# FightRate Android MVP Implementation Plan

> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** Build the first Android-native FightRate app scaffold for live combat-sport heart-rate tracking with Magene H003 BLE support.

**Architecture:** Android-native Kotlin app using Jetpack Compose for UI, pure Kotlin domain/parse logic, Android BLE APIs isolated behind a BLE package, and local persistence planned with Room. The first implementation slice creates a buildable app shell plus a tested Heart Rate Measurement parser.

**Tech Stack:** Kotlin, Gradle Kotlin DSL, Android Gradle Plugin, Jetpack Compose Material 3, Coroutines/Flow, Android BLE APIs, JUnit.

---

## File Structure

```text
settings.gradle.kts                         Project module declaration
build.gradle.kts                            Root Gradle plugin versions
gradle.properties                           Android/Kotlin build flags
app/build.gradle.kts                        Android app dependencies and config
app/src/main/AndroidManifest.xml            Permissions, activity, BLE feature flags
app/src/main/java/com/healthtracking/fightrate/MainActivity.kt
app/src/main/java/com/healthtracking/fightrate/ble/HeartRateParser.kt
app/src/main/java/com/healthtracking/fightrate/domain/model/FightSport.kt
app/src/main/java/com/healthtracking/fightrate/domain/model/HeartRateMeasurement.kt
app/src/main/java/com/healthtracking/fightrate/ui/theme/FightRateTheme.kt
app/src/main/java/com/healthtracking/fightrate/ui/theme/Color.kt
app/src/main/java/com/healthtracking/fightrate/ui/screens/HomeScreen.kt
app/src/test/java/com/healthtracking/fightrate/ble/HeartRateParserTest.kt
```

---

## Task 1: Android project scaffold

**Files:**
- Create: `settings.gradle.kts`
- Create: `build.gradle.kts`
- Create: `gradle.properties`
- Create: `app/build.gradle.kts`
- Create: `app/src/main/AndroidManifest.xml`
- Create: `app/src/main/java/com/healthtracking/fightrate/MainActivity.kt`

- [ ] **Step 1: Create Gradle project files**

Use Android app module `:app`, package `com.healthtracking.fightrate`, min SDK 26, target/compile SDK 35, Kotlin 2.x compatible Compose.

- [ ] **Step 2: Create manifest**

Declare Bluetooth permissions for Android 12+, legacy Bluetooth/location permissions for Android 11 and below, BLE feature, foreground service permissions, and `MainActivity`.

- [ ] **Step 3: Create minimal MainActivity**

Use `ComponentActivity`, `setContent`, `FightRateTheme`, and `HomeScreen`.

- [ ] **Step 4: Verify**

Run: `./gradlew :app:assembleDebug`

Expected: build succeeds when Gradle/Android SDK are installed.

---

## Task 2: Heart Rate Measurement parser, TDD first

**Files:**
- Create: `app/src/main/java/com/healthtracking/fightrate/ble/HeartRateParser.kt`
- Create: `app/src/main/java/com/healthtracking/fightrate/domain/model/HeartRateMeasurement.kt`
- Create: `app/src/test/java/com/healthtracking/fightrate/ble/HeartRateParserTest.kt`

- [ ] **Step 1: Write tests**

Cover these Bluetooth Heart Rate Measurement payloads:

```kotlin
byteArrayOf(0x00, 72)                    // uint8 BPM
byteArrayOf(0x01, 0x2C, 0x01)            // uint16 BPM = 300
byteArrayOf(0x08, 90, 0x34, 0x12)        // energy expended = 0x1234
byteArrayOf(0x10, 120, 0x00, 0x04)       // RR interval = 1024 -> 1000ms
byteArrayOf()                            // invalid empty payload
```

- [ ] **Step 2: Implement parser**

Parse flags, BPM format, optional energy expended, optional RR intervals. Throw `IllegalArgumentException` for malformed payloads.

- [ ] **Step 3: Verify**

Run: `./gradlew :app:testDebugUnitTest`

Expected: all parser tests pass.

---

## Task 3: FightRate visual shell

**Files:**
- Create: `app/src/main/java/com/healthtracking/fightrate/ui/theme/Color.kt`
- Create: `app/src/main/java/com/healthtracking/fightrate/ui/theme/FightRateTheme.kt`
- Create: `app/src/main/java/com/healthtracking/fightrate/domain/model/FightSport.kt`
- Create: `app/src/main/java/com/healthtracking/fightrate/ui/screens/HomeScreen.kt`

- [ ] **Step 1: Define design tokens**

Use the FightRate palette from the design system: black canvas, charcoal surfaces, fight orange, redline red, recovery green, muted gray text.

- [ ] **Step 2: Build static HomeScreen**

Include static UI cards for sensor status, current BPM, round timer, zone bar, sport chips, and session metrics.

- [ ] **Step 3: Verify**

Run: `./gradlew :app:assembleDebug`

Expected: app compiles and opens to a dark FightRate dashboard.

---

## Task 4: BLE connection layer placeholder

**Files:**
- Create: `app/src/main/java/com/healthtracking/fightrate/ble/HeartRateBleConstants.kt`
- Create: `app/src/main/java/com/healthtracking/fightrate/ble/HeartRateBleScanner.kt`
- Create: `app/src/main/java/com/healthtracking/fightrate/ble/HeartRateBleClient.kt`

- [ ] **Step 1: Define UUID constants**

```kotlin
HEART_RATE_SERVICE = 0000180d-0000-1000-8000-00805f9b34fb
HEART_RATE_MEASUREMENT = 00002a37-0000-1000-8000-00805f9b34fb
BODY_SENSOR_LOCATION = 00002a38-0000-1000-8000-00805f9b34fb
BATTERY_SERVICE = 0000180f-0000-1000-8000-00805f9b34fb
BATTERY_LEVEL = 00002a19-0000-1000-8000-00805f9b34fb
```

- [ ] **Step 2: Scanner contract**

Expose a Kotlin API that can later be wired to `BluetoothLeScanner` and emits scan results.

- [ ] **Step 3: Client contract**

Expose connect/disconnect and `Flow<HeartRateMeasurement>` API.

---

## Current Execution Choice

The user asked to proceed with app creation, so start with **Inline Execution** for Tasks 1–3, stopping after verification evidence and reporting environment blockers if Android SDK/Gradle is unavailable.