// @vitest-environment node
/**
 * block-patch-store — the presence fold (TASK-0093). The store keys peers
 * by (pageId, userId): upsertPresence folds a per-peer `presence` frame,
 * removePresence drops one (`presence-leave`). The block overlay is
 * untouched by presence frames (and vice versa).
 */
import { beforeEach, describe, expect, it } from "vitest";
import { useBlockPatchStore } from "../block-patch-store";
import type { Presence } from "@/lib/types";

const peer = (userId: string, extra?: Partial<Presence>): Presence => ({
  userId,
  name: `Name ${userId}`,
  color: "#123456",
  cursor: null,
  lastSeen: 1_700_000_000_000,
  ...extra,
});

const state = () => useBlockPatchStore.getState();

describe("block-patch-store — presence fold (per-peer frames, TASK-0093)", () => {
  beforeEach(() => {
    useBlockPatchStore.setState({ patches: {}, upserts: {}, deleted: {}, presence: {} });
  });

  it("upsertPresence adds a peer to the page's roster", () => {
    state().upsertPresence("pg_1", peer("u1", { cursor: { blockId: "blk_1", offset: 3 } }));
    expect(state().presence["pg_1"]).toEqual({
      u1: peer("u1", { cursor: { blockId: "blk_1", offset: 3 } }),
    });
  });

  it("a later presence frame UPDATES the same peer in place (no duplicate)", () => {
    state().upsertPresence("pg_1", peer("u1"));
    state().upsertPresence(
      "pg_1",
      peer("u1", { cursor: { blockId: "blk_2", offset: 9 }, lastSeen: 1_700_000_000_500 }),
    );
    expect(Object.keys(state().presence["pg_1"] ?? {})).toEqual(["u1"]);
    expect(state().presence["pg_1"]?.u1).toMatchObject({
      cursor: { blockId: "blk_2", offset: 9 },
      lastSeen: 1_700_000_000_500,
    });
  });

  it("different peers on the same page are both kept", () => {
    state().upsertPresence("pg_1", peer("u1"));
    state().upsertPresence("pg_1", peer("u2"));
    expect(Object.keys(state().presence["pg_1"] ?? {})).toEqual(["u1", "u2"]);
  });

  it("removePresence (presence-leave) drops exactly that peer", () => {
    state().upsertPresence("pg_1", peer("u1"));
    state().upsertPresence("pg_1", peer("u2"));
    state().removePresence("pg_1", "u1");
    expect(Object.keys(state().presence["pg_1"] ?? {})).toEqual(["u2"]);
  });

  it("removePresence for an unknown peer is a no-op (idempotent)", () => {
    state().upsertPresence("pg_1", peer("u1"));
    state().removePresence("pg_1", "ghost");
    state().removePresence("pg_1", "u1");
    state().removePresence("pg_1", "u1"); // again — no crash, no entry
    expect(state().presence["pg_1"]).toEqual({});
  });

  it("presence state is per-page (a leave on one page never touches another)", () => {
    state().upsertPresence("pg_1", peer("u1"));
    state().upsertPresence("pg_2", peer("u1"));
    state().removePresence("pg_1", "u1");
    expect(state().presence["pg_1"]).toEqual({});
    expect(Object.keys(state().presence["pg_2"] ?? {})).toEqual(["u1"]);
  });

  it("reset drops the page's presence (page unmount)", () => {
    state().upsertPresence("pg_1", peer("u1"));
    state().reset("pg_1");
    expect(state().presence["pg_1"]).toEqual({});
  });

  it("clearBlocks keeps presence (a block change must not wipe who's online)", () => {
    state().upsertPresence("pg_1", peer("u1"));
    state().clearBlocks("pg_1");
    expect(Object.keys(state().presence["pg_1"] ?? {})).toEqual(["u1"]);
  });
});