import path from "node:path";
import fs from "node:fs";
import { uploadDicomFile } from "../../core/pacs";

/**
 * 检查文件是否为 DICOM 文件（通过 Magic Number 判断）
 * @param filePath 文件路径
 * @returns 是否为 DICOM 文件
 */
const isDICOMFile = async (filePath: string) => {
  try {
    // 打开文件以进行读取
    const fileHandle = await fs.promises.open(filePath, "r");
    const buffer = Buffer.alloc(132); // 创建一个 132 字节的缓冲区

    // 从文件中读取前 132 个字节
    await fileHandle.read(buffer, 0, 132, 0);
    await fileHandle.close(); // 关闭文件

    // 检查 "DICM" 标识 (偏移 128-131 字节)
    const magicNumber = buffer.toString("utf-8", 128, 132);
    return magicNumber === "DICM";
  } catch (error) {
    console.error(`Error reading file ${filePath}:`, error);
    return false;
  }
};

/**
 * 定义一个异步函数来递归地查找.dcm文件
 * @param dir
 * @param fileList
 * @returns
 */
export const filterDicoms = async (
  dir: string,
  fileList: string[] = []
): Promise<string[]> => {
  const files = await fs.promises.readdir(dir, { withFileTypes: true });
  await Promise.all(
    files.map(async (file) => {
      const filePath = path.join(dir, file.name);
      if (file.isDirectory()) {
        await filterDicoms(filePath, fileList); // 递归调用以遍历子目录
      } else if (await isDICOMFile(filePath)) {
        fileList.push(filePath);
      }
    })
  );
  return fileList;
};

interface UploadFilesInBatchesParams {
  filePaths: string[];
  batchSize: number;
  orthancUrl?: string;
  feedback?: (detail: {
    progress: number;
    totalSuccess: number;
    totalFailed: number;
  }) => void;
}

/**
 * 批量上传文件，并提供进度更新。
 * @param filePaths 文件路径数组。
 * @param batchSize 每批上传的文件数量。
 * @param orthancUrl Orthanc 服务器的 URL。
 * @param feedback 每批处理完成后调用的回调函数。
 */
export const uploadFilesInBatches = async ({
  filePaths,
  batchSize,
  feedback,
}: UploadFilesInBatchesParams) => {
  const totalStartTime = Date.now();
  let totalSuccess = 0;
  let totalFailed = 0;
  const totalFiles = filePaths.length;

  for (let i = 0; i < totalFiles; i += batchSize) {
    const batch = filePaths.slice(i, i + batchSize);
    const batchResults = await Promise.allSettled(
      batch.map((filePath) => uploadDicomFile(filePath))
    );

    batchResults.forEach((result) => {
      if (result.status === "fulfilled" && result.value) {
        totalSuccess++;
      } else {
        totalFailed++;
      }
    });

    const actualProcessed = i + batch.length;
    const progress = Math.round((actualProcessed / totalFiles) * 100);
    const detail = {
      progress: Math.min(progress, 100),
      totalSuccess,
      totalFailed,
    };
    if (feedback) feedback(detail);
  }

  const totalEndTime = Date.now();
  console.log(
    `[上传序列] Success: ${totalSuccess}, Failed: ${totalFailed}, Total upload time: ${
      totalEndTime - totalStartTime
    } ms`
  );
};