binary.handshake.rb

require 'rspec'
# # Binary Secret Handshake

# > There are 10 types of people in the world: Those who understand binary, and those who don't.

# You and your fellow flatirons are of those in the "know" when it comes to binary decide to come up with a secret "handshake".

# ```
# 1 = wink
# 10 = double blink
# 100 = close your eyes
# 1000 = jump


# 10000 = Reverse the order of the operations in the secret handshake.
# ```

# Write a program that will convert a binary number, represented as a string (i.e. "101010"), and convert it to the appropriate sequence of events for a secret handshake.


# ```
# handshake = SecretHandshake.new "1001"
# handshake.commands # => ["wink","jump"]

# handshake = SecretHandshake.new "11001"
# handshake.commands # => ["jump","wink"]
# ```

# The program should consider strings specifying an invalid binary as the value 0.

RSpec.configure do |config|
  # Use color in STDOUT
  config.color_enabled = true

  # Use color not only in STDOUT but also in pagers and files
  config.tty = true

  # Use the specified formatter
  config.formatter = :progress # :progress, :html, :textmate
end

class SecretHandshake
  attr_reader :binary_num

  ReverseFlag = 16
  CommandList = ["wink", "double blink", "close your eyes", "jump"]

# 1 = wink
# 10 = double blink
# 100 = close your eyes
# 1000 = jump

  def initialize(binary_string)
    @binary_num = binary_string.to_i(2)
  end

  def command_list
    CommandList
  end

  def reverse_flag
    ReverseFlag
  end

  def commands
    handshake = build_handshake(binary_num, command_list)

    if reverse?
      handshake.reverse
    else
      handshake
    end
  end

  def reverse?
    (binary_num & reverse_flag) != 0
  end

  def build_handshake(binary_num, command_list)
    command_list.select.with_index do |command, i|
      (binary_num & (1 << i)) != 0
    end
  end
end

describe 'SecretHandshake' do 
  it 'should know how to wink with a 1' do
    handshake = SecretHandshake.new("1")
    handshake.commands.should eq(["wink"])
  end    

  it 'should know how to double blink with a 10' do
    handshake = SecretHandshake.new("10")
    handshake.commands.should eq(["double blink"])
  end

  it 'should know how to close your eyes with 100' do
    handshake = SecretHandshake.new("100")
    handshake.commands.should eq(["close your eyes"])
  end

  it 'should know to jump with 1000' do
    handshake = SecretHandshake.new("1000")
    handshake.commands.should eq(["jump"])
  end

  it 'should know to wink double blink with 11' do
    handshake = SecretHandshake.new("11")
    handshake.commands.should eq(["wink","double blink"]) 
  end

  it 'should know to double blink, wink, with 10011' do
    handshake = SecretHandshake.new("10011")
    handshake.commands.should eq(["double blink","wink"])
  end

  it 'should get this complicated handshake correctly' do
    handshake = SecretHandshake.new("11111")
    handshake.commands.should eq(["jump","close your eyes","double blink","wink"])
  end

  it 'should not respond to an invalid code' do
    handshake = SecretHandshake.new("binary")
    handshake.commands.should eq([])
  end
end