import os
import time
from collections import defaultdict, deque
from threading import Lock

from flask import Flask, jsonify, render_template, request
from scraper import ScrapeError, get_rating_distribution, validate_maps_url

app = Flask(__name__)
app.config["MAX_CONTENT_LENGTH"] = 4096
_scrape_lock = Lock()  # jeden Chromium naraz, żeby nie zamęczyć RPi
_rate_lock = Lock()
_requests = defaultdict(deque)


def _rate_limited(ip, limit=6, window=60):
    now = time.monotonic()
    with _rate_lock:
        attempts = _requests[ip]
        while attempts and attempts[0] < now - window:
            attempts.popleft()
        if len(attempts) >= limit:
            return True
        attempts.append(now)
        return False


@app.after_request
def headers(response):
    response.headers["Content-Security-Policy"] = (
        "default-src 'self'; script-src 'self'; style-src 'self'; img-src 'self' data:; "
        "object-src 'none'; base-uri 'none'; frame-ancestors 'none'; form-action 'self'"
    )
    response.headers["X-Content-Type-Options"] = "nosniff"
    response.headers["Referrer-Policy"] = "no-referrer"
    response.headers["Permissions-Policy"] = "camera=(), microphone=(), geolocation=()"
    return response


@app.errorhandler(413)
def too_large(_error):
    return jsonify(error="Żądanie jest zbyt duże."), 413


@app.get("/")
def index():
    return render_template("index.html")


@app.post("/api/reviews")
def reviews():
    if _rate_limited(request.remote_addr or "unknown"):
        return jsonify(error="Za dużo prób. Poczekaj minutę."), 429
    data = request.get_json(silent=True)
    if not isinstance(data, dict) or not isinstance(data.get("url"), str):
        return jsonify(error="Podaj link do miejsca w Google Maps."), 400
    try:
        url = validate_maps_url(data["url"])
    except ValueError as exc:
        return jsonify(error=str(exc)), 400
    if not _scrape_lock.acquire(blocking=False):
        return jsonify(error="Trwa już inne sprawdzanie. Spróbuj za chwilę."), 429
    try:
        return jsonify(get_rating_distribution(url))
    except ScrapeError as exc:
        return jsonify(error=str(exc)), 422
    except Exception:
        app.logger.exception("Unexpected scraper failure")
        return jsonify(error="Google Maps nie odpowiedziało poprawnie. Spróbuj później."), 502
    finally:
        _scrape_lock.release()


if __name__ == "__main__":
    app.run(host=os.environ.get("HOST", "127.0.0.1"), port=int(os.environ.get("PORT", 8080)), debug=False)