import { s3 } from "@/lib/s3";
import type { S3Body } from "@/types/s3";
import { GetObjectCommand } from "@aws-sdk/client-s3";
import type { NextRequest } from "next/server";
import { Readable } from "node:stream";

function isWebReadableStream(value: unknown): value is ReadableStream<Uint8Array> {
  return !!value && typeof (value as ReadableStream<Uint8Array>).getReader === "function";
}

function toBodyInit(body: S3Body): BodyInit {
  if (body instanceof Readable) {
    return Readable.toWeb(body) as ReadableStream<Uint8Array>;
  }
  if (isWebReadableStream(body)) {
    return body;
  }
  return body as BodyInit;
}

// Streams images from S3 for the admin app.
export async function GET(_req: NextRequest, context: { params: Promise<{ key: string[] }> }) {
  const { key } = await context.params;
  const s3Key = key.join("/");

  try {
    const command = new GetObjectCommand({
      Bucket: `${process.env.BUCKET_NAME}`,
      Key: s3Key,
    });

    const response = await s3.send(command);

    if (!response.Body) {
      return new Response("No body", { status: 500 });
    }

    const contentType = response.ContentType ?? "application/octet-stream";

    return new Response(toBodyInit(response.Body as S3Body), {
      headers: {
        "Content-Type": contentType,
        "Cache-Control": "public, max-age=3600",
        "Content-Disposition": "inline", // use 'attachment' to force download
      },
    });
  } catch (err) {
    console.error(err);
    return new Response("Image not found", { status: 404 });
  }
}