import { describe, expect, it } from "vitest";
import { emptyForAccount } from "../files";

/**
 * Switching to an account somebody shared with you showed an empty folder tree.
 *
 * The switch cleared `nodes` and `children` and stopped there, so `treeLoaded`
 * stayed true from the previous account — the sidebar never asked the new one
 * for its folders — while `dirIds` still named the old account's folders, which
 * no longer resolved against the cleared `nodes`. The result was a tree with
 * nothing in it and no error to explain it, in the one place a tree matters
 * most: someone else's files, where you have no idea what the shape should be.
 *
 * The test that matters is the last one. The bug was not bad logic, it was a
 * field nobody remembered, and the only durable guard is asserting the whole
 * set rather than the fields we happen to think of today.
 */

describe("what a switch to another account keeps", () => {
  it("keeps nothing but the new account's own id", () => {
    expect(emptyForAccount("b")).toEqual({
      accountId: "b",
      nodes: {},
      children: {},
      dirIds: [],
      treeLoaded: false,
      draggingId: null,
      error: null,
    });
  });

  it("asks the new account for its tree", () => {
    // The sidebar loads when `treeLoaded` is false. True here means an empty
    // tree for as long as the account stays selected.
    expect(emptyForAccount("b").treeLoaded).toBe(false);
  });

  it("carries no folder ids over from the account before it", () => {
    expect(emptyForAccount("b").dirIds).toEqual([]);
  });

  it("drops a drag that was in flight", () => {
    // Its id belongs to the other account and would name a different node here.
    expect(emptyForAccount("b").draggingId).toBeNull();
  });

  it("names every piece of per-account state", () => {
    // Add a per-account field to the store and forget it here, and this fails
    // rather than the field quietly following someone into another account.
    expect(Object.keys(emptyForAccount(null)).sort()).toEqual(
      ["accountId", "children", "dirIds", "draggingId", "error", "nodes", "treeLoaded"],
    );
  });
});