Project Structure and Estimation

I am going to estimate in hours because it is a small project. If it were not, I would use T-shirt sizes.

In this case, the estimates could be:

• S (Small effort): 2 hours
• M (Medium effort): 3 hours
• L (Large effort): 4 hours

1. Project Initialization (2 hours)
   • Set up a new Node.js project with Express.
     • We use Node.js and express because it allows me to cover the requirement: Every endpoint must respond with a JSON object and a status code, following the REST principles.
   • Install required dependencies (Express, Sequelize, PostgreSQL/MySQL).
   • Configure Sequelize and connect to the database. Add pool feature to handle multiple requests. helping us to cover requirement: Concurrency: the API must be able to handle multiple requests simultaneously.

• It takes just 2 hours if the developer already knows how to install the dependencies and has experience with Sequelize
• We are not going to implement load balancer or Horizontal scaling by now because is not required until we understand the number of request that we receive.

2. Database Models creation (2 hours)

   • Create models for Warehouse, Product, and Delivery.
   • We would not save routes as it seems not required
   • We should take into account that:
     • Take in mind that each product is only available on a subset of warehouses, and the route must respect this constraint.
   • Warehouse table
     • id : string
     • name : string
     • lat : float64
     • lon : float64
   • Product table
     • id : string
     • name : string
     • warehouse_ids : []string, a list of the ids of the warehouses that contains this product
   • Delivery table
     • product_ids: [] string List of all product IDs
     • lat: float64 Latitude of the delivery location
     • lon: float64 Longitude of the delivery location
     • delivery_date: string Delivery date
     • warehouse_id: [] string List of all warehouse IDs associated to the products ids

3. Warehouse and Product Endpoints (2 hours)

   • Implement Warehouse Create and Read endpoints.
   • Implement Product Create and Read endpoints.
   • Errors to handle: Error to save to database
   • Return response code 200 if everything is correct
   • Return response code 400 if error appears
   • Add unit test to test correct behavior and error for both endpoints

4. Delivery Endpoints (3 hours)

   • Implement Delivery endpoint
     • In Params:
       • product_ids, lat, lon, delivery_dat
     • Steps to implement
       • Find warehouses that contain all the required products
       • Save the information in database
       • Return error if the product is not available in the warehouses
     • Add unit test to test correct behavior and error for both endpoints
   • Use Transactions for Critical Operations: For operations that must be atomic, such as creating deliveries and ensuring the warehouse constraint, use transactions.

5. Route Calculation (4 hours)

   • Implement Create Route endpoint.
     • in params
       • delivery_ids
     • return
       • route : A list of waypoints (latitude and longitude) that represents the optimal route to deliver all products. Those waypoints correspond to delivery locations and warehouses.
       • distance : Total distance of the route in km
   • To calculate route. Implement route calculation logic.
     • Group deliveries by warehouse
       • Here we use the ids of the warehouses saved on database.
     • Calculate waypoints based on the grouped deliveries
     • Take into account delivery location as previous waypoint before return to the warehouse where the user should start the route

6. Write load Testing to test multiple requests (2 hours)

   • Test Creation of deliveries and routes at the same time