import json

from edge.alert import USER_AGENT, sign


class ServerClient:
    def __init__(self, base_url: str, device_id: str, secret: str,
                 nonce_fn, now_fn, http_get=None, http_post=None, timeout: float = 5.0):
        self.base_url = base_url.rstrip("/")
        self.device_id = device_id
        self.secret = secret
        self.nonce_fn = nonce_fn
        self.now_fn = now_fn
        self.timeout = timeout
        if http_get is None or http_post is None:
            import requests
            http_get = http_get or requests.get
            http_post = http_post or requests.post
        self._get = http_get
        self._post = http_post

    def _headers(self, body: str) -> dict:
        nonce = self.nonce_fn()
        ts = str(self.now_fn())
        # User-Agent: cafe24's WAF 403s the default python-requests UA (see edge/alert.py).
        return {"User-Agent": USER_AGENT, "X-Nonce": nonce, "X-Timestamp": ts,
                "X-Signature": sign(self.secret, nonce, ts, body)}

    def fetch_config(self) -> dict | None:
        url = f"{self.base_url}/api/config?device_id={self.device_id}"
        try:
            resp = self._get(url, headers=self._headers(""), timeout=self.timeout,
                             allow_redirects=False)
        except Exception:
            return None
        if 200 <= resp.status_code < 300:
            try:
                return resp.json()
            except Exception:
                return None
        return None

    def send_heartbeat(self, metrics: dict) -> bool:
        payload = {"device_id": self.device_id, **metrics}
        body = json.dumps(payload, sort_keys=True)
        headers = {"Content-Type": "application/json", **self._headers(body)}
        try:
            resp = self._post(f"{self.base_url}/api/heartbeat", data=body,
                              headers=headers, timeout=self.timeout, allow_redirects=False)
        except Exception:
            return False
        return 200 <= resp.status_code < 300