# Pastebin fWgRbwsb
import json
from datetime import datetime
from urllib.parse import parse_qs
​
​
def application(environ, start_response):
    with open("urls.json", "r") as file:
        urls = json.load(file)
    method = environ["REQUEST_METHOD"]
    if method == "GET":
        path = environ["PATH_INFO"]
        key = path.removeprefix("/")
        if not key or not (url_data := urls.get(key)):
            start_response("404 Not Found", [("Content-Type", "application/json")])
            return [json.dumps({"error": f"URL alias '{key}' does not exist." if key else "URL alias not provided."}).encode()]
        start_response("301 Moved Permanently", [("Location", url_data["url"])])
        return [b'']
    elif method == "POST":
        data = parse_qs(environ["wsgi.input"].readline().decode(), True)
        key, url = data.get("key", [None])[0], data.get("url", [None])[0]
        if not key or not url or key in urls:
            start_response("400 Bad Request", [("Content-Type", "application/json")])
            return [json.dumps({"error": f"URL alias '{key}' already exists." if key and url else "Alias or URL not provided."}).encode()]
        urls[key] = url_data = dict(key=key, url=url, date=datetime.now().isoformat())
        with open("urls.json", "w", encoding="utf-8") as file:
            json.dump(urls, file, indent=4, sort_keys=True)
        url_data["val"] = f'https://{environ["HTTP_HOST"]}/{key}'
        start_response("201 Created", [("Content-Type", "application/json")])
        return [json.dumps(url_data).encode()]