From dde45662bc7261df6547a5f0a921d392e055a8e7 Mon Sep 17 00:00:00 2001
From: Sugat Poudel <taguspoudel@gmail.com>
Date: Wed, 5 Jun 2024 09:05:52 -0400
Subject: [PATCH] some more helpers

---
 codec_test.go   |  4 ++++
 numbers.go      | 12 ++++++++++++
 numbers_test.go | 12 ++++++++++++
 slices.go       | 10 ++++++++++
 slices_test.go  | 13 +++++++++++++
 time.go         | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 time_test.go    | 18 ++++++++++++++++++
 7 files changed, 115 insertions(+)
 create mode 100644 numbers.go
 create mode 100644 numbers_test.go
 create mode 100644 time.go
 create mode 100644 time_test.go

diff --git a/codec_test.go b/codec_test.go
index ab3d34a..25c991e 100644
--- a/codec_test.go
+++ b/codec_test.go
@@ -51,4 +51,8 @@ func TestUnmarshalFromString(t *testing.T) {
 	require.NoError(t, err)
 	require.NotNil(t, decodedSlice)
 	require.Equal(t, []string{"foo", "bar"}, *decodedSlice)
+
+	decodedSlice, err = UnmarshalFromString[[]string]("null")
+	require.NoError(t, err)
+	require.Nil(t, decodedSlice)
 }
diff --git a/numbers.go b/numbers.go
new file mode 100644
index 0000000..75c3205
--- /dev/null
+++ b/numbers.go
@@ -0,0 +1,12 @@
+package mango
+
+// Min determines the minimum among the provided values
+func Min(vals ...int) int {
+	min := vals[0]
+	for _, val := range vals {
+		if val < min {
+			min = val
+		}
+	}
+	return min
+}
diff --git a/numbers_test.go b/numbers_test.go
new file mode 100644
index 0000000..40e75c0
--- /dev/null
+++ b/numbers_test.go
@@ -0,0 +1,12 @@
+package mango
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFindingMin(t *testing.T) {
+	min := Min(1, 2, 3, -594849)
+	assert.Equal(t, -594849, min)
+}
diff --git a/slices.go b/slices.go
index c288c2d..3a1c464 100644
--- a/slices.go
+++ b/slices.go
@@ -17,3 +17,13 @@ func Filter[F any](list []F, predicate func(F) bool) []F {
 	}
 	return filtered
 }
+
+func Find[F any](list []F, predicate func(F) bool) (F, bool) {
+	var empty F
+	for _, item := range list {
+		if predicate(item) {
+			return item, true
+		}
+	}
+	return empty, false
+}
diff --git a/slices_test.go b/slices_test.go
index 8fe70e1..864e8d3 100644
--- a/slices_test.go
+++ b/slices_test.go
@@ -4,6 +4,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestMap(t *testing.T) {
@@ -23,3 +24,15 @@ func TestFilter(t *testing.T) {
 
 	assert.Equal(t, expected, actual)
 }
+
+func TestFind(t *testing.T) {
+	lst := []int{1, 2, 3}
+
+	actual, ok := Find(lst, func(i int) bool { return i == 2 })
+	require.True(t, ok)
+	require.Equal(t, 2, actual)
+
+	actual, ok = Find(lst, func(i int) bool { return i == 45 })
+	require.False(t, ok)
+	require.Equal(t, 0, actual)
+}
diff --git a/time.go b/time.go
new file mode 100644
index 0000000..37e93da
--- /dev/null
+++ b/time.go
@@ -0,0 +1,46 @@
+package mango
+
+import (
+	"fmt"
+	"time"
+)
+
+const (
+	DurationDay  = 24 * time.Hour
+	DurationYear = 365 * DurationDay
+)
+
+func FormatSimpleDate(ts *time.Time) string {
+	if ts == nil {
+		return "never"
+	}
+	return ts.Format("01-02-06")
+}
+
+func FormatTimeSince(ts *time.Time) string {
+	if ts == nil {
+		return "never"
+	}
+	now := time.Now()
+	elapsed := now.Sub(*ts)
+	return fmt.Sprintf("%v ago", formatDuration(elapsed))
+}
+
+// imprecise formatting since we only care about the highest possible unit
+func formatDuration(d time.Duration) string {
+	if d >= DurationYear {
+		years := d / DurationYear
+		return fmt.Sprintf("%dy", years)
+	} else if d >= DurationDay {
+		days := d / DurationDay
+		return fmt.Sprintf("%dd", days)
+	} else if d >= time.Hour {
+		hours := d / time.Hour
+		return fmt.Sprintf("%dh", hours)
+	} else if d >= time.Minute {
+		minutes := d / time.Minute
+		return fmt.Sprintf("%dm", minutes)
+	}
+	seconds := d / time.Second
+	return fmt.Sprintf("%ds", seconds)
+}
diff --git a/time_test.go b/time_test.go
new file mode 100644
index 0000000..ace0199
--- /dev/null
+++ b/time_test.go
@@ -0,0 +1,18 @@
+package mango
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+	"time"
+)
+
+func TestFormatSimpleDate(t *testing.T) {
+	ts := time.Date(2021, 1, 1, 0, 0, 0, 0, time.UTC)
+	assert.Equal(t, "01-01-21", FormatSimpleDate(&ts))
+}
+
+func TestFormatTimeSince(t *testing.T) {
+	ts := time.Date(2021, 1, 1, 0, 0, 0, 0, time.UTC)
+	timeSince := FormatTimeSince(&ts)
+	assert.NotEmpty(t, timeSince)
+}