feat(views): sort tasks by their position relative to the view they're in

docs/content/doc/usage/errors.md

@@ -99,6 +99,7 @@ This document describes the different errors Vikunja can return.
 | 4023      | 409 | Tried to create a task relation which would create a cycle.                |
 | 4024      | 400 | The provided filter expression is invalid.                                 |
 | 4025      | 400 | The reaction kind is invalid.                                              |
+| 4026      | 400 | You must provide a project view ID when sorting by position.               |
 
 ## Team
 

pkg/models/error.go

@@ -1114,6 +1114,25 @@ func (err ErrInvalidReactionEntityKind) HTTPError() web.HTTPError {
 	}
 }
 
+// ErrMustHaveProjectViewToSortByPosition represents an error where no project view id was supplied
+type ErrMustHaveProjectViewToSortByPosition struct{}
+
+func (err ErrMustHaveProjectViewToSortByPosition) Error() string {
+	return "You must provide a project view ID when sorting by position"
+}
+
+// ErrCodeMustHaveProjectViewToSortByPosition holds the unique world-error code of this error
+const ErrCodeMustHaveProjectViewToSortByPosition = 4026
+
+// HTTPError holds the http error description
+func (err ErrMustHaveProjectViewToSortByPosition) HTTPError() web.HTTPError {
+	return web.HTTPError{
+		HTTPCode: http.StatusBadRequest,
+		Code:     ErrCodeMustHaveProjectViewToSortByPosition,
+		Message:  "You must provide a project view ID when sorting by position",
+	}
+}
+
 // ============
 // Team errors
 // ============

pkg/models/kanban.go

@@ -200,6 +200,7 @@ func GetTasksInBucketsForView(s *xorm.Session, view *ProjectView, opts *taskSear
 
 	opts.sortby = []*sortParam{
 		{
+			projectViewID: view.ProjectID,
 			orderBy:       orderAscending,
 			sortBy:        taskPropertyPosition,
 		},

pkg/models/task_collection.go

@@ -193,6 +193,14 @@ func (tf *TaskCollection) ReadAll(s *xorm.Session, a web.Auth, search string, pa
 	opts.page = page
 	opts.perPage = perPage
 
+	if view != nil {
+		opts.sortby = append(opts.sortby, &sortParam{
+			projectViewID: view.ID,
+			sortBy:        taskPropertyPosition,
+			orderBy:       orderAscending,
+		})
+	}
+
 	shareAuth, is := a.(*LinkSharing)
 	if is {
 		project, err := GetProjectSimpleByID(s, shareAuth.ProjectID)

pkg/models/task_collection_sort.go

@@ -20,6 +20,7 @@ type (
 	sortParam struct {
 		sortBy        string
 		orderBy       sortOrder // asc or desc
+		projectViewID int64
 	}
 
 	sortOrder string
@@ -72,5 +73,10 @@ func (sp *sortParam) validate() error {
 	if sp.orderBy != orderDescending && sp.orderBy != orderAscending {
 		return ErrInvalidSortOrder{OrderBy: sp.orderBy}
 	}
+
+	if sp.sortBy == taskPropertyPosition && sp.projectViewID == 0 {
+		return ErrMustHaveProjectViewToSortByPosition{}
+	}
+
 	return validateTaskField(sp.sortBy)
 }

pkg/models/task_search.go

@@ -53,14 +53,19 @@ func getOrderByDBStatement(opts *taskSearchOptions) (orderby string, err error)
 			return "", err
 		}
 
+		var prefix string
+		if param.sortBy == taskPropertyPosition {
+			prefix = "task_positions."
+		}
+
 		// Mysql sorts columns with null values before ones without null value.
 		// Because it does not have support for NULLS FIRST or NULLS LAST we work around this by
 		// first sorting for null (or not null) values and then the order we actually want to.
 		if db.Type() == schemas.MYSQL {
-			orderby += "`" + param.sortBy + "` IS NULL, "
+			orderby += prefix + "`" + param.sortBy + "` IS NULL, "
 		}
 
-		orderby += "`" + param.sortBy + "` " + param.orderBy.String()
+		orderby += prefix + "`" + param.sortBy + "` " + param.orderBy.String()
 
 		// Postgres and sqlite allow us to control how columns with null values are sorted.
 		// To make that consistent with the sort order we have and other dbms, we're adding a separate clause here.
@@ -253,6 +258,13 @@ func (d *dbTaskSearcher) Search(opts *taskSearchOptions) (tasks []*Task, totalCo
 		query = query.Limit(limit, start)
 	}
 
+	for _, param := range opts.sortby {
+		if param.sortBy == taskPropertyPosition {
+			query = query.Join("LEFT", "task_positions", "task_positions.task_id = tasks.id AND task_positions.project_view_id = ?", param.projectViewID)
+			break
+		}
+	}
+
 	tasks = []*Task{}
 	err = query.OrderBy(orderby).Find(&tasks)
 	if err != nil {