1 files changed, 79 insertions, 0 deletions
diff --git a/app/finders/issuables/assignee_filter.rb b/app/finders/issuables/assignee_filter.rb
new file mode 100644
index 00000000000..2e58a6b34c9
--- /dev/null
+++ b/app/finders/issuables/assignee_filter.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+module Issuables
+  class AssigneeFilter < BaseFilter
+    def filter(issuables)
+      filtered = by_assignee(issuables)
+      filtered = by_assignee_union(filtered)
+      by_negated_assignee(filtered)
+    end
+
+    def includes_user?(user)
+      Array(params[:assignee_ids]).include?(user.id) ||
+        Array(params[:assignee_id]).include?(user.id) ||
+        Array(params[:assignee_username]).include?(user.username)
+    end
+
+    private
+
+    def by_assignee(issuables)
+      if filter_by_no_assignee?
+        issuables.unassigned
+      elsif filter_by_any_assignee?
+        issuables.assigned
+      elsif has_assignee_param?(params)
+        filter_by_assignees(issuables)
+      else
+        issuables
+      end
+    end
+
+    def by_assignee_union(issuables)
+      return issuables unless or_filters_enabled? && has_assignee_param?(or_params)
+
+      issuables.assigned_to(assignee_ids(or_params))
+    end
+
+    def by_negated_assignee(issuables)
+      return issuables unless has_assignee_param?(not_params)
+
+      issuables.not_assigned_to(assignee_ids(not_params))
+    end
+
+    def filter_by_no_assignee?
+      params[:assignee_id].to_s.downcase == FILTER_NONE
+    end
+
+    def filter_by_any_assignee?
+      params[:assignee_id].to_s.downcase == FILTER_ANY
+    end
+
+    def filter_by_assignees(issuables)
+      assignee_ids = assignee_ids(params)
+
+      return issuables.none if assignee_ids.blank?
+
+      assignee_ids.each do |assignee_id|
+        issuables = issuables.assigned_to(assignee_id)
+      end
+
+      issuables
+    end
+
+    def has_assignee_param?(specific_params)
+      return if specific_params.nil?
+
+      specific_params[:assignee_ids].present? || specific_params[:assignee_id].present? || specific_params[:assignee_username].present?
+    end
+
+    def assignee_ids(specific_params)
+      if specific_params[:assignee_ids].present?
+        Array(specific_params[:assignee_ids])
+      elsif specific_params[:assignee_id].present?
+        Array(specific_params[:assignee_id])
+      elsif specific_params[:assignee_username].present?
+        User.by_username(specific_params[:assignee_username]).select(:id)
+      end
+    end
+  end
+end