#   Copyright (c) 2008 Ben Woodcroft <donttrustben somewhere near gmail.com>
#
#   This program is free software.
#   You can distribute/modify this program under the terms of
#   the GNU General Public License version 3.

# The point of this is that the 
# Bookshelf.all.reach.books.each do {|book| puts book.name}
# instead of
# Bookshelf.all.each do |bookshelf|
# bookshelf.books.each do |book|
# puts book.name
# end
# end

# Bookshelf.all.reach is a ReachableArray
# the books is an array (bookshelves) of arrays (books)
class Array
  def reach
    ReachingArray.new(self)
  end
  
  def slap
    SlappingArray.new(self)
  end
end

class ReachingArray
  # The array that this reaching array is extending. This might
  # be a real Array, or a ReachingArray
  attr_accessor :retract
  
  def initialize(retract)
    @retract = retract
  end
  
  # The method could be missing from the array, the members, or both.
  # Try to pass the method to each, in that order, accepting the first taker
  def method_missing(method, *args, &block)
    if @retract.respond_to?(method)
      # If this is an array method, just use that
      r = @retract.send(method, *args, &block)
      return r
    else
      # If this is an object-specific method, run an each on it.
      # A simple each won't work because that doesn't modify the
      # array elements in place as we want, so have to use collect
      # instead.
      @retract = @retract.collect do |o|
        unless o.kind_of?(Array)
          o.send(method, *args, &block)
        else
          # Update in 0.2.1: If the element of the array is an array
          # itself, then operate on it as a ReachingArray as well.
          o.reach.send(method, *args, &block).retract
        end
      end
      return self
    end
  end
  
  # Equality test - equality of the underlying retract
  # arrays is all that matter
  def ==(another)
    @retract <=> another.retract
  end
  
  def to_s
    method_missing(:to_s)
  end
  
  def slap
    retract.slap
  end
end

class SlappingArray
  # The array that this reaching array is extending. This might
  # be a real Array, or a ReachingArray
  attr_accessor :retract
  
  def initialize(retract)
    @retract = retract
  end
  
  # Try to pass the method to each of the array members 
  def method_missing(method, *args, &block)
    @retract = @retract.collect do |o|
      unless o.kind_of?(Array)
        o.send(method, *args, &block)
      else
        # Update in 0.2.1: If the element of the array is an array
        # itself, then operate on it as a ReachingArray as well.
        o.slap.send(method, *args, &block).retract
      end
    end
    return self
  end
  
  # Equality test - equality of the underlying retract
  # arrays is all that matter
  def ==(another)
    @retract <=> another.retract
  end
  
  def to_s
    method_missing(:to_s)
  end
  
  def reach
    retract.reach
  end
end