/**
 * Created by IntelliJ IDEA.
 * User: akshay
 * Date: 2019-08-10
 * Time: 15:41
 */
package com.example.UrlShortener.Services;

import com.example.UrlShortener.Models.Link;
import com.example.UrlShortener.Repositories.LinkRepository;
import org.springframework.stereotype.Service;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

@Service
public class LinksService {

    private LinkRepository linkRepository;

    public LinksService(LinkRepository linkRepository) {
        this.linkRepository = linkRepository;
    }

    public String MD5(String md5) throws NoSuchAlgorithmException {
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] array = md.digest(md5.getBytes());
            StringBuilder sb = new StringBuilder();
            for (byte b : array) {
                sb.append(Integer.toHexString((b & 0xFF) | 0x100).substring(1, 3));
            }
            return sb.toString().subSequence(0,6).toString();
    }

    public Link shortenUrl(String longUrl) throws Exception {
        Link link = linkRepository.findByLongUrl(longUrl);
        if (link == null) {
            link = new Link(MD5(longUrl), longUrl);
            linkRepository.save(link);
        }
        return link;
    }
}