import { describe, expect, it } from "vitest";

import { reorderFileDropPresentationItems } from "./file-drop-presentation";
import type {
  FileDropPresentationEntry,
  FileDropPresentationItem,
} from "./file-drop-types";

describe("reorderFileDropPresentationItems", () => {
  it("reorders visible entries without dropping or moving hidden source items", () => {
    const hiddenItem = {
      assetKind: "image",
      fileName: "missing.png",
      id: "image-hidden",
    } satisfies FileDropPresentationItem<"image">;
    const firstVisibleItem = {
      assetKind: "image",
      fileName: "first.png",
      id: "image-first",
      previewSrc: "data:image/png;base64,Zmlyc3Q=",
    } satisfies FileDropPresentationItem<"image">;
    const secondVisibleItem = {
      assetKind: "image",
      fileName: "second.png",
      id: "image-second",
      previewSrc: "data:image/png;base64,c2Vjb25k",
    } satisfies FileDropPresentationItem<"image">;
    const items = [hiddenItem, firstVisibleItem, secondVisibleItem];
    const visibleEntries = [
      { item: firstVisibleItem, key: firstVisibleItem.id, sourceIndex: 1 },
      { item: secondVisibleItem, key: secondVisibleItem.id, sourceIndex: 2 },
    ] satisfies readonly FileDropPresentationEntry<"image">[];

    expect(
      reorderFileDropPresentationItems(
        items,
        visibleEntries,
        firstVisibleItem.id,
        secondVisibleItem.id,
      ),
    ).toEqual([hiddenItem, secondVisibleItem, firstVisibleItem]);
    expect(items).toEqual([hiddenItem, firstVisibleItem, secondVisibleItem]);
  });

  it("returns null for missing or unchanged drag targets", () => {
    const item = {
      assetKind: "file",
      fileName: "one.txt",
      id: "file-1",
    } satisfies FileDropPresentationItem<"file">;
    const entries = [
      { item, key: item.id, sourceIndex: 0 },
    ] satisfies readonly FileDropPresentationEntry<"file">[];

    expect(reorderFileDropPresentationItems([item], entries, item.id, item.id)).toBeNull();
    expect(reorderFileDropPresentationItems([item], entries, "missing", item.id)).toBeNull();
  });
});