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# frozen_string_literal: true
class Trends::Statuses < Trends::Base
PREFIX = 'trending_statuses'
self.default_options = {
threshold: 5,
review_threshold: 3,
score_halflife: 2.hours.freeze,
decay_threshold: 0.3,
}
class Query < Trends::Query
def filtered_for!(account)
@account = account
self
end
def filtered_for(account)
clone.filtered_for!(account)
end
def to_arel
scope = Status.joins(:trend).reorder(score: :desc)
scope = scope.reorder(language_order_clause.desc, score: :desc) if preferred_languages.present?
scope = scope.merge(StatusTrend.allowed) if @allowed
scope = scope.not_excluded_by_account(@account).not_domain_blocked_by_account(@account) if @account.present?
scope = scope.offset(@offset) if @offset.present?
scope = scope.limit(@limit) if @limit.present?
scope
end
private
def language_order_clause
Arel::Nodes::Case.new.when(StatusTrend.arel_table[:language].in(preferred_languages)).then(1).else(0)
end
def preferred_languages
if @account&.chosen_languages.present?
@account.chosen_languages
else
@locale
end
end
end
def register(status, at_time = Time.now.utc)
add(status.proper, status.account_id, at_time) if eligible?(status.proper)
end
def add(status, _account_id, at_time = Time.now.utc)
record_used_id(status.id, at_time)
end
def query
Query.new(key_prefix, klass)
end
def refresh(at_time = Time.now.utc)
statuses = Status.where(id: (recently_used_ids(at_time) + StatusTrend.pluck(:status_id)).uniq).includes(:status_stat, :account)
calculate_scores(statuses, at_time)
end
def request_review
StatusTrend.pluck('distinct language').flat_map do |language|
score_at_threshold = StatusTrend.where(language: language, allowed: true).order(rank: :desc).where('rank <= ?', options[:review_threshold]).first&.score || 0
status_trends = StatusTrend.where(language: language, allowed: false).joins(:status).includes(status: :account)
status_trends.filter_map do |trend|
status = trend.status
if trend.score > score_at_threshold && !status.trendable? && status.requires_review_notification?
status.account.touch(:requested_review_at)
status
end
end
end
end
protected
def key_prefix
PREFIX
end
def klass
Status
end
private
def eligible?(status)
status.public_visibility? && status.account.discoverable? && !status.account.silenced? && status.spoiler_text.blank? && !status.sensitive? && !status.reply? && valid_locale?(status.language)
end
def calculate_scores(statuses, at_time)
items = statuses.map do |status|
expected = 1.0
observed = (status.reblogs_count + status.favourites_count).to_f
score = if expected > observed || observed < options[:threshold]
0
else
((observed - expected)**2) / expected
end
decaying_score = if score.zero? || !eligible?(status)
0
else
score * (0.5**((at_time.to_f - status.created_at.to_f) / options[:score_halflife].to_f))
end
[decaying_score, status]
end
to_insert = items.filter { |(score, _)| score >= options[:decay_threshold] }
to_delete = items.filter { |(score, _)| score < options[:decay_threshold] }
StatusTrend.transaction do
StatusTrend.upsert_all(to_insert.map { |(score, status)| { status_id: status.id, account_id: status.account_id, score: score, language: status.language, allowed: status.trendable? || false } }, unique_by: :status_id) if to_insert.any?
StatusTrend.where(status_id: to_delete.map { |(_, status)| status.id }).delete_all if to_delete.any?
StatusTrend.connection.exec_update('UPDATE status_trends SET rank = t0.calculated_rank FROM (SELECT id, row_number() OVER w AS calculated_rank FROM status_trends WINDOW w AS (PARTITION BY language ORDER BY score DESC)) t0 WHERE status_trends.id = t0.id')
end
end
end
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