package rand

import (
	"crypto/rand"
	"encoding/base64"
	"fmt"
	randv2 "math/rand/v2"
	"strings"
)

const alphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"

func Bytes(n int) ([]byte, error) {
	b := make([]byte, n)
	nRead, err := rand.Read(b)
	if err != nil {
		return nil, fmt.Errorf("bytes: %w", err)
	}
	if nRead < n {
		return nil, fmt.Errorf("bytes: didn't read enough random bytes")
	}
	return b, nil
}

func String(n int) (string, error) {
	b, err := Bytes(n)
	if err != nil {
		return "", fmt.Errorf("string: %w", err)
	}
	return base64.URLEncoding.EncodeToString(b), nil
}

func RandomInt(n int) string {
	letters := []byte("0123456789")
	l := len(letters)
	result := make([]byte, n)
	for i := range result {
		result[i] = letters[randv2.IntN(l)]
	}
	return string(result)
}

func RandomString(n int) string {
	var sb strings.Builder
	k := len(alphabet)

	for range n {
		c := alphabet[randv2.IntN(k)]
		sb.WriteByte(c)
	}

	return sb.String()
}