// server/utils/lsky.ts - Lsky 图床上传工具：下载上游图片、重命名、打标签并上传归档。
import { createError } from "h3";

interface ILskyUploadInput {
  imageUrl: string;
  userId: number;
  username?: string | null;
  recordId: bigint;
  createdAt: Date;
}

interface ILskyUploadResponse {
  status?: string | boolean;
  message?: string;
  data?: {
    public_url?: string;
    filename?: string;
    mimetype?: string;
    extension?: string;
    [key: string]: unknown;
  } | null;
  time?: number;
  [key: string]: unknown;
}

export interface ILskyUploadedImage {
  publicUrl: string;
  filename: string;
  mimetype: string;
  response: ILskyUploadResponse;
}

/**
 * 从远程图片 URL 下载图片并上传到 Lsky。
 *
 * 注意：
 * - Lsky 地址、Token、storage_id 都来自环境变量，代码不写死密钥。
 * - 文件名包含 userId、username、时间戳、recordId，方便图床侧追踪来源。
 * - 返回完整 Lsky 响应供数据库保存，但调用方不要把 token 写入日志。
 */
export const uploadImageFromUrl = async (
  input: ILskyUploadInput
): Promise<ILskyUploadedImage> => {
  const config = getLskyConfig();
  const downloadedImage = await downloadImage(input.imageUrl);
  const extension = getImageExtension(downloadedImage.mimeType, input.imageUrl);
  const filename = buildArchiveFilename({
    userId: input.userId,
    username: input.username,
    recordId: input.recordId,
    createdAt: input.createdAt,
    extension
  });

  const formData = new FormData();
  formData.append(
    "file",
    new Blob([downloadedImage.bytes], {
      type: downloadedImage.mimeType
    }),
    filename
  );
  formData.append("storage_id", String(config.storageId));
  formData.append("is_remove_exif", "true");
  formData.append("intro", `AIArtStudio image generation ${input.recordId}`);

  for (const tag of buildArchiveTags(input.userId, input.recordId)) {
    formData.append("tags[]", tag);
  }

  const response = await $fetch<ILskyUploadResponse>("/upload", {
    baseURL: config.baseUrl,
    method: "POST",
    body: formData,
    headers: {
      Accept: "application/json",
      Authorization: `Bearer ${config.token}`
    }
  });

  const publicUrl = response.data?.public_url;
  if (!isSuccessStatus(response.status) || !publicUrl) {
    throw createError({
      statusCode: 502,
      statusMessage: response.message || "图床上传失败"
    });
  }

  return {
    publicUrl,
    filename: response.data?.filename || filename,
    mimetype: response.data?.mimetype || downloadedImage.mimeType,
    response
  };
};

/** 读取并校验 Lsky 环境变量配置 */
const getLskyConfig = () => {
  const baseUrl = process.env.LSKY_BASE_URL?.replace(/\/+$/, "");
  const token = process.env.LSKY_TOKEN;
  const storageId = Number.parseInt(process.env.LSKY_STORAGE_ID ?? "", 10);

  if (!baseUrl) {
    throw new Error("LSKY_BASE_URL 未配置");
  }

  if (!token) {
    throw new Error("LSKY_TOKEN 未配置");
  }

  if (!Number.isInteger(storageId) || storageId <= 0) {
    throw new Error("LSKY_STORAGE_ID 未配置或不是有效数字");
  }

  return {
    baseUrl,
    token,
    storageId
  };
};

/** 下载上游图片二进制，保留 content-type 供上传和入库使用 */
const downloadImage = async (imageUrl: string) => {
  const response = await fetch(imageUrl);
  if (!response.ok) {
    throw new Error(`图片下载失败：${response.status}`);
  }

  // TODO: 当前会把整张图片一次性读入当前 Node 进程内存，再转 Blob 上传到图床；
  // 如果图片尺寸或并发继续增大，建议改成流式转发或落临时文件，降低内存峰值和主线程抖动。
  return {
    bytes: await response.arrayBuffer(),
    mimeType: response.headers.get("content-type") || "image/png"
  };
};

/** 构造图床文件名：userId_username_timestamp_recordId.ext */
const buildArchiveFilename = ({
  userId,
  username,
  recordId,
  createdAt,
  extension
}: {
  userId: number;
  username?: string | null;
  recordId: bigint;
  createdAt: Date;
  extension: string;
}) => {
  const safeUsername = sanitizeFilenamePart(username || "user");
  const timestamp = formatTimestamp(createdAt);
  return `${userId}_${safeUsername}_${timestamp}_${recordId.toString()}.${extension}`;
};

/** 给图片打固定标签，便于后续在图床里按项目、用户、记录和模型筛选 */
const buildArchiveTags = (userId: number, recordId: bigint) => {
  return [
    "AIArtStudio",
    `user:${userId}`,
    `record:${recordId.toString()}`,
    "model:gpt-image-2"
  ];
};

/** 清理文件名片段，避免中文/英文/数字/下划线/短横线以外的字符影响上传 */
const sanitizeFilenamePart = (value: string) => {
  const sanitized = value
    .trim()
    .replace(/[^\p{L}\p{N}_-]+/gu, "_")
    .replace(/_+/g, "_")
    .replace(/^_+|_+$/g, "");

  return sanitized || "user";
};

/** 文件名使用紧凑 UTC 时间戳，避免冒号等字符影响跨平台兼容性 */
const formatTimestamp = (date: Date) => {
  return date.toISOString().replace(/\D/g, "").slice(0, 14);
};

/** 优先按 MIME 推断扩展名，MIME 不认识时再从 URL 路径兜底 */
const getImageExtension = (mimeType: string, imageUrl: string) => {
  const fromMimeType = mimeType.split(";")[0]?.trim().toLowerCase();
  if (fromMimeType === "image/jpeg") return "jpg";
  if (fromMimeType === "image/png") return "png";
  if (fromMimeType === "image/webp") return "webp";
  if (fromMimeType === "image/gif") return "gif";

  const pathname = new URL(imageUrl).pathname;
  const extension = pathname.split(".").pop()?.toLowerCase();
  return extension && /^[a-z0-9]+$/.test(extension) ? extension : "png";
};

/** 兼容 Lsky 可能返回的布尔或字符串成功状态 */
const isSuccessStatus = (status: unknown) => {
  return status === true || status === "success" || status === "ok";
};