added support for optional Model and Record event hook tags

tools/hook/tagged.go

@@ -0,0 +1,74 @@
+package hook
+
+import (
+	"github.com/pocketbase/pocketbase/tools/list"
+)
+
+// Tagger defines an interface for event data structs that support tags/groups/categories/etc.
+// Usually used together with TaggedHook.
+type Tagger interface {
+	Tags() []string
+}
+
+// wrapped local Hook embedded struct to limit the public API surface.
+type mainHook[T Tagger] struct {
+	*Hook[T]
+}
+
+// NewTaggedHook creates a new TaggedHook with the provided main hook and optional tags.
+func NewTaggedHook[T Tagger](hook *Hook[T], tags ...string) *TaggedHook[T] {
+	return &TaggedHook[T]{
+		mainHook[T]{hook},
+		tags,
+	}
+}
+
+// TaggedHook defines a proxy hook which register handlers that are triggered only
+// if the TaggedHook.tags are empty or includes at least one of the event data tag(s).
+type TaggedHook[T Tagger] struct {
+	mainHook[T]
+
+	tags []string
+}
+
+// CanTriggerOn checks if the current TaggedHook can be triggered with
+// the provided event data tags.
+func (p *TaggedHook[T]) CanTriggerOn(tags []string) bool {
+	if len(p.tags) == 0 {
+		return true // match all
+	}
+
+	for _, t := range tags {
+		if list.ExistInSlice(t, p.tags) {
+			return true
+		}
+	}
+
+	return false
+}
+
+// PreAdd registers a new handler to the hook by prepending it to the existing queue.
+//
+// The fn handler will be called only if the event data tags satisfy p.CanTriggerOn.
+func (p *TaggedHook[T]) PreAdd(fn Handler[T]) {
+	p.mainHook.PreAdd(func(e T) error {
+		if p.CanTriggerOn(e.Tags()) {
+			return fn(e)
+		}
+
+		return nil
+	})
+}
+
+// Add registers a new handler to the hook by appending it to the existing queue.
+//
+// The fn handler will be called only if the event data tags satisfy p.CanTriggerOn.
+func (p *TaggedHook[T]) Add(fn Handler[T]) {
+	p.mainHook.Add(func(e T) error {
+		if p.CanTriggerOn(e.Tags()) {
+			return fn(e)
+		}
+
+		return nil
+	})
+}