module Polygallery
  module HasPolygallery
    extend ActiveSupport::Concern

    DEFAULTS = {
        :associations => {
            :gallery => {
                :class_name => '::Polygallery::Gallery',
                :as => :galleryable,
                :dependent => :destroy
            },
            :photos => {
                :class_name => '::Polygallery::Photo',
                :before_add => :set_nest,
                :dependent => :destroy,
                :foreign_key => :gallery_id
            }
        },
        :association_names => {
            :gallery => :gallery,
            :photos => :photos
        },
        :nested_attributes => {
            :gallery => { :reject_if => :all_blank },
            :photos => {
              :reject_if => proc {|attributes| !attributes.key?('id') && attributes['photo'].nil? },
              :allow_destroy => true }
        },
        :validates => {},
        :paperclip => {
          :styles => {:medium => '300x300#', :thumb => '100x100#'},
          :default_url => 'polygallery/thumbnail-missing.jpg'
        },
        :paperclip_validations => {
          :content_type => /\Aimage\/.*\Z/,
          :presence => false
        }
    }

    included do
    end

    module ClassMethods
      def has_polygallery(title='gallery', options={})
        if title.is_a? Hash
          options = title
          title = 'gallery'
        end

        # associations = options[:associations]
        # gallery_association = options[:associations][:gallery] if associations.present?
        # gallery_class_name =  gallery_association[:class_name] if gallery_association.present?
        defaults = HasPolygallery::DEFAULTS
        if options[:association_names].nil? && title.to_s != 'gallery'
          options[:association_names] = {
            :gallery => :"#{title}",
            :photos => :"#{title.to_s.gsub('_gallery', '')}_photos"
          }
        end
        settings = defaults.deep_merge(options)
        cattr_accessor "#{title}_settings".to_sym
        send("#{title}_settings=".to_sym, settings)

        has_one title.to_sym, -> { where(:title => title.to_s) }, settings[:associations][:gallery]
        has_many settings[:association_names][:photos],
                 :through => :"#{title}",
                 :source => settings[:association_names][:photos],
                 :class_name => settings[:associations][:photos][:class_name]
        accepts_nested_attributes_for settings[:association_names][:gallery],
                                      settings[:nested_attributes][:gallery]
        accepts_nested_attributes_for settings[:association_names][:photos],
                                      settings[:nested_attributes][:photos]

        after_initialize :build_galleries
        before_save :ensure_galleryable_set

        include HasPolygallery::LocalInstanceMethods
      end

      def polygalleries
        self.reflect_on_all_associations(:has_one)
            .select{|a| a.foreign_key == 'galleryable_id'}.map(&:name)
      end

      def has_polygallery?(gallery_title=nil)
        return polygalleries.any? if gallery_title.nil?
        polygalleries.include?(gallery_title)
      end

      # def new(*args)
      #   super(*args)
      # end

    end

    module LocalInstanceMethods
      def polygalleries
        # TODO: use association reflections instead of direct class selection
        Gallery.select('polygallery_galleries.title')
          .where(:galleryable => self)
          .group('polygallery_galleries.title')
          .map(&:title)
      end

      def has_polygallery?(gallery_title=nil)
        return polygalleries.any? if gallery_title.nil?
        polygalleries.include?(gallery_title)
      end

      def build_galleries
        return unless self.class.has_polygallery?
        self.class.polygalleries.each do |pg|
          gallery_association = send pg
          next if gallery_association.present?
          gallery_settings = self.send :"#{pg.to_s}_settings"
          if gallery_association.nil?
            built_gallery = send :"build_#{pg.to_s}",
                                 :polygallery_options => gallery_settings
            gallery_association = send :"#{pg.to_s}=", built_gallery
          end
          gallery_association.galleryable ||= self
        end
      end

      def build_first_photos
        return unless self.class.has_polygallery?
        self.class.polygalleries.each {|pg| send(pg).build_first_photo }
      end

      def first_photo
        return unless self.class.has_polygallery?
        first_p = nil
        self.class.polygalleries.each do |pg|
          gallery_settings = send :"#{pg.to_s}_settings"
          ptos = send(gallery_settings[:association_names][:photos])
                  .select{|p| p.photo.file? }
          next if ptos.empty?
          first_p = ptos.first.photo
          break
        end
        first_p || Photo.new.photo
      end

      def ensure_galleryable_set
        self.class.polygalleries.each do |pg|
          gallery_association = self.send :"#{pg}"
          gallery_association.galleryable ||= self
          gallery_association.polygallery_photos.each do |pp|
            pp.galleryable ||= self
          end
        end
      end

    end
  end
end

ActiveRecord::Base.send :include, Polygallery::HasPolygallery