-Inventory_System

Inventory & Order Management System built with ASP.NET Core & Clean Architecture. Features include role-based authentication, product & category management, purchase orders, sales invoicing, real-time stock control, PDF export, notifications, and reporting.

Designed for scalability, testability, and real-world business workflows such as product tracking, sales invoicing, stock adjustment, and purchase order lifecycle handling — including Domain Events, Background Services, and Real-Time Notifications using SignalR.

📄 API Documentation: View PDF

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🛠️ Tech Stack

• Backend: ASP.NET Core 8, EF Core
• Real-time: SignalR
• Database: SQL Server
• PDF generation: QuestPDF
• Patterns: Clean Architecture, CQRS, Domain Events

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⚙️ Requirements & Setup (Without Docker)

✅ Requirements

Make sure you have installed:

• .NET 8 SDK
• SQL Server (LocalDB or full instance)
• Visual Studio 2022 or Visual Studio Code

🚀 Setup Steps

1. Clone the repository

git clone https://github.com/your-username/Inventory_System.git
cd Inventory_System

2.Configure appsettings.json

In src/InventorySystem.Api/appsettings.json, update the configuration:

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=YOUR_SQL_SERVER;Database=InventorySystem;Trusted_Connection=True;TrustServerCertificate=True;MultipleActiveResultSets=True"
  },

  "JwtOptions": {
    "Issuer": "your-app",
    "Audience": "your-app-users",
    "SecretKey": "your-super-secret-key"
  },

  "SmtpOptions": {
    "Host": "smtp.yourmail.com",
    "Port": 587,
    "UserName": "your-email@domain.com",
    "Password": "your-email-password",
    "EnableSsl": true
  },

  "LinkOptions": {
    "BaseUrl": "http://localhost:4200"
  }
}

3. Apply EF Core migrations

dotnet ef database update --project src/InventorySystem.Infrastructure --startup-project src/InventorySystem.Api

4. Run the API

cd src/InventorySystem.Api
dotnet run

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🖥️ API Endpoints & Test Account

You can explore all API endpoints using Swagger:
Swagger UI

Test Account

Use the following credentials to test authentication and API calls:

• Email: Admin@Gmail.com
• Password: Admin#123
• DeviceId: A1

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📂 Project Structure

src/
├── InventorySystem.Api            # Presentation layer (controllers, middlewares, config)
├── InventorySystem.Application    # CQRS commands, queries, DTOs, validators
├── InventorySystem.Domain         # Entities, Enums, Domain Events
├── InventorySystem.Infrastructure # EF Core, Repositories, Identity, Services
└── Shared                         # Shared DTOs, constants, error models

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🗄️ ERD (Entity Relationship Diagram)

The diagram below shows the core tables and relationships of the Inventory & Order Management System.
It focuses on the main entities like Products, Categories, Customers, Employees, Orders, and Suppliers.

Note: Some technical or auxiliary tables (like notifications, logs, or Identity internal tables) are omitted for clarity.

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🏗️ Architecture Highlights

• ✅ Clean Architecture (Domain, Application, Infrastructure, WebAPI)
• ✅ CQRS with MediatR for commands and queries
• ✅ Domain Events for triggering side effects like:
  • 📧 Sending emails when a Purchase Order is Created, Received, or Cancelled
  • 🔔 Sending real-time SignalR notifications
  • 📉 Automatically checking for low-stock products after stock adjustments
• ✅ SignalR for real-time notifications (e.g., low stock alerts, PO updates)
• ✅ Background Services for deferred or long-running domain operations
• ✅ SQL atomic updates to guarantee stock integrity at the database level.
• ✅ Role-based Authorization (Admin, Manager, Sales, Warehouse)
• ✅ Soft Deletion, Optimistic Concurrency, FluentValidation pipeline
• ✅ Applied the Observer pattern with Domain Events, SignalR, and Background Services to decouple workflows (e.g., triggering real-time notifications and emails when purchase orders are created or updated).

🔥 Key Features

• 🔐 Authentication & Refresh Tokens
• 🧾 Sales Invoicing
• 📦 Inventory Control with value reports & manual adjustments
• 🛒 Purchase Orders (create, cancel, receive, export to PDF)
• 🧍 Employee, Customer & Supplier Management
• 📊 Sales Reports + PDF export
• 🔔 Real-time Notifications with SignalR
• 📃 Stock Adjustment Logs + PDF export

📬 Notable Domain Events

• 🟡 PurchaseOrderStatusChangedDomainEvent:

  • Sends SignalR notifications to warehouse users
  • Emails supplier with the order details

• 🔴 ProductStockDecreasedDomainEvent:

  • Automatically triggers low stock warning
  • Sends SignalR notification to managers

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🧠 How CQRS Works Here

• Commands → Handlers → Services for business logic
• Queries → Handlers for read-only views
• MediatR decouples the flow
• Validators run in the pipeline before command handlers

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PDF Previews

Purchase Order PDF:

Sales Invoice PDF:

Sales Report PDF:

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📡 Real-Time with SignalR

• NotificationHub broadcasts:
  • 🔔 New domain event-based notifications
  • 📉 Low-stock warnings
  • ✅ Purchase order status updates