from typing import NamedTuple
import re
import sys
import tomllib
from pathlib import Path
from typing import TypedDict
from collections import defaultdict
from urllib.request import urlopen
import json

TRAEFIK_HOST_RE = re.compile(r"Host\(`([a-z0-9\.-]+)`\)")

CONFIG_FILE = Path.cwd() / "config.toml"

class Route(NamedTuple):
    name: str
    destination: str
    hostname: str


class Source(TypedDict):
    type: str
    url: str
    destination: str


class Config(TypedDict):
    source: list[Source]


def parse_traefik_rule(rule: str) -> list[str]:
    if "Host(" not in rule:
        return []

    return TRAEFIK_HOST_RE.findall(rule)


def get_traefik_routes(traefik_host: str, traefik_route: str):
    with urlopen(f"{traefik_host}/api/http/routers") as response:
        api_response = json.load(response)

    routes = set()

    for router in api_response:
        hosts = parse_traefik_rule(router["rule"])

        if not hosts:
            print(f"Failed to find host for {router['rule']}", file=sys.stderr)
            continue

        if len(hosts) > 1:
            print(f"WARNING: Found multiple hosts for rule: {router['rule']}", file=sys.stderr)

        routes.add(Route(
            router["service"],
            traefik_route,
            hosts[0]
        ))

    return routes

def get_dokku_routes(dokku_exporter_url: str, dokku_route: str):
    with urlopen(dokku_exporter_url) as response:
        api_response = json.load(response)

    routes = set()

    for app in api_response:
        for vhost in app["vhosts"]:
            routes.add(Route(
                app["app"],
                dokku_route,
                vhost
            ))

    return routes


def main():
    config: Config = tomllib.loads(CONFIG_FILE.read_text())

    routes = []
    for source in config["source"]:
        match source["type"]:
            case "traefik":
                routes.extend(get_traefik_routes(source["url"], source["destination"]))
            case "dokku":
                routes.extend(get_dokku_routes(source["url"], source["destination"]))

    if len(routes) != len(set(routes)):
        raise ValueError("Conflict found!")

    grouped_routes = defaultdict(set)
    for route in routes:
        grouped_routes[route.hostname, route.destination].add(route.name)

    for (hostname, destination), names in sorted(grouped_routes.items()):
        print(f"{hostname}\t{destination};  # {', '.join(names)}")

    print("Found", len(routes), "routes, grouped into", len(grouped_routes), "groups")

if __name__ == "__main__":
    main()