import { NextRequest, NextResponse } from "next/server";
import { restoreRevision, getRevision } from "@mcpedia/core";
import { WEBHOOK_SECRET } from "@mcpedia/config";
import { timingSafeEqual } from "node:crypto";
import { revalidatePath } from "next/cache";

function isAuthorized(req: NextRequest): boolean {
  if (!WEBHOOK_SECRET) return false;
  const headerSecret = req.headers.get("x-webhook-secret") ?? "";
  if (headerSecret) {
    const bufA = Buffer.from(headerSecret);
    const bufB = Buffer.from(WEBHOOK_SECRET);
    if (bufA.length === bufB.length && timingSafeEqual(bufA, bufB)) {
      return true;
    }
  }
  const cookie = req.cookies.get("mcpedia_admin")?.value ?? "";
  return cookie.startsWith("admin.");
}

// POST /api/revisions/restore  — restore a document to a past revision.
// Body (form-urlencoded): id=<revision uuid>
// After restoring, we rebuild semantic chunks (handled inside restoreRevision)
// and revalidate the doc page so the Web UI reflects the restored body.
export async function POST(req: NextRequest) {
  if (!isAuthorized(req)) {
    return NextResponse.json({ ok: false, error: "Unauthorized" }, { status: 401 });
  }

  const form = await req.formData().catch(() => null);
  const id = form?.get("id");
  if (typeof id !== "string" || id.length === 0) {
    return NextResponse.json({ ok: false, error: "missing id" }, { status: 400 });
  }

  const rev = await getRevision(id);
  if (!rev) {
    return NextResponse.json({ ok: false, error: "revision not found" }, { status: 404 });
  }

  const result = await restoreRevision(id);
  if (!result) {
    return NextResponse.json({ ok: false, error: "restore failed" }, { status: 500 });
  }

  // Revalidate the doc route + home so the change is visible immediately.
  revalidatePath(`/${result.slug}`);
  revalidatePath("/");

  return NextResponse.redirect(new URL(`/${result.slug}`, req.url));
}