diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..bf4ae11
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module bot-pontos
+
+go 1.25.0
diff --git a/internal/domain/point.go b/internal/domain/point.go
new file mode 100644
index 0000000..0b4d917
--- /dev/null
+++ b/internal/domain/point.go
@@ -0,0 +1,14 @@
+package domain
+
+import "time"
+
+type NotificationType string
+
+const (
+	NotificationEntrada2 NotificationType = "entrada2"
+	NotificationSaida2   NotificationType = "saida2"
+)
+
+type Point struct {
+	Time time.Time
+}
\ No newline at end of file
diff --git a/internal/rules/business_day.go b/internal/rules/business_day.go
new file mode 100644
index 0000000..8fdc53f
--- /dev/null
+++ b/internal/rules/business_day.go
@@ -0,0 +1,10 @@
+package rules
+
+import "time"
+
+type BusinessDayChecker struct{}
+
+func (b BusinessDayChecker) IsBusinessDay(t time.Time) bool {
+	weekday := t.Weekday()
+	return weekday != time.Saturday && weekday != time.Sunday
+}
\ No newline at end of file
diff --git a/internal/rules/schedule_calculator.go b/internal/rules/schedule_calculator.go
new file mode 100644
index 0000000..e69de29
diff --git a/tests/rules_test.go b/tests/rules_test.go
new file mode 100644
index 0000000..dece8dd
--- /dev/null
+++ b/tests/rules_test.go
@@ -0,0 +1,29 @@
+package tests
+
+import (
+	"testing"
+	"time"
+
+	"bot-pontos/internal/rules"
+)
+
+func TestCalculosDeJornada(t *testing.T) {
+	loc, _ := time.LoadLocation("America/Sao_Paulo")
+
+	// Teste Entrada 2 (Saída1 + 55min)
+	saida1 := time.Date(2026, 8, 15, 12, 0, 0, 0, loc)
+	esperadoEntrada2 := time.Date(2026, 8, 15, 12, 55, 0, 0, loc)
+	if res := rules.CalculateEntrada2(saida1); !res.Equal(esperadoEntrada2) {
+		t.Errorf("Entrada2 incorreta. Esperado: %v, Obtido: %v", esperadoEntrada2, res)
+	}
+
+	// Teste Saída 2 (Meta 7h55)
+	entrada1 := time.Date(2026, 8, 15, 8, 0, 0, 0, loc)
+	entrada2 := time.Date(2026, 8, 15, 13, 0, 0, 0, loc)
+	// Trabalhou 4h de manhã. Faltam 3h55. Saída2 deve ser 16:55
+	esperadoSaida2 := time.Date(2026, 8, 15, 16, 55, 0, 0, loc)
+
+	if res := rules.CalculateSaida2(entrada1, saida1, entrada2); !res.Equal(esperadoSaida2) {
+		t.Errorf("Saida2 incorreta. Esperado: %v, Obtido: %v", esperadoSaida2, res)
+	}
+}
\ No newline at end of file