package dev.peerat.backend.routes.users;

import static dev.peerat.framework.RequestType.POST;

import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.lang.reflect.Constructor;
import java.net.URL;
import java.nio.ByteBuffer;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.interfaces.RSAPublicKey;
import java.util.ArrayList;
import java.util.Base64;
import java.util.Base64.Encoder;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.UUID;
import java.util.regex.Matcher;

import javax.net.ssl.HttpsURLConnection;

import org.jose4j.json.internal.json_simple.JSONAware;
import org.jose4j.json.internal.json_simple.JSONObject;

import dev.peerat.backend.bonus.extract.RouteDoc;
import dev.peerat.backend.model.PeerAtUser;
import dev.peerat.backend.repository.DatabaseRepository;
import dev.peerat.backend.utils.FormResponse;
import dev.peerat.backend.utils.Mail;
import dev.peerat.framework.Context;
import dev.peerat.framework.HttpReader;
import dev.peerat.framework.HttpWriter;
import dev.peerat.framework.Injection;
import dev.peerat.framework.Route;
import dev.peerat.framework.Router;
import dev.peerat.framework.utils.json.JsonMap;

public class MailConfirmation extends FormResponse{

	private DatabaseRepository databaseRepo;
	private Router<PeerAtUser> router;
	private String usersFilesPath;
	private KeyPairGenerator generator;
	private Encoder encoder;
	private String gitToken;
	private Map<String, String> playersWaiting;
	private Mail mail;
	private List<Random> randoms;
	
	public MailConfirmation(
			DatabaseRepository databaseRepo,
			Router<PeerAtUser> router,
			@Injection("usersFiles") String initUsersFilesPath,
			@Injection("gitToken") String gitToken,
			@Injection("waitting") Map<String, String> playersWaiting,
			Mail mail) throws NoSuchAlgorithmException{
		
		this.databaseRepo = databaseRepo;
		this.router = router;
		this.usersFilesPath = initUsersFilesPath;
		this.gitToken = gitToken;
		this.playersWaiting = playersWaiting;
		this.mail = mail;
		
		generator = KeyPairGenerator.getInstance("RSA");
		generator.initialize(4096);
		encoder = Base64.getEncoder();
		
		this.randoms = new ArrayList<>();
		
		Random random = new Random();
		int randoms = random.nextInt(10)+3;
		for(int i = 0; i < randoms; i++) this.randoms.add(new SecureRandom());
		
		try {
			Constructor<?> constructor = UUID.class.getDeclaredConstructor(byte[].class);
			constructor.setAccessible(true);
			this.uuidBuilder = constructor;
		} catch (Exception e){
			e.printStackTrace();
		}
		
		validator("pseudo", "[a-zA-Z0-9&|!?{}\\[\\]%/*\\-+=:;,_#@ ]{3,100}");
		validator("firstname", "^(?>[a-zA-Z]+ ?)+$");
		validator("lastname", "^(?>[a-zA-Z]+ ?)+$");
	}

	@RouteDoc(path = "/confirmation", responseCode = 200, responseDescription = "L'utilisateur est inscrit")
	@RouteDoc(responseCode = 403, responseDescription = "L'utilisateur est connecté")
	@RouteDoc(responseCode = 400, responseDescription = "Aucune données fournie / données invalide")

	@Route(path = "^\\/confirmation$", type = POST)
	public void exec(Matcher matcher, Context context, HttpReader reader, HttpWriter writer) throws Exception {
		if(context.isLogged()){
			context.response(403);
			return;
		}
		JsonMap json = json(reader);
		if((!areValids("email","pseudo","firstname","lastname","passwd")) || (!hasFields("code"))){
			context.response(400);
			return;
		}
		String email = json.get("email");
		String code = json.<String>get("code");
		String pseudo = json.get("pseudo");
		String firstname = json.get("firstname");
		String lastname = json.get("lastname");
		String password = json.get("passwd");
		
		String checkCode = playersWaiting.get(email);
		if(checkCode == null){
			context.response(400);
			return;
		}
		
		boolean pseudoAvailable = databaseRepo.checkPseudoAvailability(pseudo);
		boolean emailAvailable = databaseRepo.checkEmailAvailability(email);
		if(pseudoAvailable && emailAvailable){
			if(code.equals(checkCode)){
				playersWaiting.remove(email);
				int id = databaseRepo.register(pseudo, email, password, firstname, lastname, "", "", "");
				if(id >= 0){
//					createFolderToSaveSourceCode(pseudo);
//					generateGitKey(email, pseudo, password);
					context.response(200,
							"Access-Control-Expose-Headers: Authorization",
							"Authorization: Bearer " + this.router.createAuthUser(new PeerAtUser(id)));
				}else{
					context.response(400);
					JsonMap error = new JsonMap();
					error.set("username_valid", pseudo);
					error.set("email_valid", email);
					writer.write(error.toString());
					String ncode = codeGenerator()+codeGenerator();
					playersWaiting.put(email, ncode);
					mail.send(email, "Welcome @ Peer @ Code", "Your check code is "+ncode+" !");
				}
			}else{
				context.response(400);
			}
		}else{
			context.response(400);
			JsonMap error = new JsonMap();
			error.set("username_valid", pseudo);
			error.set("email_valid", email);
			writer.write(error.toString());
		}
	}
	
	private Constructor<?> uuidBuilder;
	
	private String codeGenerator() throws Exception{
		Random random = new Random();
		Random target = this.randoms.get(random.nextInt(this.randoms.size()));
		byte[] arrayOfByte = new byte[16];
		target.nextBytes(arrayOfByte);
	    arrayOfByte[6] = (byte)(arrayOfByte[6] & 0xF);
	    arrayOfByte[6] = (byte)(arrayOfByte[6] | 0x40);
	    arrayOfByte[8] = (byte)(arrayOfByte[8] & 0x3F);
	    arrayOfByte[8] = (byte)(arrayOfByte[8] | 0x80);
	    return uuidBuilder.newInstance(arrayOfByte).toString();
	}
	
	private void createFolderToSaveSourceCode(String pseudo) throws IOException {

		Files.createDirectories(Paths.get(String.format("%s/%s", usersFilesPath, pseudo)));
	}
	
	private static byte[] PREFIX = new byte[] {0,0,0,7,(byte)'s',(byte)'s',(byte)'h',(byte)'-',(byte)'r',(byte)'s',(byte)'a'};
	
	private String generateGitKey(String email, String pseudo, String password) throws Exception{
		KeyPair pair = generator.generateKeyPair(); //doit être unique ???
		
		JSONObject createUser = new JSONObject();
		createUser.put("email", email);
		createUser.put("username", pseudo);
		createUser.put("password", password);
		post("https://git-users.peerat.dev/api/v1/admin/users/", createUser);
		
		JSONObject sendKey = new JSONObject();
		RSAPublicKey pub = (RSAPublicKey) pair.getPublic();
		byte[] exponent = pub.getPublicExponent().toByteArray();
		byte[] modulus = pub.getModulus().toByteArray();
		byte[] key = new byte[19+exponent.length+modulus.length];
		System.arraycopy(PREFIX, 0, key, 0, 11);
		byte[] exLength = ByteBuffer.allocate(4).putInt(exponent.length).array();
		byte[] modLength = ByteBuffer.allocate(4).putInt(modulus.length).array();
		System.arraycopy(exLength, 0, key, 11, 4);
		System.arraycopy(exponent, 0, key, 15, exponent.length);
		System.arraycopy(modLength, 0, key, 15+exponent.length, 4);
		System.arraycopy(modulus, 0, key, 19+exponent.length, modulus.length);
		
		sendKey.put("key", "ssh-rsa "+new String(encoder.encode(key)));
		sendKey.put("read_only", false);
		sendKey.put("title", "peer_at_code_auto_push_key_"+pseudo);
		post("https://git-users.peerat.dev/api/v1/admin/users/"+pseudo+"/keys", sendKey);
		
		return new String(encoder.encode(pair.getPrivate().getEncoded()));
	}
	
	private void post(String url, JSONAware json) throws Exception{
		HttpsURLConnection connection = (HttpsURLConnection) new URL(url).openConnection();
		connection.setRequestMethod("POST");
		connection.setRequestProperty("Content-Type","application/json");
		connection.setRequestProperty("Authorization","Bearer "+this.gitToken);
		connection.setDoInput(true);
		connection.setDoOutput(true);
		
		BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(connection.getOutputStream()));
		writer.write(json.toJSONString());
		writer.flush();
		writer.close();
		
		int response = connection.getResponseCode();
		if(response != 201) throw new Exception("Call to "+url+" failed with response code "+response);
	}
}