import re
from datetime import timezone, timedelta

import requests
from dateutil.parser import parse

from exceptions import ServerCommunicationError, StationNotFoundError

parse_regex = r' to | times | in '


def handle_marudor_departures(update, context):
    command = ' '.join(context.args)
    arguments = parse_arguments(command)
    eva_id = get_eva_id_for_station_name(arguments['station'])
    departures = get_departures(eva_id)
    if ' in ' in arguments:
        departures = filter_line_names(departures, arguments[' in '])
    if ' to ' in arguments:
        departures = filter_destination(departures, arguments[' to '])
    departure_count = 4
    if ' times ' in arguments:
        departure_count = int(arguments[' times '])
    departures = departures[:departure_count]
    for reply in build_reply(departures):
        update.message.reply_text(reply)


def parse_arguments(command: str) -> dict:
    included_commands = re.findall(parse_regex, command)
    parameters = re.split(parse_regex, command)
    return dict(zip(['station'] + included_commands, parameters))


def get_eva_id_for_station_name(station_name: str) -> str:
    request = requests.get(f'https://marudor.de/api/hafas/v1/station/{station_name}')
    if request.status_code != 200:
        raise ServerCommunicationError
    response = request.json()
    if len(response) == 0 or 'id' not in response[0]:
        raise StationNotFoundError
    return response[0]['id']


def get_departures(eva_id: str) -> list:
    request = requests.get(f'https://marudor.de/api/hafas/experimental/irisCompatibleAbfahrten/{eva_id}?lookbehind=1')
    if request.status_code != 200:
        raise ServerCommunicationError
    response = request.json()
    return response['departures']


def filter_destination(departures: list, destination: str) -> list:
    departures[:] = [departure for departure in departures if
                     destination.casefold() in departure['destination'].casefold() or destination.casefold() in departure[
                         'scheduledDestination'].casefold()]
    return departures


def filter_line_names(departures: list, line_name: str) -> list:
    departures[:] = [departure for departure in departures if
                     line_name in departure['train']['name']]
    return departures


def build_reply(departures: list) -> list:
    if len(departures) == 0:
        return ['No departures found!']
    reply = [f'Next departures for station: {departures[0]["currentStation"]["title"]}']
    for departure in departures:
        reply_text = f'{departure["train"]["name"]} to "{departure["destination"]}" at ' \
                     f'{parse(departure["departure"]["time"]).astimezone(timezone(timedelta(hours=1))).strftime("%H:%M")}'

        if 'delay' in departure['departure']:
            reply_text += f' (+{str(departure["departure"]["delay"])})'

        reply.append(reply_text)
    return reply