"""Request limiting and HTML/SSE cache headers with app-scoped state."""

import time

from flask import current_app, jsonify, request


def rate_limit():
    path = request.path
    if path in ('/healthz', '/api/visitor/human/poll') or path.startswith('/static') or path.startswith('/api/human/'):
        return None
    ip = request.remote_addr or 'unknown'
    now = time.time()
    hits = current_app.extensions['rate_hits'][ip]
    while hits and now - hits[0] > 60:
        hits.pop(0)
    if len(hits) >= current_app.config['RATE_LIMIT_PER_MIN']:
        return jsonify({'e': '请求太频繁，请稍后几秒再试', 'd': 1}), 429
    hits.append(now)
    return None


def no_cache_html(response):
    if response.mimetype in ('text/html', 'text/event-stream') or request.path.startswith('/api/'):
        response.headers['Cache-Control'] = 'no-store, no-cache, must-revalidate'
        response.headers['Pragma'] = 'no-cache'
        response.headers['Expires'] = '0'
    return response