#!/usr/bin/env python3
# vim:tabstop=4 softtabstop=4 shiftwidth=4 textwidth=160 smarttab expandtab colorcolumn=160
#
# Copyright (C) 2021 Birte Kristina Friesel
#
# SPDX-License-Identifier: BSD-2-Clause

import argparse

import aiohttp
from aiohttp import web
from datetime import datetime

import json

headers = {
    "Access-Control-Allow-Origin": "*",
    "Content-Type": "application/json; charset=utf-8",
}

occupancy_map = {"MANY_SEATS": 1, "FEW_SEATS": 2, "STANDING_ONLY": 3, "FULL": 4}

occupancy_cache = dict()
eva_to_name = dict()


class EFA:
    def __init__(self, url, proximity_search=False):
        self.dm_url = url + "/XML_DM_REQUEST"
        self.dm_post_data = {
            "command": "",
            "deleteAssignedStops_dm": "1",
            "help": "Hilfe",
            "itdLPxx_id_dm": ":dm",
            "itdLPxx_mapState_dm": "",
            "itdLPxx_mdvMap2_dm": "",
            "itdLPxx_mdvMap_dm": "3406199:401077:NAV3",
            "itdLPxx_transpCompany": "vrr",
            "itdLPxx_view": "",
            "language": "de",
            "mode": "direct",
            "nameInfo_dm": "invalid",
            "nameState_dm": "empty",
            "outputFormat": "JSON",
            "ptOptionsActive": "1",
            "requestID": "0",
            "reset": "neue Anfrage",
            "sessionID": "0",
            "submitButton": "anfordern",
            "typeInfo_dm": "invalid",
            "type_dm": "stop",
            "useProxFootSearch": "0",
            "useRealtime": "1",
        }

        if proximity_search:
            self.dm_post_data["useProxFootSearch"] = "1"

    async def get_departures(self, place, name, ts):
        self.dm_post_data.update(
            {
                "itdDateDay": ts.day,
                "itdDateMonth": ts.month,
                "itdDateYear": ts.year,
                "itdTimeHour": ts.hour,
                "itdTimeMinute": ts.minute,
                "name_dm": name,
            }
        )
        if place is None:
            self.dm_post_data.pop("placeInfo_dm", None)
            self.dm_post_data.pop("placeState_dm", None)
            self.dm_post_data.pop("place_dm", None)
        else:
            self.dm_post_data.update(
                {"placeInfo_dm": "invalid", "placeState_dm": "empty", "place_dm": place}
            )
        departures = list()
        async with aiohttp.ClientSession() as session:
            async with session.post(self.dm_url, data=self.dm_post_data) as response:
                # EFA may return JSON with a text/html Content-Type, which response.json() does not like.
                departures = json.loads(await response.text())

        return departures


async def get_departures(request):
    efa_url = request.query.get("url", None)
    place = request.query.get("place", None)
    name = request.query.get("name", None)

    if not efa_url:
        return web.HTTPBadRequest(text="missing url=... parameter")
    if not name:
        return web.HTTPBadRequest(text="missing name=... parameter")

    now = datetime.now()

    reply = await EFA(efa_url).get_departures(place, name, now)

    return web.Response(body=json.dumps(reply), headers=headers)


def get_occupancy(occupancy):
    try:
        return occupancy_map[occupancy]
    except KeyError:
        return None


def build_occupancy_response(departure_list, eva, now):
    train_data = dict()

    for departure in departure_list:
        try:
            occupancy = departure["occupancy"]
            train_no = departure["servingLine"]["trainNum"]
            train_data[train_no] = {"occupancy": get_occupancy(occupancy)}
        except KeyError:
            pass

    reply = {"train": train_data}

    occupancy_cache[eva] = (now, reply)

    return web.Response(body=json.dumps(reply), headers=headers)


async def get_occupancy_by_eva(request):
    try:
        eva = int(request.match_info.get("eva"))
    except ValueError:
        return web.HTTPBadRequest(text="EVA must be a number")

    try:
        station, optid = eva_to_name[eva]
    except KeyError:
        return web.HTTPNotFound(text="Unknown EVA")

    now = datetime.now()

    if eva in occupancy_cache and now.timestamp() - occupancy_cache[eva][0] < 300:
        return web.Response(body=json.dumps(occupancy_cache[eva][1]), headers=headers)

    reply = await EFA("https://app.vrr.de/standard").get_departures(None, station, now)

    if reply.get("departureList", None):
        return build_occupancy_response(reply["departureList"], eva, now.timestamp())

    reply = await EFA(
        "https://app.vrr.de/standard", proximity_search=True
    ).get_departures(None, optid, now)

    return build_occupancy_response(
        reply.get("departureList", list()), eva, now.timestamp()
    )


if __name__ == "__main__":

    parser = argparse.ArgumentParser(description="eva to efa gateway")
    parser.add_argument("--port", type=int, metavar="PORT", default=8080)
    parser.add_argument("--prefix", type=str, metavar="PATH", default="/")
    args = parser.parse_args()

    with open("share/vrr.json", "r") as f:
        for eva, (name, optid) in json.load(f).items():
            eva_to_name[int(eva)] = name, optid

    app = web.Application()

    # legacy route
    app.add_routes([web.get(f"{args.prefix}{{eva}}.json", get_occupancy_by_eva)])

    app.add_routes([web.get(f"{args.prefix}departures", get_departures)])
    app.add_routes(
        [web.get(f"{args.prefix}occupancy-by-eva/{{eva}}.json", get_occupancy_by_eva)]
    )
    web.run_app(app, host="localhost", port=args.port)