import { describe, expect, it, vi } from 'vitest';
import {
  calculateCandidateFunnelTarget,
  currentHourlySendCount,
  startNonOverlappingSchedule,
} from '../src/main-loop.js';

describe('startNonOverlappingSchedule', () => {
  it('does not begin a second response check until the prior check settles', async () => {
    vi.useFakeTimers();
    let finishFirst: (() => void) | undefined;
    const check = vi
      .fn<() => Promise<void>>()
      .mockImplementationOnce(() => new Promise<void>((resolve) => { finishFirst = resolve; }))
      .mockResolvedValue(undefined);

    const schedule = startNonOverlappingSchedule(check, 1_000);
    expect(check).toHaveBeenCalledTimes(1);

    await vi.advanceTimersByTimeAsync(10_000);
    expect(check).toHaveBeenCalledTimes(1);

    finishFirst?.();
    await Promise.resolve();
    await vi.advanceTimersByTimeAsync(1_000);
    expect(check).toHaveBeenCalledTimes(2);

    schedule.stop();
    vi.useRealTimers();
  });

  it('does not schedule another check after stop', async () => {
    vi.useFakeTimers();
    const check = vi.fn<() => Promise<void>>().mockResolvedValue(undefined);
    const schedule = startNonOverlappingSchedule(check, 1_000);
    await Promise.resolve();
    schedule.stop();

    await vi.advanceTimersByTimeAsync(10_000);
    expect(check).toHaveBeenCalledTimes(1);
    vi.useRealTimers();
  });
});

describe('currentHourlySendCount', () => {
  it('uses the post-send limiter count without adding an extra message', () => {
    expect(currentHourlySendCount({ getStats: () => ({ messagesThisHour: 1 }) })).toBe(1);
  });
});

describe('calculateCandidateFunnelTarget', () => {
  it('tracks remaining outbound capacity instead of growing to a fixed backlog', () => {
    expect(calculateCandidateFunnelTarget(
      [{ messagesRemaining: 3 }, { messagesRemaining: 5 }],
      { maxReadyCandidates: 25, recentWindowMinutes: 60, minDelayBetweenMessagesMs: 300_000 },
    )).toBe(8);
  });

  it('retains the configured ceiling and caps capacity by the freshness window', () => {
    expect(calculateCandidateFunnelTarget(
      [{ messagesRemaining: 100 }, { messagesRemaining: 100 }],
      { maxReadyCandidates: 25, recentWindowMinutes: 30, minDelayBetweenMessagesMs: 300_000 },
    )).toBe(12);
  });

  it('stops growing inventory when no running account can send', () => {
    const options = {
      maxReadyCandidates: 25,
      recentWindowMinutes: 60,
      minDelayBetweenMessagesMs: 300_000,
    };
    expect(calculateCandidateFunnelTarget([], options)).toBe(0);
    expect(calculateCandidateFunnelTarget([{ messagesRemaining: 0 }], options)).toBe(0);
  });
});