move some logic to MiscU

src/main/java/com/olexyn/burnsmail/MiscU.java

@@ -0,0 +1,49 @@
+package com.olexyn.burnsmail;
+
+import lombok.experimental.UtilityClass;
+
+import javax.mail.Folder;
+import javax.mail.MessagingException;
+import javax.mail.Store;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import static javax.mail.Folder.READ_WRITE;
+
+@UtilityClass
+public class MiscU {
+
+    private static final String EMAIL_REGEX = "\\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\\.[A-Z]{2,6}\\b";
+    private static final Pattern PATTERN = Pattern.compile(EMAIL_REGEX, Pattern.CASE_INSENSITIVE);
+
+    public static String extractEmail(String rawFrom) {
+        Matcher matcher = PATTERN.matcher(rawFrom);
+        if (matcher.find()) {
+            return matcher.group();
+        }
+        return null;
+    }
+
+
+    private static Folder expand(Store store, Folder folder, List<String> folderPath) throws MessagingException {
+        if (folderPath.isEmpty()) {
+            return folder;
+        }
+        if (folder == null) {
+            folder = store.getFolder(folderPath.remove(0));
+        } else {
+            folder = folder.getFolder(folderPath.remove(0));
+        }
+        return expand(store, folder, folderPath);
+
+    }
+
+    public static Folder open(Store store, String folderPath) throws MessagingException {
+        var arrList = new ArrayList<>(List.of(folderPath.split("/")));
+        Folder targetFolder = expand(store, null, arrList);
+        targetFolder.open(READ_WRITE);
+        return targetFolder;
+    }
+}