#!/usr/bin/env python3
# vim:tabstop=4 softtabstop=4 shiftwidth=4 textwidth=160 smarttab expandtab colorcolumn=160

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}

cache = dict()
eva_to_name = dict()


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


def build_response(content, eva, now):
    train_data = dict()
    for train in content["raw"]:
        if train["train_no"]:
            train_data[train["train_no"]] = {
                "occupancy": get_occupancy(train["occupancy"])
            }

    reply = {"train": train_data}

    cache[eva] = (now, reply)

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


async def handle_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().timestamp()

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

    async with aiohttp.ClientSession() as session:
        async with session.get(
            f"https://vrrf.finalrewind.org/{station}.json?line=RE,RB,S&backend=efa.VRR2"
        ) as response:
            content = await response.text()
            content = json.loads(content)

            if not content["error"]:
                return build_response(content, eva, now)

    async with aiohttp.ClientSession() as session:
        async with session.get(
            f"https://vrrf.finalrewind.org/{optid}.json?line=RE,RB,S&backend=efa.VRR2&proximity_search=1"
        ) as response:
            content = await response.text()
            content = json.loads(content)

            return build_response(content, eva, now)


if __name__ == "__main__":

    parser = argparse.ArgumentParser(description="eva to efa gateway")
    parser.add_argument(
        "--eva-csv", type=str, metavar="FILE", default="haltestellenMitEva.csv"
    )
    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()
    app.add_routes([web.get(f"{args.prefix}{{eva}}.json", handle_eva)])
    web.run_app(app, host="localhost", port=args.port)