From f5cd0c1140e4a613cee9ca52b6f47701dfd24df0 Mon Sep 17 00:00:00 2001
From: fiatjaf <fiatjaf@gmail.com>
Date: Mon, 6 Nov 2023 18:35:11 -0300
Subject: [PATCH] Filter.Clone()

---
 filter.go      | 33 +++++++++++++++++++++++++++++++--
 filter_test.go | 38 ++++++++++++++++++++++++++++++++++++++
 utils.go       | 10 ++++++++++
 3 files changed, 79 insertions(+), 2 deletions(-)

diff --git a/filter.go b/filter.go
index 32eb41c..c2c07db 100644
--- a/filter.go
+++ b/filter.go
@@ -101,11 +101,11 @@ func FilterEqual(a Filter, b Filter) bool {
 		}
 	}
 
-	if a.Since != b.Since {
+	if !arePointerValuesEqual(a.Since, b.Since) {
 		return false
 	}
 
-	if a.Until != b.Until {
+	if !arePointerValuesEqual(a.Until, b.Until) {
 		return false
 	}
 
@@ -115,3 +115,32 @@ func FilterEqual(a Filter, b Filter) bool {
 
 	return true
 }
+
+func (ef Filter) Clone() Filter {
+	clone := Filter{
+		IDs:     slices.Clone(ef.IDs),
+		Authors: slices.Clone(ef.Authors),
+		Kinds:   slices.Clone(ef.Kinds),
+		Limit:   ef.Limit,
+		Search:  ef.Search,
+	}
+
+	if ef.Tags != nil {
+		clone.Tags = make(TagMap, len(ef.Tags))
+		for k, v := range ef.Tags {
+			clone.Tags[k] = slices.Clone(v)
+		}
+	}
+
+	if ef.Since != nil {
+		since := *ef.Since
+		clone.Since = &since
+	}
+
+	if ef.Until != nil {
+		until := *ef.Until
+		clone.Until = &until
+	}
+
+	return clone
+}
diff --git a/filter_test.go b/filter_test.go
index e0b0b9e..b73d024 100644
--- a/filter_test.go
+++ b/filter_test.go
@@ -91,3 +91,41 @@ func TestFilterEquality(t *testing.T) {
 		t.Error("kinds filters shouldn't be equal")
 	}
 }
+
+func TestFilterClone(t *testing.T) {
+	ts := Now() - 60*60
+	flt := Filter{
+		Kinds: []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9},
+		Tags:  TagMap{"letter": {"a", "b"}, "fruit": {"banana"}},
+		Since: &ts,
+		IDs:   []string{"9894b4b5cb5166d23ee8899a4151cf0c66aec00bde101982a13b8e8ceb972df9"},
+	}
+	clone := flt.Clone()
+	if !FilterEqual(flt, clone) {
+		t.Errorf("clone is not equal:\n %v !=\n %v", flt, clone)
+	}
+
+	clone1 := flt.Clone()
+	clone1.IDs = append(clone1.IDs, "88f0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c4eb9aaaefa459d")
+	if FilterEqual(flt, clone1) {
+		t.Error("modifying the clone ids should cause it to not be equal anymore")
+	}
+
+	clone2 := flt.Clone()
+	clone2.Tags["letter"] = append(clone2.Tags["letter"], "c")
+	if FilterEqual(flt, clone2) {
+		t.Error("modifying the clone tag items should cause it to not be equal anymore")
+	}
+
+	clone3 := flt.Clone()
+	clone3.Tags["g"] = []string{"drt"}
+	if FilterEqual(flt, clone3) {
+		t.Error("modifying the clone tag map should cause it to not be equal anymore")
+	}
+
+	clone4 := flt.Clone()
+	*clone4.Since++
+	if FilterEqual(flt, clone4) {
+		t.Error("modifying the clone since should cause it to not be equal anymore")
+	}
+}
diff --git a/utils.go b/utils.go
index 724bcaf..fcd07d9 100644
--- a/utils.go
+++ b/utils.go
@@ -93,3 +93,13 @@ func IsValidRelayURL(u string) bool {
 	}
 	return true
 }
+
+func arePointerValuesEqual[V comparable](a *V, b *V) bool {
+	if a == nil && b == nil {
+		return true
+	}
+	if a != nil && b != nil {
+		return *a == *b
+	}
+	return false
+}