import { S3Client } from "bun";
import config from "@/../config.toml";

// Bun.S3Client 단일화
const client = new S3Client({
  accessKeyId: config.s3.access_key,
  secretAccessKey: config.s3.secret_key,
  bucket: config.s3.bucket,
  endpoint: config.s3.endpoint,
});

async function warmupS3() {
  try {
    await client.exists(`__warmup_${Date.now()}__`);
  } catch (e) {
  }
}

function makeS3FileName(authorId: string, tweetId: string, mediaUrl: string, index: number) {
  const rawName = mediaUrl.split("/").pop() || `media_${Date.now()}_${index}`;
  const withoutQuery = rawName.split("?")[0]?.split("#")[0] || `media_${Date.now()}_${index}`;
  const safeName = withoutQuery.replace(/[^a-zA-Z0-9._-]/g, "_");
  return `twitter/${authorId}/${tweetId}/${safeName}`;
}

async function uploadToS3(fileName: string, mediaUrl: string, maxRetry = 3) {
  let lastError: unknown;

  // 1. 요청 시작 전 예열 수행
  await warmupS3();

  for (let attempt = 1; attempt <= maxRetry; attempt++) {
    try {
      const parsedUrl = new URL(mediaUrl);
      const isPixivImage = parsedUrl.hostname === "i.pximg.net";
      const response = await fetch(mediaUrl, {
        headers: isPixivImage
          ? {
            "Referer": "https://www.pixiv.net/",
            "User-Agent": "Mozilla/5.0 (compatible; akiyama.mizuki.guru/1.0)",
          }
          : undefined,
      });
      if (!response.ok) {
        throw new Error(`Fetch failed: ${response.status}`);
      }

      const buffer = await response.arrayBuffer();

      // 2. Bun S3 Client만 사용하여 쓰기
      // client.write는 내부적으로 효율적인 스트리밍/버퍼 처리를 수행합니다.
      await client.write(fileName, buffer, {
        type: response.headers.get("content-type") || "application/octet-stream",
      });

      return; // 성공 시 리턴
    } catch (error) {
      lastError = error;
      console.error(`[S3 upload attempt ${attempt}/${maxRetry}] key=${fileName}`, error);

      // UnknownError 발생 시 잠시 대기 후 재시도 (지수 백오프)
      if (attempt < maxRetry) {
        await Bun.sleep(attempt * 1000);
        // 재시도 전 다시 한번 예열 시도 가능
        await warmupS3();
      }
    }
  }

  // 최종 실패 전 마지막 확인 (이미 올라갔을 수도 있음)
  if (await client.exists(fileName)) {
    console.warn(`[S3 upload recovered] key=${fileName} was found after error.`);
    return;
  }

  throw lastError;
}

async function writeToS3(fileName: string, data: ArrayBuffer | Blob, contentType: string) {
  await warmupS3();
  await client.write(fileName, data, {
    type: contentType,
  });
}

export { makeS3FileName, uploadToS3, writeToS3, client as s3Client };