add project linking.

database/postgres/project.go

@@ -105,5 +105,10 @@ func (r *projectRepository) Delete(ctx context.Context, project models.Project)
 		return err
 	}
 
+	_, err = r.db.ExecContext(ctx, `DELETE FROM task_link WHERE project_id=$1`, project.ID)
+	if err != nil && err != sql.ErrNoRows {
+		return err
+	}
+
 	return nil
 }

database/postgres/tasks.go

@@ -28,7 +28,17 @@ func (r *taskRepository) Find(ctx context.Context, id string) (*models.Task, err
 }
 
 func (r *taskRepository) List(ctx context.Context, filter models.TaskFilter) ([]*models.Task, error) {
-	sq := squirrel.Select("task.*", "p.icon").From("task").PlaceholderFormat(squirrel.Dollar)
+	tasks, _, err := r.ListWithLinks(ctx, filter)
+	return tasks, err
+}
+
+func (r *taskRepository) ListWithLinks(ctx context.Context, filter models.TaskFilter) ([]*models.Task, []*models.TaskLink, error) {
+	type tasksWithLinks struct {
+		models.Task
+		LinkedProjectID *string `db:"tl_project_id"`
+	}
+
+	sq := squirrel.Select("task.*", "tl.project_id as tl_project_id", "p.icon").From("task").PlaceholderFormat(squirrel.Dollar)
 	sq = sq.Where(squirrel.Eq{"task.user_id": filter.UserID})
 	if filter.Active != nil {
 		sq = sq.Where(squirrel.Eq{"task.active": *filter.Active})
@@ -47,7 +57,12 @@ func (r *taskRepository) List(ctx context.Context, filter models.TaskFilter) ([]
 		sq = sq.Where(squirrel.Eq{"task.item_id": filter.ItemIDs})
 	}
 	if filter.ProjectIDs != nil {
-		sq = sq.Where(squirrel.Eq{"task.project_id": filter.ProjectIDs})
+		sq = sq.LeftJoin("task_link AS tl ON task.task_id = tl.task_id")
+
+		sq = sq.Where(squirrel.Or{
+			squirrel.Eq{"task.project_id": filter.ProjectIDs},
+			squirrel.Eq{"tl.project_id": filter.ProjectIDs},
+		})
 	}
 
 	sq = sq.InnerJoin("project AS p ON task.project_id = p.project_id")
@@ -55,19 +70,37 @@ func (r *taskRepository) List(ctx context.Context, filter models.TaskFilter) ([]
 
 	query, args, err := sq.ToSql()
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 
-	res := make([]*models.Task, 0, 8)
-	err = r.db.SelectContext(ctx, &res, query, args...)
+	rows := make([]tasksWithLinks, 0, 8)
+	err = r.db.SelectContext(ctx, &rows, query, args...)
 	if err != nil {
 		if err == sql.ErrNoRows {
-			return res, nil
+			return []*models.Task{}, []*models.TaskLink{}, nil
 		}
-		return nil, err
+		return nil, nil, err
 	}
 
-	return res, nil
+	added := make(map[string]bool)
+	tasks := make([]*models.Task, 0, len(rows))
+	links := make([]*models.TaskLink, 0, len(rows))
+	for _, row := range rows {
+		if row.LinkedProjectID != nil {
+			links = append(links, &models.TaskLink{
+				TaskID:    row.Task.ID,
+				ProjectID: *row.LinkedProjectID,
+			})
+		}
+
+		if !added[row.Task.ID] {
+			task := row.Task
+			tasks = append(tasks, &task)
+			added[row.Task.ID] = true
+		}
+	}
+
+	return tasks, links, nil
 }
 
 func (r *taskRepository) Insert(ctx context.Context, task models.Task) error {
@@ -101,7 +134,7 @@ func (r *taskRepository) Update(ctx context.Context, task models.Task) error {
 	if err != nil {
 		return err
 	}
-	
+
 	_, err = r.db.NamedExecContext(ctx, `UPDATE log SET item_id = :item_id WHERE task_id=:task_id`, &task)
 	if err != nil {
 		return err
@@ -110,6 +143,48 @@ func (r *taskRepository) Update(ctx context.Context, task models.Task) error {
 	return nil
 }
 
+func (r *taskRepository) CreateLink(ctx context.Context, link models.TaskLink) error {
+	_, err := r.db.NamedExecContext(ctx, `
+		INSERT INTO task_link (project_id, task_id) VALUES (:project_id, :task_id)
+		ON CONFLICT DO NOTHING
+	`, &link)
+
+	return err
+}
+
+func (r *taskRepository) DeleteLink(ctx context.Context, link models.TaskLink) error {
+	_, err := r.db.NamedExecContext(ctx, `
+		DELETE FROM task_link WHERE task_id=:task_id AND project_id=:project_id
+	`, &link)
+	if err == sql.ErrNoRows {
+		err = slerrors.NotFound("Link")
+	}
+
+	return err
+}
+
+func (r *taskRepository) UnlinkTask(ctx context.Context, task models.Task) error {
+	_, err := r.db.ExecContext(ctx, `
+		DELETE FROM task_link WHERE task_id=$1;
+	`, task.ID)
+	if err == sql.ErrNoRows {
+		err = nil
+	}
+
+	return err
+}
+
+func (r *taskRepository) UnlinkProject(ctx context.Context, project models.Project) error {
+	_, err := r.db.ExecContext(ctx, `
+		DELETE FROM task_link WHERE task_id=$1;
+	`, project.ID)
+	if err == sql.ErrNoRows {
+		err = nil
+	}
+
+	return err
+}
+
 func (r *taskRepository) Delete(ctx context.Context, task models.Task) error {
 	_, err := r.db.ExecContext(ctx, `DELETE FROM task WHERE task_id=$1`, task.ID)
 	if err != nil {
@@ -119,5 +194,10 @@ func (r *taskRepository) Delete(ctx context.Context, task models.Task) error {
 		return err
 	}
 
+	_, err = r.db.ExecContext(ctx, `DELETE FROM task_link WHERE task_id=$1`, task.ID)
+	if err != nil && err != sql.ErrNoRows {
+		return err
+	}
+
 	return nil
 }