01. SESSION AUTH

plugins {
    id "java"
    id "org.springframework.boot" version "4.0.3"
    id "io.spring.dependency-management" version "1.1.7"
}

java { toolchain { languageVersion = JavaLanguageVersion.of(21) } }

dependencies {
    implementation "org.springframework.boot:spring-boot-starter-data-jpa"
    implementation "org.springframework.boot:spring-boot-starter-thymeleaf"
    implementation "org.springframework.boot:spring-boot-starter-webmvc"
    implementation "org.springframework.security:spring-security-crypto" // BCrypt만
    developmentOnly "org.springframework.boot:spring-boot-devtools"
    compileOnly "org.projectlombok:lombok"
    runtimeOnly "org.mariadb.jdbc:mariadb-java-client"
    annotationProcessor "org.projectlombok:lombok"
    testImplementation "org.springframework.boot:spring-boot-starter-test"
}

spring.datasource.url=jdbc:mariadb://localhost:3306/boarddb
spring.datasource.username=root
spring.datasource.password=1234
spring.datasource.driver-class-name=org.mariadb.jdbc.Driver

spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.format_sql=true

spring.thymeleaf.cache=false

@Configuration  // 이 클래스가 설정 파일임을 Spring에 알림
public class AppConfig {

    @Bean  // Spring 컨테이너에 BCryptPasswordEncoder 객체를 등록
    public BCryptPasswordEncoder bCryptPasswordEncoder() {
        return new BCryptPasswordEncoder();
    }
    // 이렇게 등록해야 UserService에서 @RequiredArgsConstructor로 주입받을 수 있다
    // 3차에서는 SecurityConfig 안에 @Bean으로 옮겨진다
}

@Service @RequiredArgsConstructor
public class UserService {
    private final UserRepository userRepository;
    private final BCryptPasswordEncoder bCryptPasswordEncoder;

    public void register(UserDto userDto) {
        if (userRepository.existsByUsername(userDto.getUsername()))
            throw new IllegalArgumentException("이미 사용중인 아이디입니다.");
        if (userRepository.existsByNickname(userDto.getNickname()))
            throw new IllegalArgumentException("이미 사용중인 닉네임입니다.");

        User user = new User();
        user.setUsername(userDto.getUsername());
        user.setPassword(bCryptPasswordEncoder.encode(userDto.getPassword()));
        user.setNickname(userDto.getNickname());
        userRepository.save(user);
    }

    // 반환: User 객체 (세션에 저장하기 위해)
    public User login(String username, String password) {
        User user = userRepository.findByUsername(username)
            .orElseThrow(() -> new IllegalArgumentException("아이디 또는 비밀번호가 틀렸습니다."));
        if (!bCryptPasswordEncoder.matches(password, user.getPassword()))
            throw new IllegalArgumentException("아이디 또는 비밀번호가 틀렸습니다.");
        return user; // 2차에서는 JWT 토큰(String)을 반환하게 바뀜
    }
}

@Service @RequiredArgsConstructor
public class BoardService {
    private final BoardRepository boardRepository;

    // 반환: Page<Board> — Entity 그대로 반환 (Thymeleaf는 Entity 직접 사용 가능)
    // 2차에서는 Page<BoardDto>로 바뀜 (React는 JSON 필요)
    public Page<Board> getBoardList(int page) {
        Pageable pageable = PageRequest.of(page, 10, Sort.by("createdAt").descending());
        return boardRepository.findAllByOrderByCreatedAtDesc(pageable);
    }

    public Board getBoard(Long id, User loginUser) {
        Board board = boardRepository.findById(id)
            .orElseThrow(() -> new IllegalArgumentException("없는 게시글입니다."));
        if (loginUser == null || !board.getUser().getId().equals(loginUser.getId()))
            board.setViewCount(board.getViewCount() + 1); // 본인 글 제외 조회수 증가
        boardRepository.save(board);
        return board;
    }

    public void write(BoardDto boardDto, User user) {
        Board board = new Board();
        board.setTitle(boardDto.getTitle());
        board.setContent(boardDto.getContent());
        board.setUser(user);
        boardRepository.save(board);
    }

    @Transactional
    public void update(Long id, BoardDto boardDto, User user) {
        Board board = boardRepository.findById(id)
            .orElseThrow(() -> new IllegalArgumentException("없는 게시글입니다."));
        if (!board.getUser().getId().equals(user.getId()))
            throw new IllegalArgumentException("수정 권한이 없습니다.");
        board.setTitle(boardDto.getTitle()); // 더티체킹으로 자동 UPDATE
        board.setContent(boardDto.getContent());
    }

    @Transactional
    public void delete(Long id, User user) {
        Board board = boardRepository.findById(id)
            .orElseThrow(() -> new IllegalArgumentException("없는 게시글입니다."));
        if (!board.getUser().getId().equals(user.getId()))
            throw new IllegalArgumentException("삭제 권한이 없습니다.");
        boardRepository.delete(board);
    }
}

@Controller @RequiredArgsConstructor   // @Controller → 뷰 이름 반환
@RequestMapping("/user")
public class UserController {
    private final UserService userService;

    @GetMapping("/register")
    public String registerForm() { return "user/register"; }

    @PostMapping("/register")
    public String register(🌸 @ModelAttribute UserDto userDto, RedirectAttributes ra) {
        try {
            userService.register(userDto);
            return "redirect:/user/login";
        } catch (IllegalArgumentException e) {
            ra.addFlashAttribute("error", e.getMessage());
            return "redirect:/user/register";
        }
    }

    @GetMapping("/login")
    public String loginForm() { return "user/login"; }

    @PostMapping("/login")
    public String login(@ModelAttribute UserDto userDto,
                        HttpSession session, RedirectAttributes ra) {
        try {
            User user = userService.login(userDto.getUsername(), userDto.getPassword());
            session.setAttribute("loginUser", user); // 서버 메모리에 저장!
            return "redirect:/board/list";
        } catch (IllegalArgumentException e) {
            ra.addFlashAttribute("error", e.getMessage());
            return "redirect:/user/login";
        }
    }

    @GetMapping("/logout")
    public String logout(HttpSession session) {
        session.invalidate(); // 세션 파기
        return "redirect:/user/login";
    }
}

@Controller @RequiredArgsConstructor
@RequestMapping("/board")
public class BoardController {
    private final BoardService boardService;

    @GetMapping("/list")
    public String list(@RequestParam(defaultValue="0") int page,
                       HttpSession session, Model model) {
        User loginUser = (User) session.getAttribute("loginUser");
        if (loginUser == null) return "redirect:/user/login"; // 반복!
        model.addAttribute("boardList", boardService.getBoardList(page));
        model.addAttribute("currentPage", page);
        return "board/list";
    }

    @GetMapping("/detail/{id}")
    public String detail(@PathVariable Long id, HttpSession session, Model model) {
        User loginUser = (User) session.getAttribute("loginUser");
        if (loginUser == null) return "redirect:/user/login"; // 반복!
        model.addAttribute("board", boardService.getBoard(id, loginUser));
        model.addAttribute("loginUser", loginUser);
        return "board/detail";
    }

    @GetMapping("/write")
    public String writeForm(HttpSession session) {
        if (session.getAttribute("loginUser") == null) return "redirect:/user/login"; // 반복!
        return "board/write";
    }

    @PostMapping("/write")
    public String write(@ModelAttribute BoardDto boardDto, HttpSession session) {
        User loginUser = (User) session.getAttribute("loginUser");
        if (loginUser == null) return "redirect:/user/login"; // 반복!
        boardService.write(boardDto, loginUser);
        return "redirect:/board/list";
    }

    @GetMapping("/edit/{id}")
    public String editForm(@PathVariable Long id, HttpSession session, Model model) {
        User loginUser = (User) session.getAttribute("loginUser");
        if (loginUser == null) return "redirect:/user/login"; // 반복!
        model.addAttribute("board", boardService.getBoard(id, loginUser));
        return "board/edit";
    }

    @PostMapping("/edit/{id}")
    public String edit(@PathVariable Long id, @ModelAttribute BoardDto boardDto,
                       HttpSession session, RedirectAttributes ra) {
        User loginUser = (User) session.getAttribute("loginUser");
        if (loginUser == null) return "redirect:/user/login";
        try {
            boardService.update(id, boardDto, loginUser);
            return "redirect:/board/detail/" + id;
        } catch (IllegalArgumentException e) {
            ra.addFlashAttribute("error", e.getMessage());
            return "redirect:/board/edit/" + id;
        }
    }

    @PostMapping("/delete/{id}")
    public String delete(@PathVariable Long id, HttpSession session) {
        User loginUser = (User) session.getAttribute("loginUser");
        if (loginUser == null) return "redirect:/user/login";
        boardService.delete(id, loginUser);
        return "redirect:/board/list";
    }
}

<html xmlns:th="http://www.thymeleaf.org">
<body>
  <h2>게시판</h2>
  <a th:href="@{/board/write}">글쓰기</a>
  <a th:href="@{/user/logout}">로그아웃</a>
  <table>
    <tr><th>번호</th><th>제목</th><th>작성자</th><th>조회수</th><th>작성일</th></tr>
    <!-- th:each = for-each 반복 -->
    <tr th:each="board : ${boardList.content}">
      <td th:text="${board.id}"></td>
      <td><a th:href="@{/board/detail/{id}(id=${board.id})}"
             th:text="${board.title}"></a></td>
      <td th:text="${board.user.nickname}"></td>
      <td th:text="${board.viewCount}"></td>
      <td th:text="${board.createdAt}"></td>
    </tr>
  </table>
  <!-- 페이징 -->
  <a th:if="${currentPage > 0}"
     th:href="@{/board/list(page=${currentPage-1})}">이전</a>
  <span th:each="i : ${#numbers.sequence(0, boardList.totalPages-1)}">
    <a th:href="@{/board/list(page=${i})}" th:text="${i+1}"></a>
  </span>
  <a th:if="${currentPage < boardList.totalPages-1}"
     th:href="@{/board/list(page=${currentPage+1})}">다음</a>
</body></html>

<html xmlns:th="http://www.thymeleaf.org">
<body>
  <h2 th:text="${board.title}"></h2>
  <p>작성자: <span th:text="${board.user.nickname}"></span></p>
  <p>조회수: <span th:text="${board.viewCount}"></span></p>
  <p th:text="${board.content}"></p>
  <!-- 본인 글일 때만 수정/삭제 버튼 표시 -->
  <th:block th:if="${board.user.id == loginUser.id}">
    <a th:href="@{/board/edit/{id}(id=${board.id})}">수정</a>
    <form th:action="@{/board/delete/{id}(id=${board.id})}" method="post">
      <button type="submit">삭제</button>
    </form>
  </th:block>
  <a th:href="@{/board/list}">목록</a>
</body></html>