import { renameSync, existsSync } from "node:fs";
import { join, dirname } from "node:path";
import { safeResolvePath, safeResolveNewPath, isSystemFile } from "@/lib/workspace";

export const dynamic = "force-dynamic";
export const runtime = "nodejs";

/**
 * POST /api/workspace/rename
 * Body: { path: string, newName: string }
 *
 * Renames a file or folder within the same directory.
 * System files are protected from renaming.
 */
export async function POST(req: Request) {
  let body: { path?: string; newName?: string };
  try {
    body = await req.json();
  } catch {
    return Response.json({ error: "Invalid JSON body" }, { status: 400 });
  }

  const { path: relPath, newName } = body;
  if (!relPath || typeof relPath !== "string" || !newName || typeof newName !== "string") {
    return Response.json(
      { error: "Missing 'path' and 'newName' fields" },
      { status: 400 },
    );
  }

  if (isSystemFile(relPath)) {
    return Response.json(
      { error: "Cannot rename system file" },
      { status: 403 },
    );
  }

  // Validate newName: no slashes, no empty, no traversal
  if (newName.includes("/") || newName.includes("\\") || newName.trim() === "") {
    return Response.json(
      { error: "Invalid file name" },
      { status: 400 },
    );
  }

  const absPath = safeResolvePath(relPath);
  if (!absPath) {
    return Response.json(
      { error: "Source not found or path traversal rejected" },
      { status: 404 },
    );
  }

  const parentDir = dirname(absPath);
  const newAbsPath = join(parentDir, newName);

  // Ensure the new path stays within workspace
  const parentRel = dirname(relPath);
  const newRelPath = parentRel === "." ? newName : `${parentRel}/${newName}`;
  const validated = safeResolveNewPath(newRelPath);
  if (!validated) {
    return Response.json(
      { error: "Invalid destination path" },
      { status: 400 },
    );
  }

  if (existsSync(newAbsPath)) {
    return Response.json(
      { error: `A file named '${newName}' already exists` },
      { status: 409 },
    );
  }

  try {
    renameSync(absPath, newAbsPath);
    return Response.json({ ok: true, oldPath: relPath, newPath: newRelPath });
  } catch (err) {
    return Response.json(
      { error: err instanceof Error ? err.message : "Rename failed" },
      { status: 500 },
    );
  }
}