package services

import (
	"context"
	"math/rand"
	"time"

	"code.gurenya.net/carlsmei/muninn-aio/db"
	"code.gurenya.net/carlsmei/muninn-aio/ent/link"
)

// Key Generation Algorithm 6:51 MSK 29.07.24

var numChars = 8
var keyAlphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
var seededRand *rand.Rand = rand.New(
	rand.NewSource(time.Now().UnixNano()))

func GenerateKey(ctx context.Context) string {
	client := db.GetEntClient()
	cond := false
	key := make([]byte, numChars)

	for !cond {
		for i := range key {
			key[i] = keyAlphabet[seededRand.Intn(len(keyAlphabet))]
		}

		exists, _ := client.Link.
			Query().
			Where(link.Key(string(key))).
			Exist(ctx)

		cond = !exists
	}

	return string(key)
}