import { describe, expect, it } from 'vitest';
import { DEFAULT_WEBHOOK_QUEUE_MAX_SIZE, InMemoryEventQueue } from '../src/queue/webhookQueue.js';

describe('InMemoryEventQueue (bounded transient buffer, ARN-003)', () => {
  it('defaults maxSize to 10000', () => {
    expect(DEFAULT_WEBHOOK_QUEUE_MAX_SIZE).toBe(10_000);
    expect(new InMemoryEventQueue().maxSize).toBe(10_000);
  });

  it('rejects a non-positive or non-integer maxSize', () => {
    expect(() => new InMemoryEventQueue({ maxSize: 0 })).toThrow(/maxSize/);
    expect(() => new InMemoryEventQueue({ maxSize: -5 })).toThrow(/maxSize/);
    expect(() => new InMemoryEventQueue({ maxSize: 1.5 })).toThrow(/maxSize/);
  });

  it('accepts up to maxSize events, then answers {accepted:false, reason:"full"} without growing', () => {
    const queue = new InMemoryEventQueue({ maxSize: 2 });

    const first = queue.enqueue({ source: 'webhook', payload: { n: 1 } });
    const second = queue.enqueue({ source: 'poll', payload: { n: 2 } });
    expect(first.accepted).toBe(true);
    expect(second.accepted).toBe(true);
    if (first.accepted) expect(first.event.payload).toEqual({ n: 1 });
    expect(queue.isFull).toBe(true);

    const third = queue.enqueue({ source: 'webhook', payload: { n: 3 } });
    expect(third).toEqual({ accepted: false, reason: 'full' });
    expect(queue.size).toBe(2);
    expect(queue.peekAll().map((e) => e.payload)).toEqual([{ n: 1 }, { n: 2 }]);
  });

  it('accepts again once an event has been dequeued (FIFO)', () => {
    const queue = new InMemoryEventQueue({ maxSize: 1 });
    queue.enqueue({ source: 'webhook', payload: 'a' });
    expect(queue.enqueue({ source: 'webhook', payload: 'b' }).accepted).toBe(false);

    expect(queue.dequeue()?.payload).toBe('a');
    expect(queue.isFull).toBe(false);
    expect(queue.enqueue({ source: 'webhook', payload: 'b' }).accepted).toBe(true);
    expect(queue.dequeue()?.payload).toBe('b');
    expect(queue.dequeue()).toBeUndefined();
  });
});