"""
AIoT 文件存储路由 - COS 对象存储接口

API 路径规范：
    - POST /admin-api/aiot/storage/upload        - 后端中转上传
    - GET  /admin-api/aiot/storage/presign        - 获取预签名下载 URL
    - GET  /admin-api/aiot/storage/sts            - 获取 STS 临时凭证（前端直传）
    - GET  /admin-api/aiot/storage/upload-url     - 获取预签名上传 URL（前端直传）
"""
import os
from fastapi import APIRouter, Query, Depends, HTTPException, UploadFile, File

from app.yudao_compat import YudaoResponse, get_current_user
from app.services.oss_storage import get_oss_storage, COSStorage, _generate_object_key

router = APIRouter(prefix="/admin-api/aiot/storage", tags=["AIoT-文件存储"])


@router.post("/upload")
async def upload_file(
    file: UploadFile = File(..., description="上传文件"),
    prefix: str = Query("alerts", description="存储路径前缀"),
    current_user: dict = Depends(get_current_user),
):
    """
    后端中转上传

    文件经过后端写入 COS / 本地，返回 object_key。
    适用于服务端需要对文件做校验或处理的场景。
    """
    storage = get_oss_storage()

    # 文件大小检查（限制 20MB）
    content = await file.read()
    if len(content) > 20 * 1024 * 1024:
        raise HTTPException(status_code=400, detail="文件大小超过 20MB 限制")

    # 文件类型检查
    allowed_types = {".jpg", ".jpeg", ".png", ".gif", ".bmp", ".webp", ".mp4", ".mov", ".pdf"}
    _, ext = os.path.splitext(file.filename or "unknown.jpg")
    ext = ext.lower()
    if ext not in allowed_types:
        raise HTTPException(status_code=400, detail=f"不支持的文件类型: {ext}")

    # 确定 content_type
    content_type = file.content_type or "application/octet-stream"

    # 生成 object_key
    object_key = _generate_object_key(prefix=prefix, ext=ext)

    # 上传
    result_key = storage.upload_file(content, object_key, content_type)

    return YudaoResponse.success({
        "objectKey": result_key,
        "filename": file.filename,
        "size": len(content),
        "contentType": content_type,
    })


@router.get("/presign")
async def get_presigned_download_url(
    objectKey: str = Query(..., description="对象 Key"),
    expire: int = Query(1800, description="有效期（秒）"),
    current_user: dict = Depends(get_current_user),
):
    """
    获取预签名下载 URL

    前端查看告警截图时调用此接口，拿到临时 URL 后直接访问 COS。
    URL 过期后失效，防止泄露。
    """
    storage = get_oss_storage()
    url = storage.get_presigned_url(objectKey, expire)

    return YudaoResponse.success({
        "url": url,
        "expire": expire,
    })


@router.get("/upload-url")
async def get_presigned_upload_url(
    prefix: str = Query("alerts", description="存储路径前缀"),
    ext: str = Query(".jpg", description="文件扩展名"),
    expire: int = Query(1800, description="有效期（秒）"),
    current_user: dict = Depends(get_current_user),
):
    """
    获取预签名上传 URL

    前端拿到此 URL 后，直接 PUT 文件到 COS，无需经过后端中转。
    适用于大文件或高频上传场景。
    """
    storage = get_oss_storage()

    if not storage.is_cos_mode:
        raise HTTPException(status_code=400, detail="COS 未启用，请使用 /upload 接口")

    object_key = _generate_object_key(prefix=prefix, ext=ext)
    url = storage.get_presigned_upload_url(object_key, expire)

    if not url:
        raise HTTPException(status_code=500, detail="生成上传 URL 失败")

    return YudaoResponse.success({
        "uploadUrl": url,
        "objectKey": object_key,
        "expire": expire,
    })


@router.get("/sts")
async def get_sts_credential(
    prefix: str = Query("alerts", description="允许上传的路径前缀"),
    current_user: dict = Depends(get_current_user),
):
    """
    获取 STS 临时凭证

    前端使用 COS JS SDK 直传时，先调用此接口获取临时密钥。
    返回的 tmpSecretId / tmpSecretKey / sessionToken 用于初始化 SDK。
    凭证仅允许向指定前缀上传，不可读取或删除其他路径。
    """
    storage = get_oss_storage()

    if not storage.is_cos_mode:
        raise HTTPException(status_code=400, detail="COS 未启用，无法签发 STS 凭证")

    allow_prefix = f"{prefix}/*"
    credential = storage.get_sts_credential(allow_prefix)

    if not credential:
        raise HTTPException(status_code=500, detail="STS 凭证签发失败，请检查 COS 配置或安装 qcloud-python-sts")

    return YudaoResponse.success(credential)