# Implementation Plan: FightRate P1 Essential Features

## Overview
Implement the next FightRate feature batch as incremental, testable slices: workout sessions, round timer, configurable alerts, more robust BLE state, and sensor metadata (battery/body location). Keep PT-BR visible copy and English code identifiers.

## Architecture Decisions
- Keep local-first SQLite as source of truth.
- Add session data without replacing existing sample storage.
- Prefer pure domain logic for round timer and alerts so behavior is unit-testable.
- Keep BLE foreground service as owner of the device connection.
- Expose sensor metadata through existing service broadcasts to avoid direct BLE ownership in the ViewModel.

## Task List

### Phase 1: Domain foundation
- [ ] Add `WorkoutSession`, `WorkoutSessionStatus`, `RoundTimerConfig`, `RoundTimerSnapshot`, and calculators.
- [ ] Add unit tests for timer transitions and session summary calculations.

### Phase 2: Persistence
- [ ] Add `workout_sessions` table and nullable `session_id` on `heart_rate_samples`.
- [ ] Add safe migration from current database version.
- [ ] Add store methods to start/pause/resume/finish active sessions and insert samples with active session id.

### Phase 3: UI/ViewModel integration
- [ ] Add session and round timer state to `LiveHeartRateUiState`.
- [ ] Add ViewModel actions: start/pause/resume/finish session and update timer config.
- [ ] Add visible Compose controls in Live screen.

### Phase 4: Alerts
- [ ] Add persisted alert settings with safe defaults.
- [ ] Add configurable vibration/sound toggles and zone/limit thresholds.
- [ ] Trigger alerts from service/ViewModel without spamming.

### Phase 5: BLE hardening and metadata
- [ ] Add BLE status events for scan/connect/service/descriptor failures and unexpected disconnects.
- [ ] Add conservative reconnect/backoff in foreground service.
- [ ] Read battery level and body sensor location when available.
- [ ] Show metadata in Sensor screen.

## Review/Verification
- [ ] Run unit tests after domain/persistence slices.
- [ ] Run `./gradlew :app:testDebugUnitTest :app:assembleDebug` before final response.
- [ ] Run code review and front/UI review via fresh-context reviewers.
- [ ] Reconcile findings and fix required issues.

## Risks
| Risk | Impact | Mitigation |
|---|---|---|
| Database migration loses samples | High | Add additive migration, no DROP for current versions |
| BLE changes break screen-off tracking | High | Keep service ownership; add metadata/status only |
| UI becomes cluttered | Medium | Compact cards and PT-BR labels |
| Alert spam | Medium | Throttle alerts and use safe defaults |