package de.neitzel.roleplay.business;

import de.neitzel.roleplay.common.CreateUserRequest;
import de.neitzel.roleplay.common.UserSummary;
import de.neitzel.roleplay.data.UserEntity;
import de.neitzel.roleplay.data.UserRepository;

import jakarta.enterprise.context.ApplicationScoped;
import jakarta.inject.Inject;
import jakarta.transaction.Transactional;

import java.util.List;
import java.util.stream.Collectors;

/**
 * Business service for application users. Used by admin-only user management endpoints.
 */
@ApplicationScoped
public class UserService {

    private final UserRepository userRepository;

    @Inject
    public UserService(final UserRepository userRepository) {
        this.userRepository = userRepository;
    }

    /**
     * Returns all users as summaries (no password).
     *
     * @return list of user summaries
     */
    public List<UserSummary> listUsers() {
        return userRepository.listAll().stream()
                .map(UserService::toSummary)
                .collect(Collectors.toList());
    }

    /**
     * Creates a new user with the given username, plain password (hashed with bcrypt), and role.
     *
     * @param request create request (username, password, role)
     * @return the created user summary
     * @throws IllegalArgumentException if username is blank, password is blank, role is invalid, or username already exists
     */
    @Transactional
    public UserSummary createUser(final CreateUserRequest request) {
        String username = request.getUsername();
        String password = request.getPassword();
        String role = request.getRole();
        if (username == null || username.isBlank()) {
            throw new IllegalArgumentException("Username is required");
        }
        if (password == null || password.isBlank()) {
            throw new IllegalArgumentException("Password is required");
        }
        if (role == null || role.isBlank()) {
            throw new IllegalArgumentException("Role is required");
        }
        if (!"admin".equals(role) && !"user".equals(role)) {
            throw new IllegalArgumentException("Role must be 'admin' or 'user'");
        }
        if (userRepository.findByUsername(username) != null) {
            throw new IllegalArgumentException("Username already exists: " + username);
        }
        UserEntity entity = UserEntity.add(username, password, role);
        return toSummary(entity);
    }

    private static UserSummary toSummary(final UserEntity entity) {
        return new UserSummary(entity.getId(), entity.getUsername(), entity.getRole());
    }
}