require 'active_model'
require 'active_model/form/version'
require 'active_model/form/attributes'
require 'active_support/inflector'

module ActiveModel
  class Form
    include ActiveModel::Validations
    include ActiveModel::Conversion
    include ActiveModel
    extend ActiveModel::Naming

    def initialize(attributes=nil)
      self.assign_attributes(attributes)
    end

    # For the Rails route helpers
    def persisted?
      false
    end

    # Set the model name to change the field names generated by the Rails form helpers
    def self.model_name=(name)
      @_model_name = ActiveModel::Name.new(self, nil, name)
    end

    def self.attribute(name, type_name)
      # TODO: Make inheritance of ActiveModel::Forms do the right thing with attributes
      @_attributes ||= {}
      @_attributes[name.to_s] = self.type_from_type_name(type_name)
      self.send(:attr_accessor, name)
    end

    def self.attributes
      @_attributes ||= {}
    end

    # Returns the column object for the named attribute.
    def column_for_attribute(name)
      self.class.attributes[name.to_s]
    end

    def assign_attributes(new_attributes)
      return if new_attributes.blank?
      new_attributes = self.clean_attributes(new_attributes)
      new_attributes.each do |k, v|
        if attribute = self.class.attributes[k].presence
          send("#{k}=", attribute.parse(v))
        end
      end
    end

    protected

    def clean_attributes(attributes)
      cleaned_attributes = {}

      attributes.stringify_keys.each do |k, v|
        if k.include?("(")
          attribute_name = k.split("(").first
          cleaned_attributes[attribute_name] ||= []
          v = v.empty? ? nil : type_cast_attribute_value(k, v)
          cleaned_attributes[attribute_name][find_parameter_position(k)] ||= v
        else
          cleaned_attributes[k] = v
        end
      end

      cleaned_attributes
    end

    def self.type_from_type_name(type_name)
      classified_type_name = ActiveSupport::Inflector.classify(type_name)
      ActiveSupport::Inflector.safe_constantize("::ActiveModel::Form::#{classified_type_name}Attribute")
    end

    def type_cast_attribute_value(multiparameter_name, value)
      multiparameter_name =~ /\([0-9]*([if])\)/ ? value.send("to_" + $1) : value
    end

    def find_parameter_position(multiparameter_name)
      multiparameter_name.scan(/\(([0-9]*).*\)/).first.first.to_i - 1
    end
  end
end