discourse/lib/topic_query.rb

845 lines
29 KiB
Ruby

#
# Helps us find topics.
# Returns a TopicList object containing the topics found.
#
require_dependency 'topic_list'
require_dependency 'suggested_topics_builder'
require_dependency 'topic_query_sql'
require_dependency 'avatar_lookup'
class TopicQuery
def self.public_valid_options
@public_valid_options ||=
%i(page
before
bumped_before
topic_ids
exclude_category_ids
category
order
ascending
min_posts
max_posts
status
filter
state
search
q
group_name
tags
match_all_tags
no_subcategories
slow_platform
no_tags)
end
def self.valid_options
@valid_options ||=
public_valid_options +
%i(except_topic_ids
limit
page
per_page
visible
no_definitions)
end
# Maps `order` to a columns in `topics`
SORTABLE_MAPPING = {
'likes' => 'like_count',
'op_likes' => 'op_likes',
'views' => 'views',
'posts' => 'posts_count',
'activity' => 'bumped_at',
'posters' => 'participant_count',
'category' => 'category_id',
'created' => 'created_at'
}
cattr_accessor :results_filter_callbacks
self.results_filter_callbacks = []
attr_accessor :options, :user, :guardian
def self.add_custom_filter(key, &blk)
@custom_filters ||= {}
valid_options << key
public_valid_options << key
@custom_filters[key] = blk
end
def self.remove_custom_filter(key)
@custom_filters.delete(key)
public_valid_options.delete(key)
valid_options.delete(key)
@custom_filters = nil if @custom_filters.length == 0
end
def self.apply_custom_filters(results, topic_query)
if @custom_filters
@custom_filters.each do |key, filter|
results = filter.call(results, topic_query)
end
end
results
end
def initialize(user = nil, options = {})
options.assert_valid_keys(TopicQuery.valid_options)
@options = options.dup
@user = user
@guardian = Guardian.new(@user)
end
def joined_topic_user(list = nil)
(list || Topic).joins("LEFT OUTER JOIN topic_users AS tu ON (topics.id = tu.topic_id AND tu.user_id = #{@user.id.to_i})")
end
# Return a list of suggested topics for a topic
def list_suggested_for(topic)
return if topic.private_message? && !@user
builder = SuggestedTopicsBuilder.new(topic)
pm_params =
if topic.private_message?
group_ids = topic.topic_allowed_groups
.where('group_id IN (SELECT group_id FROM group_users WHERE user_id = :user_id)', user_id: @user.id)
.pluck(:group_id)
{
topic: topic,
my_group_ids: group_ids,
target_group_ids: topic.topic_allowed_groups.pluck(:group_id),
target_user_ids: topic.topic_allowed_users.pluck(:user_id) - [@user.id]
}
end
# When logged in we start with different results
if @user
if topic.private_message?
builder.add_results(new_messages(
pm_params.merge(count: builder.results_left)
)) unless builder.full?
builder.add_results(unread_messages(
pm_params.merge(count: builder.results_left)
)) unless builder.full?
else
builder.add_results(unread_results(topic: topic, per_page: builder.results_left), :high)
builder.add_results(new_results(topic: topic, per_page: builder.category_results_left)) unless builder.full?
end
end
if topic.private_message?
builder.add_results(related_messages_group(
pm_params.merge(count: [3, builder.results_left].max,
exclude: builder.excluded_topic_ids)
)) if pm_params[:my_group_ids].present?
builder.add_results(related_messages_user(
pm_params.merge(count: [3, builder.results_left].max,
exclude: builder.excluded_topic_ids)
))
else
builder.add_results(random_suggested(topic, builder.results_left, builder.excluded_topic_ids)) unless builder.full?
end
params = { unordered: true }
if topic.private_message?
params[:preload_posters] = true
end
create_list(:suggested, params, builder.results)
end
# The latest view of topics
def list_latest
create_list(:latest, {}, latest_results)
end
def list_read
create_list(:read, unordered: true) do |topics|
topics.where('tu.last_visited_at IS NOT NULL').order('tu.last_visited_at DESC')
end
end
def list_new
create_list(:new, { unordered: true }, new_results)
end
def list_unread
create_list(:unread, { unordered: true }, unread_results)
end
def list_posted
create_list(:posted) { |l| l.where('tu.posted') }
end
def list_bookmarks
create_list(:bookmarks) { |l| l.where('tu.bookmarked') }
end
def list_top_for(period)
score = "#{period}_score"
create_list(:top, unordered: true) do |topics|
topics = topics.joins(:top_topic).where("top_topics.#{score} > 0")
if period == :yearly && @user.try(:trust_level) == TrustLevel[0]
topics.order(TopicQuerySQL.order_top_with_pinned_category_for(score))
else
topics.order(TopicQuerySQL.order_top_for(score))
end
end
end
def list_topics_by(user)
@options[:filtered_to_user] = user.id
create_list(:user_topics) do |topics|
topics.where(user_id: user.id)
end
end
def not_archived(list, user)
list.joins("LEFT JOIN user_archived_messages um
ON um.user_id = #{user.id.to_i} AND um.topic_id = topics.id")
.where('um.user_id IS NULL')
end
def list_private_messages(user)
list = private_messages_for(user, :user)
list = not_archived(list, user)
.where('NOT (topics.participant_count = 1 AND topics.user_id = ?)', user.id)
create_list(:private_messages, {}, list)
end
def list_private_messages_archive(user)
list = private_messages_for(user, :user)
list = list.joins(:user_archived_messages).where('user_archived_messages.user_id = ?', user.id)
create_list(:private_messages, {}, list)
end
def list_private_messages_sent(user)
list = private_messages_for(user, :user)
list = list.where('EXISTS (
SELECT 1 FROM posts
WHERE posts.topic_id = topics.id AND
posts.user_id = ?
)', user.id)
list = not_archived(list, user)
create_list(:private_messages, {}, list)
end
def list_private_messages_unread(user)
list = private_messages_for(user, :user)
list = list.where("tu.last_read_post_number IS NULL OR tu.last_read_post_number < topics.highest_post_number")
create_list(:private_messages, {}, list)
end
def list_private_messages_group(user)
list = private_messages_for(user, :group)
group_id = Group.where('name ilike ?', @options[:group_name]).pluck(:id).first
list = list.joins("LEFT JOIN group_archived_messages gm ON gm.topic_id = topics.id AND
gm.group_id = #{group_id.to_i}")
list = list.where("gm.id IS NULL")
create_list(:private_messages, {}, list)
end
def list_private_messages_group_archive(user)
list = private_messages_for(user, :group)
group_id = Group.where('name ilike ?', @options[:group_name]).pluck(:id).first
list = list.joins("JOIN group_archived_messages gm ON gm.topic_id = topics.id AND
gm.group_id = #{group_id.to_i}")
create_list(:private_messages, {}, list)
end
def list_category_topic_ids(category)
query = default_results(category: category.id)
pinned_ids = query.where('pinned_at IS NOT NULL AND category_id = ?', category.id)
.limit(nil)
.order('pinned_at DESC').pluck(:id)
non_pinned_ids = query.where('pinned_at IS NULL OR category_id <> ?', category.id).pluck(:id)
(pinned_ids + non_pinned_ids)
end
def list_new_in_category(category)
create_list(:new_in_category, unordered: true, category: category.id) do |list|
list.by_newest.first(25)
end
end
def self.new_filter(list, treat_as_new_topic_start_date)
list.where("topics.created_at >= :created_at", created_at: treat_as_new_topic_start_date)
.where("tu.last_read_post_number IS NULL")
.where("COALESCE(tu.notification_level, :tracking) >= :tracking", tracking: TopicUser.notification_levels[:tracking])
end
def self.unread_filter(list, user_id, opts)
# PERF note
# We use the function first_unread_topic_for here instead of joining
# the table to assist the PostgreSQL query planner
#
# We want the query planner to have the actual value of the first_unread_topic so
# it can pick an appropriate plan. If it does not have this upfront it will just assume
# that the value will be 1/3 of the way through the topic table which makes it use terrible
# indexes for the plan.
#
col_name = opts[:staff] ? "highest_staff_post_number" : "highest_post_number"
list
.where("tu.last_read_post_number < topics.#{col_name}")
.where("COALESCE(tu.notification_level, :regular) >= :tracking",
regular: TopicUser.notification_levels[:regular], tracking: TopicUser.notification_levels[:tracking])
end
def prioritize_pinned_topics(topics, options)
pinned_clause = options[:category_id] ? "topics.category_id = #{options[:category_id].to_i} AND" : "pinned_globally AND "
pinned_clause << " pinned_at IS NOT NULL "
if @user
pinned_clause << " AND (topics.pinned_at > tu.cleared_pinned_at OR tu.cleared_pinned_at IS NULL)"
end
unpinned_topics = topics.where("NOT ( #{pinned_clause} )")
pinned_topics = topics.dup.offset(nil).where(pinned_clause)
per_page = options[:per_page] || per_page_setting
limit = per_page unless options[:limit] == false
page = options[:page].to_i
if page == 0
(pinned_topics + unpinned_topics)[0...limit] if limit
else
offset = (page * per_page) - pinned_topics.count
offset = 0 unless offset > 0
unpinned_topics.offset(offset).to_a
end
end
def create_list(filter, options = {}, topics = nil)
topics ||= default_results(options)
topics = yield(topics) if block_given?
options = options.merge(@options)
if ["activity", "default"].include?(options[:order] || "activity") &&
!options[:unordered] &&
filter != :private_messages
topics = prioritize_pinned_topics(topics, options)
end
topics = topics.to_a
if options[:preload_posters]
user_ids = []
topics.each do |ft|
user_ids << ft.user_id << ft.last_post_user_id << ft.featured_user_ids << ft.allowed_user_ids
end
avatar_lookup = AvatarLookup.new(user_ids)
topics.each do |t|
t.posters = t.posters_summary(avatar_lookup: avatar_lookup)
end
end
topics.each do |t|
t.allowed_user_ids = filter == :private_messages ? t.allowed_users.map { |u| u.id } : []
end
list = TopicList.new(filter, @user, topics, options.merge(@options))
list.per_page = per_page_setting
list
end
def latest_results(options = {})
result = default_results(options)
result = remove_muted_topics(result, @user) unless options && options[:state] == "muted".freeze
result = remove_muted_categories(result, @user, exclude: options[:category])
result = remove_muted_tags(result, @user, options)
# plugins can remove topics here:
self.class.results_filter_callbacks.each do |filter_callback|
result = filter_callback.call(:latest, result, @user, options)
end
result
end
def unread_results(options = {})
result = TopicQuery.unread_filter(
default_results(options.reverse_merge(unordered: true)),
@user&.id,
staff: @user&.staff?)
.order('CASE WHEN topics.user_id = tu.user_id THEN 1 ELSE 2 END')
self.class.results_filter_callbacks.each do |filter_callback|
result = filter_callback.call(:unread, result, @user, options)
end
suggested_ordering(result, options)
end
def new_results(options = {})
# TODO does this make sense or should it be ordered on created_at
# it is ordering on bumped_at now
result = TopicQuery.new_filter(default_results(options.reverse_merge(unordered: true)), @user.user_option.treat_as_new_topic_start_date)
result = remove_muted_topics(result, @user)
result = remove_muted_categories(result, @user, exclude: options[:category])
result = remove_muted_tags(result, @user, options)
self.class.results_filter_callbacks.each do |filter_callback|
result = filter_callback.call(:new, result, @user, options)
end
suggested_ordering(result, options)
end
protected
def per_page_setting
@options[:slow_platform] ? 15 : 30
end
def private_messages_for(user, type)
options = @options
options.reverse_merge!(per_page: per_page_setting)
result = Topic.includes(:tags)
if type == :group
result = result.includes(:allowed_users)
result = result.where("topics.id IN (SELECT topic_id FROM topic_allowed_groups
WHERE group_id IN (
SELECT group_id FROM group_users WHERE user_id = #{user.id.to_i}) AND
group_id IN (SELECT id FROM groups WHERE name ilike ?)
)", @options[:group_name])
elsif type == :user
result = result.includes(:allowed_users)
result = result.where("topics.id IN (SELECT topic_id FROM topic_allowed_users WHERE user_id = #{user.id.to_i})")
elsif type == :all
result = result.includes(:allowed_users)
result = result.where("topics.id IN (
SELECT topic_id
FROM topic_allowed_users
WHERE user_id = #{user.id.to_i}
UNION ALL
SELECT topic_id FROM topic_allowed_groups
WHERE group_id IN (
SELECT group_id FROM group_users WHERE user_id = #{user.id.to_i}
)
)")
end
result = result.joins("LEFT OUTER JOIN topic_users AS tu ON (topics.id = tu.topic_id AND tu.user_id = #{user.id.to_i})")
.order("topics.bumped_at DESC")
.private_messages
result = result.limit(options[:per_page]) unless options[:limit] == false
result = result.visible if options[:visible] || @user.nil? || @user.regular?
if options[:page]
offset = options[:page].to_i * options[:per_page]
result = result.offset(offset) if offset > 0
end
result
end
def apply_ordering(result, options)
sort_column = SORTABLE_MAPPING[options[:order]] || 'default'
sort_dir = (options[:ascending] == "true") ? "ASC" : "DESC"
# If we are sorting in the default order desc, we should consider including pinned
# topics. Otherwise, just use bumped_at.
if sort_column == 'default'
if sort_dir == 'DESC'
# If something requires a custom order, for example "unread" which sorts the least read
# to the top, do nothing
return result if options[:unordered]
end
sort_column = 'bumped_at'
end
# If we are sorting by category, actually use the name
if sort_column == 'category_id'
# TODO forces a table scan, slow
return result.references(:categories).order(TopicQuerySQL.order_by_category_sql(sort_dir))
end
if sort_column == 'op_likes'
return result.includes(:first_post).order("(SELECT like_count FROM posts p3 WHERE p3.topic_id = topics.id AND p3.post_number = 1) #{sort_dir}")
end
if sort_column.start_with?('custom_fields')
field = sort_column.split('.')[1]
return result.order("(SELECT CASE WHEN EXISTS (SELECT true FROM topic_custom_fields tcf WHERE tcf.topic_id::integer = topics.id::integer AND tcf.name = '#{field}') THEN (SELECT value::integer FROM topic_custom_fields tcf WHERE tcf.topic_id::integer = topics.id::integer AND tcf.name = '#{field}') ELSE 0 END) #{sort_dir}")
end
result.order("topics.#{sort_column} #{sort_dir}")
end
def get_category_id(category_id_or_slug)
return nil unless category_id_or_slug
category_id = category_id_or_slug.to_i
category_id = Category.where(slug: category_id_or_slug).pluck(:id).first if category_id == 0
category_id
end
# Create results based on a bunch of default options
def default_results(options = {})
options.reverse_merge!(@options)
options.reverse_merge!(per_page: per_page_setting)
# Whether to return visible topics
options[:visible] = true if @user.nil? || @user.regular?
options[:visible] = false if @user && @user.id == options[:filtered_to_user]
# Start with a list of all topics
result = Topic.unscoped
if @user
result = result.joins("LEFT OUTER JOIN topic_users AS tu ON (topics.id = tu.topic_id AND tu.user_id = #{@user.id.to_i})")
.references('tu')
end
category_id = get_category_id(options[:category])
@options[:category_id] = category_id
if category_id
if options[:no_subcategories]
result = result.where('categories.id = ?', category_id)
else
result = result.where('categories.id = :category_id OR (categories.parent_category_id = :category_id AND categories.topic_id <> topics.id)', category_id: category_id)
end
result = result.references(:categories)
if !@options[:order]
# category default sort order
sort_order, sort_ascending = Category.where(id: category_id).pluck(:sort_order, :sort_ascending).first
if sort_order
options[:order] = sort_order
options[:ascending] = !!sort_ascending ? 'true' : 'false'
end
end
end
# ALL TAGS: something like this?
# Topic.joins(:tags).where('tags.name in (?)', @options[:tags]).group('topic_id').having('count(*)=?', @options[:tags].size).select('topic_id')
if SiteSetting.tagging_enabled
result = result.preload(:tags)
if @options[:tags] && @options[:tags].size > 0
if @options[:match_all_tags]
# ALL of the given tags:
tags_count = @options[:tags].length
@options[:tags] = Tag.where(name: @options[:tags]).pluck(:id) unless @options[:tags][0].is_a?(Integer)
if tags_count == @options[:tags].length
@options[:tags].each_with_index do |tag, index|
sql_alias = ['t', index].join
result = result.joins("INNER JOIN topic_tags #{sql_alias} ON #{sql_alias}.topic_id = topics.id AND #{sql_alias}.tag_id = #{tag}")
end
else
result = result.none # don't return any results unless all tags exist in the database
end
else
# ANY of the given tags:
result = result.joins(:tags)
if @options[:tags][0].is_a?(Integer)
result = result.where("tags.id in (?)", @options[:tags])
else
result = result.where("tags.name in (?)", @options[:tags])
end
end
elsif @options[:no_tags]
# the following will do: ("topics"."id" NOT IN (SELECT DISTINCT "topic_tags"."topic_id" FROM "topic_tags"))
result = result.where.not(id: TopicTag.select(:topic_id).uniq)
end
end
result = apply_ordering(result, options)
result = result.listable_topics.includes(:category)
if options[:exclude_category_ids] && options[:exclude_category_ids].is_a?(Array) && options[:exclude_category_ids].size > 0
result = result.where("categories.id NOT IN (?)", options[:exclude_category_ids]).references(:categories)
end
# Don't include the category topics if excluded
if options[:no_definitions]
result = result.where('COALESCE(categories.topic_id, 0) <> topics.id')
end
result = result.limit(options[:per_page]) unless options[:limit] == false
result = result.visible if options[:visible]
result = result.where.not(topics: { id: options[:except_topic_ids] }).references(:topics) if options[:except_topic_ids]
if options[:page]
offset = options[:page].to_i * options[:per_page]
result = result.offset(offset) if offset > 0
end
if options[:topic_ids]
result = result.where('topics.id in (?)', options[:topic_ids]).references(:topics)
end
if search = options[:search]
result = result.where("topics.id in (select pp.topic_id from post_search_data pd join posts pp on pp.id = pd.post_id where pd.search_data @@ #{Search.ts_query(search.to_s)})")
end
# NOTE protect against SYM attack can be removed with Ruby 2.2
#
state = options[:state]
if @user && state &&
TopicUser.notification_levels.keys.map(&:to_s).include?(state)
level = TopicUser.notification_levels[state.to_sym]
result = result.where('topics.id IN (
SELECT topic_id
FROM topic_users
WHERE user_id = ? AND
notification_level = ?)', @user.id, level)
end
require_deleted_clause = true
if before = options[:before]
if (before = before.to_i) > 0
result = result.where('topics.created_at < ?', before.to_i.days.ago)
end
end
if bumped_before = options[:bumped_before]
if (bumped_before = bumped_before.to_i) > 0
result = result.where('topics.bumped_at < ?', bumped_before.to_i.days.ago)
end
end
if status = options[:status]
case status
when 'open'
result = result.where('NOT topics.closed AND NOT topics.archived')
when 'closed'
result = result.where('topics.closed')
when 'archived'
result = result.where('topics.archived')
when 'listed'
result = result.where('topics.visible')
when 'unlisted'
result = result.where('NOT topics.visible')
when 'deleted'
guardian = @guardian
if guardian.is_staff?
result = result.where('topics.deleted_at IS NOT NULL')
require_deleted_clause = false
end
end
end
if (filter = options[:filter]) && @user
action =
if filter == "bookmarked"
PostActionType.types[:bookmark]
elsif filter == "liked"
PostActionType.types[:like]
end
if action
result = result.where('topics.id IN (SELECT pp.topic_id
FROM post_actions pa
JOIN posts pp ON pp.id = pa.post_id
WHERE pa.user_id = :user_id AND
pa.post_action_type_id = :action AND
pa.deleted_at IS NULL
)', user_id: @user.id,
action: action
)
end
end
result = result.where('topics.deleted_at IS NULL') if require_deleted_clause
result = result.where('topics.posts_count <= ?', options[:max_posts]) if options[:max_posts].present?
result = result.where('topics.posts_count >= ?', options[:min_posts]) if options[:min_posts].present?
result = TopicQuery.apply_custom_filters(result, self)
@guardian.filter_allowed_categories(result)
end
def remove_muted_topics(list, user)
if user
list = list.where('COALESCE(tu.notification_level,1) > :muted', muted: TopicUser.notification_levels[:muted])
end
list
end
def remove_muted_categories(list, user, opts = nil)
category_id = get_category_id(opts[:exclude]) if opts
if user
list = list.references("cu")
.where("
NOT EXISTS (
SELECT 1
FROM category_users cu
WHERE cu.user_id = :user_id
AND cu.category_id = topics.category_id
AND cu.notification_level = :muted
AND cu.category_id <> :category_id
AND (tu.notification_level IS NULL OR tu.notification_level < :tracking)
)", user_id: user.id,
muted: CategoryUser.notification_levels[:muted],
tracking: TopicUser.notification_levels[:tracking],
category_id: category_id || -1)
end
list
end
def remove_muted_tags(list, user, opts = nil)
if user.nil? || !SiteSetting.tagging_enabled || !SiteSetting.remove_muted_tags_from_latest
list
else
if !TagUser.lookup(user, :muted).exists?
list
else
showing_tag = if opts[:filter]
f = opts[:filter].split('/')
f[0] == 'tags' ? f[1] : nil
else
nil
end
if TagUser.lookup(user, :muted).joins(:tag).where('tags.name = ?', showing_tag).exists?
list # if viewing the topic list for a muted tag, show all the topics
else
muted_tag_ids = TagUser.lookup(user, :muted).pluck(:tag_id)
list = list.where("
EXISTS (
SELECT 1
FROM topic_tags tt
WHERE tt.tag_id NOT IN (:tag_ids)
AND tt.topic_id = topics.id
) OR NOT EXISTS (SELECT 1 FROM topic_tags tt WHERE tt.topic_id = topics.id)", tag_ids: muted_tag_ids)
end
end
end
end
def new_messages(params)
TopicQuery.new_filter(messages_for_groups_or_user(params[:my_group_ids]), Time.at(SiteSetting.min_new_topics_time).to_datetime)
.limit(params[:count])
end
def unread_messages(params)
TopicQuery.unread_filter(
messages_for_groups_or_user(params[:my_group_ids]),
@user&.id,
staff: @user&.staff?)
.limit(params[:count])
end
def related_messages_user(params)
messages_for_user
.limit(params[:count])
.where('topics.id IN (
SELECT ta.topic_id
FROM topic_allowed_users ta
WHERE ta.user_id IN (:user_ids)
) OR
topics.id IN (
SELECT tg.topic_id
FROM topic_allowed_groups tg
WHERE tg.group_id IN (:group_ids)
)
', user_ids: (params[:target_user_ids] || []) + [-10],
group_ids: ((params[:target_group_ids] - params[:my_group_ids]) || []) + [-10])
end
def related_messages_group(params)
messages_for_groups_or_user(params[:my_group_ids])
.limit(params[:count])
.where('topics.id IN (
SELECT ta.topic_id
FROM topic_allowed_users ta
WHERE ta.user_id IN (:user_ids)
) OR
topics.id IN (
SELECT tg.topic_id
FROM topic_allowed_groups tg
WHERE tg.group_id IN (:group_ids)
)
', user_ids: (params[:target_user_ids] || []) + [-10],
group_ids: ((params[:target_group_ids] - params[:my_group_ids]) || []) + [-10])
end
def messages_for_groups_or_user(group_ids)
if group_ids.present?
base_messages
.where('topics.id IN (
SELECT topic_id
FROM topic_allowed_groups tg
JOIN group_users gu ON gu.user_id = :user_id AND gu.group_id = tg.group_id
WHERE gu.group_id IN (:group_ids)
)', user_id: @user.id, group_ids: group_ids)
else
messages_for_user
end
end
def messages_for_user
base_messages.where('topics.id IN (
SELECT topic_id
FROM topic_allowed_users
WHERE user_id = :user_id
)', user_id: @user.id)
end
def base_messages
query = Topic
.where('topics.archetype = ?', Archetype.private_message)
.joins("LEFT JOIN topic_users tu ON topics.id = tu.topic_id AND tu.user_id = #{@user.id.to_i}")
query = query.includes(:tags) if SiteSetting.tagging_enabled
query.order('topics.bumped_at DESC')
end
def random_suggested(topic, count, excluded_topic_ids = [])
result = default_results(unordered: true, per_page: count).where(closed: false, archived: false)
excluded_topic_ids += Category.topic_ids.to_a
result = result.where("topics.id NOT IN (?)", excluded_topic_ids) unless excluded_topic_ids.empty?
result = remove_muted_categories(result, @user)
# If we are in a category, prefer it for the random results
if topic.category_id
result = result.order("CASE WHEN topics.category_id = #{topic.category_id.to_i} THEN 0 ELSE 1 END")
end
# Best effort, it over selects, however if you have a high number
# of muted categories there is tiny chance we will not select enough
# in particular this can happen if current category is empty and tons
# of muted, big edge case
#
# we over select in case cache is stale
max = (count * 1.3).to_i
ids = RandomTopicSelector.next(max) + RandomTopicSelector.next(max, topic.category)
result.where(id: ids.uniq)
end
def suggested_ordering(result, options)
# Prefer unread in the same category
if options[:topic] && options[:topic].category_id
result = result.order("CASE WHEN topics.category_id = #{options[:topic].category_id.to_i} THEN 0 ELSE 1 END")
end
result.order('topics.bumped_at DESC')
end
end