/**
 * Pure-function unit tests for recommender logic — no DB, no HTTP.
 * These can import directly from the module without any mocking.
 */
import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
import { inferReward, dueAgeDays } from '../recommender.js';

describe('inferReward', () => {
  it('dismiss → -1', () => expect(inferReward('dismiss', null)).toBe(-1.0));
  it('snooze → +0.1', () => expect(inferReward('snooze', null)).toBe(0.1));
  it('helpful → +0.5', () => expect(inferReward('helpful', null)).toBe(0.5));
  it('not_helpful → -0.5', () => expect(inferReward('not_helpful', null)).toBe(-0.5));
  it('done with null dwell → +0.5', () => expect(inferReward('done', null)).toBe(0.5));
  it('done < 15s (reflex) → -0.3', () => expect(inferReward('done', 5_000)).toBe(-0.3));
  it('done 15s–2min (magic) → +1.0', () => expect(inferReward('done', 60_000)).toBe(1.0));
  it('done 2–10min (good) → +0.6', () => expect(inferReward('done', 300_000)).toBe(0.6));
  it('done > 10min (eventual) → +0.3', () => expect(inferReward('done', 700_000)).toBe(0.3));
  it('done exactly 15s (boundary) → magic zone', () => expect(inferReward('done', 15_000)).toBe(1.0));
  it('done exactly 2min (boundary) → good zone', () => expect(inferReward('done', 120_000)).toBe(0.6));
});

describe('dueAgeDays', () => {
  it('null due → 0', () => expect(dueAgeDays(null)).toBe(0));
  it('empty object → 0', () => expect(dueAgeDays({})).toBe(0));
  it('future date → 0 (clamped)', () => {
    const future = new Date(Date.now() + 86_400_000).toISOString();
    expect(dueAgeDays({ datetime: future })).toBe(0);
  });
  it('past date → positive age', () => {
    const twoDaysAgo = new Date(Date.now() - 2 * 86_400_000).toISOString();
    const age = dueAgeDays({ datetime: twoDaysAgo });
    expect(age).toBeGreaterThan(1.9);
    expect(age).toBeLessThan(2.1);
  });
  it('date-only field used when datetime absent', () => {
    const yesterday = new Date(Date.now() - 86_400_000).toISOString().slice(0, 10);
    expect(dueAgeDays({ date: yesterday })).toBeGreaterThan(0);
  });
});