Feature: Recurring Tasks + Smart Reminders (NLP quick-add & Expo push)

[hoangsonww]

Summary
Let users set recurring tasks (daily/weekly/monthly/custom RRULE) with smart reminders and NLP quick-add. Deliver Expo push notifications with actions (Complete / Snooze), sync via Supabase, and respect user time zones.

Why

• Core task app need: habits, bills, routines.
• Reduces churn: timely nudges → completion.
• “Type what you think” quick-add is a delight on mobile.

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Scope (MVP)

UX

• Quick-add understands:

  • pay rent every month on the 1st at 9am remind 1d
  • water plants every sat 10am, review PRs daily 5pm remind 15m
    (Use chrono-node for parsing date/time; simple keywords for repeats/reminders.)

• Task editor: Recurrence (None/Daily/Weekly/Monthly/Custom), Time zone, Reminder offsets (e.g., 1d, 1h, 15m).

• Push notification with actions: Complete, Snooze 1h (deep links to the task).

• One-off reminders for non-recurring tasks supported with same UI.

Data (Supabase)

-- store Expo push tokens
create table if not exists public.user_devices (
  id uuid primary key default gen_random_uuid(),
  user_id uuid not null references auth.users(id) on delete cascade,
  expo_push_token text not null unique,
  platform text check (platform in ('ios','android','web')) default 'ios',
  created_at timestamptz not null default now()
);

-- extend tasks
alter table public.tasks
  add column if not exists recurrence_rrule text,          -- e.g., FREQ=MONTHLY;BYMONTHDAY=1;BYHOUR=9;BYMINUTE=0
  add column if not exists tz text not null default 'UTC', -- IANA tz
  add column if not exists reminder_offsets_min int[] not null default '{30}', -- minutes before due
  add column if not exists snoozed_until timestamptz;      -- nullable

RLS

alter table public.user_devices enable row level security;
create policy device_owner
  on public.user_devices for all
  using (auth.uid() = user_id) with check (auth.uid() = user_id);
-- tasks table already owner-scoped; ensure same pattern for new columns

Server (Supabase Edge Functions + Scheduler)

• register-device: upsert expo_push_token for current user.

• dispatch-reminders (runs every minute via Supabase Scheduler):

  1. Find tasks where any due_date - offset ∈ now()..now()+1m, considering tz and snoozed_until.
  2. Send push via Expo API to all user_devices for that user.
  3. Include actions payload {action:'complete'|'snooze', taskId}.

• notification-action (HTTP): handles action callback updates (complete task / set snoozed_until = now()+interval '1 hour').

Client (React Native / Expo)

• On first launch (and Settings): request notifications permission, get Expo push token, call register-device.
• Quick-add input: try parser → build recurrence_rrule, due_date, reminder_offsets_min. Fallback to structured form.
• Deep link handling: navigate to task; apply action if present.
• Stats screen should reflect completions triggered from notifications in real-time.

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Acceptance Criteria

• User can create a recurring task with reminders via quick-add or editor.
• Devices receive a push at each reminder time; tapping Complete marks the task done; Snooze 1h sets snoozed_until and reschedules.
• Time zones honored; changing tz updates next occurrence correctly.
• Non-recurring tasks can have single reminders.
• Tokens are stored per device; removing app revokes token on next failed send.
• All operations respect RLS (no cross-user leakage).

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Implementation Notes

• RRULE: use rrule JS lib to compute next_due_at client-side; persist canonical RRULE in recurrence_rrule.
• Parsing: chrono-node for date/time; simple regex for every|daily|weekly|monthly and remind <N><m|h|d>.
• Expo: expo-notifications for token + handling responses; on Android, add notification categories for actions.
• Scheduler: Supabase Scheduled Functions cron * * * * * to call dispatch-reminders. Batch sends.

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Tasks

• DB migrations (new columns + user_devices + RLS).
• Edge functions: register-device, dispatch-reminders, notification-action.
• Client: permissions, token register, deep links, actions handler.
• Quick-add parser + editor UI for recurrence/reminders/tz.
• Tests: RRULE next-occurrence calc, reminder windows, RLS, action flows.
• Docs: README section + short GIF, env vars for Expo/Supabase functions.