class Strgen

# File lib/strgen.rb, line 25
def self.generate(&block)
  proxy = new

  if block_given?
    block.arity > 0 ? block.call(proxy) : proxy.instance_eval(&block)
  end

  proxy.merge_defaults!

  raise InvalidLengthError if proxy.length < 1

  previous = nil
  current = nil
  acc = ''
  characters = proxy.character_set

  # store the last char in case we want to
  # avoid repeating characters
  proxy.length.times do
    loop do
      current = characters.sample
      break if !proxy.exclude?(current) && (!proxy.repeat || current != previous)
    end

    acc += current
  end

  acc
end

# File lib/strgen.rb, line 84
def alpha?
  nil if alphanum
end

# File lib/strgen.rb, line 67
def character_set
  # TODO: can we do this better?
  a = []
  a.concat(SYMBOLS) if symbols
  a.concat(ALPHANUM) if alphanum
  a.concat(ALPHA) if alpha? || alpha
  a.concat(NUMBERS) if alpha? || numbers
  a.concat(LOWERCASE) if letters? || lowercase
  a.concat(UPPERCASE) if letters? || uppercase
  a
end

# File lib/strgen.rb, line 79
def exclude?(val)
  return false if exclude.nil?
  exclude.include? val
end

# File lib/strgen.rb, line 88
def letters?
  nil if alpha
end

# File lib/strgen.rb, line 55
def merge_defaults!
  TYPES.each_with_object({}) do |type, acc|
    acc[type] = true
    acc
  end.tap do |hash|
    hash.merge! length: 12, repeat: true
  end.each do |method, default|
    next unless send(method.to_sym).nil?
    send("#{method}=".to_sym, default)
  end
end

# File lib/strgen.rb, line 92
def pick_all?
  !lowercase && !uppercase && !alpha && !alphanum && !symbols
end