"""Nano Banana — Gemini 2.5 Flash Image (generativelanguage API).

POST /v1beta/models/{MODEL}:generateContent
→ candidates[0].content.parts[*].inlineData.data (b64 png)
"""
from __future__ import annotations

import logging, os
import requests

from nas_client import webhook_update_task
from providers._media import save_b64_png

logger = logging.getLogger(__name__)
GEMINI_BASE = "https://generativelanguage.googleapis.com/v1beta"
DEFAULT_MODEL = "gemini-2.5-flash-image"


def _extract_b64(data: dict):
    for cand in data.get("candidates", []):
        for part in cand.get("content", {}).get("parts", []):
            inline = part.get("inlineData") or part.get("inline_data")
            if inline and inline.get("data"):
                return inline["data"]
    return None


def run_nano_banana_generation(task_id: str, params: dict) -> None:
    try:
        if not os.getenv("GEMINI_API_KEY"):
            webhook_update_task(task_id, "failed", 0, "", error="GEMINI_API_KEY 미설정 (Windows .env)")
            return
        webhook_update_task(task_id, "processing", 10, "Nano Banana (Gemini) 호출 중...")
        model_id = params.get("model") or DEFAULT_MODEL
        body = {"contents": [{"parts": [{"text": params["prompt"]}]}]}
        resp = requests.post(
            f"{GEMINI_BASE}/models/{model_id}:generateContent",
            headers={"x-goog-api-key": os.getenv("GEMINI_API_KEY"), "Content-Type": "application/json"},
            json=body, timeout=120,
        )
        if resp.status_code != 200:
            webhook_update_task(task_id, "failed", 0, "", error=f"Gemini {resp.status_code}: {resp.text[:200]}")
            return
        b64 = _extract_b64(resp.json())
        if not b64:
            webhook_update_task(task_id, "failed", 0, "", error="Gemini 응답에 이미지 없음")
            return
        url = save_b64_png(task_id, b64)
        webhook_update_task(task_id, "succeeded", 100, "완료", image_url=url)
    except Exception as e:
        logger.exception("nano_banana task=%s 실패", task_id)
        webhook_update_task(task_id, "failed", 0, "", error=str(e))