import { expect } from "@std/expect";
import { describe, it } from "@std/testing/bdd";
import { FabricBytes } from "@commonfabric/data-model/fabric-primitives";

import { getAtPath, selectAtPath } from "../reconstruct.ts";

describe("getAtPath()", () => {
  it("returns the root for an empty path", () => {
    const root = { value: "root" };
    expect(getAtPath(root, [])).toBe(root);
  });

  it("returns values at canonical array indexes", () => {
    expect(getAtPath(["zero", "one"], ["1"])).toBe("one");
  });

  it("returns `undefined` for noncanonical array segments", () => {
    const array = ["zero", "one"];
    for (const segment of ["", "01", "1e0", "-", "length"]) {
      expect(getAtPath(array, [segment])).toBeUndefined();
    }
  });

  it("reads only own array indexes and object properties", () => {
    const sparse = new Array<string>(1);
    const arrayPrototype = Object.create(Array.prototype) as string[];
    arrayPrototype[0] = "inherited";
    Object.setPrototypeOf(sparse, arrayPrototype);
    expect(getAtPath(sparse, ["0"])).toBeUndefined();

    expect(getAtPath({}, ["toString"])).toBeUndefined();
    expect(getAtPath({ toString: "own" }, ["toString"])).toBe("own");
    expect(getAtPath({ "": "empty" }, [""])).toBe("empty");
  });

  it("reads own properties exposed by primitive values", () => {
    expect(selectAtPath("tea", ["length"])).toEqual({
      found: true,
      value: 3,
    });
    expect(selectAtPath("tea", ["1"])).toEqual({
      found: true,
      value: "e",
    });
    expect(selectAtPath({ title: "tea" }, ["title", "length"])).toEqual({
      found: true,
      value: 3,
    });
    expect(selectAtPath("tea", ["toString"])).toEqual({
      found: false,
      value: undefined,
    });
  });

  it("reports nothing found within `null`, a number, or a `FabricSpecialObject`", () => {
    const notFound = { found: false, value: undefined };
    expect(selectAtPath({ n: null }, ["n", "x"])).toEqual(notFound);
    expect(selectAtPath(5, ["x"])).toEqual(notFound);

    // `FabricBytes` has a `length`, and it is not an own property.
    const bytes = new FabricBytes(new Uint8Array([1, 2, 3]));
    expect(selectAtPath({ bytes }, ["bytes", "length"])).toEqual(notFound);
  });

  it("distinguishes stored undefined from a missing property", () => {
    expect(selectAtPath({ value: undefined }, ["value"])).toEqual({
      found: true,
      value: undefined,
    });
    expect(selectAtPath({}, ["value"])).toEqual({
      found: false,
      value: undefined,
    });
  });
});