app.py

import io
import os
import base64
from typing import Optional

import httpx
from PIL import Image
import gradio as gr
from fastapi import FastAPI

# ========== 配置 ==========
STEPFUN_ENDPOINT = os.getenv("STEPFUN_ENDPOINT", "https://api.stepfun.com/v1")
MODEL_NAME = os.getenv("STEPFUN_MODEL", "step-3")
TITLE = "StepFun · 图像问答（step-3）"
DESC = "上传图片 + 输入问题，走 StepFun OpenAI 兼容接口 /chat/completions"
# =========================

def _get_api_key() -> Optional[str]:
    # 兼容两种环境变量名
    return os.getenv("OPENAI_API_KEY") or os.getenv("STEPFUN_KEY")

def _pil_to_data_url(img: Image.Image, fmt: str = "PNG") -> str:
    buf = io.BytesIO()
    img.save(buf, format=fmt)
    b64 = base64.b64encode(buf.getvalue()).decode("utf-8")
    mime = "image/png" if fmt.upper() == "PNG" else "image/jpeg"
    return f"data:{mime};base64,{b64}"

def _post_chat(messages: list, temperature: float = 0.7, timeout: float = 60.0) -> str:
    key = _get_api_key()
    if not key:
        raise RuntimeError(
            "API Key 未设置。请在 Space 的 Settings → Variables and secrets 添加：\n"
            "OPENAI_API_KEY 或 STEPFUN_KEY（值为 StepFun API Key）。"
        )

    url = f"{STEPFUN_ENDPOINT.rstrip('/')}/chat/completions"
    headers = {
        "Authorization": f"Bearer {key}",
        "Content-Type": "application/json",
    }
    payload = {
        "model": MODEL_NAME,
        "messages": messages,
        "temperature": temperature,
    }
    r = httpx.post(url, headers=headers, json=payload, timeout=timeout)
    r.raise_for_status()
    data = r.json()
    # 兼容常见返回结构
    return data["choices"][0]["message"]["content"]

def infer(image: Optional[Image.Image], question: Optional[str]) -> str:
    if image is None:
        return "请先上传图片再提问。"
    q = (question or "").strip() or "请描述这张图片。"
    data_url = _pil_to_data_url(image, fmt="PNG")
    messages = [
        {
            "role": "user",
            "content": [
                {"type": "image_url", "image_url": {"url": data_url}},
                {"type": "text", "text": q},
            ],
        }
    ]
    try:
        return _post_chat(messages)
    except httpx.HTTPStatusError as e:
        return f"调用失败（HTTP {e.response.status_code}）：{e.response.text}"
    except Exception as e:
        return f"调用失败：{repr(e)}"

# ------- Gradio 界面 -------
demo = gr.Interface(
    fn=infer,
    inputs=[
        gr.Image(type="pil", label="上传图片"),
        gr.Textbox(label="问题", placeholder="例如：这是什么菜？怎么做？"),
    ],
    outputs=gr.Textbox(label="回答"),
    title=TITLE,
    description=DESC,
)

# ------- FastAPI 宿主应用（覆盖 /info，避免 gradio_client 的 schema 解析） -------
fastapi_app = FastAPI()

@fastapi_app.get("/health")
def health():
    return {"status": "ok"}

@fastapi_app.get("/info")
def info_stub():
    # 返回一个最小可用的对象，绕过 gradio 的 api_info 复杂逻辑
    return {
        "api": False,
        "message": "API docs 已禁用（此路由由外部 FastAPI 覆盖以规避依赖冲突）。"
    }

# 挂载 Gradio 到根路径
app = gr.mount_gradio_app(fastapi_app, demo, path="/")

# 本地调试：python app.py
if __name__ == "__main__":
    import uvicorn
    port = int(os.getenv("PORT", "7860"))
    # 注意：本地调试可以启；Spaces 不会走这里
    uvicorn.run(app, host="0.0.0.0", port=port)