import json, hashlib, os
from pathlib import Path
import httpx


class LLMClient:
    def __init__(self, model="gpt-4o-mini", timeout=15, cache_dir=".cache/llm"):
        self.model = model
        self.timeout = timeout
        self.dir = Path(cache_dir)
        self.dir.mkdir(parents=True, exist_ok=True)

    def _key(self, msgs):
        return hashlib.sha256(json.dumps(msgs, sort_keys=True).encode()).hexdigest()

    def _get(self, k):
        p = self.dir / f"{k}.json"
        return json.loads(p.read_text())["response"] if p.exists() else None

    def _set(self, k, v):
        (self.dir / f"{k}.json").write_text(json.dumps({"response": v}))

    def call(self, messages, retries=1):
        k = self._key(messages)
        c = self._get(k)
        if c:
            return c
        key = os.environ.get("LLM_API_KEY", os.environ.get("OPENAI_API_KEY", ""))
        base = os.environ.get("LLM_API_BASE", "https://api.openai.com/v1")
        for a in range(retries + 1):
            try:
                r = httpx.post(f"{base}/chat/completions", json={"model": self.model, "messages": messages},
                               headers={"Authorization": f"Bearer {key}"}, timeout=self.timeout)
                r.raise_for_status()
                v = r.json()["choices"][0]["message"]["content"]
                self._set(k, v)
                return v
            except Exception:
                if a == retries:
                    raise
        return ""