package utils

import (
	"crypto/rand"
	"encoding/binary"
	"fmt"
)

// 使用真随机数 实现摇摇乐
// 对数组随机生成 指定次数:10万次  (不得低于10万次)

func TrueRandomForLotteryDraw(int64Slice []int64, times int) (map[int64]int, int64, int, error) {
	if times < 100000 {
		times = 100000
	}
	var randInt64List []int64
	countMap := make(map[int64]int)
	for i := 0; i < times; i++ {
		randInt64, err := TrueRandomInt64Slice(int64Slice)
		if err != nil {
			return countMap, 0, 0, err
		}
		randInt64List = append(randInt64List, randInt64)
	}
	var maxTimes int = 0
	var maxId int64 = 0
	for _, num := range randInt64List {
		countMap[num]++
		if countMap[num] > maxTimes {
			maxTimes = countMap[num]
			maxId = num
		}
	}
	return countMap, maxId, maxTimes, nil
}

// 随机int64 切片

func TrueRandomInt64Slice(ids []int64) (int64, error) {
	if len(ids) == 0 {
		return 0, fmt.Errorf("len ids is zero")
	}
	if len(ids) == 1 {
		return ids[0], nil
	}
	randInt, err := TrueRandomInt(0, len(ids)-1)
	return ids[randInt], err
}

// 生成指定范围内的真随机数

func TrueRandomInt(min, max int) (int, error) {
	if min > max {
		return 0, fmt.Errorf("min cannot be greater than max")
	}
	// 生成随机字节
	var n uint32
	err := binary.Read(rand.Reader, binary.BigEndian, &n)
	if err != nil {
		return 0, err
	}
	// 映射到指定范围
	rangeSize := uint32(max - min + 1)
	result := min + int(n%rangeSize)
	return result, nil
}