Reflect GreaterThan comparison

utils/reflect.go

@@ -19,6 +19,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 package utils
 
 import (
+	"errors"
 	"fmt"
 	"reflect"
 	"strconv"
@@ -121,3 +122,34 @@ func AsMapStringIface(item interface{}) (map[string]interface{}, error) {
 	}
 	return out, nil
 }
+
+// GreaterThan attempts to compare two items
+// returns the result or error if not comparable
+func GreaterThan(item, oItem interface{}, orEqual bool) (gte bool, err error) {
+	typItem := reflect.TypeOf(item)
+	typOItem := reflect.TypeOf(oItem)
+	fmt.Println(typItem.Comparable(),
+		typOItem.Comparable(),
+		typItem,
+		typOItem,
+		typItem == typOItem)
+	if !typItem.Comparable() ||
+		!typOItem.Comparable() ||
+		typItem != typOItem {
+		return false, errors.New("incomparable")
+	}
+	if orEqual && reflect.DeepEqual(item, oItem) {
+		return true, nil
+	}
+	valItm := reflect.ValueOf(item)
+	valOItm := reflect.ValueOf(oItem)
+	switch typItem.Kind() {
+	case reflect.Float32, reflect.Float64:
+		gte = valItm.Float() > valOItm.Float()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		gte = valItm.Int() > valOItm.Int()
+	default: // unsupported comparison
+		err = fmt.Errorf("unsupported type: %v", typItem)
+	}
+	return
+}

utils/reflect_test.go

@@ -20,6 +20,7 @@ package utils
 import (
 	"reflect"
 	"testing"
+	"time"
 )
 
 func TestReflectFieldAsStringOnStruct(t *testing.T) {
@@ -138,3 +139,45 @@ func TestReflectAsMapStringIface(t *testing.T) {
 		t.Errorf("Expecting: %+v, received: %+v", expectOutMp, outMp)
 	}
 }
+
+func TestGreaterThan(t *testing.T) {
+	if _, err := GreaterThan(1, 1.2, false); err == nil || err.Error() != "incomparable" {
+		t.Error(err)
+	}
+	if _, err := GreaterThan(struct{}{},
+		map[string]interface{}{"a": "a"}, false); err == nil || err.Error() != "incomparable" {
+		t.Error(err)
+	}
+	if gte, err := GreaterThan(1.2, 1.2, true); err != nil {
+		t.Error(err)
+	} else if !gte {
+		t.Error("should be equal")
+	}
+	if gte, err := GreaterThan(1.3, 1.2, false); err != nil {
+		t.Error(err)
+	} else if !gte {
+		t.Error("should be greater than")
+	}
+	if gte, err := GreaterThan(1.2, 1.3, false); err != nil {
+		t.Error(err)
+	} else if gte {
+		t.Error("should be greater than")
+	}
+	if gte, err := GreaterThan(2, 1, false); err != nil {
+		t.Error(err)
+	} else if !gte {
+		t.Error("should be greater than")
+	}
+	if gte, err := GreaterThan(time.Duration(2*time.Second),
+		time.Duration(1*time.Second), false); err != nil {
+		t.Error(err)
+	} else if !gte {
+		t.Error("should be greater than")
+	}
+	if gte, err := GreaterThan(time.Duration(1*time.Second),
+		time.Duration(2*time.Second), false); err != nil {
+		t.Error(err)
+	} else if gte {
+		t.Error("should be less than")
+	}
+}