# -*- coding: utf-8 -*-
require 'active_support/core_ext/array/wrap'
require 'active_support/core_ext/string/inflections'
require 'active_support/core_ext/object/blank'
require 'active_support/ordered_hash'
module ActiveModel
  # Provides a modified +OrderedHash+ that you can include in your object
  # for handling error messages and interacting with Action Pack helpers.
  # 
  # A minimal implementation could be:
  # 
  #   class Person
  #   
  #     # Required dependency for ActiveModel::Errors
  #     extend ActiveModel::Naming
  # 
  #     def initialize
  #       @errors = ActiveModel::Errors.new(self)
  #     end
  #   
  #     attr_accessor :name
  #     attr_reader   :errors
  #   
  #     def validate!
  #       errors.add(:name, "can not be nil") if name == nil
  #     end
  #   
  #     # The following methods are needed to be minimally implemented
  #
  #     def read_attribute_for_validation(attr)
  #       send(attr)
  #     end
  #   
  #     def ErrorsPerson.human_attribute_name(attr, options = {})
  #       attr
  #     end
  #   
  #     def ErrorsPerson.lookup_ancestors
  #       [self]
  #     end
  #   
  #   end
  # 
  # The last three methods are required in your object for Errors to be
  # able to generate error messages correctly and also handle multiple
  # languages.  Of course, if you extend your object with ActiveModel::Translations
  # you will not need to implement the last two.  Likewise, using
  # ActiveModel::Validations will handle the validation related methods
  # for you.
  # 
  # The above allows you to do:
  # 
  #   p = Person.new
  #   p.validate!             # => ["can not be nil"]
  #   p.errors.full_messages  # => ["name can not be nil"]
  #   # etc..
  class Errors < ActiveSupport::OrderedHash
    include DeprecatedErrorMethods
    # Pass in the instance of the object that is using the errors object.
    # 
    #   class Person
    #     def initialize
    #       @errors = ActiveModel::Errors.new(self)
    #     end
    #   end
    def initialize(base)
      @base = base
      super()
    end
    alias_method :get, :[]
    alias_method :set, :[]=
    # When passed a symbol or a name of a method, returns an array of errors for the method.
    # 
    #   p.errors[:name]   #=> ["can not be nil"]
    #   p.errors['name']  #=> ["can not be nil"]
    def [](attribute)
      if errors = get(attribute.to_sym)
        errors
      else
        set(attribute.to_sym, [])
      end
    end
    # Adds to the supplied attribute the supplied error message.
    # 
    #   p.errors[:name] = "must be set"
    #   p.errors[:name] #=> ['must be set']
    def []=(attribute, error)
      self[attribute.to_sym] << error
    end
    # Iterates through each error key, value pair in the error messages hash.
    # Yields the attribute and the error for that attribute.  If the attribute
    # has more than one error message, yields once for each error message.
    # 
    #   p.errors.add(:name, "can't be blank")
    #   p.errors.each do |attribute, errors_array|
    #     # Will yield :name and "can't be blank"
    #   end
    # 
    #   p.errors.add(:name, "must be specified")
    #   p.errors.each do |attribute, errors_array|
    #     # Will yield :name and "can't be blank"
    #     # then yield :name and "must be specified"
    #   end
    def each
      each_key do |attribute|
        self[attribute].each { |error| yield attribute, error }
      end
    end
    # Returns the number of error messages.
    # 
    #   p.errors.add(:name, "can't be blank")
    #   p.errors.size #=> 1
    #   p.errors.add(:name, "must be specified")
    #   p.errors.size #=> 2
    def size
      values.flatten.size
    end
    # Returns an array of error messages, with the attribute name included
    # 
    #   p.errors.add(:name, "can't be blank")
    #   p.errors.add(:name, "must be specified")
    #   p.errors.to_a   #=>   ["name can't be blank", "name must be specified"]
    def to_a
      full_messages
    end
    # Returns the number of error messages.
    #   p.errors.add(:name, "can't be blank")
    #   p.errors.count #=> 1
    #   p.errors.add(:name, "must be specified")
    #   p.errors.count #=> 2
    def count
      to_a.size
    end
    # Returns an xml formatted representation of the Errors hash.
    # 
    #   p.errors.add(:name, "can't be blank")
    #   p.errors.add(:name, "must be specified")
    #   p.errors.to_xml   #=> Produces:
    # 
    #   #  
    #   #