module Passw

# File lib/passw.rb, line 6
def self.generate(length, options = {})
  defaults = {
    lowercase:  true, # Allow lower case characters
    uppercase:  true, # Allow uppercase characters
    symbols:    true, # Allow symbols
    numbers:    true, # Allow numbers
    duplicates: true  # Allow characters to be duplicated (less secure if true)
  }
  
  defaults.merge!(options)
  
  buffer = []
  
  buffer += lowercase if defaults[:lowercase]
  buffer += uppercase if defaults[:uppercase]
  buffer += symbols   if defaults[:symbols]
  buffer += numbers   if defaults[:numbers]
  
  base = []
  
  buffer_length = buffer.length

  (0...length.to_i).each do |i|
    if defaults[:duplicates]
      base << buffer[srand % buffer_length]
    else
      loop do
        candidate = buffer[srand % buffer_length]
        
        if !base.include? candidate
          base << candidate
          break
        end
        
        # Ensure that this loop does not run forever if duplicates are disallowed
        # In this case, we're limited to the collective size of buffered characters
        
        break if base.length == buffer_length - 1
      end
    end
  end
  
  base.shuffle.join
end

# File lib/passw.rb, line 57
def self.lowercase
  %w[a b c d e f g h i j k l m n o p q r s t u v w x y z]
end

# File lib/passw.rb, line 65
def self.numbers
  %w[0 1 2 3 4 5 6 7 8 9]
end

# File lib/passw.rb, line 53
def self.symbols
  %w[! " ' # $ % & ( ) * + , - . / : ; < = > ? ` ~ { | } @ ^]
end

# File lib/passw.rb, line 61
def self.uppercase
  %w[A B C D E F G H I J K L M N O P Q R S T U V W X Y Z]
end