Honor optional sort_order on lesson create under a module.

Accept sort_order on CreateLessonInput; SQL falls back to max+1. When set, shift sibling lessons and insert at that position (same pattern as module create). Regenerate sqlc and update Swagger.

Co-authored-by: Cursor <cursoragent@cursor.com>

db/query/lms_lessons.sql

@@ -1,17 +1,18 @@
 -- name: CreateLesson :one
 INSERT INTO lessons (module_id, title, video_url, thumbnail, description, sort_order)
 SELECT
-    $1,
-    $2,
-    $3,
-    $4,
-    $5,
-    coalesce((
-        SELECT
-            max(l.sort_order)
-        FROM lessons l
-        WHERE
-            l.module_id = $1), 0) + 1
+    sqlc.arg('module_id'),
+    sqlc.arg('title'),
+    sqlc.arg('video_url'),
+    sqlc.arg('thumbnail'),
+    sqlc.arg('description'),
+    COALESCE(sqlc.narg('sort_order')::int,
+        COALESCE((
+            SELECT
+                max(l.sort_order)
+            FROM lessons l
+            WHERE
+                l.module_id = sqlc.arg('module_id')), 0) + 1)
 RETURNING
     *;
 

docs/docs.go

@@ -10484,6 +10484,9 @@ const docTemplate = `{
                 "description": {
                     "type": "string"
                 },
+                "sort_order": {
+                    "type": "integer"
+                },
                 "thumbnail": {
                     "type": "string"
                 },

docs/swagger.json

@@ -10476,6 +10476,9 @@
                 "description": {
                     "type": "string"
                 },
+                "sort_order": {
+                    "type": "integer"
+                },
                 "thumbnail": {
                     "type": "string"
                 },

docs/swagger.yaml

@@ -418,6 +418,8 @@ definitions:
     properties:
       description:
         type: string
+      sort_order:
+        type: integer
       thumbnail:
         type: string
       title:

gen/db/lms_lessons.sql.go

@@ -19,12 +19,13 @@ SELECT
     $3,
     $4,
     $5,
-    coalesce((
-        SELECT
-            max(l.sort_order)
-        FROM lessons l
-        WHERE
-            l.module_id = $1), 0) + 1
+    COALESCE($6::int,
+        COALESCE((
+            SELECT
+                max(l.sort_order)
+            FROM lessons l
+            WHERE
+                l.module_id = $1), 0) + 1)
 RETURNING
     id, module_id, title, video_url, thumbnail, description, created_at, updated_at, sort_order
 `
@@ -35,6 +36,7 @@ type CreateLessonParams struct {
 	VideoUrl    pgtype.Text `json:"video_url"`
 	Thumbnail   pgtype.Text `json:"thumbnail"`
 	Description pgtype.Text `json:"description"`
+	SortOrder   pgtype.Int4 `json:"sort_order"`
 }
 
 func (q *Queries) CreateLesson(ctx context.Context, arg CreateLessonParams) (Lesson, error) {
@@ -44,6 +46,7 @@ func (q *Queries) CreateLesson(ctx context.Context, arg CreateLessonParams) (Les
 		arg.VideoUrl,
 		arg.Thumbnail,
 		arg.Description,
+		arg.SortOrder,
 	)
 	var i Lesson
 	err := row.Scan(

internal/domain/lesson.go

@@ -22,6 +22,8 @@ type CreateLessonInput struct {
 	VideoURL    *string `json:"video_url,omitempty"`
 	Thumbnail   *string `json:"thumbnail,omitempty"`
 	Description *string `json:"description,omitempty"`
+	// SortOrder within the module when set; omit to append after current max within module_id.
+	SortOrder *int `json:"sort_order,omitempty" validate:"omitempty,min=0"`
 }
 
 type UpdateLessonInput struct {

internal/repository/lms_lessons.go

@@ -30,12 +30,43 @@ func lessonToDomain(l dbgen.Lesson) domain.Lesson {
 }
 
 func (s *Store) CreateLesson(ctx context.Context, moduleID int64, input domain.CreateLessonInput) (domain.Lesson, error) {
+	if input.SortOrder != nil {
+		q, tx, err := s.BeginTx(ctx)
+		if err != nil {
+			return domain.Lesson{}, err
+		}
+		defer func() { _ = tx.Rollback(ctx) }()
+		target := int32(*input.SortOrder)
+		if _, err := tx.Exec(ctx,
+			`UPDATE lessons SET sort_order = sort_order + 1 WHERE module_id = $1 AND sort_order >= $2`,
+			moduleID, target,
+		); err != nil {
+			return domain.Lesson{}, err
+		}
+		l, err := q.CreateLesson(ctx, dbgen.CreateLessonParams{
+			ModuleID:    moduleID,
+			Title:       input.Title,
+			VideoUrl:    toPgText(input.VideoURL),
+			Thumbnail:   toPgText(input.Thumbnail),
+			Description: toPgText(input.Description),
+			SortOrder:   pgtype.Int4{Int32: target, Valid: true},
+		})
+		if err != nil {
+			return domain.Lesson{}, err
+		}
+		if err := tx.Commit(ctx); err != nil {
+			return domain.Lesson{}, err
+		}
+		return lessonToDomain(l), nil
+	}
+
 	l, err := s.queries.CreateLesson(ctx, dbgen.CreateLessonParams{
 		ModuleID:    moduleID,
 		Title:       input.Title,
 		VideoUrl:    toPgText(input.VideoURL),
 		Thumbnail:   toPgText(input.Thumbnail),
 		Description: toPgText(input.Description),
+		SortOrder:   pgtype.Int4{Valid: false},
 	})
 	if err != nil {
 		return domain.Lesson{}, err