import { readFile } from "fs/promises";
import { NextResponse } from "next/server";
import path from "path";

import { resolveMediaUploadPath } from "@/lib/media-storage";

type MediaFileRouteProps = {
  params: Promise<{
    segments: string[];
  }>;
};

export const dynamic = "force-dynamic";

const CONTENT_TYPES: Record<string, string> = {
  ".ico": "image/x-icon",
  ".gif": "image/gif",
  ".jpg": "image/jpeg",
  ".jpeg": "image/jpeg",
  ".png": "image/png",
  ".webp": "image/webp",
  ".svg": "image/svg+xml",
  ".pdf": "application/pdf",
};

export async function GET(_: Request, { params }: MediaFileRouteProps) {
  const { segments } = await params;
  const relativePath = segments.join("/");
  const publicPath = `/uploads/media/${relativePath}`;

  try {
    const absolutePath = resolveMediaUploadPath(publicPath);
    const fileBuffer = await readFile(absolutePath);
    const extension = path.extname(absolutePath).toLowerCase();
    const contentType = CONTENT_TYPES[extension];

    if (!contentType) {
      return new NextResponse("Not Found", { status: 404 });
    }

    const headers: Record<string, string> = {
      "Content-Type": contentType,
      "Cache-Control": "public, max-age=31536000, immutable",
      "X-Content-Type-Options": "nosniff",
    };

    // SVG is an active document type: sandbox it so an uploaded file can never
    // run script or reach our origin even if it is opened directly.
    if (extension === ".svg") {
      headers["Content-Security-Policy"] = "default-src 'none'; style-src 'unsafe-inline'; sandbox";
    }

    if (extension === ".pdf") {
      headers["Content-Disposition"] = "inline";
    }

    return new NextResponse(new Uint8Array(fileBuffer), { status: 200, headers });
  } catch {
    return new NextResponse("Not Found", {
      status: 404,
    });
  }
}