#6, update trigger expressions when renaming datapoints

main.go

@@ -711,8 +711,15 @@ func actionDatapointUpdate(w http.ResponseWriter, r *http.Request, _ *session.T)
 	var nodataSeconds int
 	nodataSeconds, _ = strconv.Atoi(r.FormValue("nodata_seconds"))
 
+	// Datapoint needs to be retrieved from database for the name.
+	// If name has changed, trigger expressions needs to be updated.
 	var dp Datapoint
-	dp.ID = id
+	dp, err = DatapointRetrieve(id, "")
+	if err != nil {
+		httpError(w, werr.Wrap(err).WithData(id).Log())
+		return
+	}
+	prevDatapointName := dp.Name
 	dp.Group = r.FormValue("group")
 	dp.Name = r.FormValue("name")
 	dp.Datatype = DatapointType(r.FormValue("datatype"))
@@ -724,6 +731,29 @@ func actionDatapointUpdate(w http.ResponseWriter, r *http.Request, _ *session.T)
 		return
 	}
 
+	// Update the trigger expressions using this
+	// datapoint name if changed.
+	if prevDatapointName != dp.Name {
+		var triggers []Trigger
+		triggers, err = TriggersRetrieveByDatapoint(dp.Name)
+		if err != nil {
+			httpError(w, werr.Wrap(err).WithData(dp.Name))
+			return
+		}
+		for _, trigger := range triggers {
+			err = trigger.RenameDatapoint(prevDatapointName, dp.Name)
+			if err != nil {
+				httpError(w, werr.Wrap(err).WithData([]string{prevDatapointName, dp.Name}))
+				return
+			}
+			err = trigger.Update()
+			if err != nil {
+				httpError(w, werr.Wrap(err).WithData([]string{prevDatapointName, dp.Name, trigger.Name}))
+				return
+			}
+		}
+	}
+
 	w.Header().Add("Location", "/datapoints")
 	w.WriteHeader(302)
 } // }}}

trigger.go

@@ -4,6 +4,8 @@ import (
 	// External
 	werr "git.gibonuddevalla.se/go/wrappederror"
 	"github.com/expr-lang/expr"
+	"github.com/expr-lang/expr/ast"
+	"github.com/expr-lang/expr/parser"
 	"github.com/lib/pq"
 
 	// Standard
@@ -22,6 +24,17 @@ type Trigger struct {
 	DatapointValues map[string]any
 }
 
+type ExprRenamePatcher struct {
+	OldName string
+	NewName string
+}
+
+func (p ExprRenamePatcher) Visit(node *ast.Node) {
+	if n, ok := (*node).(*ast.IdentifierNode); ok && n.Value == p.OldName {
+		ast.Patch(node, &ast.IdentifierNode{Value: p.NewName})
+	}
+}
+
 func TriggerCreate(sectionID int, name string) (t Trigger, err error) { // {{{
 	t.SectionID = sectionID
 	t.Name = name
@@ -127,6 +140,14 @@ func TriggerRetrieve(id int) (trigger Trigger, err error) { // {{{
 	err = json.Unmarshal(jsonData, &trigger)
 	return
 } // }}}
+func TriggerDelete(id int) (err error) { // {{{
+	_, err = service.Db.Conn.Exec(`DELETE FROM public.trigger WHERE id=$1`, id)
+	if err != nil {
+		return werr.Wrap(err).WithData(id)
+	}
+	return
+} // }}}
+
 func (t *Trigger) Validate() (ok bool, err error) { // {{{
 	if strings.TrimSpace(t.Name) == "" {
 		err = fmt.Errorf("Name can't be empty")
@@ -212,14 +233,6 @@ func (t *Trigger) Update() (err error) { // {{{
 	}
 	return
 } // }}}
-func TriggerDelete(id int) (err error) { // {{{
-	_, err = service.Db.Conn.Exec(`DELETE FROM public.trigger WHERE id=$1`, id)
-	if err != nil {
-		return werr.Wrap(err).WithData(id)
-	}
-	return
-} // }}}
-
 func (t *Trigger) Run() (output any, err error) { // {{{
 	datapoints := make(map[string]Datapoint)
 	for _, dpname := range t.Datapoints {
@@ -248,3 +261,14 @@ func (t *Trigger) Run() (output any, err error) { // {{{
 	}
 	return
 } // }}}
+func (t *Trigger) RenameDatapoint(from, to string) error { // {{{
+	tree, err := parser.Parse(t.Expression)
+	if err != nil {
+		return werr.Wrap(err).WithData(t.Expression)
+	}
+
+	ast.Walk(&tree.Node, ExprRenamePatcher{from, to})
+	t.Expression = tree.Node.String()
+
+	return nil
+} // }}}