Mimir — Android

Android client for Mimir, a self-hosted invite-only messaging network. Kotlin + Jetpack Compose, real-time DM, ephemeral WebRTC voice calls, FCM push, sideload auto-update. Named after the Norse keeper of the well of wisdom.

✨ Features

• 💬 Real-time DM — SignalR push (typing indicator, edit, soft-delete, read receipts)
• 🟢 Presence — friend online/offline + last-seen with pulsing avatar dot
• 🔍 Local search — in-memory filter on chats & friends
• 🔔 FCM push — wake-up on locked screen, rich notification (sender + content preview)
• 📞 Voice call — WebRTC P2P + TURN fallback; full-screen call UI with speaker/mic toggle
• 🌓 Material 3 theme — light/dark/system, Norse brand palette (deep blue + rune amber)
• 🎨 Custom adaptive icon — Mannaz rune (M) with amber glyph drop
• ⬇️ In-app auto-update — sideload APK + force-update gate (HTTP 426)
• 🔐 Closed-network — friend-key approval (no public discovery)
• 🚀 CI/CD — GitHub Actions: push → debug APK build + VPS upload + force-update env

📸 Screens

Login	Chats	Call
(coming soon)	(coming soon)	(coming soon)

🏗️ Architecture

graph TB
    UI[Jetpack Compose UI<br/>14 screens + bottom nav] --> VM[State machines<br/>Screen + AuthTab + AuthDetail]
    VM --> Apis[Apis factory<br/>Mimir/Admin/Friends/Messaging/Push/Call]
    Apis --> Ktor[Ktor HTTP client<br/>OkHttp + JWT bearer]
    UI --> Realtime[RealtimeClient<br/>SignalR Java client]
    UI --> Call[CallManager + CallSession<br/>WebRTC peer + signaling adapter]
    Call --> WebRTC[org.webrtc<br/>PeerConnectionFactory]
    Realtime -.->|hub/dm| Backend[mimir-api]
    Ktor -.->|/api/*| Backend
    FCM[FirebaseMessagingService] -.->|callOffer / newMessage signal| Backend
    Splash[Splash screen<br/>Android 12+ API] --> UI

    classDef ui fill:#1E3A5F,color:#FAF7F0
    class UI,VM,Splash ui

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🧰 Stack

Layer	Tech
Language	Kotlin 2.1, Coroutines, Flow
UI	Jetpack Compose, Material 3, DataStore Preferences
Network	Ktor 3.0 (OkHttp engine), kotlinx-serialization
Real-time	Microsoft SignalR Java client 8.0
WebRTC	io.github.webrtc-sdk:android 114.5735
Push	Firebase Messaging KTX (BOM 33.7) — only firebase-messaging, no Auth/Firestore/Storage
Splash	androidx.core:core-splashscreen 1.0
Build	AGP 8.7, Java 17 (Android Studio JBR), Gradle 8.10
Lint	Compose lint defaults
Min/Target SDK	24 / 34

🚀 Quick Start

# 1. Clone
git clone https://github.com/Aykuttonpc/mimir-mobile.git
cd mimir-mobile

# 2. Firebase setup (FCM push)
# Firebase Console → Add Android app (package: com.aykutcincik.mimir) → download
# Save: app/google-services.json

# 3. Build debug APK (uses deterministic mimir-debug.keystore committed to repo)
./gradlew :app:assembleDebug

# 4. Install
adb install app/build/outputs/apk/debug/app-debug.apk

The repo ships with a stable debug keystore (app/mimir-debug.keystore) so every CI build signs identically — APK updates install seamlessly without uninstall. Production release builds need a separate keystore (Sprint #14+).

🎨 Theme & Brand

Norse mythology vibe — deep nordic blue + rune amber + ember copper. Mannaz rune (ᛗ) symbolizes humanity & wisdom.

Light: #1E3A5F (deep nordic blue) + #B08544 (rune amber)
Dark:  #8FB4DC (frost blue)        + #E5C589 (warm amber)

📚 Architecture Decisions

Documented in .claudeteam/DECISIONS.md. Key mobile ADRs:

• ADR-007 Path-prefix routing (https://aykutonpc.com/mimir/)
• ADR-008 Separate backend + mobile repos
• ADR-015 Backend-authoritative version gate + in-app sideload update
• ADR-016 Friend-key approval friendship
• ADR-017 FCM signal-only push (content stays on backend)
• ADR-019 WebRTC voice call: GetStream baseline adopted

🛡️ Security Highlights

• HTTPS-only (usesCleartextTraffic=false)
• DataStore token storage (Android internal storage, app-private)
• WebRTC media is end-to-end DTLS-SRTP encrypted (DM and call content never decrypted by FCM/TURN)
• Sensitive files gitignored: .env*, secrets/, *.jks, *.keystore (debug keystore is the only explicit exception)
• mimir-debug.keystore is debug-only; production release builds use a separate keystore

🔄 CI/CD

GitHub Actions workflow at .github/workflows/deploy-apk.yml:

1. Push to master → JDK 17 + Gradle cache → assembleDebug → APK
2. SCP to VPS /opt/mimir/apks/
3. Update .env.prod (LATEST_APP_VERSION_ANDROID + URL)
4. Optional force=true dispatch → also bumps MIN_APP_VERSION_ANDROID (old APKs get HTTP 426)
5. Healthcheck on backend container, fail → no env mutation

🔌 Backend Companion

ASP.NET Core 9 backend: mimir-api

📄 License

MIT — see LICENSE.

🙏 Acknowledgments

• WebRTC PeerConnection wrapper + signaling pattern adapted from GetStream/webrtc-in-jetpack-compose (Apache 2.0).
• The pre-compiled WebRTC binary io.github.webrtc-sdk:android (BSD).
• FCM/Firebase trademarks owned by Google. Mimir uses only firebase-messaging — Firebase Auth/Firestore/Storage not used (ADR-002, ADR-017).