#!/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 uuid

import bottle
import requests


class HTTPAPI:

    def POST(self, url, headers, body):
        raise NotImplementedError()

    def PUT(self, url, headers, body):
        raise NotImplementedError()

    def GET(self, url, headers=None, body=None):
        raise NotImplementedError()

    def DELETE(self, url, headers):
        raise NotImplementedError()


class RealHTTPAPI(HTTPAPI):

    def POST(self, url, headers, body):
        assert 0
        return requests.post(url, headers=headers, data=body)

    def PUT(self, url, headers, body):
        return requests.put(url, headers=headers, data=body)

    def GET(self, url, headers=None, body=None):
        return requests.get(url, headers=headers, data=body)

    def DELETE(self, url, headers):
        return requests.delete(url, headers=headers, data=body)


class FakeResponse:

    def __init__(self, status_code, headers, body):
        self.status_code = status_code
        self.headers = dict(headers)
        self.text = body
        logging.debug(
            'FakeREsponse: status=%d headers=%r body=%r',
            status_code, headers, body)

    @property
    def ok(self):
        return self.status_code in (200, 201)

    def json(self):
        return json.loads(self.text.strip())


class FakeHTTPAPI(HTTPAPI):

    def __init__(self):
        self._memb = {}

    def POST(self, url, headers, body):
        logging.debug(
            'FakeHTTPAPI.POST url=%r headers=%r body=%r',
            url, headers, body)

        rid = str(uuid.uuid4())
        self._memb[rid] = copy.deepcopy(body)
        headers = {
            'Muck-Id': rid,
        }
        return FakeResponse(201, headers, copy.deepcopy(body))

    def PUT(self, url, headers, body):
        logging.debug(
            'FakeHTTPAPI.PUT url=%r headers=%r body=%r',
            url, headers, body)

        rid = headers.get('Muck-Id')
        if not rid:
            return FakeResponse(400, {}, 'No Muck-Id in request')

        self._memb[rid] = copy.deepcopy(body)
        headers = {
            'Muck-Id': rid,
        }
        return FakeResponse(200, headers, copy.deepcopy(body))

    def GET(self, url, headers=None, body=None):
        logging.info(
            'FakeHTTPAPI.GET url=%r headers=%r body=%r',
            url, headers, body)

        if url.endswith('/status'):
            return self._get_status()

        if url.endswith('/search'):
            return self._get_search(body)

        if url.endswith('/res'):
            return self._get_resource(headers)

        logging.error('Cannot serve url')
        assert 0

    def _get_status(self):
        body = {
            'resources': len(self._memb),
        }
        return FakeResponse(200, {}, json.dumps(body))

    def _get_search(self, body):
        cond = json.loads(body)
        logging.debug('_get_search: cond: %r', cond)
        matches = [
            rid
            for rid in self._memb
            if self._matches_cond(rid, cond)
        ]

        headers = {
            'Content-Type': 'application/json',
        }
        result = {
            'resources': matches,
        }
        return FakeResponse(200, headers, json.dumps(result))

    def _matches_cond(self, rid, cond):
        assert cond == {
            'cond': [
                {
                    'where': 'meta',
                    'op': '>=',
                    'field': 'id',
                    'pattern': '',
                }
            ]
        }
        return True

    def _get_resource(self, headers):
        if headers is None:
            logging.warning('FakeHTTPAPI.GET: no resource id in headers')
            return FakeResponse(400, {}, 'Missing headers')

        rid = headers.get('Muck-Id')
        if not rid:
            logging.warning('FakeHTTPAPI.GET: empty resource id in headers')
            return FakeResponse(404, {}, 'No such member')

        if rid not in self._memb:
            logging.debug('Members: %r', self._memb)
            return FakeResponse(404, {}, 'Retrieving member that does not exist')

        memb = self._memb[rid]
        headers = {
            'Muck-Id': rid,
            'Content-Type': 'application/json',
        }
        return FakeResponse(200, headers, memb)

    def DELETE(self, url, headers):
        logging.debug('FakeHTTPAPI.DELETE url=%r headers=%r', url, headers)

        rid = headers.get('Muck-Id')
        if not rid:
            logging.warning('FakeHTTPAPI.DELETE: empty resource id in headers')
            return FakeResponse(404, {}, 'No such member')

        if rid not in self._memb:
            logging.debug('Members: %r', self._memb)
            return FakeResponse(404, {}, 'Deleting member that does not exist')

        del self._memb[rid]
        return FakeResponse(200, {}, {})


class MuckError(Exception):

    pass


class MuckAPI:

    _copy_headers = [
        'Authorization',
        'Muck-Id',
        'Muck-Revision',
        'Muck-Owner',
    ]

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

    def _get_headers(self):
        h = {}
        for name in self._copy_headers:
            value = bottle.request.get_header(name)
            if value is not None:
                h[name] = value
                logging.debug('Copy header from request: %s: %s', name, value)
        return h

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

    def status(self):
        url = self.url('/status')
        r = self._httpapi.GET(url)
        if r.ok:
            return r.json()
        return {'resources': 0}

    def show(self, rid):
        url = self.url('/res')
        headers = self._get_headers()
        headers['Muck-Id'] = rid
        logging.info('show copied headers')
        r = self._httpapi.GET(url, headers=headers)
        logging.info('Show result: %s %s', r.status_code, r.text)
        if not r.ok:
            raise MuckError('{} {}'.format(r.status_code, r.text))
        return r.json()

    def _write(self, member, func):
        url = self.url('/res')
        headers = self._get_headers()
        headers['Content-Type'] = 'application/json'
        r = func(url, headers, json.dumps(member))
        logging.info('Write result: %s %s', r.status_code, r.text)
        if not r.ok:
            raise MuckError('{} {}'.format(r.status_code, r.text))
        rid = r.headers.get('Muck-Id')
        if not rid:
            raise MuckError('Muck did not return Muck-Id')
        return rid, r.json()

    def create(self, member):
        return self._write(member, self._httpapi.POST)

    def update(self, member):
        return self._write(member, self._httpapi.PUT)

    def delete(self):
        url = self.url('/res')
        headers = self._get_headers()
        r = self._httpapi.DELETE(url, headers)
        logging.info('Delete result: %s %s', r.status_code, r.text)
        if not r.ok:
            raise MuckError('{} {}'.format(r.status_code, r.text))

    def search(self, cond):
        url = self.url('/search')
        headers = self._get_headers()
        headers['Content-Type'] = 'application/json'
        r = self._httpapi.GET(url, headers=headers, body=json.dumps(cond))
        logging.info('Search result: %s %s', r.status_code, r.text)
        if not r.ok:
            raise MuckError('{} {}'.format(r.status_code, r.text))
        return r.json()


class API:

    def __init__(self, httpapi, bottleapp, config):
        self._add_routes(bottleapp)
        self._muck = MuckAPI(config['muck-url'], httpapi)

    def _add_routes(self, bottleapp):
        routes = [
            {
                'method': 'GET',
                'path': '/status',
                'callback': self._call(self._show_status),
            },
            {
                'method': 'GET',
                'path': '/memb',
                'callback': self._call(self._show_member),
            },
            {
                'method': 'GET',
                'path': '/search',
                'callback': self._call(self._search),
            },
            {
                'method': 'POST',
                'path': '/memb',
                'callback': self._call(self._create),
            },
            {
                'method': 'PUT',
                'path': '/memb',
                'callback': self._call(self._update),
            },
            {
                'method': 'DELETE',
                'path': '/memb',
                'callback': self._call(self._delete),
            },
        ]

        for route in routes:
            logging.debug('Adding route', repr(route))
            bottleapp.route(**route)

    def _call(self, callback):
        def helper():
            logging.debug('_call called')
            try:
                r = bottle.request
                logging.info('Request: method=%s', r.method)
                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())
                ret = callback()
            except BaseException as e:
                logging.error(str(e), exc_info=True)
                raise
            else:
                return ret
        return helper

    def _get_token(self):
        r = bottle.request
        authz = r.get_header('Authorization')
        if not authz:
            return None
        w = authz.split()
        if len(w) != 2:
            return None
        if w[0].lower() != 'bearer':
            return None
        return w[1]

    def _show_status(self):
        status = self._muck.status()
        return response(200, None, status)

    def _show_member(self):
        rid = bottle.request.get_header('Muck-Id')
        if rid is None:
            return response(400, None, 'no muck-id')
        try:
            logging.debug('API _show_member rid=%r', rid)
            res = self._muck.show(rid)
            return response(200, rid, res)
        except MuckError as e:
            return response(404, None, str(e))

    def _search(self):
        logging.debug('_search callback called')
        cond = bottle.request.json
        logging.debug('_search callback: %r', cond)
        result = self._muck.search(cond)
        return response(200, None, result)

    def _create(self):
        r = bottle.request
        if r.content_type != 'application/json':
            return response(400, None, 'wrong content type')

        obj = bottle.request.json
        logging.info('CREATE %r', repr(obj))
        rid, newobj = self._muck.create(obj)
        return response(201, rid, newobj)

    def _update(self):
        r = bottle.request
        if r.content_type != 'application/json':
            return response(400, None, 'wrong content type')

        obj = bottle.request.json
        logging.info('UPDATE %r', repr(obj))
        rid, newobj = self._muck.update(obj)
        return response(200, rid, newobj)

    def _delete(self):
        r = bottle.request
        self._muck.delete()
        return response(200, None, None)


def response(status, rid, body):
    headers = {
        'Content-Type': 'application/json',
    }
    if rid is not None:
        headers['Muck-Id'] = rid
    return bottle.HTTPResponse(
        status=status, body=json.dumps(body), headers=headers)


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 API starts')

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

if config.get('fake'):
    logging.info("Using FakeHTTPAPI")
    httpapi = FakeHTTPAPI()
else:
    logging.info("Using RealHTTPAPI")
    httpapi = RealHTTPAPI()

logging.debug('Creating API')
app = bottle.default_app()
api = API(httpapi, app, config)

logging.info('Starting application')
app.run(host='127.0.0.1', port=8080)
logglng.critical('Application ended')