#!/usr/bin/env python3
#
# Copyright 2019  Lars Wirzenius
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


import argparse
import base64
import configparser
import http
import json
import os
import sys
import traceback
import urllib.request


CONFIG_FILENAME = os.path.expanduser('~/.config/effitool/credentials.conf')
JSON = 'application/json'
URLENC = 'application/x-www-form-urlencoded'

ADMIN_SCOPES = [
    'uapi_clients_get',
    'uapi_clients_id_get',
    'uapi_clients_id_put',
    'uapi_clients_id_delete',
    'uapi_clients_post',
    'uapi_clients_id_secret_put',
    'show',
    'create',
    'update',
    'delete',
]


class Config:

    def __init__(self):
        self._cp = configparser.ConfigParser()

    def read(self, filename):
        with open(filename) as f:
            self._cp.read_file(f)

    def dump(self, f):
        self._cp.write(f)

    def servers(self):
        return [k for k in self._cp.keys() if k != 'DEFAULT']

    def get_default_server(self):
        sections = self._cp.sections()
        if len(sections) != 1:
            raise Exception('Config must have exactly one server')
        return sections[0]

    def get(self, name):
        server = self._cp[name]
        return {
            'url': server['url'],
            'client_id': server['client_id'],
            'client_secret': server['client_secret'],
        }


class HTTPAPI:

    def __init__(self, url):
        self._url = url

    def url(self, path):
        return '{}{}'.format(self._url, path)

    def request_json(self, r):
        ok = (http.HTTPStatus.OK, http.HTTPStatus.CREATED)

        status = r.getcode()
        if status not in ok:
            raise Exception('Got HTTP status {}'.format(status))

        info = r.info()
        ct = info.get_content_type()
        if ct != JSON:
            raise Exception('Response is not JSON: {}'.ct)

        body = r.read()
        return json.loads(body)

    def get(self, path):
        url = self.url(path)
        with urllib.request.urlopen(url) as r:
            return self.request_json(r)

    def get_access_token(self, client_id, client_secret, scopes):
        obj = self.post_form(
            '/token', client_id, client_secret, 
            grant_type='client_credentials', scope=' '.join(scopes))
        return obj['access_token']

    def get_json(self, token, path, headers=None, body=None):
        url = self.url(path)
        host, port, path = self.parse_url(url)

        if headers is None:
            headers = {}
        headers['Authorization'] = 'Bearer {}'.format(token)

        req = urllib.request.Request(
            url, data=body, headers=headers, method='GET')
        r = urllib.request.urlopen(req)
        return self.request_json(r)

    def get_list(self, token, path, headers=None, body=None):
        return self.get_json(token, path, headers=headers, body=body)

    def post_form(self, path, user, password, **kwargs):
        url = self.url(path)
        host, port, path = self.parse_url(url)

        data = urllib.parse.urlencode(kwargs).encode('UTF-8')
        headers = {
            'Content-type': URLENC,
            'Authorization': self.get_authorization(user, password),
        }

        req = urllib.request.Request(
            url, data=data, headers=headers, method='POST')
        r = urllib.request.urlopen(req)
        return self.request_json(r)

    def post_json(self, token, path, obj):
        return self.send_json('POST', token, path, obj)

    def put_json(self, token, path, obj, headers=None):
        return self.send_json('PUT', token, path, obj, headers=headers)

    def send_json(self, method, token, path, obj, headers=None):
        url = self.url(path)
        host, port, path = self.parse_url(url)

        data = json.dumps(obj).encode('UTF-8')

        if headers is None:
            headers = {}
        headers.update({
            'Content-type': JSON,
            'Authorization': 'Bearer {}'.format(token),
        })

        req = urllib.request.Request(
            url, data=data, headers=headers, method=method)
        r = urllib.request.urlopen(req)
        return self.request_json(r)

    def delete(self, token, path, headers=None):
        url = self.url(path)
        host, port, path = self.parse_url(url)

        if headers is None:
            headers = {}
        headers['Authorization'] = 'Bearer {}'.format(token)

        req = urllib.request.Request(url, headers=headers, method='DELETE')
        urllib.request.urlopen(req)

    def parse_url(self, url):
        parse = urllib.parse.urlparse(url)
        if parse.scheme != 'https':
            raise Exception(
                'URL scheme must be https, not {}'.format(parse.scheme))

        if ':' in parse.netloc:
            host, port = parse.netloc.split(':', 1)
            port = int(port)
        else:
            host = parse.netloc
            port = None

        return host, port, parse.path

    def get_authorization(self, user, password):
        clear = '{}:{}'.format(user, password)
        basic = base64.b64encode(clear.encode('UTF-8'))
        return 'Basic {}'.format(basic.decode('UTF-8'))


class Session:

    def __init__(self, api, token):
        self._api = api
        self._token = token

    def register_admin_client(self, client_id, client_secret):
        new_client = {
            'id': client_id,
            'allowed_scopes': ADMIN_SCOPES,
        }
        self._api.post_json(self._token, '/clients', new_client)

        client_path = '/clients/{}'.format(client_id)
        new_secret = {
            'secret': client_secret,
        }
        self._api.put_json(self._token, '{}/secret'.format(client_path), new_secret)

    def list_clients(self):
        obj = self._api.get_list(self._token, '/clients')
        return sorted(obj.get('resources', []))

    def get_client(self, client_id):
        return self._api.get_json(self._token, self._get_client_path(client_id))

    def update_client(self, client_id, client):
        self._api.put_json(self._token, self._get_client_path(client_id), client)

    def _get_client_path(self, client_id):
        return '/clients/{}'.format(client_id)

    def allow_scopes(self, client_id, scopes):
        client = self.get_client(client_id)
        client['allowed_scopes'] = uniq(client.get('allowed_scopes', []) + scopes)
        self.update_client(client_id, client)

    def deny_scopes(self, client_id, scopes):
        client = self.get_client(client_id)
        old_scopes = client.get('allowed_scopes', [])
        client['allowed_scopes'] = uniq(
            s for s in old_scopes if s not in denied_scopes)
        self.update_client(client_id, client)

    def fetch_member(self, rid):
        headers = {
            'Muck-Id': rid,
        }
        return self._api.get_json(self._token, '/memb', headers=headers)

    def get_all_member_ids(self):
        cond = {
            'where': 'meta',
            'op': '>=',
            'field': 'id',
            'pattern': '',
        }
        return self.search_members(cond)

    def get_all_members(self):
        return {
            rid: self.fetch_member(rid)
            for rid in self.get_all_member_ids()
        }

    def search_members(self, cond):
        cond = {'cond': [cond]}
        body = json.dumps(cond).encode('utf-8')
        headers = {
            'Content-Type': 'application/json',
        }
        obj = self._api.get_list(self._token, '/search', headers=headers, body=body)
        return sorted(obj.get('resources', []))


class Tool:

    def __init__(self, config):
        self._config = config

    def get_session(self, args):
        server = self.get_chosen_server(args)
        token = self.get_admin_token(server)
        api = HTTPAPI(server['url'])
        return Session(api, token)

    def servers(self):
        return self._config.servers()

    def get_server(self, name):
        return self._config.get(name)

    def get_chosen_server(self, args):
        if args['api']:
            name = args['api']
        else:
            name = self._config.get_default_server()
        return self.get_server(name)

    def get_admin_token(self, server):
        url = server['url']
        client_id = server['client_id']
        client_secret = server['client_secret']

        api = HTTPAPI(url)
        return api.get_access_token(client_id, client_secret, ADMIN_SCOPES)

    def list_servers(self, args):
        for name in self.servers():
            print('server', name)
            server = self.get_server(name)
            for key in sorted(server):
                print('  ', key, server[key])
        
    def status(self, args):
        for name in self.servers():
            server = self.get_server(name)
            url = server['url']
            api = HTTPAPI(url)
            obj = api.get('/status')
            print('server', name, obj['resources'])

    def token(self, args):
        server = self.get_chosen_server(args)
        token = self.get_admin_token(server)
        print(token)

    def register_admin_client(self, args):
        session = self.get_session(args)
        session.register_admin_client(args['client_id'], args['client_secret'])
        print('Created new admin client', args['client_id'])
        
    def list_clients(self, args):
        session = self.get_session(args)
        for name in session.list_clients():
            print(name)

    def show_client(self, args):
        session = self.get_session(args)
        client = session.get_client(args['client-name'])
        del client['hashed_secret']
        for scope in client.get('allowed_scopes', []):
            print(scope)

    def allow_scope(self, args):
        session = self.get_session(args)
        session.allow_scopes(args['client-name'], args['scope'])

    def deny_scope(self, args):
        name = args['client-name']
        denied_scopes = args['scope']
        server = self.get_chosen_server(args)
        token = self.get_admin_token(server)
        api = HTTPAPI(server['url'])
        path = '/clients/{}'.format(name)
        client = api.get_json(token, path)
        old_scopes = client.get('allowed_scopes', [])
        client['allowed_scopes'] = uniq(
            s for s in old_scopes if s not in denied_scopes)
        api.put_json(token, path, client)

    def add_member(self, args):
        with open(args['filename']) as f:
            memb = json.load(f)

        server = self.get_chosen_server(args)
        token = self.get_admin_token(server)
        api = HTTPAPI(server['url'])
        api.post_json(token, '/memb', memb)

    def show_member(self, args):
        session = self.get_session(args)
        memb = session.fetch_member(args['rid'])
        self._format_json(memb, sys.stdout)

    def update_member(self, args):
        rid = args['rid']
        with open(args['filename']) as f:
            memb = json.load(f)

        headers = {
            'Muck-Id': args['rid'],
        }

        server = self.get_chosen_server(args)
        token = self.get_admin_token(server)
        api = HTTPAPI(server['url'])
        api.put_json(token, '/memb', memb, headers=headers)

    def delete_member(self, args):
        headers = {
            'Muck-Id': args['rid'],
        }

        server = self.get_chosen_server(args)
        token = self.get_admin_token(server)
        api = HTTPAPI(server['url'])
        api.delete(token, '/memb', headers=headers)

    def list_members(self, args):
        session = self.get_session(args)
        for rid in session.get_all_member_ids():
            print(rid)

    def dump_members(self, args):
        session = self.get_session(args)
        rids = session.get_all_member_ids()
        members = session.get_all_members()
        self._format_json(members, sys.stdout)

    def _format_json(self, obj, output):
        return json.dump(obj, output, indent=4, sort_keys=True)


def uniq(items):
    return list(sorted(set(items)))


def process_args(config):
    tool = Tool(config)

    subcommands = [
        ('list-servers', tool.list_servers, []),
        ('token', tool.token, []),
        ('status', tool.status, []),
        ('register-admin-client', tool.register_admin_client, [
            ('--client-id', {'required':True}),
            ('--client-secret', {'required':True}),
        ]),
        ('list-clients', tool.list_clients, []),
        ('show-client', tool.show_client, [
            ('client-name', {}),
        ]),
        ('allow-scope', tool.allow_scope, [
            ('client-name', {}),
            ('scope', {'nargs':'*'}),
        ]),
        ('deny-scope', tool.deny_scope, [
            ('client-name', {}),
            ('scope', {'nargs':'*'}),
        ]),
        ('list-members', tool.list_members, []),
        ('dump-members', tool.dump_members, []),
        ('add-member', tool.add_member, [
            ('filename', {}),
        ]),
        ('show-member', tool.show_member, [
            ('rid', {}),
        ]),
        ('update-member', tool.update_member, [
            ('rid', {}),
            ('filename', {}),
        ]),
        ('delete-member', tool.delete_member, [
            ('rid', {}),
        ]),
    ]

    p = argparse.ArgumentParser()
    factory = p.add_subparsers()

    p.add_argument('-a', '--api')
    p.add_argument('--debug', action='store_true')

    for name, func, args in subcommands:
        pp = factory.add_parser(name)
        for name, kwargs in args:
            pp.add_argument(name, **kwargs)
        pp.set_defaults(func=func)

    args = vars(p.parse_args())
    func = args['func']
    try:
        func(args)
    except Exception as e:
        if args['debug']:
            sys.stderr.write('{}\n'.format(traceback.format_exc()))
        sys.exit(str(e))


def main():
    config = Config()
    config.read(CONFIG_FILENAME)
    args = process_args(config)


if __name__ == '__main__':
    main()