package xrand

import (
	"math/rand"
	"time"
)

func init() {
	rand.New(rand.NewSource(time.Now().UnixNano()))
}

func Int() int {
	return rand.Int()
}

func Intn(n int) int {
	return rand.Intn(n)
}

func Int31() int32 {
	return rand.Int31()
}

func Int31n(n int32) int32 {
	return rand.Int31n(n)
}

func Int63() int64 {
	return rand.Int63()
}

func Int63n(n int64) int64 {
	return rand.Int63n(n)
}

func Uint32() uint32 {
	return rand.Uint32()
}

func Uint64() uint64 {
	return rand.Uint64()
}

func Float32() float32 {
	return rand.Float32()
}

func Float64() float64 {
	return rand.Float64()
}

func Perm(n int) []int {
	return rand.Perm(n)
}

func Read(p []byte) (n int, err error) {
	return rand.Read(p)
}

func Shuffle[T any](slice []T) {
	rand.Shuffle(len(slice), func(i, j int) {
		slice[i], slice[j] = slice[j], slice[i]
	})
}

// RandomInt64 随机生成一个[min, max]之间的整数
func RandomInt64(min, max int64) int64 {
	return Int63n(max-min) + min
}

func Roll(source map[int32]int32) int32 {
	// 1. 统计权重
	// 2. roll
	// 3. 查找产出

	// 1. 统计权重
	var total = 0
	for _, v := range source {
		total += int(v)
	}

	// 2. roll
	r := rand.Intn(total) + 1

	// 3. 查找产出
	var temp = 0
	for k, v := range source {
		temp += int(v)
		if temp >= r {
			return k
		}
	}

	return 0
}