class Collection

# File lib/collection_of/collection.rb, line 17
def initialize(klass, *args)
  @options = args.extract_options!
  @klass = klass.is_a?(Class) ? klass : klass.class
  @collection = [args.first].compact.flatten
end

# File lib/collection_of/collection.rb, line 48
def <<(obj)
  checker = @options.fetch(:allow_subclasses, true) ? :is_a? : :instance_of?
  raise ArgumentError, "can only add #{@klass.name} objects" unless obj.send(checker, @klass)
  @collection << obj
end

# File lib/collection_of/collection.rb, line 83
def ==(other)
  return other == @collection if other.is_a?(self.class)
  return @collection == other if other.is_a?(Array)
  super
end

# File lib/collection_of/collection.rb, line 33
def [](item)
  return nil if empty?

  if item.is_a?(0.class)
    @collection[item]
  else
    item = item.to_sym
    detect{ |i| i.name.to_sym == item }
  end
end

# File lib/collection_of/collection.rb, line 79
def delete(*items)
  @collection = reject{ |i| items.include?(i.name) }
end

# File lib/collection_of/collection.rb, line 69
def except(*items)
  items.map!(&:to_sym)
  self.class.new(klass, reject{ |i| items.include?(i.name.to_sym) })
end

# File lib/collection_of/collection.rb, line 63
def include?(item)
  return true if @collection.include?(item)
  return keys.include?(item.to_sym) if item.respond_to?(:to_sym)
  return false
end

# File lib/collection_of/collection.rb, line 23
def initialize_clone(*)
  super

  # Clone each item in the collection
  @collection = @collection.inject([]) do |ary, item|
    ary << (item.duplicable? ? item.clone : item)
    ary
  end
end

# File lib/collection_of/collection.rb, line 58
def key?(key)
  keys.include?(key.to_sym)
end

# File lib/collection_of/collection.rb, line 54
def keys
  @collection.map{ |i| i.name.to_sym }
end

# File lib/collection_of/collection.rb, line 44
def new(*args, &block)
  @klass.new(*args, &block).tap{ |obj| @collection << obj }
end

# File lib/collection_of/collection.rb, line 74
def slice(*items)
  items.map!(&:to_sym)
  self.class.new(klass, select{ |i| items.include?(i.name.to_sym) })
end