# {Article}s are the core of the lines blog. 
# 
# An {Article} must have on or more {Author}s through {Authorable}.
# 
# An article extends FriendlyId to provide meaningful slugs instead of the usual id value. 
# 
# Slugs are unique and contain the article's title. A incremental numerical value
# is added to the slug title if the it already exists in the database.

require 'kaminari'
require 'acts-as-taggable-on'
require 'carrierwave'
require 'carrierwave/orm/activerecord'
require 'friendly_id'

module Lines
  class Article < ActiveRecord::Base
    extend FriendlyId
    friendly_id :title, use: [:slugged, :history, :finders]

    # Relations
    has_many :pictures
    has_many :authorables
    has_many :authors, through: :authorables

    attr_accessor :hero_image_file
    accepts_nested_attributes_for :pictures, :authors


    # Mount Carrierwave uploaders
    mount_uploader :hero_image, HeroImageUploader
    mount_uploader :document, DocumentUploader

    # Pagination and tagging
    paginates_per CONFIG[:articles_per_page]
    acts_as_taggable

    # Validations
    validates :title, :content, :author_ids, :published_at, presence: true
    validate :one_image_selected

    # Callbacks
    after_save :update_used_images, :refresh_sitemap

    # Model Scopes
    scope :published, -> { where(published: true).order("featured DESC, published_at DESC") }

    # Predifined hero images.
    # Images are loaded from the <tt>public/heroes</tt> directory
    HERO_IMAGES = CONFIG[:hero_images]

    # Returns URL of selected image from HERO_IMAGES array
    def short_hero_image_url
      "#{self.short_hero_image}"
    end

    # Returns array of images used in content
    def used_images
      result = content.scan(/!\[.*\]\(.*\/image\/(\d.*)\/.*\)/)
      image_ids = result.nil? ? nil : result.map{ |i| i[0].to_i }.uniq
      image_ids
    end

    # Returns the url for the hero image
    def image_url
      self.hero_image? ? self.hero_image.url : self.short_hero_image
    end

    # Returns value of subtitle
    def sub_title
      read_attribute(:sub_title) || ''
    end

  private

    # Finds images used in an articles content and associates each
    # image to the blog article
    def update_used_images
      ActionController::Base.new.expire_fragment(self)
      image_ids = self.used_images
      if !image_ids.nil?
        Picture.where(id: image_ids).each do |picture|
          picture.update_attributes(article_id: self.id)
        end
      end
    end

    # Refreshes the sitemap and pings the search engines
    def refresh_sitemap
      if self.published
        if Rails.env == 'production' && ENV["CONFIG_FILE"]
          SitemapGenerator::Interpreter.run(config_file: ENV["CONFIG_FILE"])
          SitemapGenerator::Sitemap.ping_search_engines 
        end
      end
    end

    # Validates if either a predefined hero image is selected or a custom hero
    # image uploaded. 
    def one_image_selected
      if both_images_selected || no_image_selected
        errors[:base] << 'You have to either select an image or upload one.'
      end
    end

    # Returns true if both a hero image is uploaded and a predefined hero image is selected
    def both_images_selected
      hero_image.present? && short_hero_image.present?
    end

    # Returns false if no hero image is selected or uploaded
    def no_image_selected
      !hero_image.present? && !short_hero_image.present?
    end

  end
end