import { describe, it, expect } from 'vitest';
import { runUpdate, currentMonthFile, todayISO } from './cost-stop-hook.mjs';
import { PRICING } from './cost-pricing.mjs';

describe('runUpdate (pure)', () => {
  const ep = (date, cost) => ({
    timestamps: { started_at: `${date}T12:00:00.000Z` },
    task_cost: cost,
  });

  it('adds today entry to empty existing state', () => {
    const r = runUpdate({
      episodes: [ep('2026-05-28', { classifier_input_tokens: 1_000_000 })],
      dateISO: '2026-05-28',
      existing: {},
      pricing: PRICING,
    });
    expect(r['2026-05-28']).toBeDefined();
    expect(r['2026-05-28'].classifier_usd).toBeCloseTo(3, 6);
    expect(r['2026-05-28'].episode_count).toBe(1);
  });

  it('overwrites today entry but preserves other-day entries', () => {
    const r = runUpdate({
      episodes: [ep('2026-05-28', { classifier_input_tokens: 1_000_000 })],
      dateISO: '2026-05-28',
      existing: { '2026-05-27': { total_usd: 9.99, episode_count: 5 } },
      pricing: PRICING,
    });
    expect(r['2026-05-27']).toEqual({ total_usd: 9.99, episode_count: 5 });
    expect(r['2026-05-28'].classifier_usd).toBeCloseTo(3, 6);
  });

  it('writes zero-episode-count day when no episodes match', () => {
    const r = runUpdate({
      episodes: [],
      dateISO: '2026-05-28',
      existing: {},
      pricing: PRICING,
    });
    expect(r['2026-05-28'].episode_count).toBe(0);
    expect(r['2026-05-28'].total_usd).toBe(0);
  });

  it('does not mutate the existing input object', () => {
    const existing = { '2026-05-27': { total_usd: 1 } };
    runUpdate({ episodes: [], dateISO: '2026-05-28', existing, pricing: PRICING });
    expect(Object.keys(existing)).toEqual(['2026-05-27']);
    expect(existing['2026-05-27']).toEqual({ total_usd: 1 });
  });
});

describe('todayISO', () => {
  it('returns YYYY-MM-DD string for a Date instance', () => {
    expect(todayISO(new Date('2026-05-28T15:30:00.000Z'))).toBe('2026-05-28');
  });

  it('uses UTC date components', () => {
    // Date that's late evening UTC but next day in local — ISO must reflect UTC.
    expect(todayISO(new Date('2026-05-28T23:59:59.000Z'))).toBe('2026-05-28');
  });
});

describe('currentMonthFile', () => {
  it('returns docs/observer/episodes-YYYY-MM.jsonl', () => {
    const p = currentMonthFile(new Date('2026-05-28T12:00:00.000Z'), '/repo');
    expect(p.replace(/\\/g, '/')).toBe('/repo/docs/observer/episodes-2026-05.jsonl');
  });

  it('pads month with leading zero', () => {
    const p = currentMonthFile(new Date('2026-01-05T12:00:00.000Z'), '/repo');
    expect(p.replace(/\\/g, '/')).toBe('/repo/docs/observer/episodes-2026-01.jsonl');
  });

  it('uses stateDir param (config-seam); дефолт docs/observer', () => {
    const now = new Date('2026-06-15T12:00:00.000Z');
    expect(currentMonthFile(now, '/repo', '.claude/brain-state').replace(/\\/g, '/'))
      .toBe('/repo/.claude/brain-state/episodes-2026-06.jsonl');
    expect(currentMonthFile(now, '/repo').replace(/\\/g, '/'))
      .toBe('/repo/docs/observer/episodes-2026-06.jsonl');
  });
});