import datetime
import json
import os
import random
import re
import sys
import time
from json import JSONDecodeError
from logging import INFO
from threading import Thread
from typing import Dict, Any

import bottle
# noinspection PyUnresolvedReferences
from bottle.ext.websocket import GeventWebSocketServer
# noinspection PyUnresolvedReferences
from bottle.ext.websocket import websocket
from gevent import threading
from gevent.queue import Queue, Empty
from gevent.threading import Lock
from geventwebsocket import WebSocketError
from geventwebsocket.websocket import WebSocket

import connection
import model
import server_controller
from application import ROOT_URL, COPYRIGHT_INFRINGEMENT_PROBABILITY, DB_NAME, logger
from connection import HttpError
from debug import debug
from lib.print_exc_plus import print_exc_plus
from lib.threading_timer_decorator import exit_after
from routes import valid_post_routes, upload_filtered
from util import round_to_n, rename, profile_wall_time_instead_if_profiling

FRONTEND_RELATIVE_PATH = '../frontend'

profile_wall_time_instead_if_profiling()
request_lock = Lock()  # locked until the response to the request is computed
db_commit_threads = Queue()
if debug:
    TIMEOUT = 600
else:
    TIMEOUT = 10

assert all(getattr(server_controller, route) for route in valid_post_routes)


def reset_global_variables():
    model.current_connection = None
    model.current_cursor = None
    model.current_db_name = None
    model.current_user_id = None
    del connection.push_message_queue[:]
    bottle.response.status = 500


@exit_after(TIMEOUT)
def call_controller_method_with_timeout(method, json_request: Dict[str, Any]):
    return method(json_request)


def _process(path, json_request):
    start = time.clock()
    path = path.strip().lower()
    bottle.response.content_type = 'application/json; charset=latin-1'
    reset_global_variables()
    original_request = None
    # noinspection PyBroadException
    try:
        json_request = json_request()
        original_request = json_request
        logger.log(path, INFO, message_type='handling_http_request', data=json.dumps({
            'request': json_request,
            'start': start,
        }))
        if json_request is None:
            bottle.response.status = 400
            resp = connection.BadRequest('Only json allowed.')
        elif path not in valid_post_routes:
            print('Processing time:', time.clock() - start)
            resp = connection.NotFound('URL not available')
        else:
            model.connect(DB_NAME, create_if_not_exists=True)
            method_to_call = getattr(server_controller, path)
            try:
                resp = call_controller_method_with_timeout(method_to_call, json_request)
                raise connection.Success(resp)
            except HttpError as e:
                bottle.response.status = e.code
                resp = e
        if not isinstance(resp.body, dict):
            raise TypeError('The response body should always be a dict')
        if resp.code // 100 == 2 and path in upload_filtered and random.random() < COPYRIGHT_INFRINGEMENT_PROBABILITY:
            resp = connection.UnavailableForLegalReasons('An upload filter detected a copyright infringement. '
                                                         'If you think this is an error, please try again.')
        bottle.response.status = resp.code
        if model.current_connection is not None:
            if bottle.response.status_code == 200:
                thread = Thread(target=finish_request, args=[], kwargs={'success': True}, daemon=False)
            else:
                thread = Thread(target=finish_request, args=[], kwargs={'success': False}, daemon=False)
            db_commit_threads.put(thread)
            thread.start()
        print('route=' + path, 't=' + str(round_to_n(time.clock() - start, 4)) + 's,',
              'db=' + str(model.current_db_name))
        logger.log(path, INFO, message_type='http_request_finished', data=json.dumps({
            'request': json_request,
            'response': resp.body,
            'status': resp.code,
            'start': start,
            'end': time.clock(),
        }))
        return resp.body
    except JSONDecodeError:
        return handle_error('Unable to decode JSON', path, start, original_request)
    except NotImplementedError:
        return handle_error('This feature has not been fully implemented yet.', path, start, original_request)
    except KeyboardInterrupt:
        if time.clock() - start > TIMEOUT:
            return handle_error('Processing timeout', path, start, original_request)
        else:
            raise
    except Exception:
        return handle_error('Unknown error', path, start, original_request)


def finish_request(success):
    if success:
        model.current_connection.commit()
        connection.push_messages_in_queue()
    else:
        model.current_connection.rollback()


if __name__ == '__main__':
    print('sqlite3.version', model.db.version)
    if debug:
        print('Running server in debug mode...')

    print('Preparing backend API...')


    @bottle.route('/json/<path>', method='POST')
    def process(path):
        with request_lock:
            wait_for_db_commit_threads()
            return _process(path, lambda: bottle.request.json)


    def wait_for_db_commit_threads():
        while len(db_commit_threads) > 0:
            try:
                t = db_commit_threads.get()
            except Empty:
                break
            t.join()


    print('Preparing index page...')


    @bottle.route('/', method='GET')
    def index():
        if ROOT_URL != '/':
            bottle.redirect(ROOT_URL)


    def handle_error(message, path, start, request, status=500):
        bottle.response.status = status
        print_exc_plus()
        if model.current_connection is not None:
            model.current_connection.rollback()
        print('route=' + str(path), 't=' + str(round_to_n(time.clock() - start, 4)) + 's,',
              'db=' + str(model.current_db_name))
        logger.exception(path, message_type='http_request', data=json.dumps({
            'status': status,
            'start': start,
            'end': time.clock(),
            'exception': str(sys.exc_info()),
            'request': request,
        }))
        return connection.InternalServerError(message).body


    print('Preparing websocket connections...')


    @bottle.get('/websocket', apply=[websocket])
    def websocket(ws: WebSocket):
        print('websocket connection', *ws.handler.client_address, datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"))

        while True:
            start = time.clock()
            path = None
            request_token = None
            outer_json = None

            # noinspection PyBroadException
            try:
                if ws.closed:
                    connection.ws_cleanup(ws)
                    break
                try:
                    msg = ws.read_message()
                except ConnectionResetError:
                    msg = None
                except WebSocketError as e:
                    if e.args[0] == 'Unexpected EOF while decoding header':
                        msg = None
                    else:
                        raise

                if msg is not None:  # received some message
                    with request_lock:
                        wait_for_db_commit_threads()
                        msg = bytes(msg)
                        outer_json = None
                        outer_json = bottle.json_loads(msg)
                        path = outer_json['route']
                        inner_json = outer_json['body']
                        request_token = outer_json['request_token']
                        inner_result_json = _process(path, lambda: inner_json)

                        if 'error' in inner_result_json:
                            status_code = int(inner_result_json['error'][:3])
                        else:
                            status_code = 200

                        if model.current_user_id is not None and status_code == 200:
                            # if there is a user_id involved, associate it with this websocket
                            user_id = (model.current_db_name, model.current_user_id)

                            if user_id in connection.websockets_for_user:
                                if ws not in connection.websockets_for_user[user_id]:
                                    connection.websockets_for_user[user_id].append(ws)
                            else:
                                connection.websockets_for_user[user_id] = [ws]
                            if ws in connection.users_for_websocket:
                                if user_id not in connection.users_for_websocket[ws]:
                                    connection.users_for_websocket[ws].append(user_id)
                            else:
                                connection.users_for_websocket[ws] = [user_id]

                        outer_result_json = {
                            'body': inner_result_json,
                            'http_status_code': status_code,
                            'request_token': request_token
                        }
                        outer_result_json = json.dumps(outer_result_json)
                        if ws.closed:
                            connection.ws_cleanup(ws)
                            break
                        ws.send(outer_result_json)
                        print('websocket message',
                              *ws.handler.client_address,
                              datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
                              status_code,
                              len(outer_result_json))
                else:
                    connection.ws_cleanup(ws)
                    break
            except JSONDecodeError:
                inner_result_json = handle_error('Unable to decode outer JSON', path, start, outer_json)
                status_code = 403
                inner_result_json['http_status_code'] = status_code
                if request_token is not None:
                    inner_result_json['request_token'] = request_token
                inner_result_json = json.dumps(inner_result_json)
                if ws.closed:
                    connection.ws_cleanup(ws)
                    break
                ws.send(inner_result_json)
                print('websocket message',
                      *ws.handler.client_address,
                      datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
                      status_code,
                      len(inner_result_json))
            except Exception:
                inner_result_json = handle_error('Unknown error', path, start, outer_json)
                status_code = 500
                inner_result_json['http_status_code'] = status_code
                if request_token is not None:
                    inner_result_json['request_token'] = request_token
                inner_result_json = json.dumps(inner_result_json)
                if ws.closed:
                    connection.ws_cleanup(ws)
                    break
                ws.send(inner_result_json)
                print('websocket message',
                      *ws.handler.client_address,
                      datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
                      status_code,
                      len(inner_result_json))


    def _serve_static_directory(route, root, download=False):
        method_name = ''.join(c for c in root if re.match(r'[A-Za-z]]', c))
        assert method_name not in globals()

        @bottle.route(route, method=['GET', 'OPTIONS'])
        @rename(''.join(c for c in root if re.match(r'[A-Za-z]]', c)))
        def serve_static_file(filename):
            # start = time.clock()
            # logger.log(filename, INFO, message_type='handling_http_request', data=json.dumps({
            #     'start': start,
            # }))
            # try:
            if filename == 'api.json':
                return {'endpoint': bottle.request.urlparts[0] + '://' + bottle.request.urlparts[1] + '/json/'}
            if download:
                default_name = 'ytm-' + filename
                return bottle.static_file(filename, root=root, download=default_name)
            else:
                return bottle.static_file(filename, root=root, download=False)
            # finally:
            #     logger.log(filename, INFO, message_type='http_request_finished', data=json.dumps({
            #         'status': bottle.response.status_code,
            #         'start': start,
            #         'end': time.clock(),
            #     }))


    # frontend
    print('Preparing frontend directories...')
    for subdir, dirs, files in os.walk(FRONTEND_RELATIVE_PATH):
        # subdir now has the form   ../frontend/config
        _serve_static_directory(
            route=subdir.replace('\\', '/').replace(FRONTEND_RELATIVE_PATH, '') + '/<filename>',
            root=subdir
        )

    # app
    print('Preparing app for download...')
    _serve_static_directory(
        route='/app/<filename>',
        root='../android/app/release',
        download=True,
    )

    logger.log('Server start', INFO, 'server_start', json.dumps({
        'host': '0.0.0.0',
        'port': connection.PORT,
        'debug': debug,
    }))

    # commit regularly
    log_commit_time = logger.commit()
    log_commit_delay = 15
    print(f'Committing logfile transaction took {log_commit_time}s, '
          f'scheduling to run every {log_commit_delay}s')
    threading.Timer(log_commit_delay, logger.commit).start()

    print('Running server...')
    bottle.run(host='0.0.0.0', port=connection.PORT, debug=debug, server=GeventWebSocketServer)
    logger.commit()
    model.cleanup()