class ActiveModel::Serializer

def associate(klass, *attrs)
  options = attrs.extract_options!
  attrs.each do |attr|
    define_method attr do
      object.send attr
    end unless method_defined?(attr)
    @_associations[attr] = klass.new(attr, options)
  end
end

def association_options_for_serializer(association)
  prefix    = association.options[:prefix]
  namespace = association.options[:namespace] || @namespace || self.namespace
  { scope: scope }.tap do |opts|
    opts[:namespace] = namespace if namespace
    opts[:prefix]    = prefix    if prefix
  end
end

def associations(options={})
  associations = self.class._associations
  included_associations = filter(associations.keys)
  associations.each_with_object({}) do |(name, association), hash|
    if included_associations.include? name
      if association.embed_ids?
        ids = serialize_ids association
        if association.embed_namespace?
          hash = hash[association.embed_namespace] ||= {}
          hash[association.key] = ids
        else
          hash[association.key] = ids
        end
      elsif association.embed_objects?
        if association.embed_namespace?
          hash = hash[association.embed_namespace] ||= {}
        end
        hash[association.embedded_key] = serialize association, options
      end
    end
  end
end

def attributes(*attrs)
  attrs.each do |attr|
    striped_attr = strip_attribute attr
    @_attributes << striped_attr
    define_method striped_attr do
      object.read_attribute_for_serialization attr
    end unless method_defined?(attr)
  end
end

def attributes
  filter(self.class._attributes.dup).each_with_object({}) do |name, hash|
    hash[name] = send(name)
  end
end

def build_serializer(association)
  object = send(association.name)
  association.build_serializer(object, association_options_for_serializer(association))
end

def build_serializer_class(resource, options)
  klass_name = +""
  klass_name << "#{options[:namespace]}::" if options[:namespace]
  klass_name << options[:prefix].to_s.classify if options[:prefix]
  klass_name << "#{resource.class.name}Serializer"
end

def convert_keys(hash)
  Hash[hash.map do |k,v|
    key = if k.is_a?(Symbol)
      format_key(k).to_sym
    else
      format_key(k)
    end
    [key ,v]
  end]
end

def each_possible_serializer(resource, options)
  yield build_serializer_class(resource, options)
  yield build_serializer_class(resource, {})
  yield build_serializer_class(resource.class.name.demodulize, {})
end

def embed(type, options={})
  CONFIG.embed = type
  if EMBED_IN_ROOT_OPTIONS.any? { |opt| options[opt].present? }
    CONFIG.embed_in_root = true
  end
  if options[:embed_in_root_key].present?
    CONFIG.embed_in_root_key = options[:embed_in_root_key]
  end
  ActiveSupport::Deprecation.warn <<-WARN
ice: embed is deprecated. **
e of .embed method on a Serializer will be soon removed, as this should have a global scope and not a class scope.
 use the global .setup method instead:
Model::Serializer.setup do |config|
ig.embed = :#{type}
ig.embed_in_root = #{CONFIG.embed_in_root || false}
  WARN
end

def embedded_in_root_associations
  associations = self.class._associations
  included_associations = filter(associations.keys)
  associations.each_with_object({}) do |(name, association), hash|
    if included_associations.include? name
      association_serializer = build_serializer(association)
      # we must do this always because even if the current association is not
      # embedded in root, it might have its own associations that are embedded in root
      hash.merge!(association_serializer.embedded_in_root_associations) do |key, oldval, newval|
        if oldval.respond_to?(:to_ary)
          [oldval, newval].flatten.uniq
        else
          oldval.merge(newval) { |_, oldval, newval| [oldval, newval].flatten.uniq }
        end
      end
      if association.embed_in_root?
        if association.embed_in_root_key?
          hash = hash[association.embed_in_root_key] ||= {}
        end
        serialized_data = association_serializer.serializable_object
        key = association.root_key
        if hash.has_key?(key)
          hash[key].concat(serialized_data).uniq!
        else
          hash[key] = serialized_data
        end
      end
    end
  end
end

def filter(keys)
  if @only
    keys & @only
  elsif @except
    keys - @except
  else
    keys
  end
end

def format_key(key)
  if key_format == :lower_camel
    key.to_s.camelize(:lower)
  else
    key
  end
end

def format_keys(format)
  @key_format = format
end

def has_many(*attrs)
  associate(Association::HasMany, *attrs)
end

def has_one(*attrs)
  associate(Association::HasOne, *attrs)
end

def inherited(base)
  base._root = _root
  base._attributes = (_attributes || []).dup
  base._associations = (_associations || {}).dup
end

def initialize(object, options={})
  @object        = object
  @scope         = options[:scope]
  @root          = options.fetch(:root, self.class._root)
  @polymorphic   = options.fetch(:polymorphic, false)
  @meta_key      = options[:meta_key] || :meta
  @meta          = options[@meta_key]
  @wrap_in_array = options[:_wrap_in_array]
  @only          = options[:only] ? Array(options[:only]) : nil
  @except        = options[:except] ? Array(options[:except]) : nil
  @key_format    = options[:key_format]
  @context       = options[:context]
  @namespace     = options[:namespace]
end

def json_key
  key = if root == true || root.nil?
    self.class.root_name
  else
    root
  end
  key_format == :lower_camel && key.present? ? key.camelize(:lower) : key
end

def key_format
  @key_format || self.class.key_format || CONFIG.key_format
end

def root_name
  if name
    root_name = name.demodulize.underscore.sub(/_serializer$/, '')
    CONFIG.plural_default_root ? root_name.pluralize : root_name
  end
end

def serializable_object(options={})
  self.serialization_options = options
  return @wrap_in_array ? [] : nil if @object.nil?
  hash = attributes
  hash.merge! associations(options)
  hash = convert_keys(hash) if key_format.present?
  hash = { :type => type_name(@object), type_name(@object) => hash } if @polymorphic
  @wrap_in_array ? [hash] : hash
end

def serialization_options
  @serialization_options || {}
end

def serialize(association,options={})
  build_serializer(association).serializable_object(options)
end

def serialize_id(elem, association)
  id = elem.read_attribute_for_serialization(association.embed_key)
  association.polymorphic? ? { id: id, type: type_name(elem) } : id
end

def serialize_ids(association)
  associated_data = send(association.name)
  if associated_data.respond_to?(:to_ary)
    associated_data.map { |elem| serialize_id(elem, association) }
  else
    serialize_id(associated_data, association) if associated_data
  end
end

def serializer_for(resource, options = {})
  if resource.respond_to?(:serializer_class)
    resource.serializer_class
  elsif resource.respond_to?(:to_ary)
    if defined?(::ArraySerializer)
      ::ArraySerializer
    else
      ArraySerializer
    end
  else
    each_possible_serializer(resource, options) do |klass_name|
      serializer = Serializer.serializers_cache.fetch_or_store(klass_name) do
        _const_get(klass_name)
      end
      return serializer unless serializer.nil?
    end
    nil
  end
end

def serializers_cache
  @serializers_cache ||= Concurrent::Map.new
end

def setup
  @mutex.synchronize do
    yield CONFIG
  end
end

def strip_attribute(attr)
  symbolized = attr.is_a?(Symbol)
  attr = attr.to_s.gsub(/\?\Z/, '')
  attr = attr.to_sym if symbolized
  attr
end

def type_name(elem)
  elem.class.to_s.demodulize.underscore.to_sym
end