#!/usr/bin/python3
# Copyright (C) 2018  Lars Wirzenius
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


import copy
import json
import logging
import os
import sys
import urllib
import uuid

import bottle
import jinja2
import requests


COOKIE_NAME = 'effireg'


class EffiAPI:

    _scopes = [
        'create',
        'update',
        'show',
        'delete',
        'super',
    ]

    def __init__(self, app, our_url, apiurl, client_id, client_secret, template_dir):
        self._add_routes(app)
        self._our_url = our_url
        self._apiurl = apiurl
        self._auth_url = '{}/auth'.format(apiurl)
        self._token_url = '{}/token'.format(apiurl)
        self._client_id = client_id
        self._client_secret = client_secret
        self._sessions = Sessions()
        self._pagemaker = PageMaker(template_dir)

    def _add_routes(self, bottleapp):
        routes = [
            {
                'method': 'GET',
                'path': '/',
                'callback': self._call(self._frontpage),
            },
            {
                'method': 'GET',
                'path': '/login',
                'callback': self._call(self._redirect_to_login),
            },
            {
                'method': 'GET',
                'path': '/logout',
                'callback': self._call(self._logout),
            },
            {
                'method': 'GET',
                'path': '/callback',
                'callback': self._call(self._auth_callback),
            },
        ]

        for route in routes:
            bottleapp.route(**route)

    def _call(self, callback):
        def helper():
            r = bottle.request
            logging.info('Request: path=%s', r.path)
            logging.info('Request: content type: %s', r.content_type)
            for h in r.headers:
                logging.info('Request: headers: %s: %s', h, r.get_header(h))
            logging.info('Request: body: %r', r.body.read())
            r = callback()
            logging.debug('Response: %r', r)
            return r
        return helper

    def _frontpage(self):
        session = None
        cookie = bottle.request.get_cookie(COOKIE_NAME)
        if cookie:
            session = self._sessions.find_by_cookie(cookie)

        if session is None:
            return self._not_logged_in_page()
        return self._logged_in_page(cookie)

    def _not_logged_in_page(self):
        return self._pagemaker.page('not-logged-in', {'foo': 'bar'})

    def _logged_in_page(self, cookie):
        session = self._sessions.find_by_cookie(cookie)
        if not session:
            return self._not_logged_in_page()

        members = self._get_members(session.token)
        if not members:
            return self._not_logged_in_page()

        return self._pagemaker.page(
            'logged-in',
            {
                'cookie': session.cookie,
                'token': session.token,
                'member': members[0],
            })

    def _get_members(self, token):
        rids = self._find_ids_of_resources_owned_by_user(token)
        return self._get_resources(token, rids)

    def _find_ids_of_resources_owned_by_user(self, token):
        url = '{}/search'.format(self._apiurl)
        cond = {
            'cond': [
                {
                    'op': '>=',
                    'where': 'meta',
                    'field': 'id',
                    'pattern': '',
                },
            ]
        }
        headers = {
            'Content-Type': 'application/json',
            'Authorization': 'Bearer {}'.format(token),
        }

        logging.debug('Finding owned by user: url=%s headers=%r', url, headers)
        r = requests.get(url, headers=headers, data=json.dumps(cond))
        if not r.ok:
            logging.error('{} {}'.format(r.status_code, r.text))
            return []
        obj = r.json()
        return obj['resources']

    def _get_resources(self, token, rids):
        return [
            self._get_resource(token, rid)
            for rid in rids
        ]

    def _get_resource(self, token, rid):
        logging.info('Retrieving resource %s', rid)
        url = '{}/mem'.format(self._apiurl)
        headers = {
            'Muck-Id': rid,
            'Authorization': 'Bearer {}'.format(token),
        }
        r = requests.get(url, headers=headers)
        if not r.ok:
            logging.error('{} {}'.format(r.status_code, r.text))
            return {}
        return r.json()

    def _redirect_to_frontpage(self):
        headers = {
            'Location': self._our_url,
        }
        logging.info('Redirecting with headers %s', headers)
        return bottle.HTTPResponse(status=302 , headers=headers)

    def _redirect_to_login(self):
        session = self._sessions.new()
        params = {
            'response_type': 'code',
            'scope': ' '.join(self._scopes),
            'client_id': self._client_id,
            'state': session.state,
            'redirect_uri': '{}/callback'.format(self._our_url),
        }

        auth_url = '{}?{}'.format(
            self._auth_url, urllib.parse.urlencode(params))

        headers = {
            'Location': auth_url,
        }

        logging.info('Redirecting with headers %s', headers)
        return bottle.HTTPResponse(status=302 , headers=headers)

    def _auth_callback(self):
        code = bottle.request.query.get('code')
        state = bottle.request.query.get('state')
        if code is None or state is None:
            return regesta_api.bad_request_response()

        token = self._get_token_using_authz_code(code)

        session = self._sessions.find_by_state(state)
        if session is None:
            return self._redirect_to_login()

        session.token = token

        logging.debug('Redirecting to / with cookie %s', session.cookie)
        bottle.response.set_cookie(COOKIE_NAME, session.cookie, path='/')
        bottle.redirect(self._our_url)
        return None

        headers = {
            'Location': self._our_url,
        }
        r = bottle.HTTPResponse(302, headers=headers)
        r.set_cookie(COOKIE_NAME, session.cookie, path='/')
        logging.debug('Redirecting to / with cookie %s', session.cookie)
        return r

    def _get_token_using_authz_code(self, code):
        auth = (self._client_id, self._client_secret)
        data = {
            'grant_type': 'authorization_code',
            'code': code,
        }

        url = self._token_url
        logging.debug('Requesting token using authz code from %s', url)
        r = requests.post(url, auth=auth, data=data)
        if not r.ok:
            logging.error(
                'Could not get token using authz code: %s %s',
                r.status_code, r.text)
            raise bottle.HTTPError(500)
        obj = r.json()
        return obj[u'access_token']

    def _logout(self):
        cookie = bottle.request.get_cookie(COOKIE_NAME)
        if not cookie:
            return self._redirect_to_frontpage()

        session = self._sessions.find_by_cookie(cookie)
        self._sessions.delete(session)

        logging.debug('Redirecting to / without')
        bottle.response.delete_cookie(COOKIE_NAME, path='/')
        bottle.redirect(self._our_url)
        return None


class PageMaker:

    def __init__(self, dirname):
        self._dirname = os.path.abspath(dirname)

    def page(self, basename, variables):
        logging.debug(
            'PageMaker: dirname=%s basename=%s variables=%r',
            self._dirname, basename, variables)
        loader = jinja2.FileSystemLoader(self._dirname)
        env = jinja2.Environment(
            loader=loader,
            autoescape=lambda foo: True,
            extensions=['jinja2.ext.autoescape'])

        template = env.get_template('{}.j2'.format(basename))
        return template.render(**variables)


class Session:

    def __init__(self):
        self.id = str(uuid.uuid4())
        self.state = str(uuid.uuid4())
        self.cookie = str(uuid.uuid4())
        self.token = None


class Sessions:

    def __init__(self):
        self._sessions = []

    def new(self):
        session = Session()
        self._sessions.append(session)
        return session

    def delete(self, session):
        self._sessions = [s for s in self._sessions if s.id != session.id]

    def find_by_state(self, state):
        return self._find(lambda s: s.state == state)

    def find_by_cookie(self, cookie):
        return self._find(lambda s: s.cookie == cookie)

    def _find(self, is_this_it):
        for session in self._sessions:
            if is_this_it(session):
                return session
        return None


def main():
    with open(sys.argv[1]) as f:
        config = json.load(f)

    logging.basicConfig(
        filename=config['log'], level=logging.DEBUG,
        format='%(asctime)s %(levelname)s %(message)s')

    logging.info('Effi-reg starts')

    if config.get('pid'):
        pid = os.getpid()
        with open(config['pid'], 'w') as f:
            f.write(str(pid))

    app = bottle.default_app()
    api = EffiAPI(
        app, config['our-url'], config['api-url'],
        config['client-id'], config['client-secret'],
        config['templates'])
    app.run(host='127.0.0.1', port=8181)


if __name__ == '__main__':
    main()