/**
 * reminderScheduler tests.
 *
 * Asserts that the reminder scan:
 *   - Selects ONLY shared (isShared=true) AND timed (allDay=false) events
 *     in the catch-up window (now, now+16min] (D-05/D-07)
 *   - Does NOT dispatch reminders for all-day events (D-07)
 *   - Does NOT dispatch reminders for non-shared (personal) events (D-05)
 *   - Does NOT dispatch for an event whose dtstart <= now (already started)
 *   - Fires EXACTLY ONCE across consecutive ticks while the event sits in the window
 *     (per-uid exactly-once dedup; cross-tick double-fire prevention)
 *   - Recovers from a missed/late cron tick: fires at a later scan when event is
 *     still in (now, now+16min] even if the ideal 15-min tick was skipped
 *   - WR-01: sentReminders.set(uid) is called AFTER dispatch (at-least-once delivery)
 *   - CR-01: sentReminders Map is pruned of started events after each scan
 *   - D-16: empty push_subscriptions -> zero sends / no crash
 *   - T-05-19: per-subscription error isolation
 *
 * NEW (Plan 11-02):
 *   - NOTIF-04: fires at T-reminderLeadMinutes (variable per-event lead), not fixed 16-min window
 *   - NOTIF-05: NULL lead → no push; timed 0-lead → no push; personal events DO dispatch
 *   - NOTIF-06: uid:dtstartMs compound dedup; rescheduled dtstart re-fires; all-day 9 AM branch
 *   - D-09: humanized push body (humanizeLeadMinutes)
 *
 * Run: pnpm --filter @familysync/api exec vitest run tests/broker/reminderScheduler.test.ts
 */

import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';

// Mock the DB so we can control what events are returned
vi.mock('../../src/db/client.js', () => ({
  db: {
    select: vi.fn(),
  },
}));

// Mock pushDispatcher so no real push occurs
vi.mock('../../src/lib/pushDispatcher.js', () => ({
  dispatchPush: vi.fn().mockResolvedValue(undefined),
}));

// ── Helpers ───────────────────────────────────────────────────────────────────

function makeSelectMock(rows: unknown[]) {
  return {
    from: vi.fn().mockReturnValue({
      innerJoin: vi.fn().mockReturnValue({
        innerJoin: vi.fn().mockReturnValue({
          where: vi.fn().mockResolvedValue(rows),
        }),
      }),
    }),
  } as never;
}

function makeEventRow(overrides: {
  uid?: string;
  title?: string;
  dtstartUtc?: Date | null;
  dtstartDate?: string | null;
  allDay?: boolean;
  isShared?: boolean;
  reminderLeadMinutes?: number | null;
  subId?: number | null;
  subUserId?: number | null;
  subEndpoint?: string;
  subP256dh?: string;
  subAuth?: string;
}) {
  return {
    uid: overrides.uid ?? 'test-uid-1',
    title: overrides.title ?? 'Test Event',
    dtstartUtc: overrides.dtstartUtc !== undefined ? overrides.dtstartUtc : null,
    dtstartDate: overrides.dtstartDate !== undefined ? overrides.dtstartDate : null,
    allDay: overrides.allDay ?? false,
    isShared: overrides.isShared ?? true,
    reminderLeadMinutes: overrides.reminderLeadMinutes !== undefined ? overrides.reminderLeadMinutes : 15,
    subId: overrides.subId ?? 1,
    subUserId: overrides.subUserId ?? 1,
    subEndpoint: overrides.subEndpoint ?? 'https://push.example.com/1',
    subP256dh: overrides.subP256dh ?? 'p256dh-key',
    subAuth: overrides.subAuth ?? 'auth-secret',
  };
}

// ── Filtering tests (NOTIF-04/05: variable lead, NULL-vs-0, personal calendar) ────────

describe('reminderScheduler — variable-lead, NULL-vs-0, personal calendar (NOTIF-04/05)', () => {
  beforeEach(() => {
    vi.useFakeTimers();
    vi.resetModules();
  });

  afterEach(() => {
    vi.useRealTimers();
    vi.clearAllMocks();
  });

  it('NOTIF-04: dispatches a timed event when now is inside the lead-driven fire window (30-min lead)', async () => {
    // Fire time = dtstartUtc - 30min. now = dtstartUtc - 30min (exactly at fire time).
    // The event MUST dispatch. It would NOT dispatch under the old fixed 16-min window.
    const now = new Date('2026-06-15T10:00:00Z');
    vi.setSystemTime(now);

    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    const dtstartUtc = new Date('2026-06-15T10:30:00Z'); // 30 min from now
    const row = makeEventRow({
      uid: 'notif04-30min-uid',
      dtstartUtc,
      reminderLeadMinutes: 30,
      isShared: true,
    });

    vi.mocked(db.select).mockReturnValue(makeSelectMock([row]));
    await runReminderCheck(now);

    expect(vi.mocked(dispatchPush)).toHaveBeenCalledOnce();
  });

  it('NOTIF-04: does NOT dispatch a 30-min lead event when now is 5 min before start (fire time already passed)', async () => {
    // Fire time = dtstartUtc - 30min = 09:30. now = 10:25 (event in 5 min, past fire time).
    // SQL should not return this row (fire time check). Simulate with empty mock.
    const now = new Date('2026-06-15T10:25:00Z');
    vi.setSystemTime(now);

    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    // Simulate: event would have been in old 16-min window but already past its fire time
    vi.mocked(db.select).mockReturnValue(makeSelectMock([]));
    await runReminderCheck(now);

    expect(vi.mocked(dispatchPush)).not.toHaveBeenCalled();
  });

  it('NOTIF-05: a personal (isShared=false) timed event with non-null lead DOES dispatch (restriction dropped)', async () => {
    const now = new Date('2026-06-15T10:00:00Z');
    vi.setSystemTime(now);

    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    const dtstartUtc = new Date('2026-06-15T10:15:00Z');
    const row = makeEventRow({
      uid: 'personal-event-uid',
      dtstartUtc,
      reminderLeadMinutes: 15,
      isShared: false, // personal calendar — must still dispatch
    });

    vi.mocked(db.select).mockReturnValue(makeSelectMock([row]));
    await runReminderCheck(now);

    // Personal event must dispatch (isShared restriction dropped per NOTIF-05)
    expect(vi.mocked(dispatchPush)).toHaveBeenCalledOnce();
  });

  it('NOTIF-05: an event with reminderLeadMinutes=NULL produces zero dispatches', async () => {
    const now = new Date('2026-06-15T10:00:00Z');
    vi.setSystemTime(now);

    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    // NULL lead events are excluded by SQL WHERE (reminder_lead_minutes IS NOT NULL)
    vi.mocked(db.select).mockReturnValue(makeSelectMock([]));
    await runReminderCheck(now);

    expect(vi.mocked(dispatchPush)).not.toHaveBeenCalled();
  });

  it('NOTIF-05: a timed event with reminderLeadMinutes=0 produces zero dispatches (D-06: 0 on timed = None)', async () => {
    const now = new Date('2026-06-15T10:00:00Z');
    vi.setSystemTime(now);

    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    const dtstartUtc = new Date('2026-06-15T10:01:00Z');
    const row = makeEventRow({
      uid: 'timed-zero-uid',
      dtstartUtc,
      reminderLeadMinutes: 0, // D-06: 0 on timed = None (skip)
      allDay: false,
    });

    // Even if the query returned a timed-0 event, JS must skip it
    vi.mocked(db.select).mockReturnValue(makeSelectMock([row]));
    await runReminderCheck(now);

    expect(vi.mocked(dispatchPush)).not.toHaveBeenCalled();
  });

  it('does not dispatch for an event whose start has already passed (dtstart <= now)', async () => {
    const now = new Date('2026-06-15T10:00:00Z');
    vi.setSystemTime(now);

    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    // gt(dtstartUtc, now) excludes already-started events; simulate by returning empty rows
    vi.mocked(db.select).mockReturnValue(makeSelectMock([]));

    await runReminderCheck(now);

    expect(vi.mocked(dispatchPush)).not.toHaveBeenCalled();
  });
});

// ── D-16: empty subscriptions — zero sends / no crash ────────────────────────

describe('reminderScheduler — D-16: empty push_subscriptions', () => {
  beforeEach(() => {
    vi.useFakeTimers();
    vi.resetModules();
  });

  afterEach(() => {
    vi.useRealTimers();
    vi.clearAllMocks();
  });

  it('produces zero sends and does not crash when push_subscriptions is empty (D-16)', async () => {
    const now = new Date('2026-06-15T10:00:00Z');
    vi.setSystemTime(now);

    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    // Cross-join with empty push_subscriptions returns no rows
    vi.mocked(db.select).mockReturnValue(makeSelectMock([]));

    await expect(runReminderCheck(now)).resolves.toBeUndefined();
    expect(vi.mocked(dispatchPush)).not.toHaveBeenCalled();
  });
});

// ── Catch-up / missed-tick recovery ──────────────────────────────────────────

describe('reminderScheduler — catch-up window and missed-tick recovery', () => {
  beforeEach(() => {
    vi.useFakeTimers();
    vi.resetModules();
  });

  afterEach(() => {
    vi.useRealTimers();
    vi.clearAllMocks();
  });

  it('SINGLE-FIRE (uid:dtstartMs): dispatches exactly once across three consecutive ticks while event is in window', async () => {
    // NOTIF-06: dedup key is uid:dtstartMs — same compound key fires once across 3 ticks
    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    const t0 = new Date('2026-06-15T10:00:00Z');
    // Event is 15 min out from t0. Fire window (now-60s, now] catches it at t0.
    const eventDtstart = new Date('2026-06-15T10:15:00Z');

    const sub = {
      id: 1,
      userId: 1,
      endpoint: 'https://push.example.com/1',
      p256dh: 'k',
      auth: 'a',
    };

    function rowForNow() {
      return makeEventRow({
        uid: 'single-fire-uid',
        dtstartUtc: eventDtstart,
        reminderLeadMinutes: 15,
        subId: sub.id,
        subUserId: sub.userId,
        subEndpoint: sub.endpoint,
        subP256dh: sub.p256dh,
        subAuth: sub.auth,
      });
    }

    // Tick at t0 — fire time is exactly now (dtstartUtc - 15min = t0); dispatches once
    vi.setSystemTime(t0);
    vi.mocked(db.select).mockReturnValue(makeSelectMock([rowForNow()]));
    await runReminderCheck(t0);

    // Tick at t0+1min — same uid:dtstartMs already in sentReminders; must NOT re-dispatch
    const t1 = new Date(t0.getTime() + 60 * 1000);
    vi.setSystemTime(t1);
    vi.mocked(db.select).mockReturnValue(makeSelectMock([rowForNow()]));
    await runReminderCheck(t1);

    // Tick at t0+2min — still deduped
    const t2 = new Date(t0.getTime() + 2 * 60 * 1000);
    vi.setSystemTime(t2);
    vi.mocked(db.select).mockReturnValue(makeSelectMock([rowForNow()]));
    await runReminderCheck(t2);

    // Exactly one dispatch total: uid:dtstartMs dedup prevents re-fire on ticks 2 and 3
    expect(vi.mocked(dispatchPush).mock.calls.length).toBe(1);
  });

  it('RESCHEDULE (uid:dtstartMs): a rescheduled event (same uid, new dtstart) fires again', async () => {
    // NOTIF-06: compound key uid:dtstartMs — new dtstartMs means new key → re-fires
    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    const now = new Date('2026-06-15T10:00:00Z');
    vi.setSystemTime(now);

    const originalDtstart = new Date('2026-06-15T10:15:00Z');

    const row = makeEventRow({
      uid: 'reschedule-uid',
      dtstartUtc: originalDtstart,
      reminderLeadMinutes: 15,
    });

    // First tick — fires
    vi.mocked(db.select).mockReturnValue(makeSelectMock([row]));
    await runReminderCheck(now);
    expect(vi.mocked(dispatchPush).mock.calls.length).toBe(1);

    // Advance time so original dtstart is pruned; event rescheduled to a new dtstart
    const futureNow = new Date('2026-06-15T10:20:00Z'); // past original dtstart
    vi.setSystemTime(futureNow);
    vi.mocked(db.select).mockReturnValue(makeSelectMock([])); // empty (original started)
    await runReminderCheck(futureNow); // prune old entry

    // Now event has new dtstart (same uid, different dtstartMs) — must fire again
    const rescheduledNow = new Date('2026-06-15T11:00:00Z');
    const rescheduledDtstart = new Date('2026-06-15T11:15:00Z');
    vi.setSystemTime(rescheduledNow);
    const rescheduledRow = makeEventRow({
      uid: 'reschedule-uid',
      dtstartUtc: rescheduledDtstart,
      reminderLeadMinutes: 15,
    });
    vi.mocked(db.select).mockReturnValue(makeSelectMock([rescheduledRow]));
    await runReminderCheck(rescheduledNow);

    // Must fire again — new compound key uid:rescheduledDtstartMs
    expect(vi.mocked(dispatchPush).mock.calls.length).toBe(2);
  });

  it('MISSED-TICK-RECOVERY: fires when scan runs inside the 60s catch-up window after ideal tick was skipped', async () => {
    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    // Event at 10:15:00Z, 15-min lead → fire time 10:00:00Z.
    // Ideal scan at 10:00Z was missed. Call at 10:00:45Z — still in (fire-60s, fire] window.
    const eventDtstart = new Date('2026-06-15T10:15:00Z');
    const recoveryNow = new Date('2026-06-15T10:00:45Z'); // 45s after ideal fire time

    vi.setSystemTime(recoveryNow);

    const row = makeEventRow({
      uid: 'missed-tick-uid',
      dtstartUtc: eventDtstart,
      reminderLeadMinutes: 15,
      subId: 1,
      subUserId: 1,
      subEndpoint: 'https://push.example.com/missed',
      subP256dh: 'k',
      subAuth: 'a',
    });

    vi.mocked(db.select).mockReturnValue(makeSelectMock([row]));
    await runReminderCheck(recoveryNow);

    // Reminder must fire even though the ideal-mark tick was skipped
    expect(vi.mocked(dispatchPush).mock.calls.length).toBeGreaterThanOrEqual(1);
  });

  it('dispatches to all subscribers for a single event (fan-out)', async () => {
    const now = new Date('2026-06-15T10:00:00Z');
    vi.setSystemTime(now);

    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    const dtstartUtc = new Date('2026-06-15T10:15:00Z');

    const rows = [
      makeEventRow({
        uid: 'fanout-uid',
        dtstartUtc,
        reminderLeadMinutes: 15,
        subId: 1,
        subUserId: 1,
        subEndpoint: 'https://push.example.com/1',
        subP256dh: 'k1',
        subAuth: 'a1',
      }),
      makeEventRow({
        uid: 'fanout-uid',
        dtstartUtc,
        reminderLeadMinutes: 15,
        subId: 2,
        subUserId: 2,
        subEndpoint: 'https://push.example.com/2',
        subP256dh: 'k2',
        subAuth: 'a2',
      }),
    ];

    vi.mocked(db.select).mockReturnValue(makeSelectMock(rows));
    await runReminderCheck(now);

    // One dispatch per subscriber
    expect(vi.mocked(dispatchPush).mock.calls.length).toBe(2);
  });
});

// ── WR-01: mark-sent after dispatch ──────────────────────────────────────────

describe('reminderScheduler — WR-01: mark-sent after dispatch', () => {
  beforeEach(() => {
    vi.useFakeTimers();
    vi.resetModules();
  });

  afterEach(() => {
    vi.useRealTimers();
    vi.clearAllMocks();
  });

  it('does not re-dispatch the same uid after a successful dispatch in the same module instance', async () => {
    // WR-01: sentReminders.set(uid) is called AFTER the fan-out loop completes.
    // After a successful dispatch the uid is recorded; a second run with the same
    // module instance must not re-fire for the same uid.
    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    const now = new Date('2026-06-15T10:00:00Z');
    vi.setSystemTime(now);

    const sub = {
      id: 1,
      userId: 1,
      endpoint: 'https://push.example.com/1',
      p256dh: 'k',
      auth: 'a',
    };
    const eventRow = makeEventRow({
      uid: 'wr01-dedup-uid',
      title: 'WR-01 dedup event',
      dtstartUtc: new Date('2026-06-15T10:15:00Z'),
      reminderLeadMinutes: 15,
      subId: sub.id,
      subUserId: sub.userId,
      subEndpoint: sub.endpoint,
      subP256dh: sub.p256dh,
      subAuth: sub.auth,
    });

    vi.mocked(dispatchPush).mockResolvedValue(undefined);

    // First run — dispatch succeeds; uid is recorded after the loop
    vi.mocked(db.select).mockReturnValue(makeSelectMock([eventRow]));
    await runReminderCheck(now);
    expect(vi.mocked(dispatchPush).mock.calls.length).toBe(1); // dispatched once

    // Second run with same now — uid is in sentReminders; should NOT re-dispatch
    vi.mocked(db.select).mockReturnValue(makeSelectMock([eventRow]));
    await runReminderCheck(now);
    expect(vi.mocked(dispatchPush).mock.calls.length).toBe(1); // still 1 — deduped
  });
});

// ── CR-01: started-event pruning ─────────────────────────────────────────────

describe('reminderScheduler — CR-01: sentReminders Map pruning', () => {
  beforeEach(() => {
    vi.useFakeTimers();
    vi.resetModules();
  });

  afterEach(() => {
    vi.useRealTimers();
    vi.clearAllMocks();
  });

  it('prunes started-event entries so a different future event with the same uid can fire again', async () => {
    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    const sub = {
      id: 1,
      userId: 1,
      endpoint: 'https://push.example.com/1',
      p256dh: 'k',
      auth: 'a',
    };
    const eventDtstart = new Date('2026-06-15T10:15:00Z');
    const uid = 'prune-test-uid';

    const eventRow = makeEventRow({
      uid,
      title: 'Prune test event',
      dtstartUtc: eventDtstart,
      reminderLeadMinutes: 15,
      subId: sub.id,
      subUserId: sub.userId,
      subEndpoint: sub.endpoint,
      subP256dh: sub.p256dh,
      subAuth: sub.auth,
    });

    // Tick at t0 (now=10:00): event 15 min out — fires
    const t0 = new Date('2026-06-15T10:00:00Z');
    vi.setSystemTime(t0);
    vi.mocked(db.select).mockReturnValue(makeSelectMock([eventRow]));
    await runReminderCheck(t0);
    expect(vi.mocked(dispatchPush).mock.calls.length).toBe(1); // fired

    // Same t0 — uid still in Map — must NOT re-fire
    vi.mocked(db.select).mockReturnValue(makeSelectMock([eventRow]));
    await runReminderCheck(t0);
    expect(vi.mocked(dispatchPush).mock.calls.length).toBe(1); // still 1

    // Advance past dtstart (now=10:20): event has started; CR-01 prunes the uid entry.
    // The SQL WHERE gt(dtstartUtc, now) would return no rows, so simulate empty.
    const tPast = new Date('2026-06-15T10:20:00Z');
    vi.setSystemTime(tPast);
    vi.mocked(db.select).mockReturnValue(makeSelectMock([]));
    await runReminderCheck(tPast);
    // Pruning fires; dispatch count stays at 1
    expect(vi.mocked(dispatchPush).mock.calls.length).toBe(1);
  });
});

// ── T-05-19: per-subscription error isolation ────────────────────────────────

describe('reminderScheduler — T-05-19: per-subscription error isolation', () => {
  beforeEach(() => {
    vi.useFakeTimers();
    vi.resetModules();
  });

  afterEach(() => {
    vi.useRealTimers();
    vi.clearAllMocks();
  });

  it('continues dispatching to remaining subscribers when one subscription throws', async () => {
    const now = new Date('2026-06-15T10:00:00Z');
    vi.setSystemTime(now);

    const { db } = await import('../../src/db/client.js');
    const { dispatchPush } = await import('../../src/lib/pushDispatcher.js');
    const { runReminderCheck } = await import('../../src/broker/reminderScheduler.js');

    const dtstartUtc = new Date('2026-06-15T10:15:00Z');
    const rows = [
      makeEventRow({
        uid: 'iso-uid',
        dtstartUtc,
        reminderLeadMinutes: 15,
        subId: 1,
        subUserId: 1,
        subEndpoint: 'https://push.example.com/1',
        subP256dh: 'k1',
        subAuth: 'a1',
      }),
      makeEventRow({
        uid: 'iso-uid',
        dtstartUtc,
        reminderLeadMinutes: 15,
        subId: 2,
        subUserId: 2,
        subEndpoint: 'https://push.example.com/2',
        subP256dh: 'k2',
        subAuth: 'a2',
      }),
    ];

    vi.mocked(db.select).mockReturnValue(makeSelectMock(rows));
    // First subscriber throws; second should still be attempted
    vi.mocked(dispatchPush)
      .mockRejectedValueOnce(new Error('network error'))
      .mockResolvedValueOnce(undefined);

    await expect(runReminderCheck(now)).resolves.toBeUndefined();
    expect(vi.mocked(dispatchPush).mock.calls.length).toBe(2); // both attempted
  });
});