halkyon/docs/adr/0033-halkyon-todo.md

# ADR 0033: Halkyon Todo, what it does and how it looks

- **Status:** decided 1 Nov 2026, by the developer (D1–D10 below, the agent's
  recommendations taken as a whole). Built the same day: steps 1 to 3, Today and
  Upcoming as lists, and recurrence (step 4 without reminders and the week strip).
- **Numbering:** 0025–0029 are held (ADR 0030's note), 0032 is Jellyfin's; this is the
  next free number.
- **Builds on:** ADR 0030, D7, D12, D14, D15 and D60 (Train's sealed rows, its shell, its
  frame and settings, which Todo takes); ADR 0017 (the account's keys); ADR 0031 (Todo's
  icon); Train's D61 (What's new).

## Context

On 1 Nov 2026 the developer asked for work on Todo to start from 68 screenshots of
Todoist's Android app (31 Oct 2026, `~/Downloads/todoist-screenshots-mobile/`), "following
the same foundational reasoning of Halkyon Learn and Halkyon Train": when the bar and when
the rail, a wash of strawberry, settings grouped as theirs. What the screenshots show:

- **Five tabs** (Inbox, Today, Search, Upcoming, Browse), a floating add button above the
  bar, the bar's items and the button's side set by the person; Browse holds the
  projects, Reporting, templates and the cog to Settings.
- **A task** has a title, a description, a **date** (optional time and **duration**,
  "06:30–07:00") and, apart from it, a **deadline** (date only, its own icon, neutral
  colour; a task may have a deadline and no date), a priority (P1–P4), labels, reminders
  (relative to the time, automatic 30 minutes before a timed task; by location in the paid
  plans), a recurrence (completing it moves it on; its sub-tasks reset), sub-tasks
  (counted "0/5" on its row), comments with attachments. Rows colour the date by meaning
  (overdue red, tomorrow orange, this week purple).
- **Projects** have sections (name, description, count), seen as a list, as a **board** (a
  column a section, paged) or as a **calendar** (a week strip opening into the month, an
  agenda below). **Today** puts Overdue first, with Reschedule for all of them;
  **Upcoming** is an agenda from today on, or a **3-day** grid of hours where a long press
  picks 30 minutes. Every view has its own **Display** sheet: layout, completed tasks,
  grouping, sorting, filters by date, deadline, priority and label.
- **The task sheet** shows a row for each field set and a chip for each one not, the
  sub-tasks, and a comment field at its foot; **quick add** is a card above the keyboard
  with chips (date, deadline, priority, reminders, project), dates recognised in what is
  typed.
- **Productivity**: a daily and weekly goal, streaks, karma, days off and a vacation mode;
  **Reporting**, the completed tasks by day.
- **Settings**: Account, General (home view, smart dates, reset sub-tasks, the week's
  first day, how "next week" and "weekend" are read, swipe actions), Theme, Navigation
  bar, Quick Add, Productivity, Reminders, Notifications (a morning overview and an evening
  review), About, What's new.

## Decisions (1 Nov 2026, the developer's)

- **D1 Todo's frame is Train's (ADR 0030, D60)**: go_router with a `StatefulShellRoute`,
  every tab keeping its own stack; halkyon_ui's `NavigationFrame`, a bar floating above the
  foot below medium windows and a rail with Todo's icon on top from medium on, a tick on
  every choice; Todo's account sheet goes. Over a frame of Todo's own, which would make the
  three apps behave differently on the same window.
- **D2 Four tabs: Today, Upcoming, Inbox, Browse** (recommended, over Todoist's five and over
  a bar the person arranges). Today opens. Browse holds the projects, the labels and,
  later, saved filters, with the cog to Settings atop it as Train's Home and Profile carry
  theirs. **Search** is an icon in every tab's app bar, not a tab, as neither Learn nor
  Train gives search a tab. **Adding a task** is a floating button above the bar
  (Train's `TabScreen` places it clear of the bar), on the rail's screen from medium
  windows on. From expanded windows on, a task opens in a pane beside its list, as Train's
  Maps opens a route's map beside the list (Material's list–detail layout), and in a
  bottom sheet below. Arranging the bar may come later; Search may become a tab if it
  proves to be used as one.
- **D3 Every screen washes down from the top in strawberry** (the developer's):
  `TopGradient` under the app's `ScreenColor`, `PaletteColor.strawberry`, as Learn's in
  cobalt and Train's in carrot; buttons and links stay cobalt.
- **D4 Settings as Learn's and Train's** (the developer's): a screen over the tabs,
  grouped in `SectionCard`s. Sync's card first (as Learn's), the operator's card for
  whoever operates the instance, then Todo's own groups (*Tasks*: the week's first day
  from the language unless set, resetting sub-tasks; *Reminders*: the automatic reminder
  before a timed task, snoozing), the account near the foot (halkyon_app's
  `AccountTiles`, `SimpleLoginSection`, `AccountSecuritySection`), What's new and About
  Halkyon Todo last, the version small below them. Groups come as their settings are
  built; none is shown empty.
- **D5 Todo's rows are sealed, always, as Train's (ADR 0030, D7, D15)**, synced with
  `serverpod_offline_sync`: every payload ADR 0017's sealed content under the person's
  data key (`content_key`, halkyon_app's `PayloadEnvelope`), nothing readable in a column,
  not a title nor a date. Recommended over readable rows (ADR 0002's default), which would
  let the server send reminders by email and a morning overview, and would make shared
  projects simpler: what a person plans to do is theirs, the server needs to read none of
  it to sync it, and Todo's rows can't be unsealed later without the person's devices. So
  **reminders are scheduled on the device**, as local notifications on each device that
  holds the account's keys; there is no email reminder and no overview the server writes.
  A project shared later is sealed under a key its members share, which is that step's to
  decide.
- **D6 Four tables: `project`, `section`, `task`, `label`** (recommended, as Train keeps a
  workout and its series apart, D14): one row each, changed when edited, the last writer
  winning, every payload JSON with a `schemaVersion`, UUID v7 ids. Inbox is a project the
  app makes once per person, under a row ID keyed by the account (Train's D57,
  `keyedRowId`), not marked in its payload (as built, 1 Nov): every device makes the
  same row, so two making it offline write one, and the instance can tell neither
  which row is the Inbox nor whose it is; a payload's mark would let a moved row
  claim to be it. A **sub-task** is a task naming its
  parent. A task's payload: title, description, its project and section, its parent, its
  place among its siblings, a **date** (a day, or a day and a time with an optional
  duration, the time as the person's wall clock with its time zone), a **deadline** (a
  day), a priority (1–4), its labels' ids, a recurrence (D7), its reminders, when it was
  completed. Completing a recurring task moves its date on and writes the occurrence done
  into its payload's history, so Reporting can count it. Comments and attachments are a
  later step (attachments need sealed files, which no Halkyon app has yet).
- **D7 A recurrence is a structured rule, set through a picker** (recommended, over
  parsing what is typed): every n days, weeks (on which weekdays), months (on which day,
  or the nth weekday), years, from the date or from completion, until a day or for n
  times. Dates and tokens typed into quick add ("tomorrow 6am", "every Monday", `#project`,
  `p1`), in English and German, are a later step, built on the same rule.
  As built (1 Nov): the rule is part of the task's date (`Repeat` in `TaskDate`, its
  payload's `date.repeat`), so a task without a date doesn't recur and clearing the date
  ends it; schema 1 holds it, as no task was written before. Done, a task counted from its
  date moves to the rule's first day after both its date and today (an overdue one isn't
  moved onto a day already past), counted from completion it moves the rule's units on
  from today, on no particular weekday; its deadline moves as far, its time is kept, its
  done sub-tasks open again, and when it was done is added to its `completions`. Undo
  writes back every task that changed. The picker offers the rules that fit its day
  (every day, every weekday, its weekday, its day or nth weekday of the month, its day of
  the year) and a rule of the person's own; weeks start on Monday for every n weeks, until
  the week's first day is a setting (D4).
- **D8 The first version** (recommended): Inbox and projects with sections, shown as a
  list; sub-tasks; Today (Overdue first, rescheduling them together, then today's); Upcoming
  as an agenda with the week strip opening into the month; the task sheet (rows for the
  fields set, chips for the others, the sub-tasks); quick add; labels; completed tasks shown
  or hidden per view; reminders on the device. **Later**, each put to the developer when
  its turn comes: the board and calendar layouts, Upcoming's 3-day grid, each view's
  Display sheet (grouping, sorting, filters), saved filters, Reporting and goals (karma
  not before the developer asks for it), location reminders, comments and attachments,
  typed dates, sharing.
- **D9 Colours that mean something come from halkyon_ui's palette** (recommended): a
  project's colour is picked from `PaletteColor`, with its localised name, as Learn's
  colours are; priorities and dates take palette colours chosen not to blur against the
  strawberry wash, so overdue and P1 are **cerise**, not strawberry, P2 carrot, P3
  cobalt, P4 none; tomorrow and this week as Todoist's meanings go, in palette colours.
  Each is checked against the wash in light and dark before it is kept.
- **D10 The icon stays as ADR 0031 drew it** (cobalt through pacific into fern), though
  the wash is strawberry: Learn's icon ends in strawberry and washes in cobalt, so an
  app's wash and its icon already differ, and Todo's and Meditate's icons are kept
  related (ADR 0031, D1). The agent made no recommendation; this is the default the
  decision of 1 Nov left in place, to be asked again if the screens look wrong beside it.

## Steps

1. **The frame**: go_router and `NavigationFrame` with the four tabs (empty screens that
   say what comes), the strawberry wash, the cog, Settings as D4 with what exists today
   (the account, What's new, About, the version); the account sheet removed.
2. **The first synced model**: `content_key` and `project` (Inbox made once), its gateway
   and repository on Learn's and Train's pattern, the server's access rules each with a
   test asserting denial; walked through with the developer as the first of Todo's.
3. **Tasks**: `section`, `task`, `label`; Inbox and a project's list; the task sheet; quick
   add.
4. **Today and Upcoming**, recurrence (D7), reminders on the device.
5. Todo's first release (0.1.0), its *What's new* drafted by `tool/release.dart`.

## Consequences

- No email reminder, morning overview or evening review: the server can't read what is
  due. A device without the account's keys neither reads nor writes Todo's rows, as in
  Train.
- Todo's server holds no logic over tasks; what Today, Upcoming and Reporting show is
  worked out on the device, over every task the person has. That is fine for thousands of
  tasks; a person with far more would need the device to keep an index of its own.
- Sharing a project is harder than with readable rows (a key per shared project, its
  members' keys wrapping it); D5 accepts that for now.