# 017 — Alert definitions & settings persistence

## Summary

Foundation for the alerting feature: a persisted `AlertRule` model plus CRUD,
following the shape `Settings` already uses for `CssEntry`/`Profiles`
([008](008-settings-model.md)) — one process-wide list, saved to disk on every
mutation.

An `AlertRule` has:

- A **condition** (see [018](018-alert-trigger-evaluation.md) for the types and
  how they're evaluated) — for this ticket, just store it as an opaque, already
  parsed/validated value; don't implement evaluation here.
- A **sink**: for now, only `Ntfy { topic: String, server: Option<String> }`
  (`server` defaults to `https://ntfy.sh` when absent) — modeled as an enum so
  [additional sinks](020-alerts-webapp-ui.md) can be added later without
  reshaping `AlertRule`.
- Bookkeeping: `id`, `name`, `enabled: bool`.

## Scope

- `AlertRule` struct (or similar) in a new `src/alerts.rs`, `Vec<AlertRule>`
  added to `Settings` (`src/settings.rs`), persisted the same way
  `css_entries`/`profiles` already are.
- CRUD methods on `Settings` (create/update/delete/list), mirroring
  `import_css`/`remove_css`'s pattern: mutate in memory, then `self.save(...)`.
- HTTP endpoints in `src/api.rs` for CRUD, matching the existing settings
  endpoints' conventions (routes, status codes, error JSON shape).
- Id generation: reuse the approach in `generate_imported_css_id` (hash
  name+content+timestamp) rather than adding a `uuid` dependency.

## Acceptance criteria

- Alert rules round-trip through `save`/`load` like the rest of `Settings`
  (see `round_trips_through_save_and_load` for the existing pattern to extend).
- CRUD endpoints create, list, update, and delete rules, and reject unknown
  ids the same way `CssError::NotFound` does today.
- No evaluation or delivery logic lives here — this ticket only stores rules.

## Depends on

- [008 — Settings model](008-settings-model.md)

## Depended on by

- [018 — Alert trigger evaluation](018-alert-trigger-evaluation.md)
- [019 — Ntfy sink delivery](019-ntfy-sink-delivery.md)
- [020 — Alerts webapp UI](020-alerts-webapp-ui.md)