package importfunc

import (
	"bufio"
	"fmt"
	"math/rand"
	"os"
)

func GenerateUserIdMap() {

	list := make([]int64, 0)
	for i := int64(1000000); i < 100000000; i++ {
		list = append(list, i)
	}
	rand.Shuffle(99000000, func(i, j int) {
		list[i], list[j] = list[j], list[i]
	})

	j := 1
	for i := 0; i < len(list); i += 1000000 {
		lower := i
		upper := i + 999999
		if upper >= len(list) {
			upper = len(list) - 1
		}
		WriteAsList(list[lower:upper], j)
		j++
	}

}

func WriteAsList(list []int64, seq int) {
	pathurl := fmt.Sprintf("/Users/Caeru/Desktop/file/user_id_map%v.txt", seq)
	outfile, err := os.OpenFile(pathurl, os.O_WRONLY|os.O_CREATE, 0666)
	if err != nil {
		fmt.Printf("Open File Err : %v", err)
	}

	defer outfile.Close()

	writer := bufio.NewWriter(outfile)

	for i := range list {
		outfile.WriteString(fmt.Sprintf("%v:%v\n", 1000000*seq+i, list[i]))
	}
	writer.Flush()
	fmt.Printf("%dth file has generated\n", seq)
}