fix #557: guide permission-driven VPD flow

src/main/java/com/cloudhandson/vpdbackoffice/service/VpdPolicyService.java

@@ -20,6 +20,8 @@ import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 import org.springframework.dao.DataAccessException;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.stereotype.Service;
@@ -32,6 +34,9 @@ public class VpdPolicyService {
   private static final long CATALOG_CACHE_MILLIS = 60_000L;
   private static final String COMMON_POLICY_NAME = "CB_PERMISSION_SELECT_POLICY";
   private static final String DEFAULT_PERMISSION_FILTER_FUNCTION = "CB_AGENT_DOC_VPD_FILTER";
+  private static final Pattern RETURN_LITERAL = Pattern.compile(
+      "(?is)\\bRETURN\\s+'((?:''|[^'])*)'\\s*;"
+  );
 
   private final VpdPolicyMapper mapper;
   private final JdbcTemplate jdbcTemplate;
@@ -94,6 +99,10 @@ public class VpdPolicyService {
     );
   }
 
+  public String currentUser() {
+    return jdbcTemplate.queryForObject("SELECT USER FROM dual", String.class);
+  }
+
   @Transactional
   public void saveFilterFunction(String functionOwnerValue, String functionNameValue, String filterPredicateValue) {
     String functionName = requiredIdentifier(functionNameValue, "Function name");
@@ -275,6 +284,75 @@ public class VpdPolicyService {
     return new VpdPolicyDetail(policy, buildAddPolicyBlock(policy));
   }
 
+  public String findPolicyDescription(String objectOwner, String objectName, String policyName) {
+    String description;
+    try {
+      description = mapper.findPolicyDescription(objectOwner, objectName, policyName);
+    } catch (DataAccessException ignored) {
+      description = null;
+    }
+    return description == null || description.isBlank()
+        ? objectOwner + "." + objectName + "에 요청마다 현재 권한체계의 행 접근 조건을 적용하는 " + policyName + " policy입니다."
+        : description;
+  }
+
+  public String findFilterDescription(String functionOwner, String functionName) {
+    String description;
+    try {
+      description = mapper.findFilterDescription(functionOwner, functionName);
+    } catch (DataAccessException ignored) {
+      description = null;
+    }
+    return description == null || description.isBlank()
+        ? (DEFAULT_PERMISSION_FILTER_FUNCTION.equalsIgnoreCase(functionName)
+            ? "사용자·그룹·역할·TAG 권한을 동적으로 합쳐 VPD predicate를 반환합니다."
+            : "이 Filter function이 반환하는 predicate로 조회 행을 제한합니다.")
+        : description;
+  }
+
+  /**
+   * Returns the literal predicate used by a simple standalone Filter function created by this UI.
+   * Packaged or system-managed functions intentionally return an empty string because their
+   * source is not a single editable literal.
+   */
+  public String findFilterPredicate(String owner, String packageName, String functionName) {
+    if (packageName != null && !packageName.isBlank()
+        || DEFAULT_PERMISSION_FILTER_FUNCTION.equalsIgnoreCase(functionName)) {
+      return "";
+    }
+    try {
+      VpdFunctionSource source = findFunctionSource(owner, null, functionName);
+      if (source.source() == null) {
+        return "";
+      }
+      Matcher matcher = RETURN_LITERAL.matcher(source.source());
+      return matcher.find() ? matcher.group(1).replace("''", "'") : "";
+    } catch (DataAccessException | AppException ignored) {
+      return "";
+    }
+  }
+
+  @Transactional
+  public void savePolicyDescription(String objectOwner, String objectName, String policyName, String description) {
+    String normalized = normalizeDescription(description);
+    mapper.upsertPolicyDescription(
+        requiredIdentifier(objectOwner, "Object owner"),
+        requiredIdentifier(objectName, "Object name"),
+        requiredIdentifier(policyName, "Policy name"),
+        normalized
+    );
+  }
+
+  @Transactional
+  public void saveFilterDescription(String functionOwner, String functionName, String description) {
+    String normalized = normalizeDescription(description);
+    mapper.upsertFilterDescription(
+        requiredIdentifier(functionOwner, "Function owner"),
+        requiredIdentifier(functionName, "Function name"),
+        normalized
+    );
+  }
+
   public VpdObjectFilterDetail findObjectFilterDetail(String objectOwner, String objectName) {
     String normalizedOwner = requiredIdentifier(objectOwner, "Object owner");
     String normalizedObject = requiredIdentifier(objectName, "Object name");
@@ -611,6 +689,17 @@ public class VpdPolicyService {
     return String.join(",", statements);
   }
 
+  private String normalizeDescription(String value) {
+    String normalized = value == null ? "" : value.trim();
+    if (normalized.isBlank()) {
+      throw new AppException("정책/필터 설명은 필수입니다.");
+    }
+    if (normalized.length() > 500) {
+      throw new AppException("정책/필터 설명은 500자 이내여야 합니다.");
+    }
+    return normalized;
+  }
+
   private String escapeSqlLiteral(String value) {
     return value.replace("'", "''");
   }