require_relative 'group'

class Hash
  alias_method :names, :keys
end

module Woyo

module Attributes

  def attribute *attrs, &block
    send :_attributes, attrs, ivn: '@attributes', &block
  end

  def attributes *attrs, &block
    send :_attributes, attrs, ivn: '@attributes', &block
  end

  def _attributes attrs, ivn:, &block
    if instance_variable_defined? ivn
      ivar = instance_variable_get ivn
    else
      ivar = instance_variable_set ivn, Woyo::Attributes::AttributesHash.new 
    end
    return ivar if attrs.empty?
    attrs.each do |attr|
      case
      when attr.kind_of?( Hash )
        attr.each do |attr_sym,default|
          define_attr_methods attr_sym, default, ivn: ivn
          ivar[attr_sym] = send "#{attr_sym}_default"
        end
      when block
        define_attr_methods attr, block, ivn: ivn
        ivar[attr] = send "#{attr}_default"
      else
        unless ivar.include? attr
          define_attr_methods attr, ivn: ivn
          ivar[attr] = nil
        end
      end
    end
  end

  def define_attr_methods( attr, default = nil, ivn: )
    define_attr_default attr, default
    define_attr_equals attr, ivn: ivn
    define_attr attr, ivn: ivn
    if default == true || default == false    # boolean convenience methods
      define_attr? attr
      define_attr! attr
    end
  end

  def define_attr_default attr, default
    define_singleton_method "#{attr}_default" do
      default
    end
  end

  def define_attr_equals( attr, ivn: )
    define_singleton_method "#{attr}=" do |arg|
      ivar = instance_variable_get ivn
      ivar[attr] = arg
    end
  end

  def define_attr( attr, ivn: )
    define_singleton_method attr do |arg = nil|
      ivar = instance_variable_get ivn
      return ivar[attr] = arg unless arg.nil?
      case
      when ivar[attr].kind_of?( Hash )
        true_attribute_match = ivar[attr].detect { |name,value| ivar[name] == true }
        return true_attribute_match[1] if true_attribute_match
        ivar[attr]
      when ivar[attr].respond_to?( :call )
        return ivar[attr].arity == 0 ? ivar[attr].call : ivar[attr].call(self)
      else
        ivar[attr]
      end
    end
  end

  def define_attr? attr
    define_singleton_method "#{attr}?" do
      ( send attr ) ? true : false
    end
  end

  def define_attr! attr
    define_singleton_method "#{attr}!" do
      send "#{attr}=", true
    end
  end

  def is? attr
    send "#{attr}?"
  end

  def is attr
    send "#{attr}=", true
  end

  def groups
    @groups
  end

  def group sym, *attrs
    @groups ||= {}
    grp = @groups[sym] ? @groups[sym] : ( @groups[sym] = Woyo::Attributes::Group.new attributes )
    attributes *attrs
    attrs.each do |attr|
      if attr.kind_of? Hash
        attr.each do |attr_sym,default_value|
          grp << attr_sym
        end
      else
        grp << attr
      end
    end
    define_singleton_method sym do
      @groups[sym]  
    end
    grp
  end

  def exclusions
    @exclusions
  end
 
  def exclusion sym, *attrs
    @exclusions ||= {}
    exc = @exclusions[sym] ? @exclusions[sym] : ( @exclusions[sym] = Woyo::Attributes::Exclusion.new attributes )
    attributes *attrs
    attrs.each do |attr|
      define_attr? attr
      define_attr! attr
      if attr.kind_of? Hash
        attr.each do |attr_sym,default_value|
          exc << attr_sym
        end
      else
        exc << attr
      end
    end
    define_singleton_method sym do
      @exclusions[sym]
    end
    exc
  end

end

end