feat(design): 添加360视频和3D模型生成功能支持

- 在Design模型中新增video_url字段用于存储360度展示视频URL
- 在DesignImage模型中新增model_3d_url字段用于存储3D模型URL
- 设计路由新增生成视频接口，调用火山引擎即梦3.0 Pro API生成展示视频
- 设计路由新增生成3D模型接口，调用腾讯混元3D服务生成.glb格式3D模型
- 新增本地文件删除工具，支持强制重新生成时清理旧文件
- 设计响应Schema中添加video_url和model_3d_url字段支持前后端数据传递
- 前端设计详情页新增360度旋转3D模型展示区，支持生成、重新生成和下载3D模型
- 实现录制3D模型展示视频功能，支持捕获model-viewer旋转画面逐帧合成WebM文件下载
- 引入@google/model-viewer库作为3D模型Web组件展示支持
- 管理后台新增即梦视频生成和腾讯混元3D模型生成配置界面，方便服务密钥管理
- 前端API增加生成视频和生成3D模型接口请求方法，超时设置为10分钟以支持长时间处理
- 优化UI交互提示，新增生成中状态显示和错误提示，提升用户体验和操作反馈

backend/app/models/design.py

@@ -25,6 +25,7 @@ class Design(Base):
     surface_finish = Column(String(50), nullable=True, comment="表面处理")
     usage_scene = Column(String(50), nullable=True, comment="用途场景")
     image_url = Column(Text, nullable=True, comment="设计图URL")
+    video_url = Column(Text, nullable=True, comment="360度展示视频URL")
     status = Column(String(20), default="generating", comment="状态")
     created_at = Column(DateTime, server_default=func.now(), comment="创建时间")
     updated_at = Column(DateTime, server_default=func.now(), onupdate=func.now(), comment="更新时间")

backend/app/models/design_image.py

@@ -20,6 +20,7 @@ class DesignImage(Base):
     model_used = Column(String(50), nullable=True, comment="使用的AI模型: flux-dev/seedream-4.5")
     prompt_used = Column(Text, nullable=True, comment="实际使用的英文prompt")
     sort_order = Column(Integer, default=0, comment="排序")
+    model_3d_url = Column(Text, nullable=True, comment="3D模型URL(.glb)")
     created_at = Column(DateTime, server_default=func.now(), comment="创建时间")
 
     # 关联关系

backend/app/routers/designs.py

@@ -1,17 +1,40 @@
 """
 设计相关路由
-提供设计生成、查询、删除、下载接口
+提供设计生成、查询、删除、下载、视频生成、3D模型生成接口
 """
 import os
+import logging
 from fastapi import APIRouter, Depends, HTTPException, status, Query
 from fastapi.responses import FileResponse, RedirectResponse
 from sqlalchemy.orm import Session
 
 from ..database import get_db
-from ..models import User, Design
+from ..models import User, Design, DesignImage
 from ..schemas import DesignCreate, DesignResponse, DesignListResponse, DesignImageResponse
 from ..utils.deps import get_current_user
 from ..services import design_service
+from ..services import ai_video_generator
+from ..services import ai_3d_generator
+
+logger = logging.getLogger(__name__)
+
+# uploads 基础目录
+UPLOADS_BASE = os.path.join(os.path.dirname(os.path.dirname(os.path.dirname(__file__))), "uploads")
+
+
+def _delete_local_file(url_path: str):
+    """删除本地存储的文件（如 /uploads/videos/xxx.mp4）"""
+    if not url_path or not url_path.startswith("/uploads/"):
+        return
+    rel_path = url_path.lstrip("/uploads/")
+    full_path = os.path.join(UPLOADS_BASE, rel_path)
+    if os.path.exists(full_path):
+        try:
+            os.remove(full_path)
+            logger.info(f"已删除旧文件: {full_path}")
+        except Exception as e:
+            logger.warning(f"删除旧文件失败: {full_path}, {e}")
+
 
 router = APIRouter(prefix="/api/designs", tags=["设计"])
 
@@ -29,6 +52,7 @@ def design_to_response(design: Design) -> DesignResponse:
                 model_used=img.model_used,
                 prompt_used=img.prompt_used,
                 sort_order=img.sort_order,
+                model_3d_url=img.model_3d_url,
             )
             for img in design.images
         ]
@@ -66,6 +90,7 @@ def design_to_response(design: Design) -> DesignResponse:
         surface_finish=design.surface_finish,
         usage_scene=design.usage_scene,
         image_url=design.image_url,
+        video_url=design.video_url,
         images=images,
         status=design.status,
         created_at=design.created_at,
@@ -219,3 +244,115 @@ def download_design(
         filename=f"design_{design_id}.png",
         media_type="image/png"
     )
+
+
+@router.post("/{design_id}/generate-video", response_model=DesignResponse)
+async def generate_video(
+    design_id: int,
+    force: bool = Query(False, description="强制重新生成"),
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user)
+):
+    """
+    为设计生成 360 度旋转展示视频
+    取设计的多视角图片，通过火山引擎即梦 3.0 Pro 生成视频
+    """
+    design = design_service.get_design_by_id(db=db, design_id=design_id, user_id=current_user.id)
+    if not design:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="设计不存在")
+
+    # 已有视频且不强制重生时直接返回
+    if design.video_url and not force:
+        return design_to_response(design)
+
+    # 强制重生时删除旧视频文件
+    if force and design.video_url:
+        _delete_local_file(design.video_url)
+        design.video_url = None
+
+    # 收集多视角图片 URL
+    image_urls = []
+    if design.images:
+        for img in sorted(design.images, key=lambda x: x.sort_order):
+            if img.image_url:
+                image_urls.append(img.image_url)
+    if not image_urls and design.image_url:
+        image_urls.append(design.image_url)
+
+    if not image_urls:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="设计没有图片，无法生成视频")
+
+    logger.info(f"设计 {design_id} 生成视频，共收集到 {len(image_urls)} 张图片")
+
+    try:
+        video_url = await ai_video_generator.generate_video(image_urls)
+        design.video_url = video_url
+        db.commit()
+        db.refresh(design)
+        return design_to_response(design)
+    except Exception as e:
+        logger.error(f"视频生成失败: {e}")
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=f"视频生成失败: {str(e)}"
+        )
+
+
+@router.post("/{design_id}/generate-3d", response_model=DesignResponse)
+async def generate_3d_model(
+    design_id: int,
+    force: bool = Query(False, description="强制重新生成"),
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user)
+):
+    """
+    为设计生成 3D 模型
+    收集所有多视角图片，取效果图（45度视角）生成 .glb 格式 3D 模型
+    """
+    design = design_service.get_design_by_id(db=db, design_id=design_id, user_id=current_user.id)
+    if not design:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="设计不存在")
+
+    # 检查是否已有 3D 模型（第一张图片）
+    if design.images and not force:
+        first_img = sorted(design.images, key=lambda x: x.sort_order)[0]
+        if first_img.model_3d_url:
+            return design_to_response(design)
+
+    # 强制重生时删除旧文件
+    if force and design.images:
+        first_img = sorted(design.images, key=lambda x: x.sort_order)[0]
+        if first_img.model_3d_url:
+            _delete_local_file(first_img.model_3d_url)
+            first_img.model_3d_url = None
+
+    # 收集所有多视角图片 URL 和视角名称
+    image_urls = []
+    view_names = []
+    if design.images:
+        for img in sorted(design.images, key=lambda x: x.sort_order):
+            if img.image_url:
+                image_urls.append(img.image_url)
+                view_names.append(img.view_name or "效果图")
+    if not image_urls and design.image_url:
+        image_urls.append(design.image_url)
+        view_names.append("效果图")
+
+    if not image_urls:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="设计没有图片，无法生成3D模型")
+
+    try:
+        model_url = await ai_3d_generator.generate_3d_model(image_urls, view_names)
+        # 将 3D 模型 URL 保存到第一张图片
+        if design.images:
+            first_img = sorted(design.images, key=lambda x: x.sort_order)[0]
+            first_img.model_3d_url = model_url
+        db.commit()
+        db.refresh(design)
+        return design_to_response(design)
+    except Exception as e:
+        logger.error(f"3D 模型生成失败: {e}")
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=f"3D 模型生成失败: {str(e)}"
+        )

backend/app/schemas/design.py

@@ -16,6 +16,7 @@ class DesignImageResponse(BaseModel):
     model_used: Optional[str] = None
     prompt_used: Optional[str] = None
     sort_order: int = 0
+    model_3d_url: Optional[str] = None
 
     class Config:
         from_attributes = True
@@ -51,6 +52,7 @@ class DesignResponse(BaseModel):
     surface_finish: Optional[str] = None
     usage_scene: Optional[str] = None
     image_url: Optional[str] = None
+    video_url: Optional[str] = None
     images: List[DesignImageResponse] = []
     status: str
     created_at: datetime

backend/app/services/ai_3d_generator.py

@@ -0,0 +1,309 @@
+"""
+AI 3D 模型生成服务
+使用腾讯混元3D (Hunyuan3D) API 将设计图片生成 3D 模型（.glb 格式）
+"""
+import asyncio
+import hashlib
+import hmac
+import io
+import json
+import logging
+import os
+import time
+import uuid
+import zipfile
+from datetime import datetime, timezone
+from typing import Optional
+
+import httpx
+
+from .config_service import get_config_value
+
+logger = logging.getLogger(__name__)
+
+# 腾讯混元3D API 配置
+HUNYUAN3D_HOST = "ai3d.tencentcloudapi.com"
+HUNYUAN3D_SERVICE = "ai3d"
+HUNYUAN3D_VERSION = "2025-05-13"
+HUNYUAN3D_REGION = "ap-guangzhou"
+SUBMIT_TIMEOUT = 30
+POLL_TIMEOUT = 15
+MAX_POLL_ATTEMPTS = 120  # 约 10 分钟
+POLL_INTERVAL = 5
+
+
+def _get_tencent_credentials() -> tuple:
+    """获取腾讯云 SecretId 和 SecretKey"""
+    secret_id = get_config_value("TENCENT_SECRET_ID", "")
+    secret_key = get_config_value("TENCENT_SECRET_KEY", "")
+    if not secret_id or not secret_key:
+        raise RuntimeError("未配置 TENCENT_SECRET_ID 或 TENCENT_SECRET_KEY，无法生成 3D 模型")
+    return secret_id, secret_key
+
+
+def _sign_tc3(secret_key: str, date: str, service: str, string_to_sign: str) -> str:
+    """TC3-HMAC-SHA256 签名"""
+    def _hmac_sha256(key: bytes, msg: str) -> bytes:
+        return hmac.new(key, msg.encode("utf-8"), hashlib.sha256).digest()
+
+    secret_date = _hmac_sha256(("TC3" + secret_key).encode("utf-8"), date)
+    secret_service = _hmac_sha256(secret_date, service)
+    secret_signing = _hmac_sha256(secret_service, "tc3_request")
+    return hmac.new(secret_signing, string_to_sign.encode("utf-8"), hashlib.sha256).hexdigest()
+
+
+def _build_auth_headers(secret_id: str, secret_key: str, action: str, payload: str) -> dict:
+    """构造腾讯云 API TC3-HMAC-SHA256 签名请求头"""
+    timestamp = int(time.time())
+    date = datetime.fromtimestamp(timestamp, tz=timezone.utc).strftime("%Y-%m-%d")
+
+    # 1. 拼接规范请求串
+    http_request_method = "POST"
+    canonical_uri = "/"
+    canonical_querystring = ""
+    ct = "application/json; charset=utf-8"
+    canonical_headers = f"content-type:{ct}\nhost:{HUNYUAN3D_HOST}\nx-tc-action:{action.lower()}\n"
+    signed_headers = "content-type;host;x-tc-action"
+    hashed_payload = hashlib.sha256(payload.encode("utf-8")).hexdigest()
+    canonical_request = (
+        f"{http_request_method}\n{canonical_uri}\n{canonical_querystring}\n"
+        f"{canonical_headers}\n{signed_headers}\n{hashed_payload}"
+    )
+
+    # 2. 拼接待签名字符串
+    algorithm = "TC3-HMAC-SHA256"
+    credential_scope = f"{date}/{HUNYUAN3D_SERVICE}/tc3_request"
+    hashed_canonical = hashlib.sha256(canonical_request.encode("utf-8")).hexdigest()
+    string_to_sign = f"{algorithm}\n{timestamp}\n{credential_scope}\n{hashed_canonical}"
+
+    # 3. 计算签名
+    signature = _sign_tc3(secret_key, date, HUNYUAN3D_SERVICE, string_to_sign)
+
+    # 4. 拼接 Authorization
+    authorization = (
+        f"{algorithm} Credential={secret_id}/{credential_scope}, "
+        f"SignedHeaders={signed_headers}, Signature={signature}"
+    )
+
+    return {
+        "Authorization": authorization,
+        "Content-Type": ct,
+        "Host": HUNYUAN3D_HOST,
+        "X-TC-Action": action,
+        "X-TC-Version": HUNYUAN3D_VERSION,
+        "X-TC-Region": HUNYUAN3D_REGION,
+        "X-TC-Timestamp": str(timestamp),
+    }
+
+
+async def _call_hunyuan3d_api(action: str, params: dict) -> dict:
+    """调用腾讯混元3D API 通用方法"""
+    secret_id, secret_key = _get_tencent_credentials()
+    payload = json.dumps(params)
+    headers = _build_auth_headers(secret_id, secret_key, action, payload)
+    url = f"https://{HUNYUAN3D_HOST}"
+
+    async with httpx.AsyncClient(timeout=SUBMIT_TIMEOUT) as client:
+        resp = await client.post(url, content=payload, headers=headers)
+        data = resp.json()
+
+    # 检查腾讯云 API 错误
+    response = data.get("Response", {})
+    error = response.get("Error")
+    if error:
+        code = error.get("Code", "Unknown")
+        message = error.get("Message", "未知错误")
+        raise RuntimeError(f"混元3D API 错误 [{code}]: {message}")
+
+    return response
+
+
+# 视角名称 → 混元3D MultiViewImages 视角映射
+# 默认3.0版本只支持 back, left, right
+_VIEW_NAME_MAP = {
+    "侧面图": "left",
+    "背面图": "back",
+}
+
+
+async def generate_3d_model(image_urls: list, view_names: Optional[list] = None) -> str:
+    """
+    调用腾讯混元3D 专业版 API 将图片生成 3D 模型
+
+    Args:
+        image_urls: 多视角图片 URL 列表
+        view_names: 对应的视角名称列表（效果图/正面图/侧面图/背面图）
+
+    Returns:
+        .glb 3D 模型文件的远程 URL
+
+    Raises:
+        RuntimeError: 3D 模型生成失败
+    """
+    if not image_urls:
+        raise RuntimeError("没有可用的图片，无法生成 3D 模型")
+
+    if not view_names:
+        view_names = ["效果图"] + ["未知"] * (len(image_urls) - 1)
+
+    # 选择主图（正面图优先，其次效果图，否则第一张）
+    main_url = None
+    multi_views = []
+
+    for url, name in zip(image_urls, view_names):
+        if name == "正面图" and not main_url:
+            main_url = url
+        elif name in _VIEW_NAME_MAP:
+            multi_views.append({"ViewType": _VIEW_NAME_MAP[name], "ViewImageUrl": url})
+        elif not main_url:
+            main_url = url
+        # 其他未知视角跳过
+
+    # 如果没有找到主图，用第一张
+    if not main_url:
+        main_url = image_urls[0]
+
+    logger.info(f"3D 模型生成: 主图=1张, 多视角={len(multi_views)}张")
+
+    # Step 1: 提交图生3D任务（统一使用专业版）
+    job_id = await _submit_3d_task(main_url, multi_views)
+    logger.info(f"3D 模型生成任务已提交(专业版): job_id={job_id}")
+
+    # Step 2: 轮询等待结果
+    remote_url = await _poll_3d_result(job_id)
+    logger.info(f"3D 模型生成完成: {remote_url[:80]}...")
+
+    # Step 3: 下载模型文件到本地（解决 CORS 跨域问题）
+    model_url = await _download_model_to_local(remote_url)
+    logger.info(f"模型文件已保存到本地: {model_url}")
+
+    return model_url
+
+
+async def _submit_3d_task(image_url: str, multi_views: Optional[list] = None) -> str:
+    """
+    提交图生3D任务到腾讯混元3D 专业版
+
+    Returns:
+        job_id
+    """
+    params = {
+        "ImageUrl": image_url,
+    }
+
+    # 有多视角图片则附带
+    if multi_views:
+        params["MultiViewImages"] = multi_views
+
+    response = await _call_hunyuan3d_api("SubmitHunyuanTo3DProJob", params)
+
+    job_id = response.get("JobId")
+    if not job_id:
+        raise RuntimeError(f"混元3D 响应中未找到 JobId: {response}")
+
+    return job_id
+
+
+async def _poll_3d_result(job_id: str) -> str:
+    """
+    轮询 3D 模型生成结果（专业版）
+
+    Returns:
+        远程模型文件 URL
+    """
+    query_action = "QueryHunyuanTo3DProJob"
+
+    for attempt in range(1, MAX_POLL_ATTEMPTS + 1):
+        await asyncio.sleep(POLL_INTERVAL)
+
+        try:
+            response = await _call_hunyuan3d_api(query_action, {"JobId": job_id})
+        except RuntimeError as e:
+            logger.warning(f"轮询 3D 结果失败 (attempt={attempt}): {e}")
+            continue
+
+        status = response.get("Status", "")
+
+        if status == "DONE":
+            result_files = response.get("ResultFile3Ds", [])
+            logger.info(f"3D 结果文件列表: {result_files}")
+            # 优先找 ZIP 格式（包含所有格式：GLB/OBJ/FBX/STL等）
+            for f in result_files:
+                if f.get("Type", "").upper() == "ZIP":
+                    return f.get("Url", "")
+            # 没有 ZIP，找 GLB
+            for f in result_files:
+                if f.get("Type", "").upper() == "GLB":
+                    return f.get("Url", "")
+            # 都没有，取第一个有 URL 的文件
+            for f in result_files:
+                file_url = f.get("Url", "")
+                if file_url:
+                    return file_url
+            raise RuntimeError(f"3D 模型生成成功但未找到模型 URL: {response}")
+
+        elif status == "FAIL":
+            error_code = response.get("ErrorCode", "")
+            error_msg = response.get("ErrorMessage", "未知错误")
+            raise RuntimeError(f"3D 模型生成失败 [{error_code}]: {error_msg}")
+
+        else:
+            if attempt % 6 == 0:
+                logger.info(f"3D 模型生成中... (attempt={attempt}, status={status})")
+
+    raise RuntimeError(f"3D 模型生成超时: 轮询 {MAX_POLL_ATTEMPTS} 次后仍未完成")
+
+
+async def _download_model_to_local(remote_url: str) -> str:
+    """
+    下载远程模型文件到本地 uploads/models/ 目录
+    支持 .zip（解压提取 .glb 并同时保留 zip）和直接的 .glb 文件
+
+    Returns:
+        本地路径（/uploads/models/xxx.glb）
+    """
+    # 确保目录存在
+    models_dir = os.path.join(os.path.dirname(os.path.dirname(os.path.dirname(__file__))), "uploads", "models")
+    os.makedirs(models_dir, exist_ok=True)
+
+    # 下载远程文件
+    async with httpx.AsyncClient(timeout=120, follow_redirects=True) as client:
+        resp = await client.get(remote_url)
+        if resp.status_code != 200:
+            raise RuntimeError(f"下载 3D 模型文件失败: HTTP {resp.status_code}")
+        file_data = resp.content
+
+    url_path = remote_url.split('?')[0].lower()
+    file_id = uuid.uuid4().hex
+
+    # 判断是否为 zip 文件（检查 URL 后缀 或 文件头 PK）
+    is_zip = url_path.endswith('.zip') or file_data[:2] == b'PK'
+
+    if is_zip:
+        # 保存原始 zip 包（供用户下载完整模型）
+        zip_path = os.path.join(models_dir, f"{file_id}.zip")
+        with open(zip_path, "wb") as f:
+            f.write(file_data)
+        logger.info(f"ZIP 包已保存: {zip_path} ({len(file_data)} bytes)")
+
+        # 解压提取 glb
+        glb_content = None
+        with zipfile.ZipFile(io.BytesIO(file_data)) as zf:
+            logger.info(f"ZIP 文件内容: {zf.namelist()}")
+            for name in zf.namelist():
+                if name.lower().endswith('.glb'):
+                    glb_content = zf.read(name)
+                    logger.info(f"从 zip 中提取 GLB: {name} ({len(glb_content)} bytes)")
+                    break
+
+        if glb_content is None:
+            raise RuntimeError("zip 中未找到 .glb 文件")
+        file_data = glb_content
+
+    # 保存 glb 文件
+    glb_path = os.path.join(models_dir, f"{file_id}.glb")
+    with open(glb_path, "wb") as f:
+        f.write(file_data)
+
+    logger.info(f"GLB 文件已保存: {glb_path} ({len(file_data)} bytes)")
+    return f"/uploads/models/{file_id}.glb"

backend/app/services/ai_video_generator.py

@@ -0,0 +1,392 @@
+"""
+AI 视频生成服务
+使用火山引擎 即梦3.0 Pro (Jimeng Video 3.0 Pro) 将设计图生成 360 度旋转展示视频
+
+API 文档: https://www.volcengine.com/docs/85621/1777001
+认证方式: Volcengine V4 签名 (Access Key + Secret Key)
+API 端点: https://visual.volcengineapi.com
+"""
+import asyncio
+import base64
+import hashlib
+import hmac
+import io
+import json
+import logging
+import math
+import os
+import uuid
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Optional, List
+from urllib.parse import quote
+
+import httpx
+from PIL import Image
+
+from .config_service import get_config_value
+
+# 视频本地存储目录
+VIDEO_UPLOAD_DIR = Path(__file__).resolve().parent.parent.parent / "uploads" / "videos"
+VIDEO_UPLOAD_DIR.mkdir(parents=True, exist_ok=True)
+
+logger = logging.getLogger(__name__)
+
+# 火山引擎视觉 API 配置
+VISUAL_API_HOST = "visual.volcengineapi.com"
+VISUAL_API_URL = f"https://{VISUAL_API_HOST}"
+REGION = "cn-north-1"
+SERVICE = "cv"
+API_VERSION = "2022-08-31"
+
+# 即梦3.0 Pro req_key
+REQ_KEY_I2V = "jimeng_ti2v_v30_pro"  # 支持传 image_urls 做图生视频
+
+# 超时与轮询配置
+SUBMIT_TIMEOUT = 30
+POLL_TIMEOUT = 15
+MAX_POLL_ATTEMPTS = 120  # 约 10 分钟
+POLL_INTERVAL = 5
+
+
+# ============================================================
+# Volcengine V4 签名实现
+# ============================================================
+
+def _sign(key: bytes, msg: str) -> bytes:
+    return hmac.new(key, msg.encode("utf-8"), hashlib.sha256).digest()
+
+
+def _get_signature_key(secret_key: str, date_stamp: str, region: str, service: str) -> bytes:
+    k_date = _sign(secret_key.encode("utf-8"), date_stamp)
+    k_region = _sign(k_date, region)
+    k_service = _sign(k_region, service)
+    k_signing = _sign(k_service, "request")
+    return k_signing
+
+
+def _build_signed_headers(
+    access_key: str,
+    secret_key: str,
+    action: str,
+    body: str,
+) -> dict:
+    """
+    构建带 V4 签名的请求头
+
+    参考: https://www.volcengine.com/docs/6369/67269
+    """
+    now = datetime.now(timezone.utc)
+    date_stamp = now.strftime("%Y%m%d")
+    amz_date = now.strftime("%Y%m%dT%H%M%SZ")
+
+    # 请求参数
+    canonical_querystring = f"Action={quote(action, safe='')}&Version={quote(API_VERSION, safe='')}"
+
+    # 规范请求头
+    content_type = "application/json"
+    canonical_headers = (
+        f"content-type:{content_type}\n"
+        f"host:{VISUAL_API_HOST}\n"
+        f"x-date:{amz_date}\n"
+    )
+    signed_headers = "content-type;host;x-date"
+
+    # Payload hash
+    payload_hash = hashlib.sha256(body.encode("utf-8")).hexdigest()
+
+    # 规范请求
+    canonical_request = (
+        f"POST\n"
+        f"/\n"
+        f"{canonical_querystring}\n"
+        f"{canonical_headers}\n"
+        f"{signed_headers}\n"
+        f"{payload_hash}"
+    )
+
+    # 待签字符串
+    credential_scope = f"{date_stamp}/{REGION}/{SERVICE}/request"
+    string_to_sign = (
+        f"HMAC-SHA256\n"
+        f"{amz_date}\n"
+        f"{credential_scope}\n"
+        f"{hashlib.sha256(canonical_request.encode('utf-8')).hexdigest()}"
+    )
+
+    # 签名
+    signing_key = _get_signature_key(secret_key, date_stamp, REGION, SERVICE)
+    signature = hmac.new(signing_key, string_to_sign.encode("utf-8"), hashlib.sha256).hexdigest()
+
+    # Authorization 头
+    authorization = (
+        f"HMAC-SHA256 "
+        f"Credential={access_key}/{credential_scope}, "
+        f"SignedHeaders={signed_headers}, "
+        f"Signature={signature}"
+    )
+
+    return {
+        "Content-Type": content_type,
+        "Host": VISUAL_API_HOST,
+        "X-Date": amz_date,
+        "Authorization": authorization,
+    }
+
+
+# ============================================================
+# 视频生成核心逻辑
+# ============================================================
+
+def _get_volc_keys() -> tuple:
+    """获取火山引擎 Access Key 和 Secret Key"""
+    access_key = get_config_value("VOLC_ACCESS_KEY", "")
+    secret_key = get_config_value("VOLC_SECRET_KEY", "")
+    if not access_key or not secret_key:
+        raise RuntimeError(
+            "未配置 VOLC_ACCESS_KEY 或 VOLC_SECRET_KEY，无法使用即梦视频生成。"
+            "请在管理后台 系统配置 中添加火山引擎 Access Key 和 Secret Key。"
+        )
+    return access_key, secret_key
+
+
+async def _merge_images_to_base64(image_urls: List[str]) -> str:
+    """
+    下载多张图片并拼接为一张网格图，返回 base64 编码
+
+    拼接策略:
+    - 1张: 直接使用
+    - 2张: 1×2 横向拼接
+    - 3~4张: 2×2 网格拼接
+    """
+    # 下载所有图片
+    images = []
+    async with httpx.AsyncClient(timeout=30, follow_redirects=True) as client:
+        for url in image_urls:
+            try:
+                resp = await client.get(url)
+                resp.raise_for_status()
+                img = Image.open(io.BytesIO(resp.content)).convert("RGB")
+                images.append(img)
+                logger.info(f"下载图片成功: {url[:60]}... 尺寸={img.size}")
+            except Exception as e:
+                logger.warning(f"下载图片失败: {url[:60]}... {e}")
+
+    if not images:
+        raise RuntimeError("没有成功下载任何图片")
+
+    # 只有1张时直接使用
+    if len(images) == 1:
+        merged = images[0]
+    else:
+        # 统一尺寸到最大尺寸
+        max_w = max(img.width for img in images)
+        max_h = max(img.height for img in images)
+
+        # 计算网格布局
+        n = len(images)
+        if n == 2:
+            cols, rows = 2, 1
+        else:
+            cols = 2
+            rows = math.ceil(n / cols)
+
+        # 创建拼接画布（白色背景）
+        canvas_w = cols * max_w
+        canvas_h = rows * max_h
+        merged = Image.new("RGB", (canvas_w, canvas_h), (255, 255, 255))
+
+        for idx, img in enumerate(images):
+            r = idx // cols
+            c = idx % cols
+            # 居中放置
+            x = c * max_w + (max_w - img.width) // 2
+            y = r * max_h + (max_h - img.height) // 2
+            merged.paste(img, (x, y))
+
+        logger.info(f"图片拼接完成: {n}张 -> {cols}x{rows}网格, 尺寸={merged.size}")
+
+    # 转 base64
+    buf = io.BytesIO()
+    merged.save(buf, format="JPEG", quality=90)
+    b64 = base64.b64encode(buf.getvalue()).decode("utf-8")
+    logger.info(f"拼接图 base64 长度: {len(b64)}")
+    return b64
+
+
+async def generate_video(
+    image_urls: List[str],
+    prompt: str = "",
+    duration_seconds: int = 5,
+) -> str:
+    """
+    调用即梦3.0 Pro 生成 360 度旋转展示视频
+
+    Args:
+        image_urls: 多视角图片 URL 列表（取第一张作为首帧）
+        prompt: 视频生成提示词
+        duration_seconds: 预留参数（即梦目前固定帧数）
+
+    Returns:
+        生成的视频远程 URL
+
+    Raises:
+        RuntimeError: 视频生成失败
+    """
+    access_key, secret_key = _get_volc_keys()
+
+    logger.info(f"传入视频生成的图片数量: {len(image_urls)}")
+
+    # 即梦API只支持单张图片输入，取第一张（正面效果图）作为基准
+    first_url = image_urls[0]
+    logger.info(f"使用第一张图片生成视频: {first_url[:80]}...")
+
+    # 从配置读取默认 prompt
+    if not prompt:
+        prompt = get_config_value("VIDEO_PROMPT", "")
+    if not prompt:
+        prompt = (
+            "玉雕作品在摄影棚内缓慢旋转360度展示全貌，"
+            "专业珠宝摄影灯光，纯白色背景，平稳旋转，"
+            "展示正面、侧面、背面各个角度，电影级画质"
+        )
+
+    # Step 1: 提交任务（只传第一张图片URL）
+    task_id = await _submit_video_task(access_key, secret_key, first_url, prompt)
+    logger.info(f"即梦视频生成任务已提交: task_id={task_id}")
+
+    # Step 2: 轮询等待结果
+    remote_video_url = await _poll_video_result(access_key, secret_key, task_id)
+    logger.info(f"即梦视频生成完成: {remote_video_url[:80]}...")
+
+    # Step 3: 下载视频到本地存储（即梦URL有效期约 1 小时，必须保存到本地）
+    local_path = await _download_video_to_local(remote_video_url)
+    logger.info(f"视频已保存到本地: {local_path}")
+
+    return local_path
+
+
+async def _submit_video_task(
+    access_key: str,
+    secret_key: str,
+    image_url: str,
+    prompt: str,
+) -> str:
+    """提交图生视频任务到即梦3.0 Pro，使用单张图片URL"""
+    action = "CVSync2AsyncSubmitTask"
+
+    logger.info(f"提交即梦视频任务，图片URL: {image_url[:80]}...")
+
+    payload = {
+        "req_key": REQ_KEY_I2V,
+        "prompt": prompt,
+        "image_urls": [image_url],
+        "seed": -1,
+        "frames": int(get_config_value("VIDEO_FRAMES", "121")),
+        "aspect_ratio": "1:1",  # 玉雕展示用正方形
+    }
+
+    body = json.dumps(payload, ensure_ascii=False)
+    headers = _build_signed_headers(access_key, secret_key, action, body)
+    url = f"{VISUAL_API_URL}?Action={action}&Version={API_VERSION}"
+
+    async with httpx.AsyncClient(timeout=SUBMIT_TIMEOUT) as client:
+        resp = await client.post(url, content=body, headers=headers)
+        if resp.status_code != 200:
+            logger.error(f"即梦视频任务提交失败: status={resp.status_code}, body={resp.text[:500]}")
+            resp.raise_for_status()
+        data = resp.json()
+
+    # 检查响应
+    code = data.get("code", 0)
+    if code != 10000:
+        msg = data.get("message", "未知错误")
+        raise RuntimeError(f"即梦视频任务提交失败 (code={code}): {msg}")
+
+    task_id = data.get("data", {}).get("task_id")
+    if not task_id:
+        raise RuntimeError(f"即梦响应中未找到 task_id: {data}")
+
+    return task_id
+
+
+async def _poll_video_result(
+    access_key: str,
+    secret_key: str,
+    task_id: str,
+) -> str:
+    """轮询视频生成结果"""
+    action = "CVSync2AsyncGetResult"
+
+    payload = {
+        "req_key": REQ_KEY_I2V,
+        "task_id": task_id,
+    }
+
+    body = json.dumps(payload, ensure_ascii=False)
+
+    for attempt in range(1, MAX_POLL_ATTEMPTS + 1):
+        await asyncio.sleep(POLL_INTERVAL)
+
+        # 每次轮询需要重新签名（时间戳不同）
+        headers = _build_signed_headers(access_key, secret_key, action, body)
+        url = f"{VISUAL_API_URL}?Action={action}&Version={API_VERSION}"
+
+        try:
+            async with httpx.AsyncClient(timeout=POLL_TIMEOUT) as client:
+                resp = await client.post(url, content=body, headers=headers)
+                if resp.status_code != 200:
+                    logger.warning(f"轮询即梦视频结果失败 (attempt={attempt}): status={resp.status_code}, body={resp.text[:300]}")
+                    continue
+                data = resp.json()
+        except Exception as e:
+            logger.warning(f"轮询即梦视频异常 (attempt={attempt}): {e}")
+            continue
+
+        code = data.get("code", 0)
+        task_data = data.get("data", {})
+        status = task_data.get("status", "")
+
+        if status == "done" and code == 10000:
+            video_url = task_data.get("video_url", "")
+            if video_url:
+                return video_url
+            raise RuntimeError(f"即梦视频生成完成但未找到 video_url: {data}")
+
+        elif status == "done" and code != 10000:
+            msg = data.get("message", "未知错误")
+            raise RuntimeError(f"即梦视频生成失败 (code={code}): {msg}")
+
+        elif status in ("not_found", "expired"):
+            raise RuntimeError(f"即梦视频任务状态异常: {status}")
+
+        else:
+            # in_queue / generating
+            if attempt % 6 == 0:
+                logger.info(f"即梦视频生成中... (attempt={attempt}, status={status})")
+
+    raise RuntimeError(f"即梦视频生成超时: 轮询 {MAX_POLL_ATTEMPTS} 次后仍未完成")
+
+
+async def _download_video_to_local(remote_url: str) -> str:
+    """
+    下载远程视频到本地 uploads/videos/ 目录
+
+    Returns:
+        本地视频的 URL 路径，如 /uploads/videos/xxx.mp4
+    """
+    filename = f"{uuid.uuid4().hex}.mp4"
+    local_file = VIDEO_UPLOAD_DIR / filename
+
+    try:
+        async with httpx.AsyncClient(timeout=120, follow_redirects=True) as client:
+            resp = await client.get(remote_url)
+            resp.raise_for_status()
+            local_file.write_bytes(resp.content)
+            logger.info(f"视频下载完成: {len(resp.content)} 字节 -> {local_file}")
+    except Exception as e:
+        logger.error(f"视频下载失败: {e}")
+        raise RuntimeError(f"视频下载失败: {e}")
+
+    # 返回相对 URL 路径（和图片一样通过 /uploads/ 静态服务访问）
+    return f"/uploads/videos/{filename}"