get POST access parameters."""

        params = {}

        # Get the form parameters

        input_exp = re.compile('<input[^>]*>')

        type_exp = re.compile('type="hidden"')
        id_exp = re.compile('id="([^"]*)"')
        name_exp = re.compile('name="([^"]*)"')
        value_exp = re.compile('value="([^"]*)"')

        form = re.compile('platformDialogForm.*form>').search(content).group()

        form = form.replace('\\u003C', '<')
        form = form.replace('\\', '')

        for inp in input_exp.findall(form):

            match = type_exp.search(inp)

            if match is None:
                continue

            name = name_exp.search(inp)

            if name is None:
                continue
            else:
                name = name.group(1)

            value = value_exp.search(inp)

            if value is None:
                value = ''
            else:
                value = value.group(1)

            params[name] = value

        return params


    def get_tinder_token(self):
        """Get an access token for Tinder."""

        # Cf. https://developers.facebook.com/docs/facebook-login/manually-build-a-login-flow

        params = {
            "redirect_uri": "fb464891386855067://authorize/",
            "scope": "user_birthday,user_photos,user_education_history,email,user_relationship_details" \
                     + ",user_friends,user_work_history,user_likes",
            "response_type": "token,signed_request",
            "client_id": "464891386855067"
        }

        url = 'https://www.facebook.com/v2.6/dialog/oauth'

        response = self._session.get(url, params=params)

        params = self._build_access_params(str(response.content))

        response = self._session.post('https://www.facebook.com/v2.6/dialog/oauth/confirm?dpr=1', data=params)

        token_exp = re.compile('access_token=([^&]*)&')

        match = token_exp.search(str(response.content))

        if match is None:
            raise FbAuthenticationError

        return match.group(1)