import { describe, expect, test } from "bun:test";

import { createMessageContextStore } from "./message-context";

const workbook = { id: "workbook", text: "In Budget.xlsx." };
const selection = (label: string) => ({
  id: "selection",
  label,
  detail: `${label} in Budget.xlsx`,
  text: `Selected ${label}.`,
});

describe("createMessageContextStore", () => {
  test("sends every item and shows only labeled ones", () => {
    const store = createMessageContextStore([workbook, selection("A1")]);
    expect(store.forSend()).toBe("In Budget.xlsx.\n\nSelected A1.");
    expect(store.pills()).toEqual([
      { id: "selection", label: "A1", detail: "A1 in Budget.xlsx", excluded: false },
    ]);
  });

  test("leaves an excluded pill out until its label changes", () => {
    const store = createMessageContextStore([workbook, selection("A1")]);
    let notified = 0;
    store.subscribe(() => {
      notified += 1;
    });
    store.exclude("selection");
    expect(store.forSend()).toBe("In Budget.xlsx.");
    expect(store.pills()[0]?.excluded).toBe(true);
    // The same selection with new values stays left out.
    store.set([workbook, { ...selection("A1"), text: "Selected A1, now 42." }]);
    expect(store.forSend()).toBe("In Budget.xlsx.");
    // A new selection comes back.
    store.set([workbook, selection("B2:C3")]);
    expect(store.forSend()).toBe("In Budget.xlsx.\n\nSelected B2:C3.");
    expect(store.pills()[0]?.excluded).toBe(false);
    expect(notified).toBe(2);
  });

  test("brings an excluded pill back on include", () => {
    const store = createMessageContextStore([selection("A1")]);
    store.exclude("selection");
    expect(store.forSend()).toBeUndefined();
    store.include("selection");
    expect(store.forSend()).toBe("Selected A1.");
  });

  test("keeps pills stable when nothing visible changes", () => {
    const store = createMessageContextStore([workbook, selection("A1")]);
    const before = store.pills();
    store.set([workbook, { ...selection("A1"), text: "Selected A1 again." }]);
    expect(store.pills()).toBe(before);
  });

  test("accepts text, an unlabeled item that can't be excluded, and a function", () => {
    expect(createMessageContextStore("  On the billing page. ").forSend()).toBe(
      "On the billing page.",
    );
    const quiet = createMessageContextStore(workbook);
    quiet.exclude("workbook");
    expect(quiet.forSend()).toBe("In Budget.xlsx.");
    let reads = 0;
    const lazy = createMessageContextStore(() => {
      reads += 1;
      return `read ${reads}`;
    });
    expect(lazy.pills()).toEqual([]);
    expect(lazy.forSend()).toBe("read 1");
    expect(lazy.forSend()).toBe("read 2");
    expect(createMessageContextStore(undefined).forSend()).toBeUndefined();
  });
});