import os
import os.path
import json

from collections import defaultdict
from datetime import datetime
from threading import Thread

from flask import current_app
from flask_mail import Mail, Message


mail = Mail()


def async(f):

    def wrapper(*args, **kwargs):
        thr = Thread(target=f, args=args, kwargs=kwargs)
        thr.start()

    return wrapper


@async
def send_async_mail(msg):
    mail.send(msg)


def _send_mail(server_name, status, last_updated):

    current_app.logger.info('Try sending mail')
    try:
        msg = Message('[Ennstatus] %s went %s' % (server_name, status),
                      sender='ennstatus@enn.lu')
        msg.add_recipient(current_app.config['SERVER_ADMINS'][server_name])
        msg.body = ('%s went to %s. I received the last update at %s'
                    % (server_name, status, last_updated))
        send_async_mail(msg)
    except KeyError:
        current_app.logger.error('Admin for %s not found!' % server_name)
    except AssertionError:
        pass
    except Exception as e:
        current_app.logger.error('Unexpected error: %s' % e,
                                 exc_info=True)
    current_app.logger.info('Finished trying!')


def _check_server(data):

    server_name = data['server_name']
    last_updated = data['last_updated']
    filename = os.path.join('data', '.'.join([server_name.lower(), 'json']))

    date = datetime.strptime(last_updated, '%d-%m-%Y %H:%M:%S')
    now = datetime.utcnow()
    delta = now - date

    if delta.days >= 7:
        os.remove(filename)
        current_app.logger.error('%s was removed!' % server_name)
        return False
    elif data['server_status'] == 'Offline':
        return data

    if delta.seconds >= 3600:
        status = 'Offline'
    elif delta.seconds >= 1200:
        status = 'Unknown'
    else:
        status = None

    if status is not None:
        current_app.logger.error('%s is set to %s' % (server_name,
                                 status))

        if (data['server_status'] == 'Unknown' and status == 'Offline') \
           or (data['server_status'] == 'Online' and status == 'Unknown'):
            _send_mail(server_name, status, last_updated)

        for key in ('server_status', 'tor_status'):
            data[key] = status

        with open(filename, mode='w', encoding='utf-8') as file_object:
            json.dump(data, file_object)

    return data


def _load_single_server(filename):

    try:
        with open(filename, encoding='utf-8') as f:
            server = json.load(f)
    except IOError:
        return False

    server = _check_server(server)
    return server


def single_server(name):

    filename = ''.join(['data/', name, '.json'])
    return _load_single_server(filename)


def _get_json_files(root, files):

    for f in files:
        if f.endswith('.json'):
            yield os.path.join(root, f)


def all_servers():

    for root, _, files in os.walk('data'):
        for f in _get_json_files(root, files):
            yield _load_single_server(f)


def all_servers_by_type(type):

    for server in all_servers():
        try:
            if server['server_type'] == type:
                yield server
        except TypeError:
            continue


def split_all_servers_to_types():

    servers = defaultdict(list)

    for server in all_servers():
        try:
            servers[server['server_type']].append(server)
        except TypeError:
            continue

    return servers