🕵️‍♂️ CallInspector

CallInspector is a modular, production-grade diagnostic engine designed to validate Android device hardware and network integrity before critical video calls.

It goes beyond simple API checks by implementing low-level socket probes, automated hardware analysis, and mathematical scoring models to grade device health.

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🚀 Key Features

📡 Network Diagnostic Engine

Instead of relying on simple HTTP checks, CallInspector implements a custom networking stack:

• TCP Socket Probes: Measures raw TCP handshake latency to bypass ICMP restrictions.
• Jitter Calculation: Computes variance between packet arrivals in real-time.
• Throughput Testing: Streams data from a dedicated CDN to measure true bandwidth.
• Packet Loss Estimation: Detects dropped socket connections.

📸 Automated Sensor Validation

• CameraX ImageAnalysis: Uses background threads to analyze pixel luminosity buffers (YUV_420_888) to mathematically verify if the lens is functioning or covered.
• Microphone Amplitude: Visualizes raw audio input levels using MediaRecorder.

📦 Dynamic Feature Module

Demonstrates advanced modularization capabilities:

• Service Status Dashboard: A completely separate module (:dynamic_status_module) delivered via Play Feature Delivery.
• Architecture: Implements the "Logic in Base, UI in Dynamic" pattern to solve Hilt dependency graph constraints while keeping the APK size optimized.

📊 Health Scoring Algorithm

• Aggregates 15+ metrics into a weighted score (0-100).
• Generates a final "Device Grade" (A+ to F).
• Logic verified by Unit Tests using Mockk.

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🛠 Tech Stack

Category	Library / Technology	Usage
Language	Kotlin	100% Codebase
UI	Jetpack Compose	Material3 Design System
Architecture	MVI / Clean Architecture	Unidirectional Data Flow
Injection	Hilt	Dependency Injection
Concurrency	Coroutines + Flow	Reactive Data Streams
Networking	Retrofit + Java Sockets	API & Latency Probes
Hardware	CameraX	Hardware Abstraction
Testing	Mockk + Turbine	Unit Testing Flows & Logic
Persistence	Room	Local SQLite Database

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🏗 Architecture & Modularization

The project follows a scalable MVVM + Clean Architecture pattern, designed to separate concerns and ensure testability.

Module Structure

The app is modularized by feature to support Dynamic Delivery and Strict Dependency Boundaries.

:app (Base Module)
 ├── core/              # Shared Logic (Network, Dispatchers, Utils)
 ├── diagnostics/       # Feature: Hardware Tests (Mic, Cam, Socket Probe)
 ├── navigation/        # App Navigation Graph
 └── status/            # Feature Logic: Service Status (ViewModel/Repo)

:dynamic-status-module (Dynamic Feature)
 └── presentation/      # UI: Service Status Screen (Compose)
     └── Loaded via Reflection at runtime to reduce initial APK size.

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📜 Audit History & Persistence

• Local Database (Room): Automatically persists every diagnostic run for compliance and historical comparison.
• Structured Reporting: Saves granular details (latency, jitter, sensor pass/fail status) alongside the final grade.
• Offline Access: Review past audit results without network connectivity.

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🏗 Architecture Overview

The app follows strict Clean Architecture principles to ensure testability and separation of concerns.

graph TD
    subgraph "Base Module (:app)"
        UI["Presentation Layer<br>(ViewModels + Compose)"]
        Domain["Domain Layer<br>(UseCases + Interfaces)"]
        Data["Data Layer<br>(Repositories + Implementations)"]
    end

    subgraph "Dynamic Feature (:dynamic_status_module)"
        DFM["Dynamic UI<br>(Status Dashboard)"]
    end

    %% Architecture Flow
    UI --> Domain
    Domain --> Data
    
    %% Dynamic Feature Logic (Logic in Base, UI in Dynamic)
    DFM -->|Depends on| UI
    UI -.->|Loads via Reflection| DFM

    %% Data Sources
    Data --> Remote["Remote Data<br>(TCP Sockets / Retrofit)"]
    Data --> Hardware["Device Hardware<br>(CameraX / Mic)"]
    Data --> Local["Persistence<br>(Room Database)"]

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📸 Screenshots

Dashboard	Diagnostics
Status Check & Features	Real-time Socket Analysis

Device Capabilities	Service Status (DFM)
Hardware Audit	Dynamic Feature Module

Final Report
Automated Scoring Engine

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