class ActiveModel::Serializer

def self._attributes
  _attributes_data.keys
end

def self.adapter
  ActiveModelSerializers::Adapter.lookup(config.adapter)
end

def self.associate(reflection)
  key = reflection.options[:key] || reflection.name
  self._reflections[key] = reflection
end

def self.attribute(attr, options = {}, &block)
  key = options.fetch(:key, attr)
  _attributes_data[key] = Attribute.new(attr, options, block)
end

def self.attributes(*attrs)
  attrs = attrs.first if attrs.first.class == Array
  attrs.each do |attr|
    attribute(attr)
  end
end

def self.belongs_to(name, options = {}, &block)
  associate(BelongsToReflection.new(name, options, block))
end

def self.get_serializer_for(klass, namespace = nil)
  return nil unless config.serializer_lookup_enabled
  cache_key = ActiveSupport::Cache.expand_cache_key(klass, namespace)
  serializers_cache.fetch_or_store(cache_key) do
    # NOTE(beauby): When we drop 1.9.3 support we can lazify the map for perfs.
    lookup_chain = serializer_lookup_chain_for(klass, namespace)
    serializer_class = lookup_chain.map(&:safe_constantize).find { |x| x && x < ActiveModel::Serializer }
    if serializer_class
      serializer_class
    elsif klass.superclass
      get_serializer_for(klass.superclass, namespace)
    else
      nil # No serializer found
    end
  end
end

def self.has_many(name, options = {}, &block) # rubocop:disable Style/PredicateName
  associate(HasManyReflection.new(name, options, block))
end

def self.has_one(name, options = {}, &block) # rubocop:disable Style/PredicateName
  associate(HasOneReflection.new(name, options, block))
end

def self.include_directive_from_options(options)
  if options[:include_directive]
    options[:include_directive]
  elsif options[:include]
    JSONAPI::IncludeDirective.new(options[:include], allow_wildcard: true)
  else
    ActiveModelSerializers.default_include_directive
  end
end

def self.inherited(base)
  super
  base._attributes_data = _attributes_data.dup
  base._reflections = _reflections.dup
  base._links = _links.dup
end

def self.link(name, *args, &block)
  options = args.extract_options!
  # For compatibility with the use case of passing link directly as string argument
  # without block, we are creating a wrapping block
  _links[name] = Link.new(name, options, block || ->(_serializer) { args.first })
end

def self.meta(value = nil, &block)
  self._meta = block || value
end

def self.serialization_adapter_instance
  @serialization_adapter_instance ||= ActiveModelSerializers::Adapter::Attributes
end

def self.serializer_for(resource_or_class, options = {})
  if resource_or_class.respond_to?(:serializer_class)
    resource_or_class.serializer_class
  elsif resource_or_class.respond_to?(:to_ary)
    config.collection_serializer
  else
    resource_class = resource_or_class.class == Class ? resource_or_class : resource_or_class.class
    options.fetch(:serializer) { get_serializer_for(resource_class, options[:namespace]) }
  end
end

def self.serializer_lookup_chain_for(klass, namespace = nil)
  lookups = ActiveModelSerializers.config.serializer_lookup_chain
  Array[*lookups].flat_map do |lookup|
    lookup.call(klass, self, namespace)
  end.compact
end

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

def self.type(type)
  self._type = type && type.to_s
end

def as_json(adapter_opts = nil)
  serializable_hash(adapter_opts)
end

def associations(include_directive = ActiveModelSerializers.default_include_directive, include_slice = nil)
  include_slice ||= include_directive
  return Enumerator.new {} unless object
  Enumerator.new do |y|
    (self.instance_reflections ||= self.class._reflections.deep_dup).each do |key, reflection|
      next if reflection.excluded?(self)
      next unless include_directive.key?(key)
      association = reflection.build_association(self, instance_options, include_slice)
      y.yield association
    end
  end
end

def associations_hash(adapter_options, options, adapter_instance)
  include_directive = options.fetch(:include_directive)
  include_slice = options[:include_slice]
  associations(include_directive, include_slice).each_with_object({}) do |association, relationships|
    adapter_opts = adapter_options.merge(include_directive: include_directive[association.key], adapter_instance: adapter_instance)
    relationships[association.key] = association.serializable_hash(adapter_opts, adapter_instance)
  end
end

def attributes(requested_attrs = nil, reload = false)
  @attributes = nil if reload
  @attributes ||= self.class._attributes_data.each_with_object({}) do |(key, attr), hash|
    next if attr.excluded?(self)
    next unless requested_attrs.nil? || requested_attrs.include?(key)
    hash[key] = attr.value(self)
  end
end

def attributes_hash(_adapter_options, options, adapter_instance)
  if self.class.cache_enabled?
    fetch_attributes(options[:fields], options[:cached_attributes] || {}, adapter_instance)
  elsif self.class.fragment_cache_enabled?
    fetch_attributes_fragment(adapter_instance, options[:cached_attributes] || {})
  else
    attributes(options[:fields], true)
  end
end

def initialize(object, options = {})
  self.object = object
  self.instance_options = options
  self.root = instance_options[:root]
  self.scope = instance_options[:scope]
  return if !(scope_name = instance_options[:scope_name]) || respond_to?(scope_name)
  define_singleton_method scope_name, -> { scope }
end

def json_key
  root || _type ||
    begin
      object.class.model_name.to_s.underscore
    rescue ArgumentError
      'anonymous_object'
    end
end

def read_attribute_for_serialization(attr)
  if respond_to?(attr)
    send(attr)
  else
    object.read_attribute_for_serialization(attr)
  end
end

def serializable_hash(adapter_options = nil, options = {}, adapter_instance = self.class.serialization_adapter_instance)
  adapter_options ||= {}
  options[:include_directive] ||= ActiveModel::Serializer.include_directive_from_options(adapter_options)
  if (fieldset = adapter_options[:fieldset])
    options[:fields] = fieldset.fields_for(json_key)
  end
  resource = attributes_hash(adapter_options, options, adapter_instance)
  relationships = associations_hash(adapter_options, options, adapter_instance)
  resource.merge(relationships)
end

def success?
  true
end