From adc88893038e5f2ae2bb535e965cf21a61c3dda4 Mon Sep 17 00:00:00 2001
From: 1eedaegon <d8726243@gmail.com>
Date: Tue, 2 Apr 2024 11:33:10 +0900
Subject: [PATCH] feat: Add Json marshalling, unmarshalling

---
 hashset.go      | 34 ++++++++++++++++++++++++++++++++++
 hashset_test.go | 17 ++++++++++++++++-
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/hashset.go b/hashset.go
index 2891bb6..df9bb63 100644
--- a/hashset.go
+++ b/hashset.go
@@ -1,6 +1,8 @@
 package hashset
 
 import (
+	"encoding/json"
+	"fmt"
 	"reflect"
 	"sync"
 )
@@ -147,6 +149,38 @@ func (s *Set) ToSlice() []interface{} {
 	return uniTypeSlice
 }
 
+func (s *Set) MarshalJSON() ([]byte, error) {
+	stringMap := make(map[string]bool)
+	// s.mu.RLock()
+	for k, v := range s.hash {
+		if reflect.TypeOf(k).Kind() == reflect.Func {
+			fmt.Printf("[WARN] Skipped function pointer value in set: %v (hashset - MarshalJSON)", k)
+			continue
+		}
+		key := fmt.Sprintf("%v", k)
+		stringMap[key] = v
+	}
+	// s.mu.RUnlock()
+	jsonByte, err := json.Marshal(stringMap)
+	if err != nil {
+		return nil, err
+	}
+	return jsonByte, nil
+}
+func (s *Set) UnmarshalJSON(data []byte) error {
+	stringMap := make(map[string]bool)
+	// Here, it is guaranteed that Unmarshal will be appropriate.
+	s.mu.Lock()
+	if err := json.Unmarshal(data, &stringMap); err != nil {
+		return err
+	}
+	s.mu.Unlock()
+	for k := range stringMap {
+		s.Add(k)
+	}
+	return nil
+}
+
 // MakeComparable returns pointer(address) not comparable types: slice, map, function
 func MakeComparable(element interface{}) interface{} {
 	/*
diff --git a/hashset_test.go b/hashset_test.go
index a872c2d..24d3f7f 100644
--- a/hashset_test.go
+++ b/hashset_test.go
@@ -1,6 +1,7 @@
 package hashset
 
 import (
+	"encoding/json"
 	"reflect"
 	"strconv"
 	"sync"
@@ -127,8 +128,10 @@ func TestConvertToSet(t *testing.T) {
 func TestConvertToSlice(t *testing.T) {
 	caseSlice := []int{1, 2, 3}
 	caseSliceTwo := []string{"1", "a", "b"}
+	// Splitting slices
 	s := New(caseSlice, caseSliceTwo)
 	require.Equal(t, 6, s.Len())
+	// Converting set to slice
 	arr := s.ToSlice()
 	require.Equal(t, 6, len(arr))
 	require.True(t, reflect.ValueOf(arr).Kind() == reflect.Slice)
@@ -136,7 +139,6 @@ func TestConvertToSlice(t *testing.T) {
 	require.Contains(t, arr, 3)
 	require.Contains(t, arr, "1")
 	require.Contains(t, arr, "b")
-
 }
 
 func TestUnion(t *testing.T) {
@@ -170,6 +172,19 @@ func TestIntersection(t *testing.T) {
 func TestDifference(t *testing.T)      {}
 func TestFunctionElement(t *testing.T) {}
 func TestStructElement(t *testing.T)   {}
+
+func TestMarshalJSON(t *testing.T) {
+
+	caseSlice := []int{1, 2, 3}
+	caseSliceTwo := []string{"1", "a", "b"}
+	// Splitting slices
+	s := New(caseSlice, caseSliceTwo)
+	ms, err := json.Marshal(s)
+	require.NoError(t, err)
+	s2 := New()
+	err = json.Unmarshal(ms, s2)
+	require.NoError(t, err)
+}
 func TestConcurrentAddElement10Goroutine100000Loop(t *testing.T) {
 	var wg sync.WaitGroup
 	s := New()