Separate the long method into smaller one to reduce nested method

Author: Jianwen0451

src/main/java/seedu/address/logic/parser/AutocompleteParser.java

@@ -268,22 +268,32 @@ private ArrayList<String> getAllFilesInArchiveDirectory() {
 
         // Check if the directory exists and is indeed a directory
         if (directory.exists() && directory.isDirectory()) {
-            // List all files and directories in the specified path
-            File[] files = directory.listFiles();
-            assert (files != null);
-            ArrayList<String> result = new ArrayList<>();
-            for (File file : files) {
-                // add file name if it is a json file
-                if (isJson(file)) {
-                    result.add(file.getName());
-                }
-            }
-            return result;
+            // Get all files and directories in the specified path
+            return getAllJsonFiles(directory);
         } else {
+            // Return an empty list if the directory does not exist
             return new ArrayList<>();
         }
     }
 
+    /**
+     * Gets all the json file name from a directory of given Path
+     * @param directory The file path to the directory
+     * @return An array list of all json file name
+     * */
+    private ArrayList<String> getAllJsonFiles(File directory) {
+        File[] files = directory.listFiles();
+        assert (files != null);
+        ArrayList<String> result = new ArrayList<>();
+        for (File file : files) {
+            // add file name if it is a json file
+            if (isJson(file)) {
+                result.add(file.getName());
+            }
+        }
+        return result;
+    }
+
     /**
      * checks if the given file is a json file.
      * @param file the file to check
@@ -292,6 +302,8 @@ private boolean isJson(File file) {
         return file.isFile() && file.getName().toLowerCase().endsWith(".json");
     }
 
+
+
     private String getStringWithPrefix(String word, String command) {
         if (word.length() <= 1) {
             return command;