📱 TechFix - Enterprise Edge-Powered Repair Management System

A massively scalable, multi-role Android application powered by Cloudflare's serverless edge computing and D1 SQLite.

Bridging the gap between technicians, shop managers, and customers with sub-millisecond edge latency.

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🎯 Project Overview

TechFix is a comprehensive, enterprise-grade mobile platform designed to orchestrate the entire lifecycle of device repairs. Built natively for Android, the application eliminates operational bottlenecks using an ultra-fast, serverless backend via Cloudflare Workers and D1 (SQLite at the Edge).

From real-time geospatial routing of customer requests to multi-tier Role-Based Access Control (RBAC), inventory management, and robust financial reporting, TechFix brings modern edge-computing architecture to technical repair chains.

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🌟 Advanced System Highlights

• 📍 Algorithmic Geospatial Auto-Routing: Integrates the Haversine formula on the backend to dynamically calculate the distance from a customer's GPS coordinates to all active branches. Automatically assigns repairs to the nearest branch with available technicians and required spare parts.
• ⚡ Global Edge-Native Speed: APIs are executed globally within milliseconds of the end user via Cloudflare Workers. Database queries are distributed and optimized using Cloudflare D1.
• 🛡️ Zero-Trust Security & RBAC: Features auto-generated secure credentials for new staff, forced mandatory password resets upon first login, and strict RBAC enforced via stateless JWTs verified at the edge.
• 📸 Cloud-Native Media Storage: Seamless integration with Cloudinary for uploading and tracking device condition images, pre-repair, and post-repair photographic evidence.
• 📡 Offline-Ready Mobile Architecture: Built with modern Android standards utilizing Room Database for intelligent local caching, ensuring technicians can view their tasks even with spotty connectivity.

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🏗️ System Architecture

TechFix embraces an Edge-First Architecture. By distributing backend logic directly on Cloudflare's CDN edge nodes, the app guarantees high availability and minimal latency for data-heavy operations.

graph TD
    %% Entities
    APP[📱 Android Native App<br>Retrofit / Java]
    EDGE[⚡ Cloudflare Worker<br>Serverless REST API<br>Geospatial Algorithm]
    D1[(🗄️ Cloudflare D1<br>Edge SQLite Database)]
    CLOUDINARY[☁️ Cloudinary API<br>Image & Object Storage]
    
    %% Relationships
    APP -- "JSON via HTTPS" --> EDGE
    EDGE -- "SQL Transactions" --> D1
    APP -- "Multipart Upload" --> CLOUDINARY
    EDGE -- "Signed Tokens" --> CLOUDINARY
    
    %% Styling
    classDef mobile fill:#3DDC84,stroke:#fff,stroke-width:2px,color:#000
    classDef cf fill:#F38020,stroke:#fff,stroke-width:2px,color:#fff
    classDef db fill:#003B57,stroke:#fff,stroke-width:2px,color:#fff
    classDef cloud fill:#3448C5,stroke:#fff,stroke-width:2px,color:#fff
    
    class APP mobile
    class EDGE cf
    class D1 db
    class CLOUDINARY cloud

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👥 Comprehensive Role Modules (The Team)

TechFix is a collaborative masterpiece built around four distinct domains, each meticulously crafted to handle a specific facet of the repair business lifecycle.

🧠 Member 1: Core Backend, API & Edge Security

Domain: Cloudflare Workers API, D1 Database, JWT Authentication, and Global Business Logic.

• Orchestrates the serverless REST API using Node.js on Cloudflare Workers.
• Designs and maintains the Cloudflare D1 SQLite relational database schema ensuring ACID compliance.
• Implements the PBKDF2 SHA-256 password hashing and stateless JWT validation.
• Enforces strict Role-Based Authorization, API validation, and error handling.
• Powers the complex business rules for appointment lifecycles and technician assignment tracking.

📱 Member 2: Customer Repair Journey

Domain: Customer UI, Appointments, and Repair Tracking.

• Provides the frontend experience for end-users to register, login, and manage their devices.
• Drives the Book a Repair flow allowing customers to select services, dates, times, and map coordinates.
• Builds the live Repair Tracking timeline (REQUESTED → ASSIGNED → DIAGNOSING → REPAIRING → TESTING → COMPLETED).
• Manages the complete Repair History viewing functionality for transparency.

🏢 Member 3: Branch & Technician Administration

Domain: Control Center, Admin Dashboard, Staff Allocation.

• Creates the Management Dashboard to view overall business health and system metrics.
• Manages Branch Operations, including geospatial coordinates and branch status.
• Administers the Technician Roster, assigning skills, specialization, and managing availability states (AVAILABLE, BUSY, OFF_DUTY, ON_LEAVE).
• Handles the manual override Technician Assignment UI, pairing pending repairs with the correct staff.

💰 Member 4: Inventory, Finances & Reports

Domain: Spare Parts management, Payments processing, Analytics.

• Constructs the Spare Parts Ledger, tracking stock quantity, prices, and low-stock alerts.
• Integrates Payment Processing screens, tracking payment intents (PAID, FAILED, REFUNDED), capturing receipts, and total costs based on parts consumed.
• Builds dynamic Management Reports visualizing Revenue, Active Repairs, Parts utilization, and Branch performance metrics.

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🗄️ Database Schema Snapshot

The D1 database is highly normalized to ensure data integrity during parallel API transactions and automated routing algorithms.

erDiagram
    USERS ||--o| CUSTOMERS : "has profile"
    USERS ||--o| TECHNICIANS : "has profile"
    CUSTOMERS ||--o{ APPOINTMENTS : "books"
    CUSTOMERS ||--o{ DEVICES : "owns"
    BRANCHES ||--o{ INVENTORY : "stocks parts"
    BRANCHES ||--o{ TECHNICIANS : "employs"
    APPOINTMENTS ||--o{ REPAIR_HISTORY : "tracks status"
    APPOINTMENTS ||--o{ REPAIR_PARTS : "consumes"
    APPOINTMENTS ||--o| PAYMENTS : "generates invoice"

    USERS {
        string id PK
        string role "Admin, Manager, Tech, Customer"
        string email
        string password_hash
    }
    APPOINTMENTS {
        string id PK
        string status "Requested, Diagnosing, Completed"
        float customer_lat
        float customer_lng
    }
    INVENTORY {
        string id PK
        string part_name
        int stock_level
        float price
    }

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🔐 Advanced Security Implementations

• PBKDF2 Edge Hashing: Passwords are never stored in plaintext. They are salted and hashed natively inside the V8 engine on the Cloudflare Edge using high-iteration PBKDF2 (SHA-256).
• Stateless JWT Authorization: API tokens are generated and signed with Web Crypto API HMAC. The Worker middleware validates claims natively without requiring a database lookup for every request.
• Strict Role Boundaries: All endpoints utilize granular interceptors to match the exact role claim (Admin, Manager, Technician, Customer) required before routing transactions.
• SQL Injection Prevention: 100% parameterized queries via D1 SQLite Bindings natively prevent payload injection. Case-insensitive routing enforces email collision checks via LOWER() SQL.

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🚀 Complete Deployment Guide

Follow these steps to deploy both the highly-available backend and the native Android frontend.

1️⃣ Serverless Edge Backend (Cloudflare Workers + D1)

Prerequisites:

• Install Node.js and NPM.
• Install Wrangler CLI globally: npm install -g wrangler

Click to expand backend deployment steps

1. Login to Cloudflare

   npx wrangler login

2. Navigate to the Backend Directory

   cd cloudflare-backend

3. Initialize the Database Create a new D1 database via your Cloudflare Dashboard, or using the CLI:

   npx wrangler d1 create techfix-db

   Copy the generated database_id and paste it into cloudflare-backend/wrangler.toml.
4. Set Environment Variables Ensure JWT_SECRET is populated in your wrangler.toml file under the [vars] block for token generation to work successfully.
5. Run the Schema Migrations Push the table structures to your remote D1 instance:

   npx wrangler d1 execute techfix-db --remote --file=./schema.sql

6. Deploy the Worker globally

   npx wrangler deploy

   This will output a live CDN URL (e.g., https://techfix-backend.<your-subdomain>.workers.dev).

2️⃣ Mobile Frontend (Android Studio)

Prerequisites:

• Install Android Studio (Giraffe or later).
• Java Development Kit (JDK 17).

Click to expand Android setup steps

1. Open the Project Open the root TECHFIX folder inside Android Studio.

2. Connect the Edge Backend Open the following file: app/src/main/java/com/mad/techfix/network/RetrofitClient.java

   Replace the BASE_URL with your fully unified Cloudflare Worker deployment URL:

   private static final String BASE_URL = "https://techfix-backend.<your-subdomain>.workers.dev/";

3. Sync and Build

   • Wait for Gradle to sync dependencies.
   • Click Run (Shift + F10) to launch the app on an emulator or physical device.

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📸 Application Gallery

(Add your application screenshots here in an organized grid)

Customer Dashboard	Repair Tracking	Admin Analytics	Parts Ledger

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Developed dynamically for the Mobile Application Development Module.

Licensed under the MIT License
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