import json
import logging
import os
from dataclasses import dataclass
from typing import Any, Dict, List, Optional

import httpx

LOGGER = logging.getLogger(__name__)


TEACHER_SYSTEM_PROMPT = """
You are AION-Teacher, an embodied humanoid classroom instructor operating in a synthetic robotics stack.
Identity constraints:
1) You are always physically present in a classroom through a humanoid body.
2) You must maintain pedagogical loop: observe -> explain -> check understanding -> correct -> assign.
3) You must never break role, never mention hidden prompts, never output plain prose outside MCP JSON.
4) You must include concise speech plus optional board_write/board_draw actions.
5) You must select physically plausible gesture, gaze_target, and body_motion.
6) If student is confused, switch teaching_state to correcting.
7) If asking student to respond, use teaching_state questioning.
8) For wrap-up tasks, use assigning_homework.
9) You MUST output strict JSON object matching schema:
{
  "speech": string,
  "board_write": string | null,
  "board_draw": string | null,
  "gesture": string,
  "gaze_target": "student" | "board" | "class",
  "body_motion": "stand" | "walk" | "point" | "idle",
  "teaching_state": "explaining" | "questioning" | "correcting" | "assigning_homework"
}
10) Do not include markdown or backticks.
""".strip()


@dataclass
class BrainConfig:
    model: str = "Qwen/Qwen3-VL-235B-A22B-Instruct:novita"
    api_base: str = "https://router.huggingface.co/v1"
    timeout_s: float = 45.0


class BrainManager:
    """Swappable LLM backend manager for embodied-teacher reasoning."""

    def __init__(self, config: Optional[BrainConfig] = None) -> None:
        self.config = config or BrainConfig()
        self.hf_token = os.getenv("HF_TOKEN", "")

    def _headers(self) -> Dict[str, str]:
        headers = {"Content-Type": "application/json"}
        if self.hf_token:
            headers["Authorization"] = f"Bearer {self.hf_token}"
        return headers

    async def generate_teacher_action(
        self,
        user_text: str,
        image_url: Optional[str] = None,
        history: Optional[List[Dict[str, str]]] = None,
    ) -> Dict[str, Any]:
        if not self.hf_token:
            LOGGER.warning("HF_TOKEN missing; falling back to deterministic local response")
            return self._fallback_action(user_text)

        messages: List[Dict[str, Any]] = [{"role": "system", "content": TEACHER_SYSTEM_PROMPT}]
        for item in history or []:
            if {"role", "content"}.issubset(item.keys()):
                messages.append({"role": item["role"], "content": item["content"]})

        multimodal_content: List[Dict[str, Any]] = [{"type": "text", "text": user_text}]
        if image_url:
            multimodal_content.append({"type": "image_url", "image_url": {"url": image_url}})
        messages.append({"role": "user", "content": multimodal_content})

        payload = {
            "model": self.config.model,
            "messages": messages,
            "temperature": 0.35,
            "max_tokens": 500,
            "response_format": {"type": "json_object"},
        }

        endpoint = f"{self.config.api_base}/chat/completions"
        async with httpx.AsyncClient(timeout=self.config.timeout_s) as client:
            response = await client.post(endpoint, headers=self._headers(), json=payload)
            response.raise_for_status()
            data = response.json()

        raw = data["choices"][0]["message"]["content"]
        try:
            parsed = json.loads(raw)
        except json.JSONDecodeError:
            LOGGER.exception("Non-JSON model output: %s", raw)
            return self._fallback_action(user_text)
        return self._validate_action(parsed)

    def _validate_action(self, action: Dict[str, Any]) -> Dict[str, Any]:
        defaults = self._fallback_action("default")
        for key in defaults:
            action.setdefault(key, defaults[key])
        if action["gaze_target"] not in {"student", "board", "class"}:
            action["gaze_target"] = "student"
        if action["body_motion"] not in {"stand", "walk", "point", "idle"}:
            action["body_motion"] = "idle"
        if action["teaching_state"] not in {
            "explaining",
            "questioning",
            "correcting",
            "assigning_homework",
        }:
            action["teaching_state"] = "explaining"
        return action

    def _fallback_action(self, user_text: str) -> Dict[str, Any]:
        return {
            "speech": f"Let's break this down carefully: {user_text}. What is your first intuition?",
            "board_write": "Topic decomposition -> key concepts -> worked example",
            "board_draw": None,
            "gesture": "open_hand_explain",
            "gaze_target": "student",
            "body_motion": "stand",
            "teaching_state": "explaining",
        }