add project linking.

api/task.go

@@ -92,6 +92,15 @@ func Task(g *gin.RouterGroup, db database.Database) {
 				return nil, slerrors.NotFound("Destination project")
 			}
 
+			// Delete any links that would have been ran over.
+			err = db.Tasks().DeleteLink(c.Request.Context(), models.TaskLink{
+				TaskID:    task.ID,
+				ProjectID: project.ID,
+			})
+			if err != nil {
+				return nil, slerrors.BadRequest(err.Error())
+			}
+
 			task.ProjectID = project.ID
 		}
 
@@ -111,6 +120,57 @@ func Task(g *gin.RouterGroup, db database.Database) {
 		return task, nil
 	}))
 
+	g.PUT("/:id/link/:project_id", handler("taskLink", func(c *gin.Context) (interface{}, error) {
+		task, err := l.FindTask(c.Request.Context(), c.Param("id"))
+		if err != nil {
+			return nil, err
+		}
+
+		project, err := l.FindProject(c.Request.Context(), c.Param("project_id"))
+		if err != nil {
+			return nil, err
+		}
+
+		if task.ProjectID == project.ID {
+			return nil, slerrors.BadRequest("You cannot link a task within its own project")
+		}
+
+		err = db.Tasks().CreateLink(c.Request.Context(), models.TaskLink{
+			TaskID:    task.ID,
+			ProjectID: project.ID,
+		})
+
+		return &models.TaskLink{
+			TaskID:    task.ID,
+			ProjectID: project.ID,
+		}, nil
+	}))
+
+	g.DELETE("/:id/link/:project_id", handler("taskLink", func(c *gin.Context) (interface{}, error) {
+		task, err := l.FindTask(c.Request.Context(), c.Param("id"))
+		if err != nil {
+			return nil, err
+		}
+
+		project, err := l.FindProject(c.Request.Context(), c.Param("project_id"))
+		if err != nil {
+			return nil, err
+		}
+
+		err = db.Tasks().DeleteLink(c.Request.Context(), models.TaskLink{
+			TaskID:    task.ID,
+			ProjectID: project.ID,
+		})
+		if err != nil {
+			return nil, err
+		}
+
+		return &models.TaskLink{
+			TaskID:    task.ID,
+			ProjectID: project.ID,
+		}, nil
+	}))
+
 	g.DELETE("/:id", handler("task", func(c *gin.Context) (interface{}, error) {
 		task, err := l.FindTask(c.Request.Context(), c.Param("id"))
 		if err != nil {