require 'i18n'

I18n.load_path += Dir[
  File.join(File.dirname(__FILE__), 'locale'.freeze, '*.yml'.freeze)
]

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

    def self.predicate(key, options = {})
      I18n.translate(:"ransack.predicates.#{key}", :default => key.to_s)
    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)
      }
      predicate = Predicate.detect_from_string(original_name)
      attributes_str = original_name.sub(/_#{predicate}$/, Constants::EMPTY)
      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.association(key, options = {})
      unless context = options.delete(:context)
        raise ArgumentError, "A context is required to translate associations"
      end

      defaults =
        if key.blank?
          [:"#{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

  private

    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}_/, Constants::EMPTY)
      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.default_attribute_name
      ["ransack.attributes.#{i18n_key(@context.klass)}.#{@name}".to_sym]
    end

    def self.fallback_args
      if @include_associated
        '%{association_name} %{attr_fallback_name}'.freeze
      else
        '%{attr_fallback_name}'.freeze
      end
    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.attr_fallback_name(associated_class)
      I18n.t(
        :"ransack.attributes.#{fallback_class(associated_class)}.#{@attr_name}",
        :default => default_interpolation(associated_class)
        )
    end

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

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

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

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

    def self.i18n_key(klass)
      # if ActiveRecord::VERSION::MAJOR == 3 && ActiveRecord::VERSION::MINOR == 0
      #   klass.model_name.i18n_key.to_s.tr('.', '/')
      # else
      #   klass.model_name.i18n_key.to_s
      # end
      raise "not implemented"
    end
  end
end