docbrown/app/models/billboard.rb

class Billboard < ApplicationRecord
  include Taggable
  acts_as_taggable_on :tags
  resourcify
  belongs_to :creator, class_name: "User", optional: true
  belongs_to :audience_segment, optional: true

  # rubocop:disable Layout/LineLength
  ALLOWED_PLACEMENT_AREAS = %w[sidebar_left sidebar_left_2 sidebar_right feed_first feed_second feed_third home_hero post_sidebar post_comments].freeze
  # rubocop:enable Layout/LineLength
  ALLOWED_PLACEMENT_AREAS_HUMAN_READABLE = ["Sidebar Left (First Position)",
                                            "Sidebar Left (Second Position)",
                                            "Sidebar Right (Home)",
                                            "Home Feed First",
                                            "Home Feed Second",
                                            "Home Feed Third",
                                            "Home Hero",
                                            "Sidebar Right (Individual Post)",
                                            "Below the comment section"].freeze

  HOME_FEED_PLACEMENTS = %w[feed_first feed_second feed_third].freeze

  MAX_TAG_LIST_SIZE = 25
  POST_WIDTH = 775
  SIDEBAR_WIDTH = 350
  LOW_IMPRESSION_COUNT = 1_000
  RANDOM_RANGE_MAX_FALLBACK = 5
  NEW_AND_PRIORITY_RANGE_MAX_FALLBACK = 35

  attribute :target_geolocations, :geolocation_array
  enum display_to: { all: 0, logged_in: 1, logged_out: 2 }, _prefix: true
  enum type_of: { in_house: 0, community: 1, external: 2 }

  belongs_to :organization, optional: true
  has_many :billboard_events, foreign_key: :display_ad_id, inverse_of: :billboard, dependent: :destroy

  validates :placement_area, presence: true,
                             inclusion: { in: ALLOWED_PLACEMENT_AREAS }
  validates :body_markdown, presence: true
  validates :organization, presence: true, if: :community?
  validates :weight, numericality: { greater_than_or_equal_to: 0, less_than_or_equal_to: 10_000 }
  validates :audience_segment_type,
            inclusion: { in: AudienceSegment.type_ofs },
            allow_blank: true
  validate :valid_audience_segment_match,
           :validate_in_house_hero_ads,
           :valid_manual_audience_segment,
           :validate_tag,
           :validate_geolocations

  before_save :process_markdown
  after_save :generate_billboard_name
  after_save :refresh_audience_segment, if: :should_refresh_audience_segment?

  scope :approved_and_published, -> { where(approved: true, published: true) }

  scope :search_ads, lambda { |term|
                       where "name ILIKE :search OR processed_html ILIKE :search OR placement_area ILIKE :search",
                             search: "%#{term}%"
                     }

  scope :seldom_seen, ->(area) { where("impressions_count < ?", low_impression_count(area)).or(where(priority: true)) }

  self.table_name = "display_ads"

  def self.for_display(area:, user_signed_in:, user_id: nil, article: nil, user_tags: nil, location: nil)
    permit_adjacent = article ? article.permit_adjacent_sponsors? : true

    billboards_for_display = Billboards::FilteredAdsQuery.call(
      billboards: self,
      area: area,
      user_signed_in: user_signed_in,
      article_id: article&.id,
      article_tags: article&.cached_tag_list_array || [],
      organization_id: article&.organization_id,
      permit_adjacent_sponsors: permit_adjacent,
      user_id: user_id,
      user_tags: user_tags,
      location: location,
    )

    case rand(99) # output integer from 0-99
    when (0..random_range_max(area)) # smallest range, 5%
      # We are always showing more of the good stuff — but we are also always testing the system to give any a chance to
      # rise to the top. 5 out of every 100 times we show an ad (5%), it is totally random. This gives "not yet
      # evaluated" stuff a chance to get some engagement and start showing up more. If it doesn't get engagement, it
      # stays in this area.
      billboards_for_display.sample
    when (random_range_max(area)..new_and_priority_range_max(area)) # medium range, 30%
      # Here we sample from only billboards with fewer than 1000 impressions (with a fallback
      # if there are none of those, causing an extra query, but that shouldn't happen very often).
      relation = billboards_for_display.seldom_seen(area)
      weighted_random_selection(relation) || billboards_for_display.sample
    else # large range, 65%

      # Ads that get engagement have a higher "success rate", and among this category, we sample from the top 15 that
      # meet that criteria. Within those 15 top "success rates" likely to be clicked, there is a weighting towards the
      # top ranked outcome as well, and a steady decline over the next 15 — that's because it's not "Here are the top 15
      # pick one randomly", it is actually "Let's cut off the query at a random limit between 1 and 15 and sample from
      # that". So basically the "limit" logic will result in 15 sets, and then we sample randomly from there. The
      # "first ranked" ad will show up in all 15 sets, where as 15 will only show in 1 of the 15.
      billboards_for_display.limit(rand(1..15)).sample
    end
  end

  def self.weighted_random_selection(relation)
    base_query = relation.to_sql
    random_val = rand.to_f

    query = <<-SQL
      WITH base AS (#{base_query}),
      weighted AS (
        SELECT *, weight,
        SUM(weight) OVER () AS total_weight,
        SUM(weight) OVER (ORDER BY id ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS running_weight
        FROM base
      )
      SELECT *, running_weight, ? * total_weight AS random_value FROM weighted
      WHERE running_weight >= ? * total_weight
      ORDER BY running_weight ASC
      LIMIT 1
    SQL

    relation.find_by_sql([query, random_val, random_val]).first
  end

  # Temporary ENV configs, to eventually be replaced by permanent configurations
  # once we determine what the appropriate long-term config approach is.

  def self.low_impression_count(placement_area)
    ApplicationConfig["LOW_IMPRESSION_COUNT_FOR_#{placement_area.upcase}"] ||
      ApplicationConfig["LOW_IMPRESSION_COUNT"] ||
      LOW_IMPRESSION_COUNT
  end

  def self.random_range_max(placement_area)
    selected_number = ApplicationConfig["SELDOM_SEEN_MIN_FOR_#{placement_area.upcase}"] ||
      ApplicationConfig["SELDOM_SEEN_MIN"] ||
      RANDOM_RANGE_MAX_FALLBACK
    selected_number.to_i
  end

  def self.new_and_priority_range_max(placement_area)
    selected_number = ApplicationConfig["SELDOM_SEEN_MAX_FOR_#{placement_area.upcase}"] ||
      ApplicationConfig["SELDOM_SEEN_MAX"] ||
      NEW_AND_PRIORITY_RANGE_MAX_FALLBACK
    selected_number.to_i
  end

  def human_readable_placement_area
    ALLOWED_PLACEMENT_AREAS_HUMAN_READABLE[ALLOWED_PLACEMENT_AREAS.find_index(placement_area)]
  end

  def validate_tag
    # check there are not too many tags
    return errors.add(:tag_list, I18n.t("models.article.too_many_tags")) if tag_list.size > MAX_TAG_LIST_SIZE

    validate_tag_name(tag_list)
  end

  def validate_geolocations
    target_geolocations.each do |geo|
      unless geo.valid?(:targeting)
        errors.add(:target_geolocations, I18n.t("models.billboard.invalid_location", location: geo.to_iso3166))
      end
    end
  end

  def validate_in_house_hero_ads
    return unless placement_area == "home_hero" && type_of != "in_house"

    errors.add(:type_of, "must be in_house if billboard is a Home Hero")
  end

  def audience_segment_type
    @audience_segment_type ||= audience_segment&.type_of
  end

  def audience_segment_type=(type)
    errors.delete(:audience_segment_type)
    @audience_segment_type = type
  end

  # This needs to correspond with Rails built-in method signature
  # rubocop:disable Style/OptionHash
  def as_json(options = {})
    overrides = {
      "audience_segment_type" => audience_segment_type,
      "tag_list" => cached_tag_list,
      "exclude_article_ids" => exclude_article_ids.join(","),
      "target_geolocations" => target_geolocations.map(&:to_iso3166)
    }
    super(options.merge(except: %i[tags tag_list target_geolocations])).merge(overrides)
  end
  # rubocop:enable Style/OptionHash

  # exclude_article_ids is an integer array, web inputs are comma-separated strings
  # ActiveRecord normalizes these in a bad way, so we are intervening
  def exclude_article_ids=(input)
    adjusted_input = input.is_a?(String) ? input.split(",") : input
    adjusted_input = adjusted_input&.filter_map { |value| value.presence&.to_i }
    write_attribute :exclude_article_ids, (adjusted_input || [])
  end

  private

  def generate_billboard_name
    return unless name.nil?

    self.name = "Billboard #{id}"
    save!
  end

  def process_markdown
    return unless body_markdown_changed?

    if FeatureFlag.enabled?(:consistent_rendering)
      extracted_process_markdown
    else
      original_process_markdown
    end
  end

  def extracted_process_markdown
    renderer = ContentRenderer.new(body_markdown || "", source: self)
    self.processed_html = renderer.process(prefix_images_options: { width: prefix_width,
                                                                    synchronous_detail_detection: true }).processed_html
    self.processed_html = processed_html.delete("\n")
  end

  def original_process_markdown
    renderer = Redcarpet::Render::HTMLRouge.new(hard_wrap: true, filter_html: false)
    markdown = Redcarpet::Markdown.new(renderer, Constants::Redcarpet::CONFIG)
    initial_html = markdown.render(body_markdown)
    stripped_html = ActionController::Base.helpers.sanitize initial_html,
                                                            tags: MarkdownProcessor::AllowedTags::BILLBOARD,
                                                            attributes: MarkdownProcessor::AllowedAttributes::BILLBOARD
    html = stripped_html.delete("\n")
    self.processed_html = Html::Parser.new(html)
      .prefix_all_images(width: prefix_width, synchronous_detail_detection: true).html
  end

  def prefix_width
    placement_area.include?("sidebar") ? SIDEBAR_WIDTH : POST_WIDTH
  end

  def refresh_audience_segment
    AudienceSegmentRefreshWorker.perform_async(audience_segment_id)
  end

  def should_refresh_audience_segment?
    change_relevant_to_audience = saved_change_to_approved? ||
      saved_change_to_published? ||
      saved_change_to_audience_segment_id?

    change_relevant_to_audience &&
      audience_segment &&
      audience_segment.updated_at < 1.day.ago
  end

  def valid_audience_segment_match
    return if audience_segment.blank? || audience_segment_type.blank?

    errors.add(:audience_segment_type) if audience_segment.type_of.to_s != audience_segment_type.to_s
  end

  def valid_manual_audience_segment
    return if audience_segment_type != "manual"

    errors.add(:audience_segment_type) if audience_segment.blank?
  end
end