Alien Invasion Simulator

This project implements a simple Alien Invasion simulator CLI.

• Principle
• Assumptions
• Parameters
• Install
• Run
• Examples
• Tests
• Help
• Documentation

Principle

The principle of the simulation is:

• a world describes a list of cities and their possible links to other cities
• a link can be set in any direction of this set: {North, East, South, West}
• some aliens are spawned randomly in the world
• the aliens move randomly from one city to another existing link
• when two aliens meet in a city they fight so that:
  • city gets destroyed (so do the links to this city)
  • the aliens are trapped (so that they are not able to move anymore)
• the simulation ends when:
  • all the cities are destroyed
  • all the aliens are trapped
  • a maximum number of steps is reached

Assumptions

The following assumptions have been made :

• the city names don't include any space (which should be replaced by any other character). For example, use New-York instead of New York.
• aliens are spawned once at the beginning of the simulation
• the validity off the links is not checked (meaning that a city may be linked to the same city through several directions)

Parameters

The following parameters are available :

• aliens (shorthanded to n) the number of aliens spawned at startup (defaults to 5)
• steps (shorthanded to s) the number of maximum steps allowed (defaults to 10,000)
• file (shorthanded to m) the path of the world map file (defaults to map.txt)

Install

From Source

Step 1: Install Golang

• Install a correctly configured Go toolchain (version 1.17+).
• Make sure that your GOPATH and GOBIN environment variables are properly set up.

Step 2: Get source code

#Download sources from github
git clone https://github.com/jpraynaud/alien-invasion-simulator

# Go to sources directory
cd alien-invasion-simulator

# Checkout master branch
git checkout master

Step 3 : Build binary

# Build
go build -o bin/alien-invasion cmd/cli/main.go

Step 4 : Verify

# Verify
./bin/alien-invasion --help

# or Build and Run
go run cmd/cli/main.go --help

That should output something like:

An alien invasion simulator.
More informations available at: https://github.com/jpraynaud/alien-invasion-simulator

Usage:
  alien-invasion [flags]

Flags:
  -n, --aliens uint   total number of aliens (default 5)
  -m, --file string   world map file path (default "map.txt")
  -h, --help          help for alien-invasion
  -s, --steps uint    maximum number of steps (default 10000)

Run

# Run
./bin/alien-invasion

# or
go run cmd/cli/main.go

That should output something like:

London has been destroyed by Alien #3 and Alien #1
Warsaw has been destroyed by Alien #4 and Alien #2

Roma north=Geneva west=Barcelona
Athens
Stockholm
Geneva
Paris north=Brussels south=Barcelona east=Berlin
Brussels
Berlin north=Stockholm
Barcelona north=Paris east=Roma

Examples

• Set number of spawned aliens:

# Run
./bin/alien-invasion -n 100

# or
go run cmd/cli/main.go --aliens 100

• Set maximum number of steps:

# Run
./bin/alien-invasion -s 5

# or
go run cmd/cli/main.go --steps 5

• Set map file path:

# Run
./bin/alien-invasion -m ../maps-directory/other-map.txt

# or
go run cmd/cli/main.go --file ../maps-directory/other-map.txt

• Combine options:

# Run
./bin/alien-invasion -n 4 -s 10

# or
go run cmd/cli/main.go --aliens 4 --steps 10

Tests

Run unit tests:

# Test with code coverage
go test -cover ./...

# Test with verbose output
go test -cover -v ./...

Help

Get help:

# Help with executable
./bin/alien-invasion -h

# or
go run cmd/cli/main.go --help

Documentation