import requests
from typing import List, Dict, Optional

from config import (
    OPENROUTER_API_KEY,
    OPENROUTER_BASE_URL,
    TEACHER_MODEL,
    TEACHER_FALLBACK_MODELS,
    TEACHER_TEMPERATURE,
    TEACHER_MAX_TOKENS,
)

class TeacherModel:
    """
    OpenRouter teacher client with:
    - Primary model
    - Fallback models
    - Detailed error logging
    """

    def __init__(self):
        self.api_key = OPENROUTER_API_KEY
        self.base_url = OPENROUTER_BASE_URL
        self.session = requests.Session()

        self.last_status_code: Optional[int] = None
        self.last_error: str = ""
        self.last_model_tried: str = ""
        self.last_response_text: str = ""

    def is_available(self) -> bool:
        return bool(self.api_key)

    def _call_model(
        self,
        model_id: str,
        messages: List[Dict],
        temperature: float,
        max_tokens: int
    ) -> Optional[str]:

        headers = {
            "Content-Type": "application/json",
            "Authorization": f"Bearer {self.api_key}",
            "Accept": "application/json",
            # recommended by OpenRouter
            "HTTP-Referer": "https://huggingface.co/spaces/vedaco/veda-programming",
            "X-Title": "Veda Programming Assistant",
        }

        payload = {
            "model": model_id,
            "messages": messages,
            "temperature": float(temperature),
            "max_tokens": int(max_tokens),
            "stream": False
        }

        r = self.session.post(self.base_url, headers=headers, json=payload, timeout=60)

        self.last_status_code = r.status_code
        self.last_response_text = r.text[:2000]

        if r.status_code != 200:
            try:
                err = r.json()
            except Exception:
                err = {"raw": r.text}

            self.last_error = f"HTTP {r.status_code}: {err}"
            return None

        data = r.json()
        if "error" in data:
            self.last_error = f"OpenRouter error field: {data['error']}"
            return None

        choices = data.get("choices") or []
        if not choices:
            self.last_error = f"No choices in response: {data}"
            return None

        msg = choices[0].get("message") or {}
        content = msg.get("content", "")

        if not content:
            self.last_error = f"Empty content: {data}"
            return None

        self.last_error = ""
        return content

    def ask(
        self,
        user_message: str,
        conversation_history: Optional[List[Dict[str, str]]] = None,
        temperature: float = None,
        max_tokens: int = None
    ) -> Optional[str]:

        if not self.is_available():
            self.last_error = "OPENROUTER_API_KEY missing"
            print("[Teacher] Missing OPENROUTER_API_KEY")
            return None

        temperature = TEACHER_TEMPERATURE if temperature is None else float(temperature)
        max_tokens = TEACHER_MAX_TOKENS if max_tokens is None else int(max_tokens)

        messages = [
            {
                "role": "system",
                "content": (
                    "You are a helpful programming assistant. "
                    "Answer clearly. When asked to write code, output correct Python code. "
                    "Use markdown code blocks like ```python ... ```."
                )
            }
        ]

        if conversation_history:
            for m in conversation_history[-10:]:
                role = m.get("role", "user")
                content = m.get("content", "")
                if content:
                    messages.append({"role": role, "content": content})

        messages.append({"role": "user", "content": user_message})

        candidates = [TEACHER_MODEL] + list(TEACHER_FALLBACK_MODELS)

        for model_id in candidates:
            self.last_model_tried = model_id
            out = self._call_model(model_id, messages, temperature, max_tokens)
            if out:
                return out
            print(f"[Teacher] Failed model {model_id}: {self.last_error}")

        return None

teacher = TeacherModel()