Untie statuses from the project directly (tie to workflows)

app/controllers/tasks_controller.rb

@@ -11,7 +11,7 @@ class TasksController < ApplicationController
                Task.all
              end
 
-    @tasks = @tasks.includes(:status, :workflow, project: :task_statuses)
+    @tasks = @tasks.includes(:status, :project, workflow: :task_statuses)
   end
 
   def show; end

app/models/project.rb

@@ -7,8 +7,8 @@ class Project < ApplicationRecord
   validates :code, exclusion: { in: %w[new] }, uniqueness: true, format: { with: /\A[a-z][a-z0-9]{1,}\z/ }
 
   has_many :tasks, dependent: :restrict_with_exception
-  has_many :task_statuses, dependent: :destroy
   has_many :workflows, dependent: :destroy
+  has_many :task_statuses, through: :workflows
 
   has_rich_text :description
 

app/models/task_status.rb

@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
 class TaskStatus < ApplicationRecord
-  belongs_to :project
   belongs_to :workflow
+  has_one :project, through: :workflow
 
   enum :category, { backlog: 100, analysis: 1000, development: 20_000, fulfillment: 60_000 }
 
-  validates :name, presence: true, uniqueness: { scope: :project }
+  validates :name, presence: true, uniqueness: { scope: :workflow }
   validates :category, presence: true
   validate :associations_should_have_same_project
 

app/models/workflow.rb

@@ -4,7 +4,7 @@ class Workflow < ApplicationRecord
   belongs_to :project
 
   has_many :tasks, dependent: :restrict_with_exception
-  has_many :statuses, class_name: 'TaskStatus', dependent: :restrict_with_error
+  has_many :task_statuses, dependent: :restrict_with_error
 
   enum :icon, { task: 'task', warning: 'warning' }, default: 'task', scopes: false
   enum :color, { blue: 'blue', gray: 'gray', yellow: 'yellow', red: 'red' }, default: 'gray', scopes: false

app/view_models/tasks/statuses/selector_view_model.rb

@@ -17,16 +17,15 @@ module Tasks
         view_context.render(
           partial: 'tasks/status_selector',
           locals: { task: @task, id: dom_id, with_form: @with_form,
-                    project_task_statuses:,
+                    workflow_task_statuses:,
                     task_status_badge: ->(status) { task_status_badge(status, view_context) }}
         )
       end
 
       private
 
-      def project_task_statuses
+      def workflow_task_statuses
-        # TODO: refactor because it causes N+1 (task statuses loaded separately)
+        @task.workflow.task_statuses.sort_by { |e| [e.category, e.name] }
-        @task.project.task_statuses.default_order
       end
 
       def task_status_badge(status, view_context)

app/views/tasks/_status_selector.html.slim

@@ -1,7 +1,7 @@
 details.dropdown.task-status-selector id=id data-controller="tasks--status-selector"
   summary= task_status_badge[task.status]
   ul
-    - project_task_statuses.each do |status|
+    - workflow_task_statuses.each do |status|
       li
         a href="#" data-status-id="#{status.id}" data-action="tasks--status-selector#changeStatus:prevent" = task_status_badge[status]
   - if with_form

db/migrate/20260321132125_change_task_statuses_uniqueness.rb

@@ -0,0 +1,9 @@
+class ChangeTaskStatusesUniqueness < ActiveRecord::Migration[8.1]
+  def change
+    change_table :task_statuses, bulk: true do |t|
+      t.remove_index %i[project_id name], unique: true
+      t.remove_index %i[project_id category name]
+      t.index %i[workflow_id name], unique: true
+    end
+  end
+end

db/migrate/20260321132550_add_null_false_to_task_statuses_workflow.rb

@@ -0,0 +1,5 @@
+class AddNullFalseToTaskStatusesWorkflow < ActiveRecord::Migration[8.1]
+  def change
+    change_column_null :task_statuses, :workflow_id, false
+  end
+end

db/migrate/20260321132740_drop_project_id_from_task_statuses.rb

@@ -0,0 +1,5 @@
+class DropProjectIdFromTaskStatuses < ActiveRecord::Migration[8.1]
+  def change
+    remove_reference :task_statuses, :project, foreign_key: true
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.1].define(version: 2026_03_21_115521) do
+ActiveRecord::Schema[8.1].define(version: 2026_03_21_132740) do
   create_table "action_text_rich_texts", charset: "utf8mb4", collation: "utf8mb4_uca1400_ai_ci", force: :cascade do |t|
     t.text "body", size: :long
     t.datetime "created_at", null: false
@@ -73,12 +73,9 @@ ActiveRecord::Schema[8.1].define(version: 2026_03_21_115521) do
     t.integer "category", limit: 2, null: false, unsigned: true
     t.datetime "created_at", null: false
     t.string "name", null: false
-    t.bigint "project_id", null: false
     t.datetime "updated_at", null: false
-    t.bigint "workflow_id"
+    t.bigint "workflow_id", null: false
-    t.index ["project_id", "category", "name"], name: "index_task_statuses_on_project_id_and_category_and_name"
+    t.index ["workflow_id", "name"], name: "index_task_statuses_on_workflow_id_and_name", unique: true
-    t.index ["project_id", "name"], name: "index_task_statuses_on_project_id_and_name", unique: true
-    t.index ["project_id"], name: "index_task_statuses_on_project_id"
     t.index ["workflow_id"], name: "index_task_statuses_on_workflow_id"
   end
 
@@ -117,7 +114,6 @@ ActiveRecord::Schema[8.1].define(version: 2026_03_21_115521) do
   add_foreign_key "active_storage_attachments", "active_storage_blobs", column: "blob_id"
   add_foreign_key "active_storage_variant_records", "active_storage_blobs", column: "blob_id"
   add_foreign_key "sessions", "users"
-  add_foreign_key "task_statuses", "projects"
   add_foreign_key "tasks", "projects"
   add_foreign_key "tasks", "task_statuses", column: "status_id"
   add_foreign_key "workflows", "projects"