module Ransack::Translate

def self.associated_attribute(associated_class)
  if associated_class
    translated_attribute(associated_class)
  else
    translated_ancestor_attributes
  end
end

def self.association(key, options = {})
  unless context = options.delete(:context)
    raise ArgumentError, "A context is required to translate associations"
  end
  defaults =
    if key.blank?
      [:"ransack.models.#{i18n_key(context.klass)}",
       :"#{context.klass.i18n_scope}.models.#{i18n_key(context.klass)}"]
    else
      [:"ransack.associations.#{i18n_key(context.klass)}.#{key}"]
    end
  defaults << context.traverse(key).model_name.human
  options = { :count => 1, :default => defaults }
  I18n.translate(defaults.shift, options)
end

def self.association_name
  association(@assoc_path, :context => @context) if @include_associated
end

def self.attr_fallback_name(associated_class)
  I18n.t(
    :"ransack.attributes.#{fallback_class(associated_class)}.#{@attr_name}",
    :default => default_interpolation(associated_class)
    )
end

def self.attribute(key, options = {})
  unless context = options.delete(:context)
    raise ArgumentError, "A context is required to translate attributes"
  end
  original_name = key.to_s
  base_class = context.klass
  base_ancestors = base_class.ancestors.select {
    |x| x.respond_to?(:model_name)
  }
  attributes_str = original_name.dup # will be modified by ⬇
  predicate = Predicate.detect_and_strip_from_string!(attributes_str)
  attribute_names = attributes_str.split(/_and_|_or_/)
  combinator = attributes_str.match(/_and_/) ? :and : :or
  defaults = base_ancestors.map do |klass|
    "ransack.attributes.#{i18n_key(klass)}.#{original_name}".to_sym
  end
  translated_names = attribute_names.map do |name|
    attribute_name(context, name, options[:include_associations])
  end
  interpolations = {
    :attributes => translated_names.join(" #{Translate.word(combinator)} ")
  }
  if predicate
    defaults << "%{attributes} %{predicate}".freeze
    interpolations[:predicate] = Translate.predicate(predicate)
  else
    defaults << "%{attributes}".freeze
  end
  defaults << options.delete(:default) if options[:default]
  options.reverse_merge! :count => 1, :default => defaults
  I18n.translate(defaults.shift, options.merge(interpolations))
end

def self.attribute_name(context, name, include_associations = nil)
  @context, @name = context, name
  @assoc_path = context.association_path(name)
  @attr_name = @name.sub(/^#{@assoc_path}_/, ''.freeze)
  associated_class = @context.traverse(@assoc_path) if @assoc_path.present?
  @include_associated = include_associations && associated_class
  defaults = default_attribute_name << fallback_args
  options = { :count => 1, :default => defaults }
  interpolations = build_interpolations(associated_class)
  I18n.translate(defaults.shift, options.merge(interpolations))
end

def self.build_interpolations(associated_class)
  {
    :attr_fallback_name => attr_fallback_name(associated_class),
    :association_name   => association_name
  }
  .reject { |_, value| value.nil? }
end

def self.default_attribute_name
  ["ransack.attributes.#{i18n_key(@context.klass)}.#{@name}".to_sym]
end

def self.default_interpolation(associated_class)
  [
    associated_attribute(associated_class),
    ".attributes.#{@attr_name}".to_sym,
    @attr_name.humanize
  ]
  .flatten
end

def self.fallback_args
  if @include_associated
    '%{association_name} %{attr_fallback_name}'.freeze
  else
    '%{attr_fallback_name}'.freeze
  end
end

def self.fallback_class(associated_class)
  i18n_key(associated_class || @context.klass)
end

def self.i18n_key(klass)
  klass.model_name.i18n_key.to_s.freeze
end

def self.i18n_key(klass)
  raise "not implemented"
end

def self.predicate(key, options = {})
  I18n.translate(:"ransack.predicates.#{key}", :default => key.to_s)
end

def self.translated_ancestor_attributes
  @context.klass.ancestors
  .select { |ancestor| ancestor.respond_to?(:model_name) }
  .map { |ancestor| translated_attribute(ancestor) }
end

def self.translated_attribute(associated_class)
  key = "#{associated_class.i18n_scope}.attributes.#{
    i18n_key(associated_class)}.#{@attr_name}"
  ["#{key}.one".to_sym, key.to_sym]
end

def self.word(key, options = {})
  I18n.translate(:"ransack.#{key}", :default => key.to_s)
end