From d29025e958231e9950d046010423dee4975fb3f1 Mon Sep 17 00:00:00 2001
From: fiatjaf <fiatjaf@gmail.com>
Date: Mon, 30 Sep 2024 00:39:26 -0300
Subject: [PATCH] CompareEvent/Ptr/Reverse utils.

---
 utils.go      | 41 ++++++++++++++++++++++++++++++++++++++++
 utils_test.go | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 93 insertions(+)

diff --git a/utils.go b/utils.go
index 984204b..165f31a 100644
--- a/utils.go
+++ b/utils.go
@@ -35,3 +35,44 @@ func CompareEvent(a, b Event) int {
 	}
 	return cmp.Compare(a.CreatedAt, b.CreatedAt)
 }
+
+func CompareEventReverse(b, a Event) int {
+	if a.CreatedAt == b.CreatedAt {
+		return strings.Compare(a.ID, b.ID)
+	}
+	return cmp.Compare(a.CreatedAt, b.CreatedAt)
+}
+
+func CompareEventPtr(a, b *Event) int {
+	if a == nil {
+		if b == nil {
+			return 0
+		} else {
+			return -1
+		}
+	} else if b == nil {
+		return 1
+	}
+
+	if a.CreatedAt == b.CreatedAt {
+		return strings.Compare(a.ID, b.ID)
+	}
+	return cmp.Compare(a.CreatedAt, b.CreatedAt)
+}
+
+func CompareEventPtrReverse(b, a *Event) int {
+	if a == nil {
+		if b == nil {
+			return 0
+		} else {
+			return -1
+		}
+	} else if b == nil {
+		return 1
+	}
+
+	if a.CreatedAt == b.CreatedAt {
+		return strings.Compare(a.ID, b.ID)
+	}
+	return cmp.Compare(a.CreatedAt, b.CreatedAt)
+}
diff --git a/utils_test.go b/utils_test.go
index 89e4056..1b850ee 100644
--- a/utils_test.go
+++ b/utils_test.go
@@ -1,9 +1,11 @@
 package nostr
 
 import (
+	"slices"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestIsValidRelayURL(t *testing.T) {
@@ -24,3 +26,53 @@ func TestIsValidRelayURL(t *testing.T) {
 		assert.Equal(t, test.want, got)
 	}
 }
+
+func TestEventsCompare(t *testing.T) {
+	list := []Event{
+		{CreatedAt: 12},
+		{CreatedAt: 8},
+		{CreatedAt: 26},
+		{CreatedAt: 1},
+	}
+
+	slices.SortFunc(list, CompareEvent)
+	require.Equal(t, []Event{
+		{CreatedAt: 1},
+		{CreatedAt: 8},
+		{CreatedAt: 12},
+		{CreatedAt: 26},
+	}, list)
+
+	slices.SortFunc(list, CompareEventReverse)
+	require.Equal(t, []Event{
+		{CreatedAt: 26},
+		{CreatedAt: 12},
+		{CreatedAt: 8},
+		{CreatedAt: 1},
+	}, list)
+}
+
+func TestEventsComparePtr(t *testing.T) {
+	list := []*Event{
+		{CreatedAt: 12},
+		{CreatedAt: 8},
+		{CreatedAt: 26},
+		{CreatedAt: 1},
+	}
+
+	slices.SortFunc(list, CompareEventPtr)
+	require.Equal(t, []*Event{
+		{CreatedAt: 1},
+		{CreatedAt: 8},
+		{CreatedAt: 12},
+		{CreatedAt: 26},
+	}, list)
+
+	slices.SortFunc(list, CompareEventPtrReverse)
+	require.Equal(t, []*Event{
+		{CreatedAt: 26},
+		{CreatedAt: 12},
+		{CreatedAt: 8},
+		{CreatedAt: 1},
+	}, list)
+}