import { describe, expect, test } from "bun:test";
import { deepestValidTarget, reorderGroups, visualIndex } from "../src/index.ts";

describe("dnd pure behavior", () => {
  test("moves across groups without mutation", () => {
    const input = new Map([
      ["a", ["1", "2"]],
      ["b", ["3"]],
    ]);
    const result = reorderGroups(input, {
      ids: ["2"],
      from: [{ group: "a", index: 1 }],
      to: { group: "b", index: 0 },
    });
    expect(result.get("a")).toEqual(["1"]);
    expect(result.get("b")).toEqual(["2", "3"]);
    expect(input.get("a")).toEqual(["1", "2"]);
  });
  test("mirrors horizontal RTL index", () =>
    expect(visualIndex(0, 4, "horizontal", "rtl")).toBe(3));
  test("selects deepest valid target", () =>
    expect(
      deepestValidTarget(
        [
          { depth: 1, location: { group: "a", index: 0 } },
          { depth: 3, location: { group: "b", index: 0 } },
        ],
        (location) => location.group === "b",
      )?.depth,
    ).toBe(3));
});