emiliodavidcs / wallbox-php-backend-kata

Coding challenge for Wallbox

Backend Challenge

Solution

How to execute the application

1. Install project dependencies.

   composer install
   

2. Create a text file with valid input as described in the INPUT section below (or use the example one: app/example/example-electric-vehicle-navigation.txt).
3. Execute the command app:electric-vehicle:navigation with the file as its only and required argument.

Here is an execution command with the example input file:

./app/app.php app:electric-vehicle:navigation ./app/example/example-electric-vehicle-navigation.txt

This will output to the console the information about the city created, the electric vehicles deployed and where they ended their navigation.

The final position of each electric vehicle can be found in ElectricVehicleCollection after the navigation has finished, so it can be saved into a file if required, for example.

Executing tests

In order to run the application test, execute the PHPUnit command

phpunit tests

Improvements proposal

Nothing is perfect and there is always a way to improve, these are some of those things that could make this application even better:

• Give each electric vehicle, city and instruction a UUID and refer to them through a shared UuiDValueObject and a repository.
• Through command design pattern (which base is already implemented in this app), let the user go back and forth through the navigation.
• Display a visual representation of the navigation.
• Add some more validations:
  • City limits are not negative integers.
  • ...
• Improve test model generators to some kind of fixtures or a more robust alternative.
• Increase tests coverage.

Learning Competencies

• Challenge understanding.
• Implement Object Oriented Desing, DDD, patterns and best practices.
• Implement tests.
• Manipulate Input/Output correctly.

The challenge

We've received a user story from product team. A group of electric vehicles (EV) with autopilot are being landed by Wallbox on a city. The area of that city, which is curiously rectangular, must be navigated by these EVs so that their on-board webcams and detectors can get a complete view of the surrounding terrain. A EV's position and location is represented by a combination of x and y coordinates, and a letter representing one of the four cardinal compass points. The area is divided up into a grid to simplify the navigation. An example position might be 0, 0, N, which means the EV is in the bottom left corner and facing North. All the EVs are positionated in the city area, and to represent that we'll get an input like 0, 0, N, being the first digit the x axis and the second one y axis and the last letter is the direction where the EV is heading. Taking into account that the only possible letters are: N, E, S and W. The EVs can only receive the following instructions: R, L and M (move forward). 'R' and 'L' make the rover spin 90 degrees left or right respectively, without moving from its current spot. 'M' means move forward one grid point, and maintain the same heading.

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INPUT:

The first line of input is the upper-right coordinates of the area (akka area limit), the lower-left coordinates are assumed to be 0,0. The rest of the input is information pertaining to the EVs that have been deployed. Each EV should has two lines of input. The first line gives the EV's position, and the second line is a series of instructions telling the EV how to explore the area. The position is made up of two integers, and a letter separated by spaces, corresponding to the x and y co-ordinates and the EV's orientation. Each EV will be finished sequentially, which means that the second EV won't start to move until the first one has finished moving. Take into account that only one EV can be in the same position.

OUTPUT

The output for each EV should be its final co-ordinates and heading.

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Input Cheat Sheet

The output for each EV should be its final co-ordinates and heading.

Test Input:

5 5
1 2 N
LMLMLMLMM
3 3 E
MMRMMRMRRM

Expected Output:

1 3 N
5 1 E