Per the user's ask: stop dumping 12 presets in front of the user. Walk
them through "pick a frequency, then configure it." Each choice
expands its config inline below the radio.
Picker (now 8 top-level choices):
○ Don't repeat (one-off)
○ Every N minutes → number input (1-59)
○ Every N hours → number input (1-23) at :MM
○ Every day at HH:MM (uses outer time picker)
○ Every week at HH:MM → weekday chip multi-select
○ Every month at HH:MM → day-of-month input (1-31)
○ Every year at HH:MM → month select + day input
○ Custom cron expression… → free-form textbox
Behaviour:
- Selecting a row reveals only that row's config; the others stay
collapsed so the screen stays calm.
- HH:MM in every "at HH:MM" label tracks the outer time picker — change
the time and every label updates instantly. Same for the cron
expression the picker emits.
- Every config change recompiles to a single cron string and pushes a
`{ kind: "cron", cron: "..." }` spec up to the parent. Empty weekday
list yields null (config not yet valid).
- Editing an existing reminder calls `flowFromCron(rule, firstFire)`
which reverse-engineers a flow state from the stored cron — including
expanding `1-5` ranges into a weekday chip list — so the right radio
is highlighted and config inputs are pre-populated.
- Anything not recognised by `flowFromCron` (legacy RRULE, hand-rolled
cron) lands on "Custom cron expression…" with the literal expression
in the textbox.
Helpers in `lib/recurrence.ts`:
- `FreqChoice` ("none" | "minute" | "hour" | "day" | "week" | "month"
| "year" | "cron") + `FlowState` interface with all config fields.
- `freqChoices(firstFire)` → first-fire-aware label list for the radio.
- `defaultFlowState(firstFire)` → seeds sensible defaults (today's
weekday, day-of-month, month, etc.).
- `flowToCron(flow, firstFire)` → cron string or null. Clamps
out-of-range integers.
- `flowFromCron(rule, firstFire)` → best-effort reverse mapping.
- `isoWeekdayToCron(iso)` → maps ISO 1-7 (Mon..Sun) to cron 0-6
(Sun..Sat).
Removed: the previous `presetToSpec` / `matchPreset` / `presetDescriptors`
+ `presetCron` family. They're superseded by the flow helpers.
Tests (+11 in recurrence.test.ts; total 139 web + 26 bot + 17 shared
= 182):
- freqChoices order and time-bearing labels
- flowToCron for every freq + config combination, including empty
weekday list returning null
- clamp behaviour for out-of-range minute/month-day/month integers
- isoWeekdayToCron for Mon..Sun
- defaultFlowState seeded fields
- flowFromCron round-trips every flow output exactly
- BYDAY range expansion (1-5 → [1,2,3,4,5])
- unrecognised expressions land on the cron textbox
- buildRrule + specFromRrule still handle CRON: prefixed strings
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>