from flask import Blueprint, request, url_for, session, redirect, abort, flash
from flask_oauthlib.client import OAuth, OAuthException
from flask_login import LoginManager, login_user, logout_user, current_user, login_required, UserMixin

from .caps import cap_required


class SpaceAuth(LoginManager):
    def __init__(self, app=None, *args, **kwargs):
        self.oauth = OAuth()
        self.remote = self.oauth.remote_app(
            'spaceauth',
            base_url='https://sso.hackerspace.pl/api/',
            access_token_url='https://sso.hackerspace.pl/oauth/token',
            authorize_url='https://sso.hackerspace.pl/oauth/authorize',
            request_token_params={'scope': 'profile:read'},
            app_key='SPACEAUTH')
        self.remote.tokengetter(self.tokengetter)

        bp = Blueprint('spaceauth', __name__)
        bp.add_url_rule('/login', 'login', self.login_view_handler)
        bp.add_url_rule('/logout', 'logout', self.logout_view_handler)
        bp.add_url_rule('/callback', 'callback', self.callback_view_handler)
        self.blueprint = bp

        super(SpaceAuth, self).__init__()
        self.refresh_view = 'spaceauth.login'
        self.login_view = 'spaceauth.login'
        self.user_loader(self.user_loader_handler)

        if app:
            self.init_app(app, *args, **kwargs)

    def init_app(self, app, url_prefix='/oauth'):
        self.oauth.init_app(app)
        super(SpaceAuth, self).init_app(app)
        app.register_blueprint(self.blueprint, url_prefix=url_prefix)

        @app.errorhandler(OAuthException)
        def errorhandler(err):
            flash('OAuth error occured', 'error')
            return redirect('/')

    def login_view_handler(self):
        session['spaceauth_next'] = request.args.get('next') or request.referrer
        return self.remote.authorize(
            callback=url_for('spaceauth.callback', _external=True)
            )

    def logout_view_handler(self):
        # TODO revoke token
        session.pop('spaceauth_token', None)
        session.pop('spaceauth_next', None)
        logout_user()
        return redirect('/')

    def callback_view_handler(self):
        resp = self.remote.authorized_response()
        if resp is None:
            raise OAuthException(
                'Access denied', type=request.args.get('error'))

        # TODO encrypt token...?
        session['spaceauth_token'] = resp['access_token']
        profile = self.remote.get('profile').data

        login_user(self.user_loader_handler(profile['username'], profile))
        return redirect(session.pop('spaceauth_next', None) or '/')

    def tokengetter(self):
        return (session.get('spaceauth_token'), '')

    def user_loader_handler(self, uid, profile=None):
        """
        Default user loader just to differentiate authenticated user from
        anonymous.
        """

        user = UserMixin()
        user.id = uid
        return user

    def user_profile(self):
        return self.remote.get('profile').data