Hacker School Phonebook

phonebook.rb

#!/usr/bin/env ruby
require 'thor'
class PhoneBookCLI < Thor
  no_commands do
    def wrap_errors(&block)
      begin
        instance_eval &block
      rescue Exception => e
        say "#{e.message}", :red
        exit
      end
    end
  end

  
  desc "create FILENAME", "create a new phonebook at FILENAME"
  def create(filename)
    #TODO: check that path is actually in current directory
    wrap_errors do
      Phonebook.create(filename)
    end
    say "created phonebook #{filename} in the current directory"
  end

  desc "lookup PATTERN PHONEBOOK", "lookup PATTERN in PHONEBOOK"
  def lookup(pattern, filename)
    wrap_errors do
      numbers = Phonebook.new(filename).lookup(pattern)
      numbers.each do |name, number|
        say "#{name} #{number}"
      end
    end
  end


  desc "reverse-lookup NUMBER PHONEBOOK", "reverse lookup NUMBER from PHONEBOOK"
  def reverse_lookup(number, filename)
    wrap_errors do
      phonebook = Phonebook.new(filename)
      numbers = phonebook.reverse_lookup(number)
      numbers.each do |name, number|
        say "#{name} #{number}"
      end
    end
  end

  desc "add NAME NUMBER PHONEBOOK", "add NAME, NUMBER to PHONEBOOK"
  def add(name, number, filename)
    wrap_errors do
      phonebook = Phonebook.new(filename)
      phonebook.save!
      say "Added #{name}, #{number} to #{filename}"
    end
  end

  desc "change NAME NUMBER PHONEBOOK", "change NAME to NUMBER in PHONEBOOK"
  def change(name, number, filename)
    wrap_errors do
      phonebook = Phonebook.new(filename)
      phonebook.change(name, number)
      phonebook.save!
      say "Changed #{name} to  #{number} in #{filename}"
    end
  end

  desc "remove NAME PHONEBOOK", "remove NAME from PHONEBOOK"
  def remove(name, phonebook)
    wrap_errors do
      phonebook = Phonebook.new(filename)
      phonebook.remove(name, number)      
      phonebook.save!
      say "Removed #{name} from #{filename}"
    end
  end
end

class Phonebook
  def self.create(filename)
    if File.exists?(filename)
      raise "Error: file #{filename} already exists"
    end
    #Creates a new empty phonebook
    File.open(filename,"w") do |f| 
      f.write({}.to_yaml)
    end
  end

  def initialize(filename)
    unless File.exists?(filename)
      raise "Error: phonebook #{filename} doesn't exist"
      exit
    end
    @filename = filename
    @phonebook = YAML.load_file(filename)
  end

  def save!
    File.open(@filename,"w") do |f| 
      f.write(@phonebook.to_yaml)
    end
  end

  def add(name, number)
    if @phonebook[name]
      raise "Error: #{name} is already in phonebook"
    end
    @phonebook[name] = number
  end

  def change(name,number)
    unless @phonebook[name]
      raise "Error: #{name} is not in phonebook"
    end
    @phonebook[name] = number
  end

  def remove(name,number)
    unless @phonebook[name]
      raise "Error: #{name} is not in phonebook"
    end
    @phonebook[name] = nil
  end
  
  def lookup(pattern)
    results = @phonebook.select { |k,val| k.start_with? pattern}
    if results.empty?
      raise "Error: #{pattern} not found in phonebook"
    end
    results
  end

  def reverse_lookup(number)
    results = @phonebook.select{ |k, val| val == number}
    if results.empty?
      raise "Error: #{number} not found in phonebook"
    end
    results
  end
end

PhoneBookCLI.start(ARGV)