From f7abc4e941c3b16e0b67f8175af6b30e0591e033 Mon Sep 17 00:00:00 2001
From: tx7do <yanglinbo@gmail.com>
Date: Mon, 23 Sep 2024 21:31:56 +0800
Subject: [PATCH] feat: math.

---
 math/math.go               |  27 ++++
 rand/rand.go               | 131 ++++++++++++++++-
 rand/rand_test.go          | 285 ++++++++++++++++++++++++++++++++++++-
 uuid/test_trans.go         |   7 -
 uuid/{trans.go => uuid.go} |   1 +
 uuid/uuid_test.go          |  66 +++++++++
 6 files changed, 502 insertions(+), 15 deletions(-)
 delete mode 100644 uuid/test_trans.go
 rename uuid/{trans.go => uuid.go} (99%)
 create mode 100644 uuid/uuid_test.go

diff --git a/math/math.go b/math/math.go
index c03b55a..6fa05a0 100644
--- a/math/math.go
+++ b/math/math.go
@@ -42,3 +42,30 @@ func StandardDeviation(num []float64) float64 {
 	var variance = Variance(mean, num)
 	return math.Sqrt(variance)
 }
+
+// SumInt 计算整数数组的和
+func SumInt[T int | int32 | int64](array []T) int64 {
+	var sum int64
+	for _, v := range array {
+		sum = sum + int64(v)
+	}
+	return sum
+}
+
+// SumUint 计算整数数组的和
+func SumUint[T uint | uint32 | uint64](array []T) uint64 {
+	var sum uint64
+	for _, v := range array {
+		sum = sum + uint64(v)
+	}
+	return sum
+}
+
+// SumFloat 计算浮点数数组的和
+func SumFloat[T float32 | float64](array []T) float64 {
+	var sum float64
+	for _, v := range array {
+		sum = sum + float64(v)
+	}
+	return sum
+}
diff --git a/rand/rand.go b/rand/rand.go
index 865a56f..664815b 100644
--- a/rand/rand.go
+++ b/rand/rand.go
@@ -3,16 +3,50 @@ package rand
 import (
 	"math/rand"
 	"time"
+
+	"github.com/tx7do/go-utils/math"
 )
 
-var RANDOM = rand.New(rand.NewSource(time.Now().UnixNano()))
+var rnd = rand.New(rand.NewSource(time.Now().UnixNano()))
+
+func init() {
+	rnd = rand.New(rand.NewSource(time.Now().UnixNano()))
+}
+
+func Float32() float32 {
+	return rnd.Float32()
+}
+
+func Float64() float64 {
+	return rnd.Float64()
+}
+
+func Intn(n int) int {
+	return rnd.Intn(n)
+}
+
+func Int31n(n int32) int32 {
+	return rnd.Int31n(n)
+}
+
+func Int63n(n int64) int64 {
+	return rnd.Int63n(n)
+}
 
 // RandomInt 根据区间产生随机数
 func RandomInt(min, max int) int {
 	if min >= max {
 		return max
 	}
-	return RANDOM.Intn(max-min) + min
+	return min + Intn(max-min+1)
+}
+
+// RandomInt32 根据区间产生随机数
+func RandomInt32(min, max int32) int32 {
+	if min >= max {
+		return max
+	}
+	return min + Int31n(max-min+1)
 }
 
 // RandomInt64 根据区间产生随机数
@@ -20,5 +54,96 @@ func RandomInt64(min, max int64) int64 {
 	if min >= max {
 		return max
 	}
-	return RANDOM.Int63n(max-min) + min
+	return min + Int63n(max-min+1)
+}
+
+// RandomString 随机字符串，包含大小写字母和数字
+func RandomString(l int) string {
+	bytes := make([]byte, l)
+	for i := 0; i < l; i++ {
+		x := Intn(3)
+		switch x {
+		case 0:
+			bytes[i] = byte(RandomInt(65, 90)) //大写字母
+		case 1:
+			bytes[i] = byte(RandomInt(97, 122))
+		case 2:
+			bytes[i] = byte(Intn(10))
+		}
+	}
+	return string(bytes)
+}
+
+// RandomChoice 随机选择数组中的元素
+func RandomChoice[T any](array []T, n int) []T {
+	if n <= 0 {
+		return nil
+	}
+	if n == 1 {
+		return []T{array[Intn(len(array))]}
+	}
+
+	tmp := make([]T, len(array))
+	copy(tmp, array)
+	if len(tmp) <= n {
+		return tmp
+	}
+
+	Shuffle(tmp)
+
+	return tmp[:n]
+}
+
+// Shuffle 随机打乱数组
+func Shuffle[T any](array []T) {
+	if array == nil {
+		return
+	}
+
+	for i := range array {
+		j := Intn(i + 1)
+		array[i], array[j] = array[j], array[i]
+	}
+}
+
+// WeightedChoice 根据权重随机，返回对应选项的索引，O(n)
+func WeightedChoice(weightArray []int) int {
+	if weightArray == nil {
+		return -1
+	}
+
+	total := math.SumInt(weightArray)
+	rv := Int63n(total)
+	for i, v := range weightArray {
+		if rv < int64(v) {
+			return i
+		}
+		rv -= int64(v)
+	}
+
+	return len(weightArray) - 1
+}
+
+// NonWeightedChoice 根据权重随机，返回对应选项的索引，O(n). 权重大于等于0
+func NonWeightedChoice(weightArray []int) int {
+	if weightArray == nil {
+		return -1
+	}
+
+	for i, weight := range weightArray {
+		if weight < 0 {
+			weightArray[i] = 0
+		}
+	}
+
+	total := math.SumInt(weightArray)
+	rv := Int63n(total)
+	for i, v := range weightArray {
+		if rv < int64(v) {
+			return i
+		}
+		rv -= int64(v)
+	}
+
+	return len(weightArray) - 1
 }
diff --git a/rand/rand_test.go b/rand/rand_test.go
index ababa70..7cfe084 100644
--- a/rand/rand_test.go
+++ b/rand/rand_test.go
@@ -7,11 +7,286 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestRandomInt(t *testing.T) {
+func TestFloat32_GeneratesValueWithinRange(t *testing.T) {
 	for i := 0; i < 1000; i++ {
-		n := RandomInt(1, 100)
-		fmt.Println(n)
-		assert.True(t, n >= 1)
-		assert.True(t, n < 100)
+		value := Float32()
+		assert.True(t, value >= 0.0)
+		assert.True(t, value < 1.0)
 	}
 }
+
+func TestFloat32_GeneratesDifferentValues(t *testing.T) {
+	values := make(map[float32]bool)
+	for i := 0; i < 1000; i++ {
+		value := Float32()
+		values[value] = true
+	}
+	assert.Greater(t, len(values), 1)
+}
+
+func TestFloat64_GeneratesValueWithinRange(t *testing.T) {
+	for i := 0; i < 1000; i++ {
+		value := Float64()
+		assert.True(t, value >= 0.0)
+		assert.True(t, value < 1.0)
+	}
+}
+
+func TestFloat64_GeneratesDifferentValues(t *testing.T) {
+	values := make(map[float64]bool)
+	for i := 0; i < 1000; i++ {
+		value := Float64()
+		values[value] = true
+	}
+	assert.Greater(t, len(values), 1)
+}
+
+func TestRandomInt(t *testing.T) {
+	for i := 0; i < 1000; i++ {
+		n := RandomInt(1, 10)
+		fmt.Println(n)
+		assert.True(t, n >= 1)
+		assert.True(t, n <= 100)
+	}
+}
+
+func TestRandomInt_MinEqualsMax(t *testing.T) {
+	n := RandomInt(5, 5)
+	assert.Equal(t, 5, n)
+}
+
+func TestRandomInt_MinGreaterThanMax(t *testing.T) {
+	n := RandomInt(10, 5)
+	assert.Equal(t, 5, n)
+}
+
+func TestRandomInt_NegativeRange(t *testing.T) {
+	for i := 0; i < 1000; i++ {
+		n := RandomInt(-10, -1)
+		assert.True(t, n >= -10)
+		assert.True(t, n <= -1)
+	}
+}
+
+func TestRandomInt_ZeroRange(t *testing.T) {
+	for i := 0; i < 1000; i++ {
+		n := RandomInt(0, 0)
+		assert.Equal(t, 0, n)
+	}
+}
+
+func TestShuffle_EmptyArray(t *testing.T) {
+	var array []int
+	Shuffle(array)
+	assert.Equal(t, array, array)
+}
+
+func TestShuffle_SingleElementArray(t *testing.T) {
+	array := []int{1}
+	Shuffle(array)
+	assert.Equal(t, []int{1}, array)
+}
+
+func TestShuffle_MultipleElementsArray(t *testing.T) {
+	array := []int{1, 2, 3, 4, 5}
+	original := make([]int, len(array))
+	copy(original, array)
+	Shuffle(array)
+	assert.ElementsMatch(t, original, array)
+}
+
+func TestShuffle_ArrayWithDuplicates(t *testing.T) {
+	array := []int{1, 2, 2, 3, 3, 3}
+	original := make([]int, len(array))
+	copy(original, array)
+	Shuffle(array)
+	fmt.Println(array)
+	assert.ElementsMatch(t, original, array)
+}
+
+func TestRandomChoice_EmptyArray(t *testing.T) {
+	result := RandomChoice([]int{}, 3)
+	assert.Nil(t, result)
+}
+
+func TestRandomChoice_NegativeN(t *testing.T) {
+	array := []int{1, 2, 3}
+	result := RandomChoice(array, -1)
+	assert.Nil(t, result)
+}
+
+func TestRandomChoice_ZeroN(t *testing.T) {
+	array := []int{1, 2, 3}
+	result := RandomChoice(array, 0)
+	assert.Nil(t, result)
+}
+
+func TestRandomChoice_NGreaterThanArrayLength(t *testing.T) {
+	array := []int{1, 2, 3}
+	result := RandomChoice(array, 5)
+	assert.ElementsMatch(t, array, result)
+}
+
+func TestRandomChoice_NEqualToArrayLength(t *testing.T) {
+	array := []int{1, 2, 3}
+	result := RandomChoice(array, 3)
+	assert.ElementsMatch(t, array, result)
+}
+
+func TestRandomChoice_NLessThanArrayLength(t *testing.T) {
+	array := []int{1, 2, 3, 4, 5}
+	result := RandomChoice(array, 3)
+	assert.Len(t, result, 3)
+}
+
+func TestRandomInt32_MinEqualsMax(t *testing.T) {
+	result := RandomInt32(5, 5)
+	assert.Equal(t, int32(5), result)
+}
+
+func TestRandomInt32_MinGreaterThanMax(t *testing.T) {
+	result := RandomInt32(10, 5)
+	assert.Equal(t, int32(5), result)
+}
+
+func TestRandomInt32_PositiveRange(t *testing.T) {
+	for i := 0; i < 1000; i++ {
+		result := RandomInt32(1, 10)
+		assert.True(t, result >= 1)
+		assert.True(t, result <= 10)
+	}
+}
+
+func TestRandomInt32_NegativeRange(t *testing.T) {
+	for i := 0; i < 1000; i++ {
+		result := RandomInt32(-10, -1)
+		assert.True(t, result >= -10)
+		assert.True(t, result <= -1)
+	}
+}
+
+func TestRandomInt32_ZeroRange(t *testing.T) {
+	for i := 0; i < 1000; i++ {
+		result := RandomInt32(0, 0)
+		assert.Equal(t, int32(0), result)
+	}
+}
+
+func TestRandomInt64_MinEqualsMax(t *testing.T) {
+	result := RandomInt64(5, 5)
+	assert.Equal(t, int64(5), result)
+}
+
+func TestRandomInt64_MinGreaterThanMax(t *testing.T) {
+	result := RandomInt64(10, 5)
+	assert.Equal(t, int64(5), result)
+}
+
+func TestRandomInt64_PositiveRange(t *testing.T) {
+	for i := 0; i < 1000; i++ {
+		result := RandomInt64(1, 10)
+		assert.True(t, result >= 1)
+		assert.True(t, result <= 10)
+	}
+}
+
+func TestRandomInt64_NegativeRange(t *testing.T) {
+	for i := 0; i < 1000; i++ {
+		result := RandomInt64(-10, -1)
+		assert.True(t, result >= -10)
+		assert.True(t, result <= -1)
+	}
+}
+
+func TestRandomInt64_ZeroRange(t *testing.T) {
+	for i := 0; i < 1000; i++ {
+		result := RandomInt64(0, 0)
+		assert.Equal(t, int64(0), result)
+	}
+}
+
+func TestRandomString_LengthZero(t *testing.T) {
+	result := RandomString(0)
+	assert.Equal(t, "", result)
+}
+
+func TestRandomString_PositiveLength(t *testing.T) {
+	result := RandomString(10)
+	assert.Len(t, result, 10)
+}
+
+func TestRandomString_ContainsOnlyValidCharacters(t *testing.T) {
+	result := RandomString(100)
+	for _, char := range result {
+		assert.True(t, (char >= 'A' && char <= 'Z') || (char >= 'a' && char <= 'z') || (char >= '0' && char <= '9'))
+	}
+}
+
+func TestRandomString_NegativeLength(t *testing.T) {
+	result := RandomString(-5)
+	assert.Equal(t, "", result)
+}
+
+func TestWeightedChoice_EmptyArray(t *testing.T) {
+	result := WeightedChoice([]int{})
+	assert.Equal(t, -1, result)
+}
+
+func TestWeightedChoice_AllZeroWeights(t *testing.T) {
+	result := WeightedChoice([]int{0, 0, 0})
+	assert.Equal(t, 2, result)
+}
+
+func TestWeightedChoice_NegativeWeights(t *testing.T) {
+	result := WeightedChoice([]int{-1, -2, -3})
+	assert.Equal(t, 2, result)
+}
+
+func TestWeightedChoice_MixedWeights(t *testing.T) {
+	weightArray := []int{1, 0, 3, 0, 2}
+	counts := make([]int, len(weightArray))
+	for i := 0; i < 1000; i++ {
+		choice := WeightedChoice(weightArray)
+		counts[choice]++
+	}
+	assert.Greater(t, counts[0], 0)
+	assert.Greater(t, counts[2], 0)
+	assert.Greater(t, counts[4], 0)
+}
+
+func TestWeightedChoice_SingleElement(t *testing.T) {
+	result := WeightedChoice([]int{5})
+	assert.Equal(t, 0, result)
+}
+
+func TestNonWeightedChoice_EmptyArray(t *testing.T) {
+	result := NonWeightedChoice([]int{})
+	assert.Equal(t, -1, result)
+}
+
+func TestNonWeightedChoice_AllZeroWeights(t *testing.T) {
+	result := NonWeightedChoice([]int{0, 0, 0})
+	assert.Equal(t, 2, result)
+}
+
+func TestNonWeightedChoice_NegativeWeights(t *testing.T) {
+	result := NonWeightedChoice([]int{-1, -2, -3})
+	assert.Equal(t, 2, result)
+}
+
+func TestNonWeightedChoice_MixedWeights(t *testing.T) {
+	weightArray := []int{1, 0, 3, 0, 2}
+	counts := make([]int, len(weightArray))
+	for i := 0; i < 1000; i++ {
+		choice := NonWeightedChoice(weightArray)
+		counts[choice]++
+	}
+	assert.Greater(t, counts[0], 0)
+	assert.Greater(t, counts[2], 0)
+	assert.Greater(t, counts[4], 0)
+}
+
+func TestNonWeightedChoice_SingleElement(t *testing.T) {
+	result := NonWeightedChoice([]int{5})
+	assert.Equal(t, 0, result)
+}
diff --git a/uuid/test_trans.go b/uuid/test_trans.go
deleted file mode 100644
index 3e2ae66..0000000
--- a/uuid/test_trans.go
+++ /dev/null
@@ -1,7 +0,0 @@
-package uuid
-
-import "testing"
-
-func TestUUID(t *testing.T) {
-
-}
diff --git a/uuid/trans.go b/uuid/uuid.go
similarity index 99%
rename from uuid/trans.go
rename to uuid/uuid.go
index 3cd0cf6..1efd4b8 100644
--- a/uuid/trans.go
+++ b/uuid/uuid.go
@@ -2,6 +2,7 @@ package uuid
 
 import (
 	"github.com/google/uuid"
+
 	"github.com/tx7do/go-utils/trans"
 )
 
diff --git a/uuid/uuid_test.go b/uuid/uuid_test.go
new file mode 100644
index 0000000..e01edef
--- /dev/null
+++ b/uuid/uuid_test.go
@@ -0,0 +1,66 @@
+package uuid
+
+import (
+	"testing"
+
+	"github.com/google/uuid"
+)
+
+func TestUUID(t *testing.T) {
+	t.Run("ToUuidPtr_NilString", func(t *testing.T) {
+		var str *string
+		result := ToUuidPtr(str)
+		if result != nil {
+			t.Errorf("expected nil, got %v", result)
+		}
+	})
+
+	t.Run("ToUuidPtr_ValidString", func(t *testing.T) {
+		str := "550e8400-e29b-41d4-a716-446655440000"
+		result := ToUuidPtr(&str)
+		if result == nil || result.String() != str {
+			t.Errorf("expected %v, got %v", str, result)
+		}
+	})
+
+	t.Run("ToUuidPtr_InvalidString", func(t *testing.T) {
+		str := "invalid-uuid"
+		result := ToUuidPtr(&str)
+		if result != nil {
+			t.Errorf("expected nil, got %v", result)
+		}
+	})
+
+	t.Run("ToUuid_ValidString", func(t *testing.T) {
+		str := "550e8400-e29b-41d4-a716-446655440000"
+		result := ToUuid(str)
+		if result.String() != str {
+			t.Errorf("expected %v, got %v", str, result)
+		}
+	})
+
+	t.Run("ToUuid_InvalidString", func(t *testing.T) {
+		str := "invalid-uuid"
+		result := ToUuid(str)
+		if result.String() == str {
+			t.Errorf("expected invalid UUID, got %v", result)
+		}
+	})
+
+	t.Run("ToStringPtr_NilUUID", func(t *testing.T) {
+		var id *uuid.UUID
+		result := ToStringPtr(id)
+		if result != nil {
+			t.Errorf("expected nil, got %v", result)
+		}
+	})
+
+	t.Run("ToStringPtr_ValidUUID", func(t *testing.T) {
+		id := uuid.MustParse("550e8400-e29b-41d4-a716-446655440000")
+		result := ToStringPtr(&id)
+		expected := "550e8400-e29b-41d4-a716-446655440000"
+		if result == nil || *result != expected {
+			t.Errorf("expected %v, got %v", expected, result)
+		}
+	})
+}