basic item filter wip

pkg/itemfilter/chain.go

@@ -0,0 +1,45 @@
+package itemfilter
+
+import "github.com/hectorgimenez/d2go/pkg/nip"
+
+type evaluationChain struct {
+	links []link
+}
+
+type link struct {
+	Result  bool
+	Operand nip.Operand
+}
+
+func (ch *evaluationChain) Add(result bool, operand nip.Operand) {
+	ch.links = append(ch.links, link{
+		Result:  result,
+		Operand: operand,
+	})
+}
+
+func (ch *evaluationChain) Evaluate() bool {
+	if len(ch.links) == 1 {
+		return ch.links[0].Result
+	}
+
+	result := ch.links[0].Result
+	operand := ch.links[0].Operand
+	for i, eval := range ch.links {
+		if i == 0 {
+			continue
+		}
+
+		if i < len(ch.links) {
+			switch operand {
+			case nip.OperandAnd:
+				result = result && eval.Result
+			case nip.OperandOr:
+				result = result || eval.Result
+			}
+		}
+		operand = eval.Operand
+	}
+
+	return result
+}