# -*- coding: utf-8 -*-
"""
HF Router (OpenAI-compatible) chat-completions wrapper for Hugging Face Spaces.

Uses:
POST https://router.huggingface.co/v1/chat/completions

Requirements:
- HF_TOKEN must have "Inference Providers" permission
- If model is gated, accept license with the same HF account
"""

import os
import traceback
from typing import List, Dict

import httpx

HF_TOKEN = os.getenv("HF_TOKEN")
# İstersen provider'ı zorlamak için: "google/gemma-3-4b-it:hf-inference"
MODEL_ID = os.getenv("MODEL_ID", "meta-llama/Llama-3.2-3B-Instruct")


def generate_response(
    messages: List[Dict],
    max_tokens: int = 512,
    temperature: float = 0.7,
) -> str:
    if not HF_TOKEN:
        return "Error: HF_TOKEN is not set. Add it in Space Settings -> Secrets."

    url = "https://router.huggingface.co/v1/chat/completions"
    headers = {
        "Authorization": f"Bearer {HF_TOKEN}",
        "Content-Type": "application/json",
    }
    payload = {
        "model": MODEL_ID,
        "messages": messages,
        "max_tokens": max_tokens,
        "temperature": temperature,
    }

    try:
        with httpx.Client(timeout=90) as http:
            r = http.post(url, headers=headers, json=payload)

        if r.status_code >= 400:
            # Body'yi bas: 401/403/404/429 vs hemen anlaşılır
            return f"Error: HTTP {r.status_code}\n\n{r.text}"

        data = r.json()
        return data["choices"][0]["message"]["content"].strip()

    except Exception as e:
        return f"Error: {repr(e)}\n\n{traceback.format_exc()}"


def calculate_expression(expression: str) -> str:
    """Simple calculator for financial expressions (safe eval)."""
    import re
    import math

    allowed_names = {
        "abs": abs,
        "round": round,
        "min": min,
        "max": max,
        "pow": pow,
        "sqrt": math.sqrt,
        "log": math.log,
        "exp": math.exp,
        "pi": math.pi,
        "e": math.e,
    }

    try:
        expr = expression.strip()
        if not re.match(r"^[\d\s\+\-\*\/\.\(\)\^]+$", expr.replace("**", "^")):
            return "Calculation error: invalid characters in expression."

        result = eval(expr, {"__builtins__": {}}, allowed_names)
        return f"{result:,.2f}"
    except Exception as e:
        return f"Calculation error: {str(e)}"