import { NextRequest, NextResponse } from "next/server";
import { auth } from "@/auth";
import { randomUUID } from "crypto";
import { generateHetznerPresignedUploadUrl, sanitizeFileName } from "@/lib/storage";

export const maxDuration = 10;

const ALLOWED_FOLDERS = new Set(["videos", "image"]);

/**
 * POST /api/upload/presign
 * Body: { fileName: string, contentType: string, folder?: "videos" | "image" }
 *
 * Returns a presigned PUT URL so the browser can upload large files (video
 * versions, footage plates) directly to Hetzner Object Storage, bypassing
 * this app's server entirely — and with it any reverse-proxy / CDN body
 * size limits (nginx `client_max_body_size`, Cloudflare's 100MB edge cap,
 * etc). The returned `key`/`url` is passed straight to the relevant server
 * action (createVersion, addFootagePlate, ...) once the direct upload
 * finishes — no bytes ever touch the Next.js server.
 */
export async function POST(req: NextRequest) {
  const session = await auth();
  if (!session?.user) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  let body: unknown;
  try {
    body = await req.json();
  } catch {
    return NextResponse.json({ error: "Invalid JSON" }, { status: 400 });
  }

  const { fileName, contentType, folder } = body as {
    fileName?: unknown;
    contentType?: unknown;
    folder?: unknown;
  };

  if (!fileName || typeof fileName !== "string") {
    return NextResponse.json({ error: "fileName is required" }, { status: 400 });
  }
  if (!contentType || typeof contentType !== "string") {
    return NextResponse.json({ error: "contentType is required" }, { status: 400 });
  }

  const targetFolder = typeof folder === "string" && ALLOWED_FOLDERS.has(folder) ? folder : "videos";

  if (targetFolder === "videos" && !contentType.match(/^video\//)) {
    return NextResponse.json({ error: "Only video files are accepted" }, { status: 400 });
  }
  if (targetFolder === "image" && !contentType.match(/^image\//)) {
    return NextResponse.json({ error: "Only image files are accepted" }, { status: 400 });
  }

  const key = `${targetFolder}/${randomUUID()}-${sanitizeFileName(fileName)}`;

  try {
    const presignedUrl = await generateHetznerPresignedUploadUrl(key, contentType);
    return NextResponse.json({ presignedUrl, key, url: `/api/files/${key}` });
  } catch (err) {
    console.error("[upload/presign]", err);
    return NextResponse.json(
      { error: "Failed to generate upload URL. Check Hetzner storage configuration." },
      { status: 500 }
    );
  }
}