import { test } from "node:test";
import assert from "node:assert/strict";
import { pruneSelection, selectGroups } from "./selection";
import { buildSearchHandoff, type HandoffGroup } from "./aiHandoff";

test("pruneSelection drops slugs no longer present", () => {
  const next = pruneSelection(new Set(["a", "b", "c"]), new Set(["b", "c", "d"]));
  assert.deepEqual([...next].sort(), ["b", "c"]);
});

test("pruneSelection keeps everything when all still present", () => {
  const next = pruneSelection(new Set(["a", "b"]), new Set(["a", "b", "x"]));
  assert.deepEqual([...next].sort(), ["a", "b"]);
});

test("pruneSelection empties when nothing matches", () => {
  assert.equal(pruneSelection(new Set(["a"]), new Set(["z"])).size, 0);
});

test("selectGroups filters to the selection, preserving result order", () => {
  const groups = [{ slug: "a" }, { slug: "b" }, { slug: "c" }];
  assert.deepEqual(
    selectGroups(groups, new Set(["c", "a"])).map((g) => g.slug),
    ["a", "c"],
  );
  assert.deepEqual(selectGroups(groups, new Set<string>()), []);
});

test("getGrounding('selection') = selectGroups routed through buildSearchHandoff", () => {
  const groups: HandoffGroup[] = [
    { slug: "a", title: "A", channel: "Ch", uploadDate: "20240101", hits: [{ start: 5, text: "alpha line" }] as never },
    { slug: "b", title: "B", channel: "Ch", uploadDate: "20240102", hits: [{ start: 9, text: "beta line" }] as never },
    { slug: "c", title: "C", channel: "Ch", uploadDate: "20240103", hits: [{ start: 1, text: "gamma line" }] as never },
  ];
  const selected = new Set(["a", "c"]);
  const chosen = selectGroups(groups, selected);
  // Mirrors the session's selectionGrounding: the selected groups, full excerpts.
  const handoff = buildSearchHandoff(chosen, () => undefined, ["q"], {
    maxVideos: chosen.length,
    fullExcerptVideos: chosen.length,
    maxHitsPerVideo: 4,
  });
  // Only the selected videos, in order, each carrying its excerpt.
  assert.deepEqual(handoff.videos.map((v) => v.key), ["a", "c"]);
  assert.equal(handoff.videos[0].snippets[0].text, "alpha line");
  assert.equal(handoff.videos[1].snippets[0].text, "gamma line");
  assert.equal(handoff.totalVideos, 2);
});