import { describe, expect, it } from "vitest";
import { AUTO_DISMISS_MS, MAX_TOASTS, createToastStore } from "./toastStore";

function fakeTimers() {
  let next = 1;
  const pending = new Map<number, { fn: () => void; ms: number }>();
  return {
    setTimer: (fn: () => void, ms: number) => {
      const id = next++;
      pending.set(id, { fn, ms });
      return id;
    },
    clearTimer: (id: unknown) => void pending.delete(id as number),
    fireAll: () => [...pending.entries()].forEach(([id, t]) => (pending.delete(id), t.fn())),
    pending,
  };
}

describe("toast store", () => {
  it("auto-dismisses non-error toasts after the delay", () => {
    const timers = fakeTimers();
    const store = createToastStore(timers);
    store.add("success", "Saved");
    store.add("info", "FYI");
    expect([...timers.pending.values()].map((t) => t.ms)).toEqual([AUTO_DISMISS_MS, AUTO_DISMISS_MS]);
    timers.fireAll();
    expect(store.getSnapshot()).toHaveLength(0);
  });

  it("keeps errors until they are closed", () => {
    const timers = fakeTimers();
    const store = createToastStore(timers);
    const id = store.add("error", "Failed", "details");
    expect(timers.pending.size).toBe(0);
    timers.fireAll();
    expect(store.getSnapshot()).toEqual([{ id, kind: "error", title: "Failed", subtitle: "details" }]);
    store.dismiss(id);
    expect(store.getSnapshot()).toHaveLength(0);
  });

  it("dismiss cancels the timer and is idempotent", () => {
    const timers = fakeTimers();
    const store = createToastStore(timers);
    const id = store.add("success", "x");
    store.dismiss(id);
    expect(timers.pending.size).toBe(0);
    store.dismiss(id);
    expect(store.getSnapshot()).toHaveLength(0);
  });

  it("notifies subscribers with a new snapshot reference per change", () => {
    const store = createToastStore(fakeTimers());
    let calls = 0;
    const off = store.subscribe(() => calls++);
    const before = store.getSnapshot();
    store.add("info", "a");
    expect(calls).toBe(1);
    expect(store.getSnapshot()).not.toBe(before);
    const same = store.getSnapshot();
    store.dismiss(999);
    expect(calls).toBe(1);
    expect(store.getSnapshot()).toBe(same);
    off();
    store.add("info", "b");
    expect(calls).toBe(1);
  });

  it("caps the stack and drops the oldest first, cancelling its timer", () => {
    const timers = fakeTimers();
    const store = createToastStore(timers);
    for (let i = 0; i < MAX_TOASTS + 2; i++) store.add("success", `t${i}`);
    const titles = store.getSnapshot().map((t) => t.title);
    expect(titles).toHaveLength(MAX_TOASTS);
    expect(titles[0]).toBe("t2");
    expect(timers.pending.size).toBe(MAX_TOASTS);
  });

  it("clear empties the stack and cancels timers", () => {
    const timers = fakeTimers();
    const store = createToastStore(timers);
    store.add("success", "a");
    store.add("error", "b");
    store.clear();
    expect(store.getSnapshot()).toHaveLength(0);
    expect(timers.pending.size).toBe(0);
  });
});