5 files changed, 182 insertions, 0 deletions
diff --git a/app/models/account_suggestions/global_source.rb b/app/models/account_suggestions/global_source.rb
new file mode 100644
index 00000000000..ac764de50f5
--- /dev/null
+++ b/app/models/account_suggestions/global_source.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+class AccountSuggestions::GlobalSource < AccountSuggestions::Source
+  def key
+    :global
+  end
+
+  def get(account, skip_account_ids: [], limit: 40)
+    account_ids = account_ids_for_locale(account.user_locale) - [account.id] - skip_account_ids
+
+    as_ordered_suggestions(
+      scope(account).where(id: account_ids),
+      account_ids
+    ).take(limit)
+  end
+
+  def remove(_account, _target_account_id)
+    nil
+  end
+
+  private
+
+  def scope(account)
+    Account.searchable
+           .followable_by(account)
+           .not_excluded_by_account(account)
+           .not_domain_blocked_by_account(account)
+  end
+
+  def account_ids_for_locale(locale)
+    Redis.current.zrevrange("follow_recommendations:#{locale}", 0, -1).map(&:to_i)
+  end
+
+  def to_ordered_list_key(account)
+    account.id
+  end
+end
diff --git a/app/models/account_suggestions/past_interactions_source.rb b/app/models/account_suggestions/past_interactions_source.rb
new file mode 100644
index 00000000000..d169394f11a
--- /dev/null
+++ b/app/models/account_suggestions/past_interactions_source.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+class AccountSuggestions::PastInteractionsSource < AccountSuggestions::Source
+  include Redisable
+
+  def key
+    :past_interactions
+  end
+
+  def get(account, skip_account_ids: [], limit: 40)
+    account_ids = account_ids_for_account(account.id, limit + skip_account_ids.size) - skip_account_ids
+
+    as_ordered_suggestions(
+      scope.where(id: account_ids),
+      account_ids
+    ).take(limit)
+  end
+
+  def remove(account, target_account_id)
+    redis.zrem("interactions:#{account.id}", target_account_id)
+  end
+
+  private
+
+  def scope
+    Account.searchable
+  end
+
+  def account_ids_for_account(account_id, limit)
+    redis.zrevrange("interactions:#{account_id}", 0, limit).map(&:to_i)
+  end
+
+  def to_ordered_list_key(account)
+    account.id
+  end
+end
diff --git a/app/models/account_suggestions/setting_source.rb b/app/models/account_suggestions/setting_source.rb
new file mode 100644
index 00000000000..be9eff23350
--- /dev/null
+++ b/app/models/account_suggestions/setting_source.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+class AccountSuggestions::SettingSource < AccountSuggestions::Source
+  def key
+    :staff
+  end
+
+  def get(account, skip_account_ids: [], limit: 40)
+    return [] unless setting_enabled?
+
+    as_ordered_suggestions(
+      scope(account).where(setting_to_where_condition).where.not(id: skip_account_ids),
+      usernames_and_domains
+    ).take(limit)
+  end
+
+  def remove(_account, _target_account_id)
+    nil
+  end
+
+  private
+
+  def scope(account)
+    Account.searchable
+           .followable_by(account)
+           .not_excluded_by_account(account)
+           .not_domain_blocked_by_account(account)
+           .where(locked: false)
+           .where.not(id: account.id)
+  end
+
+  def usernames_and_domains
+    @usernames_and_domains ||= setting_to_usernames_and_domains
+  end
+
+  def setting_enabled?
+    setting.present?
+  end
+
+  def setting_to_where_condition
+    usernames_and_domains.map do |(username, domain)|
+      Arel::Nodes::Grouping.new(
+        Account.arel_table[:username].lower.eq(username.downcase).and(
+          Account.arel_table[:domain].lower.eq(domain&.downcase)
+        )
+      )
+    end.reduce(:or)
+  end
+
+  def setting_to_usernames_and_domains
+    setting.split(',').map do |str|
+      username, domain = str.strip.gsub(/\A@/, '').split('@', 2)
+      domain           = nil if TagManager.instance.local_domain?(domain)
+
+      next if username.blank?
+
+      [username, domain]
+    end.compact
+  end
+
+  def setting
+    Setting.bootstrap_timeline_accounts
+  end
+
+  def to_ordered_list_key(account)
+    [account.username, account.domain]
+  end
+end
diff --git a/app/models/account_suggestions/source.rb b/app/models/account_suggestions/source.rb
new file mode 100644
index 00000000000..bd1068d201e
--- /dev/null
+++ b/app/models/account_suggestions/source.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+class AccountSuggestions::Source
+  def key
+    raise NotImplementedError
+  end
+
+  def get(_account, **kwargs)
+    raise NotImplementedError
+  end
+
+  def remove(_account, target_account_id)
+    raise NotImplementedError
+  end
+
+  protected
+
+  def as_ordered_suggestions(scope, ordered_list)
+    return [] if ordered_list.empty?
+
+    map = scope.index_by(&method(:to_ordered_list_key))
+
+    ordered_list.map { |ordered_list_key| map[ordered_list_key] }.compact.map do |account|
+      AccountSuggestions::Suggestion.new(
+        account: account,
+        source: key
+      )
+    end
+  end
+
+  def to_ordered_list_key(_account)
+    raise NotImplementedError
+  end
+end
diff --git a/app/models/account_suggestions/suggestion.rb b/app/models/account_suggestions/suggestion.rb
new file mode 100644
index 00000000000..2c6f4d27f5c
--- /dev/null
+++ b/app/models/account_suggestions/suggestion.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AccountSuggestions::Suggestion < ActiveModelSerializers::Model
+  attributes :account, :source
+
+  delegate :id, to: :account, prefix: true
+end