package com.billpaymentservice.bbps.serviceImpl;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.billpaymentservice.bbps.config.JwtUtil;
import com.billpaymentservice.bbps.dto.UserDetailsDTO;
import com.billpaymentservice.bbps.dto.auth.AuthResponse;
import com.billpaymentservice.bbps.dto.auth.LoginRequest;
import com.billpaymentservice.bbps.dto.auth.OtpSendResponse;
import com.billpaymentservice.bbps.dto.auth.RegisterRequest;
import com.billpaymentservice.bbps.dto.auth.UserDto;
import com.billpaymentservice.bbps.dto.auth.VerifyOtpRequest;
import com.billpaymentservice.bbps.dto.response.AuthResponses;
import com.billpaymentservice.bbps.entites.UserEntity;
import com.billpaymentservice.bbps.repository.UserRepository;
import com.billpaymentservice.bbps.repository.UsersDetailsRepository;
import com.billpaymentservice.bbps.service.AuthService;
import com.billpaymentservice.bbps.util.Helper;
import com.billpaymentservice.bbps.util.OtpClient;

import java.util.Optional;

@Service
public class AuthServiceImpl implements AuthService {

	private static final Logger LOGGER = LoggerFactory.getLogger(AuthServiceImpl.class);

	private final UserRepository userRepository;
	private final OtpClient otpClient;
	private final Helper helper;
	private final UsersDetailsRepository userRepo;

	private final JwtUtil jwtUtil;

	public AuthServiceImpl(UserRepository userRepository, OtpClient otpClient, Helper helper,
			UsersDetailsRepository userRepo, JwtUtil jwtUtil) {
		this.userRepository = userRepository;
		this.otpClient = otpClient;
		this.helper = helper;
		this.userRepo = userRepo;
		this.jwtUtil = jwtUtil;
	}

	@Override
	public OtpSendResponse sendOtp(LoginRequest request) {
		Optional<UserEntity> existing = userRepository.findByMobile(request.getMobile());

		if (existing.isPresent()) {
			UserEntity u = existing.get();
			UserDto dto = new UserDto(u.getId(), u.getMobile(), u.getName(), u.getEmail(), u.getAge());
			return null;
		}
		// delegate to external OTP provider
		return otpClient.sendOtp(request.getMobile());
	}

	@Override
	public AuthResponses verifyOtp(VerifyOtpRequest request) {
		boolean ok = otpClient.verifyOtp(request.getMobile(), request.getOtp());
		LOGGER.info("OTP STATUS" + ok);
		if (ok) {
			return new AuthResponses("", "Invalid OTP", "Failed", 401, null);
		}
		String mobileNo = request.getMobile();
		try {

			Optional<UserEntity> byAdminEmail = userRepo.findByMobile(mobileNo);

			if (byAdminEmail.isPresent()) {
				UserEntity user = byAdminEmail.get();
				String token = jwtUtil.generateToken(user.getMobile());

				LOGGER.info("Generated JWT token for mobileNo: " + mobileNo);

				Object userDetailsDTO = null;

				if (user != null) {
					userDetailsDTO = UserDetailsDTO.builder().id(user.getId()).userEmailId(user.getEmail())
							.userMobNo(user.getMobile()).userName(user.getName()).userAge(user.getAge()).build();
				}
				return new AuthResponses(token, "Success", "Login Done", 200, userDetailsDTO);
			} else {
				return new AuthResponses("", "User Not Found", "Authentication failed", 401, null);
			}

		} catch (Exception ex) {
			System.out.println(
					"Error occurred during login for mobile no: " + mobileNo + " Exception: " + ex.getMessage());

			return AuthResponses.builder().status("Unauthorized").message("Authentication failed: " + ex.getMessage())
					.statusCode(401).build();
		}

//		Optional<UserEntity> userOpt = userRepository.findByMobile(request.getMobile());
//		if (userOpt.isPresent()) {
//			UserEntity user = userOpt.get();
//			UserDto dto = new UserDto(user.getId(), user.getMobile(), user.getName(), user.getEmail(), user.getAge());
//			return new AuthResponse(true, "Login successful", true, dto);
//		} else {
//			return new AuthResponse(true, "OTP verified; user not found - proceed to registration", false, null);
//		}
	}

	@Override
	@Transactional
	public AuthResponse registerUser(RegisterRequest request) {
		Optional<UserEntity> existing = userRepository.findByMobile(request.getMobile());
		if (existing.isPresent()) {
			UserEntity u = existing.get();
			UserDto dto = new UserDto(u.getId(), u.getMobile(), u.getName(), u.getEmail(), u.getAge());
			return new AuthResponse(false, "User already exists", true, dto);
		}

		UserEntity user = helper.createNewUser(request);
		user = userRepository.save(user);
		UserDto dto = new UserDto(user.getId(), user.getMobile(), user.getName(), user.getEmail(), user.getAge());
		return new AuthResponse(true, "Registration successful", true, dto);
	}

	@Override
	public UserEntity findByMobile(String mobile) {
		return userRepository.findByMobile(mobile).orElse(null);
	}

	@Override
	public AuthResponses authenticateUser(LoginRequest loginRequest) {
		LOGGER.info("Processing login for Request: " + loginRequest);

		try {
			String mobileNo = loginRequest.getMobile();

			Optional<UserEntity> byAdminEmail = userRepo.findByMobile(mobileNo);

			if (byAdminEmail.isPresent()) {
				UserEntity user = byAdminEmail.get();
				String token = jwtUtil.generateToken(user.getMobile());

				LOGGER.info("Generated JWT token for mobileNo: " + mobileNo);

				Object userDetailsDTO = null;

				if (user != null) {
					userDetailsDTO = UserDetailsDTO.builder().id(user.getId()).userEmailId(user.getEmail())
							.userMobNo(user.getMobile()).userName(user.getName()).userAge(user.getAge()).build();
				}
				return new AuthResponses(token, "Success", "Login Done", 200, userDetailsDTO);
			} else {
				return new AuthResponses("", "User Not Found", "Authentication failed", 401, null);
			}

		} catch (Exception ex) {
			System.out.println("Error occurred during login for mobile no: " + loginRequest.getMobile() + " Exception: "
					+ ex.getMessage());

			return AuthResponses.builder().status("Unauthorized").message("Authentication failed: " + ex.getMessage())
					.statusCode(401).build();
		}
	}
}