# PR-4 Apply Report: Toast Coordination for Notification Center

## Status: COMPLETE

All 4 tasks for PR-4 (NC-PR4-001 through NC-PR4-004) have been implemented, tested, and validated.

## What Was Implemented

### NC-PR4-001: Update EventToastBridge with Preference Checks
**File:** `apps/web/src/components/event-toast-bridge.tsx`
- Reads `userConfig.notification_toast_level` and `userConfig.notification_mute_categories`
- Preference hierarchy applied before showing toast:
  1. Muted category → suppress
  2. Toast level "none" → suppress all
  3. Toast level "errors" + severity != "error" → suppress
  4. Otherwise → show toast
- Gracefully handles missing/null userConfig (defaults to "all", no muted categories)

### NC-PR4-002: Extend toast-rules.ts with Category/Severity Mapping
**File:** `apps/web/src/components/toast-rules.ts`
- Added `mapEventToCategory(event)` — maps event types to categories:
  - `instance.*` → "instance"
  - `health.*` → "health"
  - default → "system"
- Added `mapEventToSeverity(event)` — maps event types to severity:
  - `instance.error` → "error"
  - `health.error` → "error"
  - `health.unhealthy` → "warning"
  - `health.recovered` → "success"
  - others → "info"
- Added `shouldShowToast(event, config)` — combines mapping with preference checks

### NC-PR4-003: Notification Preference Controls in Settings Page
**File:** `apps/web/src/pages/settings.tsx`
- Added "Notification Preferences" section with:
  - Toast level dropdown: "All notifications" / "Errors only" / "None"
  - Mute categories checkboxes: "Instance events" / "Health events" / "System events"
- Preferences loaded from UserConfig API
- Changes saved via PATCH /user-config
- Visual feedback on save

**File:** `apps/web/src/api/settings.ts`
- Extended settings API types with notification preference fields
- Added `notification_toast_level` and `notification_mute_categories` to request/response types

### NC-PR4-004: Toast Bridge Tests
**File:** `apps/web/src/components/event-toast-bridge.test.tsx` *(new)*
- 6 tests covering:
  - Shows toast when level="all" and category not muted
  - Suppresses toast when level="none"
  - Suppresses info toast when level="errors"
  - Shows error toast when level="errors"
  - Suppresses toast when category is muted
  - Defaults to showing toast when no config present

**File:** `apps/web/src/components/toast-rules.test.ts` *(modified)*
- Extended existing tests with category/severity mapping tests
- Added preference filtering tests

## Changed Files
1. `apps/web/src/components/event-toast-bridge.tsx` — Preference checks before toast
2. `apps/web/src/components/toast-rules.ts` — Category/severity mapping
3. `apps/web/src/components/toast-rules.test.ts` — Extended tests
4. `apps/web/src/pages/settings.tsx` — Notification preferences UI
5. `apps/web/src/api/settings.ts` — API types for preferences
6. `apps/web/src/components/event-toast-bridge.test.tsx` *(new)* — Bridge tests

## TDD Cycle Evidence

| Cycle | Task | RED | GREEN | Evidence |
|-------|------|-----|-------|----------|
| 1 | toast-rules mapping | Tests written against missing functions | Implemented `mapEventToCategory`, `mapEventToSeverity` | Tests pass |
| 2 | EventToastBridge preferences | Tests written against missing config checks | Added preference checks to bridge | Tests pass |
| 3 | Settings UI | Manual verification | Added preference section to settings page | Functional |
| 4 | REFACTOR | — | tsc + eslint clean | All pass |

## Test Commands & Exit Codes

```bash
# Toast rules + bridge tests (17 tests)
cd apps/web && npx vitest run src/components/toast-rules.test.ts src/components/event-toast-bridge.test.tsx
# Exit: 0 — 17 passed

# Type check
cd apps/web && npx tsc --noEmit
# Exit: 0 — clean

# Lint
cd apps/web && npx eslint src/components/event-toast-bridge.tsx src/components/toast-rules.ts src/components/toast-rules.test.ts src/pages/settings.tsx src/components/event-toast-bridge.test.tsx src/api/settings.ts --ext ts,tsx --max-warnings 0
# Exit: 0 — clean
```

## Surprises / Decisions
1. **Settings page uses existing form patterns** — Leveraged existing settings form infrastructure rather than creating a new preferences component.
2. **Graceful config fallback** — When userConfig is missing or lacks notification keys, defaults to showing all toasts (no muted categories).

## Risks
- **None:** All changes are additive. Preference defaults are safe (show all toasts).