package com.xuqm.demo.service;

import com.xuqm.common.exception.BusinessException;
import com.xuqm.demo.entity.DemoUserEntity;
import com.xuqm.demo.repository.DemoUserRepository;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;

@Service
public class DemoUserService {

    private final DemoUserRepository userRepository;
    private final PasswordEncoder passwordEncoder;

    public DemoUserService(DemoUserRepository userRepository, PasswordEncoder passwordEncoder) {
        this.userRepository = userRepository;
        this.passwordEncoder = passwordEncoder;
    }

    public record UserProfile(String appId, String userId, String nickname, String avatar, String gender) {}

    @Transactional(readOnly = true)
    public UserProfile getProfile(String appId, String userId) {
        DemoUserEntity user = userRepository.findByAppIdAndUserId(appId, userId)
                .orElseThrow(() -> new BusinessException(404, "User not found"));
        return toProfile(user);
    }

    @Transactional
    public UserProfile updateProfile(String appId, String userId, String nickname, String avatar, String gender) {
        DemoUserEntity user = userRepository.findByAppIdAndUserId(appId, userId)
                .orElseThrow(() -> new BusinessException(404, "User not found"));

        if (nickname != null && !nickname.isBlank()) {
            user.setNickname(nickname);
        }
        if (avatar != null) {
            user.setAvatar(avatar.isBlank() ? null : avatar);
        }
        if (gender != null) {
            try {
                user.setGender(DemoUserEntity.Gender.valueOf(gender.toUpperCase()));
            } catch (IllegalArgumentException e) {
                throw new BusinessException(400, "Invalid gender value: " + gender);
            }
        }

        userRepository.save(user);
        return toProfile(user);
    }

    @Transactional
    public void resetPassword(String appId, String userId, String oldPassword, String newPassword) {
        DemoUserEntity user = userRepository.findByAppIdAndUserId(appId, userId)
                .orElseThrow(() -> new BusinessException(404, "User not found"));

        if (!passwordEncoder.matches(oldPassword, user.getPasswordHash())) {
            throw new BusinessException(401, "Old password is incorrect");
        }
        if (newPassword == null || newPassword.length() < 6) {
            throw new BusinessException(400, "New password must be at least 6 characters");
        }

        user.setPasswordHash(passwordEncoder.encode(newPassword));
        userRepository.save(user);
    }

    @Transactional(readOnly = true)
    public List<UserProfile> searchUsers(String appId, String keyword) {
        if (keyword == null || keyword.isBlank()) {
            throw new BusinessException(400, "Search keyword must not be blank");
        }
        return userRepository.searchByKeyword(appId, keyword.trim())
                .stream()
                .map(this::toProfile)
                .toList();
    }

    private UserProfile toProfile(DemoUserEntity user) {
        return new UserProfile(
                user.getAppId(),
                user.getUserId(),
                user.getNickname(),
                user.getAvatar(),
                user.getGender() != null ? user.getGender().name() : DemoUserEntity.Gender.UNKNOWN.name()
        );
    }
}