Add comparator BETWEEN and fix multi-names parameter code extractor

internal/mongo/generator_test.go

@@ -411,6 +411,44 @@ func (r *UserRepositoryMongo) FindByAgeGreaterThanEqual(ctx context.Context, arg
 	}
 	return entities, nil
 }
+`,
+		},
+		{
+			Name: "find with Between comparator",
+			MethodSpec: spec.MethodSpec{
+				Name: "FindByAgeBetween",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Name: "fromAge", Type: code.SimpleType("int")},
+					{Name: "toAge", Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.ArrayType{ContainedType: code.PointerType{ContainedType: code.SimpleType("UserModel")}},
+					code.SimpleType("error"),
+				},
+				Operation: spec.FindOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Predicates: []spec.Predicate{
+							{Comparator: spec.ComparatorBetween, Field: "Age"},
+						},
+					},
+				},
+			},
+			ExpectedCode: `
+func (r *UserRepositoryMongo) FindByAgeBetween(ctx context.Context, arg0 int, arg1 int) ([]*UserModel, error) {
+	cursor, err := r.collection.Find(ctx, bson.M{
+		"age": bson.M{"$gte": arg0, "$lte": arg1},
+	})
+	if err != nil {
+		return nil, err
+	}
+	var entities []*UserModel
+	if err := cursor.All(ctx, &entities); err != nil {
+		return nil, err
+	}
+	return entities, nil
+}
 `,
 		},
 		{

internal/mongo/models.go

@@ -14,8 +14,10 @@ type querySpec struct {
 
 func (q querySpec) Code() string {
 	var predicateCodes []string
-	for i, predicate := range q.Predicates {
-		predicateCodes = append(predicateCodes, predicate.Code(i))
+	var argIndex int
+	for _, predicate := range q.Predicates {
+		predicateCodes = append(predicateCodes, predicate.Code(argIndex))
+		argIndex += predicate.Comparator.NumberOfArguments()
 	}
 
 	var lines []string
@@ -53,6 +55,8 @@ func (p predicate) Code(argIndex int) string {
 		return fmt.Sprintf(`"%s": bson.M{"$gt": arg%d}`, p.Field, argIndex)
 	case spec.ComparatorGreaterThanEqual:
 		return fmt.Sprintf(`"%s": bson.M{"$gte": arg%d}`, p.Field, argIndex)
+	case spec.ComparatorBetween:
+		return fmt.Sprintf(`"%s": bson.M{"$gte": arg%d, "$lte": arg%d}`, p.Field, argIndex, argIndex+1)
 	case spec.ComparatorIn:
 		return fmt.Sprintf(`"%s": bson.M{"$in": arg%d}`, p.Field, argIndex)
 	}