FEATURE: [dca2] add position callback

pkg/strategy/dca2/strategy.go

@@ -100,7 +100,8 @@ type Strategy struct {
 
 	// callbacks
 	common.StatusCallbacks
-	profitCallbacks []func(*ProfitStats)
+	profitCallbacks   []func(*ProfitStats)
+	positionCallbacks []func(*types.Position)
 }
 
 func (s *Strategy) ID() string {
@@ -229,6 +230,9 @@ func (s *Strategy) Run(ctx context.Context, _ bbgo.OrderExecutor, session *bbgo.
 
 		// update take profit price here
 		s.updateTakeProfitPrice()
+
+		// emit position update
+		s.EmitPosition(position)
 	})
 
 	s.OrderExecutor.ActiveMakerOrders().OnFilled(func(o types.Order) {

pkg/strategy/dca2/strategy_callbacks.go

@@ -2,6 +2,10 @@
 
 package dca2
 
+import (
+	"github.com/c9s/bbgo/pkg/types"
+)
+
 func (s *Strategy) OnProfit(cb func(*ProfitStats)) {
 	s.profitCallbacks = append(s.profitCallbacks, cb)
 }
@@ -11,3 +15,13 @@ func (s *Strategy) EmitProfit(profitStats *ProfitStats) {
 		cb(profitStats)
 	}
 }
+
+func (s *Strategy) OnPosition(cb func(*types.Position)) {
+	s.positionCallbacks = append(s.positionCallbacks, cb)
+}
+
+func (s *Strategy) EmitPosition(position *types.Position) {
+	for _, cb := range s.positionCallbacks {
+		cb(position)
+	}
+}