Architecture

This section covers the technical architecture of DiveSuite: decisions, system design, and database schema.

Overview

DiveSuite follows a layered architecture with clear separation of concerns:

graph TB
    subgraph "UI Layer"
        RN[React Native Screens]
    end

    subgraph "State Management"
        ZS[Zustand Stores]
    end

    subgraph "Service Layer"
        PS[Planning Service]
        LS[Logging Service]
        AS[Analysis Service]
        AI[AI Service]
    end

    subgraph "Core Layer"
        DE[Deco Engine<br/>Rust/WASM]
        DAL[Data Access Layer<br/>Repositories]
    end

    subgraph "Storage"
        DB[(WatermelonDB<br/>SQLite)]
        FS[File Storage]
    end

    RN --> ZS
    ZS --> PS & LS & AS & AI
    PS --> DE
    PS & LS & AS --> DAL
    AI -.->|"advisory only"| PS
    DAL --> DB
    LS --> FS

Key Decisions

Decision	Choice	Rationale
AD-01	UUID v4 primary keys	Global uniqueness for offline-first sync
AD-02	WatermelonDB	Built-in sync, lazy loading, RN-optimized
AD-03	Rust/WASM deco engine	Type safety, performance, cross-platform
AD-04	Zustand	Lightweight state management, no boilerplate
AD-05	5-tab navigation	Plan, Log, Community, Stats, Profile
AD-06	i18next	i18n from day one (EN + DE)
AD-07	AI behind interface	Never coupled to UI or deco engine
AD-08	Offline-first	Local DB is source of truth
AD-09	UI library TBD	Evaluate in M0 (Tamagui, Paper, Gluestack)
AD-10	Feature-based folders	Code organized by feature, not layer
AD-11	Opt-in analytics	Privacy-first, GDPR compliant

Safety Architecture

Critical: AI Isolation

AI services are strictly isolated from safety-critical calculations:

User Input -> AI Service -> Suggested Parameters
                                ->
                        User Verification
                                ->
                        Deco Engine (Rust)
                                ->
                        Validated Plan Output

AI never directly generates decompression schedules. AI output is always treated as unverified user input that must flow through the normal validation path.

Tech Stack Summary

Layer	Technology
Framework	React Native + Expo
Language	TypeScript (strict mode)
Deco Engine	Rust -> WebAssembly
Database	WatermelonDB (SQLite)
State	Zustand
i18n	i18next
Navigation	expo-router
Styling	TBD (Tamagui, Paper, or Gluestack)