[FEAT] Google OAuth code 토큰 교환 및 로그인 처리 구현

.gitignore

@@ -39,6 +39,8 @@ out/
 ### environment files ###
 .env
 .env.prod
+load-env.ps1
 
 ### docker test ###
-docker-compose.override.yml
+docker-compose.override.yml
+

load-env.ps1

@@ -0,0 +1,15 @@
+Get-Content ".env" | ForEach-Object {
+    $line = $_.Trim()
+
+    if ($line -eq "" -or $line.StartsWith("#")) {
+        return
+    }
+
+    $name, $value = $line.Split("=", 2)
+
+    if ($name -and $value) {
+        [Environment]::SetEnvironmentVariable($name.Trim(), $value.Trim(), "Process")
+    }
+}
+
+Write-Host "Loaded .env variables into current PowerShell process."

src/main/java/ceos/ipx/IpxBeApplication.java

@@ -5,12 +5,14 @@
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.boot.context.properties.ConfigurationPropertiesScan;
 
 @EnableConfigurationProperties({
 		GoogleOAuthProperties.class,
 		FrontendOAuthProperties.class
 })
 @SpringBootApplication
+@ConfigurationPropertiesScan
 public class IpxBeApplication {
 
 	public static void main(String[] args) {

src/main/java/ceos/ipx/domain/auth/controller/AuthController.java

@@ -26,6 +26,8 @@
 import ceos.ipx.domain.auth.service.GoogleOAuthService;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestParam;
+import ceos.ipx.domain.auth.dto.GoogleOAuthTokenRequest;
+import ceos.ipx.domain.auth.dto.OAuthTokenResponse;
 
 import java.net.URI;
 
@@ -165,4 +167,26 @@ public ResponseEntity<Void> handleGoogleOAuthCallback(
                 .location(URI.create(frontendCallbackUrl))
                 .build();
     }
+
+    @Operation(
+            summary = "Google OAuth code 토큰 교환 및 로그인 처리",
+            description = "FE OAuth Callback 화면에서 받은 Google Authorization Code를 전달받아 Google 사용자 정보를 조회하고, 기존 Google 회원이면 로그인 성공 처리하며 신규 Google 사용자이면 추가 회원가입 필요 상태를 반환합니다."
+    )
+    @ApiResponses({
+            @io.swagger.v3.oas.annotations.responses.ApiResponse(responseCode = "200", description = "Google OAuth 로그인 성공 또는 추가 회원가입 필요"),
+            @io.swagger.v3.oas.annotations.responses.ApiResponse(responseCode = "400", description = "입력값 검증 실패"),
+            @io.swagger.v3.oas.annotations.responses.ApiResponse(responseCode = "403", description = "비활성화된 계정"),
+            @io.swagger.v3.oas.annotations.responses.ApiResponse(responseCode = "409", description = "일반 로그인 계정으로 가입된 이메일"),
+            @io.swagger.v3.oas.annotations.responses.ApiResponse(responseCode = "502", description = "Google 토큰 교환 또는 사용자 정보 조회 실패"),
+            @io.swagger.v3.oas.annotations.responses.ApiResponse(responseCode = "500", description = "서버 내부 오류")
+    })
+    @PostMapping("/oauth/token")
+    public ResponseEntity<ApiResponse<OAuthTokenResponse>> exchangeGoogleOAuthToken(
+            @Valid @RequestBody GoogleOAuthTokenRequest request,
+            HttpServletResponse httpServletResponse
+    ) {
+        OAuthTokenResponse response = authService.exchangeGoogleOAuthToken(request, httpServletResponse);
+
+        return ResponseEntity.ok(ApiResponse.ok(response));
+    }
 }

src/main/java/ceos/ipx/domain/auth/dto/GoogleOAuthTokenRequest.java

@@ -0,0 +1,13 @@
+package ceos.ipx.domain.auth.dto;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import jakarta.validation.constraints.NotBlank;
+
+@Schema(description = "Google OAuth code 토큰 교환 요청")
+public record GoogleOAuthTokenRequest(
+
+        @NotBlank(message = "Google Authorization Code는 필수입니다.")
+        @Schema(description = "Google Authorization Code", example = "4/0AbCdEf...")
+        String code
+) {
+}

src/main/java/ceos/ipx/domain/auth/dto/GoogleTokenResponse.java

@@ -0,0 +1,24 @@
+package ceos.ipx.domain.auth.dto;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public record GoogleTokenResponse(
+
+        @JsonProperty("access_token")
+        String accessToken,
+
+        @JsonProperty("expires_in")
+        Long expiresIn,
+
+        @JsonProperty("refresh_token")
+        String refreshToken,
+
+        String scope,
+
+        @JsonProperty("token_type")
+        String tokenType,
+
+        @JsonProperty("id_token")
+        String idToken
+) {
+}

src/main/java/ceos/ipx/domain/auth/dto/GoogleUserInfoResponse.java

@@ -0,0 +1,9 @@
+package ceos.ipx.domain.auth.dto;
+
+public record GoogleUserInfoResponse(
+        String id,
+        String email,
+        String name,
+        String picture
+) {
+}

src/main/java/ceos/ipx/domain/auth/dto/OAuthLoginStatus.java

@@ -0,0 +1,6 @@
+package ceos.ipx.domain.auth.dto;
+
+public enum OAuthLoginStatus {
+    LOGIN_SUCCESS,
+    NEED_SIGNUP
+}

src/main/java/ceos/ipx/domain/auth/dto/OAuthSignupRequiredResponse.java

@@ -0,0 +1,20 @@
+package ceos.ipx.domain.auth.dto;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+@Schema(description = "OAuth 회원가입 필요 응답")
+public record OAuthSignupRequiredResponse(
+
+        @Schema(description = "OAuth 회원가입 토큰")
+        String oauthSignupToken,
+
+        @Schema(description = "Google 이메일", example = "test@gmail.com")
+        String email,
+
+        @Schema(description = "Google 이름", example = "홍길동")
+        String name,
+
+        @Schema(description = "가입 제공자", example = "GOOGLE")
+        String provider
+) {
+}

src/main/java/ceos/ipx/domain/auth/dto/OAuthTokenResponse.java

@@ -0,0 +1,62 @@
+package ceos.ipx.domain.auth.dto;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+@Schema(description = "OAuth token 교환 결과 응답")
+public record OAuthTokenResponse(
+
+        @Schema(description = "OAuth 로그인 처리 상태", example = "LOGIN_SUCCESS")
+        OAuthLoginStatus status,
+
+        @Schema(description = "JWT AccessToken")
+        String accessToken,
+
+        @Schema(description = "토큰 타입", example = "Bearer")
+        String tokenType,
+
+        @Schema(description = "AccessToken 만료 시간(초)", example = "3600")
+        Long expiresIn,
+
+        @Schema(description = "로그인한 사용자 정보")
+        LoginUserResponse user,
+
+        @Schema(description = "OAuth 회원가입 토큰")
+        String oauthSignupToken,
+
+        @Schema(description = "Google 이메일", example = "test@gmail.com")
+        String email,
+
+        @Schema(description = "Google 이름", example = "홍길동")
+        String name,
+
+        @Schema(description = "가입 제공자", example = "GOOGLE")
+        String provider
+) {
+    public static OAuthTokenResponse loginSuccess(LoginResponse loginResponse) {
+        return new OAuthTokenResponse(
+                OAuthLoginStatus.LOGIN_SUCCESS,
+                loginResponse.accessToken(),
+                loginResponse.tokenType(),
+                loginResponse.expiresIn(),
+                loginResponse.user(),
+                null,
+                null,
+                null,
+                null
+        );
+    }
+
+    public static OAuthTokenResponse needSignup(OAuthSignupRequiredResponse signupResponse) {
+        return new OAuthTokenResponse(
+                OAuthLoginStatus.NEED_SIGNUP,
+                null,
+                null,
+                null,
+                null,
+                signupResponse.oauthSignupToken(),
+                signupResponse.email(),
+                signupResponse.name(),
+                signupResponse.provider()
+        );
+    }
+}

src/main/java/ceos/ipx/domain/auth/service/AuthService.java

@@ -20,7 +20,11 @@
 import ceos.ipx.domain.auth.dto.PasswordResetRequest;
 import ceos.ipx.domain.user.entity.UserProvider;
 import java.util.regex.Pattern;
-
+import ceos.ipx.domain.auth.dto.GoogleOAuthTokenRequest;
+import ceos.ipx.domain.auth.dto.GoogleTokenResponse;
+import ceos.ipx.domain.auth.dto.GoogleUserInfoResponse;
+import ceos.ipx.domain.auth.dto.OAuthSignupRequiredResponse;
+import ceos.ipx.domain.auth.dto.OAuthTokenResponse;
 
 @Service
 @RequiredArgsConstructor
@@ -39,6 +43,8 @@ public class AuthService {
     private final AccessTokenBlacklistService accessTokenBlacklistService;
     private final CookieUtils cookieUtils;
     private final EmailVerificationService emailVerificationService;
+    private final GoogleOAuthClient googleOAuthClient;
+    private final OAuthSignupTokenService oauthSignupTokenService;
 
     @Transactional
     public SignUpResponse signUp(SignUpRequest request) {
@@ -111,6 +117,19 @@ public LoginResponse login(LoginRequest request, HttpServletResponse httpServlet
         );
     }
 
+    @Transactional
+    public OAuthTokenResponse exchangeGoogleOAuthToken(
+            GoogleOAuthTokenRequest request,
+            HttpServletResponse httpServletResponse
+    ) {
+        GoogleTokenResponse googleTokenResponse = googleOAuthClient.exchangeCodeForToken(request.code());
+        GoogleUserInfoResponse googleUserInfo = googleOAuthClient.getUserInfo(googleTokenResponse.accessToken());
+
+        return userRepository.findByEmail(googleUserInfo.email())
+                .map(user -> handleExistingGoogleOAuthUser(user, httpServletResponse))
+                .orElseGet(() -> handleNewGoogleOAuthUser(googleUserInfo));
+    }
+
     public ReissueResponse reissue(String refreshToken, HttpServletResponse httpServletResponse) {
         if (refreshToken == null || refreshToken.isBlank()) {
             throw new BusinessException(ErrorCode.REFRESH_TOKEN_NOT_FOUND);
@@ -176,6 +195,47 @@ public void resetPassword(PasswordResetRequest request) {
         emailVerificationService.deletePasswordResetVerification(request.getVerificationToken(), email);
     }
 
+    private OAuthTokenResponse handleExistingGoogleOAuthUser(
+            User user,
+            HttpServletResponse httpServletResponse
+    ) {
+        if (!user.isActive()) {
+            throw new BusinessException(ErrorCode.INACTIVE_USER);
+        }
+
+        if (user.getProvider() == UserProvider.LOCAL) {
+            throw new BusinessException(ErrorCode.SOCIAL_LOGIN_NOT_ALLOWED);
+        }
+
+        if (user.getProvider() != UserProvider.GOOGLE) {
+            throw new BusinessException(ErrorCode.LOGIN_FAILED);
+        }
+
+        String accessToken = jwtTokenProvider.createAccessToken(user);
+        String refreshToken = jwtTokenProvider.createRefreshToken(user);
+
+        refreshTokenService.saveRefreshToken(
+                user.getId(),
+                refreshToken,
+                jwtTokenProvider.getRefreshTokenExpirationSeconds()
+        );
+
+        cookieUtils.addRefreshTokenCookie(
+                httpServletResponse,
+                refreshToken,
+                jwtTokenProvider.getRefreshTokenExpirationSeconds()
+        );
+
+        LoginResponse loginResponse = new LoginResponse(
+                accessToken,
+                jwtTokenProvider.getTokenType(),
+                jwtTokenProvider.getAccessTokenExpirationSeconds(),
+                LoginUserResponse.from(user)
+        );
+
+        return OAuthTokenResponse.loginSuccess(loginResponse);
+    }
+
     private void validatePasswordResetUser(User user) {
         if (!user.isActive()) {
             throw new BusinessException(ErrorCode.INACTIVE_USER);
@@ -204,6 +264,19 @@ private void validateNewPassword(String newPassword, String newPasswordConfirm,
         }
     }
 
+    private OAuthTokenResponse handleNewGoogleOAuthUser(GoogleUserInfoResponse googleUserInfo) {
+        String oauthSignupToken = oauthSignupTokenService.saveGoogleUserInfo(googleUserInfo);
+
+        OAuthSignupRequiredResponse signupResponse = new OAuthSignupRequiredResponse(
+                oauthSignupToken,
+                googleUserInfo.email(),
+                googleUserInfo.name(),
+                UserProvider.GOOGLE.name()
+        );
+
+        return OAuthTokenResponse.needSignup(signupResponse);
+    }
+
     @Transactional
     public void logout(
             String authorizationHeader,