require 'activesupport'

module Morph
  VERSION = "0.2.3"

  def self.object_from_key key
    begin
      name = key.to_s
      type = name.constantize
    rescue NameError => e
      Object.const_set name, Class.new
      type = name.constantize
      type.send(:include, Morph)
    end
    object = type.new
  end

  def self.add_to_object object, attributes
    attributes.each do |key, value|
      attribute = key.gsub(':',' ')
      attribute = attribute.underscore

      if value.is_a?(String)
        object.morph(attribute, value)
      elsif value.is_a?(Array)
        object.morph(attribute.pluralize, value)
      elsif value.is_a? Hash
        child_object = object_from_key key
        add_to_object child_object, value
        object.morph(attribute, child_object)
      end
    end
  end

  def self.from_hash hash
    if hash.keys.size == 1
      key = hash.keys.first
      object = object_from_key key
      if hash[key].is_a? Hash
        attributes = hash[key]
        add_to_object object, attributes
      end
      object
    else
      raise 'hash must have single key'
    end
  end

  def self.included(base)
    base.extend ClassMethods
    base.send(:include, InstanceMethods)
    base.send(:include, MethodMissing)
  end

  module ClassMethods

    @@adding_morph_method = Hash.new {|hash,klass| hash[klass] = false }
    @@morph_methods = Hash.new {|hash,klass| hash[klass] = {} }

    def morph_methods
      @@morph_methods[self].keys.sort
    end

    def adding_morph_method= true_or_false
      @@adding_morph_method[self] = true_or_false
    end

    def class_def name, &block
      class_eval { define_method name, &block }
    end

    def show_ruby
      begin
        require 'ruby2ruby'
        puts Ruby2Ruby.translate(self)
      rescue LoadError
        puts "You need to install the ruby2ruby gem before calling show_ruby"
      end
    end

    def script_generate options={}
      name = self.name.to_s.split('::').last
      name = yield name if block_given?
      generator = options[:generator] || 'rspec_model'
      line = ["ruby script/destroy #{generator} #{name}; ruby script/generate #{generator} #{name}"]
      morph_methods.select{|m| not(m =~ /=$/) }.each {|attribute| line << " #{attribute}:string"}
      line.join('')
    end

    protected

      def method_added symbol
        @@morph_methods[self][symbol.to_s] = true if @@adding_morph_method[self]
      end

      def method_removed symbol
        @@morph_methods[self].delete symbol.to_s if @@morph_methods[self].has_key? symbol.to_s
      end

  end

  module MethodMissing
    def method_missing symbol, *args
      is_writer = symbol.to_s =~ /=$/
      is_writer ? morph_method_missing(symbol, *args) : super
    end
  end

  module InstanceMethods

    #
    # Set attribute value(s). Adds accessor methods to class if
    # they are not already present.
    #
    # Can be called with a +string+ and a value, a +symbol+ and a value,
    # or with a +hash+ of attribute to value pairs. For example.
    #
    #   require 'rubygems'; require 'morph'
    #
    #   class Order; include Morph; end
    #
    #   order = Order.new
    #   order.morph :drink => 'tea', :sugars => 2, 'milk' => 'yes please'
    #   order.morph 'Payment type:', 'will wash dishes'
    #   order.morph :lemon, false
    #
    #   p order # -> #<Order:0x33c50c @lemon=false, @milk="yes please",
    #                @payment_type="will wash dishes", @sugars=2, @drink="tea">
    #
    def morph attributes_or_label, value=nil
      if attributes_or_label.is_a? Hash
        attributes_or_label.each { |a, v| morph(a, v) }
      else
        attribute = convert_to_morph_method_name(attributes_or_label)
        send("#{attribute}=".to_sym, value)
      end
    end

    def morph_attributes
      attributes = self.class.morph_methods.inject({}) do |hash, attribute|
        unless attribute =~ /=\Z/
          symbol = attribute.to_sym
          value = send(symbol)

          value.each do |key, v|
            value[key] = v.morph_attributes if v.respond_to?(:morph_attributes)
          end if value.is_a? Hash

          value = value.collect {|v| v.respond_to?(:morph_attributes) ? v.morph_attributes : v } if value.is_a? Array
          value = value.morph_attributes if value.respond_to? :morph_attributes


          hash[symbol] = value
        end
        hash
      end
    end

    def morph_method_missing symbol, *args
      attribute = symbol.to_s.chomp '='

      if Object.instance_methods.include?(attribute)
        raise "'#{attribute}' is an instance_method on Object, cannot create accessor methods for '#{attribute}'"
      elsif argument_provided? args
        base = self.class
        base.adding_morph_method = true

        if block_given?
          yield base, attribute
        else
          # base.class_eval "attr_accessor :#{attribute}"
          base.class_eval "def #{attribute}; @#{attribute}; end; def #{attribute}=(value); @#{attribute} = value; end"
          send(symbol, *args)
        end
        base.adding_morph_method = false
      end
    end

    private

      def argument_provided? args
        args.size > 0 && !args[0].nil? && !(args[0].is_a?(String) && args[0].strip.size == 0)
      end

      def convert_to_morph_method_name label
        name = label.to_s.downcase.tr('()*',' ').gsub('%','percentage').strip.chomp(':').strip.gsub(/\s/,'_').squeeze('_')
        name = '_'+name if name =~ /^\d/
        name
      end
  end
end