🛒 Grocery Store Delivery Portal

A .NET 8 Web API for managing grocery orders and delivery scheduling. The core challenge: dynamically generating available delivery time slots per product category, with hard capacity constraints enforced through domain logic — not database triggers or manual checks.

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🚀 Features

• Dynamic Slot Generation — Delivery time slots are auto-generated based on each product category's allowed days and time windows — no hardcoded slots
• Capacity Enforcement — Slots with 4+ scheduled deliveries are automatically marked unavailable; enforced in domain logic, not the UI
• CQRS with MediatR — All operations flow through command/query handlers, keeping controllers thin and logic testable
• Clean Architecture — Domain, Application, Core, Infrastructure, and API layers fully separated
• Unit Tested — Application layer covered with xUnit tests
• Vanilla JS Frontend — Lightweight frontend included for demo purposes

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🏗️ Architecture

Src/
├── Grocery_Store_Task_API/             # Presentation Layer — Controllers, Program.cs
├── Grocery_Store_Task_APPLICATION/     # Application Layer — CQRS Handlers, DTOs, Validators
├── Grocery_Store_Task_CORE/            # Core Layer — Shared interfaces and abstractions
├── Grocery_Store_Task_DOMAIN/          # Domain Layer — Entities, Enums, Business Rules
├── Grocery_Store_Task_INFRASTRUCTURE/  # Infrastructure Layer — EF Core, Repositories
Tests/
└── Grocery_Store_Task_APPLICATIONTests/ # xUnit tests for Application layer
GroceryStoreTaskFrontend/               # Vanilla JS/HTML/CSS demo frontend

How a request flows:

1. HTTP request hits a Controller (API layer)
2. Controller sends a Command or Query via MediatR
3. The appropriate Handler in the Application layer processes it
4. Handler calls Domain logic and Repository interfaces
5. Infrastructure layer executes database operations
6. Result returns back up through the layers

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🧠 The Scheduling Problem

The interesting domain challenge here is slot generation. Each product category defines:

• Allowed delivery days (e.g., Monday, Wednesday, Friday)
• Time windows (e.g., 9am–12pm, 2pm–6pm)
• Capacity limit (max 4 deliveries per slot)

When a customer browses available slots, the system dynamically generates valid slots for the next N days based on the category's rules, then filters out any that are already at capacity. No slots are pre-stored — they're computed on demand.

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🛠️ Tech Stack

Category	Technology
Framework	ASP.NET Core Web API (.NET 8)
Pattern	CQRS + MediatR
ORM	Entity Framework Core
Database	SQL Server
Testing	xUnit
Frontend	Vanilla JavaScript, HTML, CSS
API Docs	Swagger / Swashbuckle

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📚 API Endpoints

Products

Method	Endpoint	Description
GET	/api/Products	Get all products with their categories
GET	/api/Products/{id}	Get product by ID

Delivery Slots

Method	Endpoint	Description
GET	/api/Slots/available/{categoryId}	Get available slots for a product category
POST	/api/Slots/book	Book a delivery slot

Orders

Method	Endpoint	Description
POST	/api/Orders	Create a new order with a booked slot
GET	/api/Orders/{id}	Get order details

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📸 Screenshots

Products List

Time Slot Selection

Order Flow

API Documentation

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📦 Getting Started

Prerequisites

• .NET 8 SDK
• SQL Server

Setup

1. Clone the repository

   git clone https://github.com/AhmedMTwab/GroceryStoreTask.git
   cd GroceryStoreTask

2. Configure the connection string in Src/Grocery_Store_Task_API/appsettings.json

   {
     "ConnectionStrings": {
       "DefaultConnection": "Server=.;Database=GroceryStoreDb;Trusted_Connection=True;"
     }
   }

   📌 Database Connection Note: This application is connected to a deployed database, so you don't need to change the connection string. However, if the deployed database fails or you want to use your own database, you can update the connection string above.

3. Apply migrations

   dotnet ef database update --project Src/Grocery_Store_Task_INFRASTRUCTURE

4. Run the API

   dotnet run --project Src/Grocery_Store_Task_API

5. Open the frontend — open GroceryStoreTaskFrontend/index.html in your browser, or access Swagger at https://localhost:5001

Running Tests

dotnet test Tests/Grocery_Store_Task_APPLICATIONTests

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👤 Author

Ahmed Mohamed Eltwab