units,lesson as standalone

database/migrations/20260709000005-add-order-index-and-is-required-to-tasks.js

@@ -0,0 +1,39 @@
+'use strict';
+
+// Part 1B — task_lists' tasks currently sort only by createdAt (no ordering
+// column exists). Add order_index (position within the list) and is_required
+// (mirrors unit_quizzes.is_required — an optional task doesn't block anything
+// after it in the sequencing lock).
+
+module.exports = {
+  async up(queryInterface, Sequelize) {
+    await queryInterface.addColumn('tasks', 'order_index', {
+      type: Sequelize.INTEGER,
+      allowNull: false,
+      defaultValue: 0,
+      after: 'deadline',
+    });
+    await queryInterface.addColumn('tasks', 'is_required', {
+      type: Sequelize.BOOLEAN,
+      allowNull: false,
+      defaultValue: true,
+      after: 'order_index',
+    });
+
+    // Backfill existing rows with a stable order matching current createdAt
+    // sort, so tasks don't all collapse to order_index 0 on first use.
+    await queryInterface.sequelize.query(`
+      UPDATE tasks t SET order_index = sub.rn - 1
+      FROM (
+        SELECT task_id, ROW_NUMBER() OVER (PARTITION BY task_list_id ORDER BY "createdAt" ASC) AS rn
+        FROM tasks
+      ) sub
+      WHERE t.task_id = sub.task_id
+    `);
+  },
+
+  async down(queryInterface) {
+    await queryInterface.removeColumn('tasks', 'is_required');
+    await queryInterface.removeColumn('tasks', 'order_index');
+  },
+};