feat: simple eventbus

pkg/eventbus/eventbus.go

@@ -0,0 +1,83 @@
+package eventbus
+
+import (
+	"fmt"
+	"polaris/pkg/utils"
+	"reflect"
+)
+
+type EventBus struct {
+	handlers utils.Map[string, []EventHandler]
+}
+
+type EventHandler struct {
+	callback     reflect.Value
+	async bool
+}
+
+func New() *EventBus {
+	return &EventBus{
+		handlers: utils.Map[string, []EventHandler]{},
+	}
+}
+
+func (e *EventBus) Subscribe(event string, fn any) error{
+	if reflect.TypeOf(fn).Kind() != reflect.Func {
+		return fmt.Errorf("handler must be a function: %v", reflect.TypeOf(fn).Kind())
+	}
+	if handlers, ok := e.handlers.Load(event); ok {
+		handlers = append(handlers, EventHandler{
+			callback: reflect.ValueOf(fn),})
+		e.handlers.Store(event, handlers)
+	} else {
+		e.handlers.Store(event, []EventHandler{
+			{callback: reflect.ValueOf(fn)},
+		})
+	}
+	return nil
+}
+
+func (e *EventBus) SubscribeAsync(event string, fn any) error{
+	if reflect.TypeOf(fn).Kind() != reflect.Func {
+		return fmt.Errorf("handler must be a function: %v", reflect.TypeOf(fn).Kind())
+	}
+
+	if handlers, ok := e.handlers.Load(event); ok {
+		handlers = append(handlers, EventHandler{
+			callback: reflect.ValueOf(fn), async: true,
+		})
+		e.handlers.Store(event, handlers)
+	} else {
+		e.handlers.Store(event, []EventHandler{
+			{callback: reflect.ValueOf(fn), async: true},
+		})
+	}
+	return nil
+}
+
+func (e *EventBus) Publish(event string, args... any) {
+	if handlers, ok := e.handlers.Load(event); ok {
+		for _, handler := range handlers {
+			args1 := reflectArgs(handler,args...)
+			if handler.async {
+				go handler.callback.Call(args1)
+			} else {
+				handler.callback.Call(args1)
+			}
+		}
+	}
+}
+
+func reflectArgs(handler EventHandler,args... any) []reflect.Value {
+	funcType := handler.callback.Type()
+	passedArguments := make([]reflect.Value, len(args))
+	for i, v := range args {
+		if v == nil {
+			passedArguments[i] = reflect.New(funcType.In(i)).Elem()
+		} else {
+			passedArguments[i] = reflect.ValueOf(v)
+		}
+	}
+
+	return passedArguments
+}