Improve user interaction.

Code refactor.

10 files changed, 419 insertions, 93 deletions

diff --git a/src/main/java/com/keuin/kbackupfabric/KBCommandsRegister.java b/src/main/java/com/keuin/kbackupfabric/KBCommandsRegister.java
index b9baf44..a27753f 100644
--- a/src/main/java/com/keuin/kbackupfabric/KBCommandsRegister.java
+++ b/src/main/java/com/keuin/kbackupfabric/KBCommandsRegister.java
@@ -1,6 +1,7 @@
 package com.keuin.kbackupfabric;
 
 import com.keuin.kbackupfabric.backup.suggestion.BackupNameSuggestionProvider;
+import com.keuin.kbackupfabric.ui.KBCommands;
 import com.keuin.kbackupfabric.util.PermissionValidator;
 import com.mojang.brigadier.CommandDispatcher;
 import com.mojang.brigadier.arguments.StringArgumentType;
diff --git a/src/main/java/com/keuin/kbackupfabric/KBPluginEvents.java b/src/main/java/com/keuin/kbackupfabric/KBPluginEvents.java
index e1d5cbd..8992d17 100644
--- a/src/main/java/com/keuin/kbackupfabric/KBPluginEvents.java
+++ b/src/main/java/com/keuin/kbackupfabric/KBPluginEvents.java
@@ -4,6 +4,8 @@ import com.keuin.kbackupfabric.backup.BackupFilesystemUtil;
 import com.keuin.kbackupfabric.backup.suggestion.BackupNameSuggestionProvider;
 import com.keuin.kbackupfabric.metadata.BackupMetadata;
 import com.keuin.kbackupfabric.metadata.MetadataHolder;
+import com.keuin.kbackupfabric.ui.KBCommands;
+import com.keuin.kbackupfabric.util.DateUtil;
 import com.keuin.kbackupfabric.util.PrintUtil;
 import net.fabricmc.api.ModInitializer;
 import net.fabricmc.fabric.api.event.server.ServerStartCallback;
@@ -15,8 +17,6 @@ import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.ObjectInputStream;
-import java.text.SimpleDateFormat;
-import java.util.Date;
 
 import static org.apache.commons.io.FileUtils.forceDelete;
 
@@ -39,11 +39,14 @@ public final class KBPluginEvents implements ModInitializer, ServerStartCallback
     public void onStartServer(MinecraftServer server) {
 
         if (!(server instanceof MinecraftDedicatedServer))
-            throw new RuntimeException("KBackup is a server-side-only plugin. Please do not use it in Minecraft client.");
+            throw new RuntimeException("KBackup is a server-side-only plugin. Please do not use it in client-side.");
 
         // Initialize player manager reference
         PrintUtil.setPlayerManager(server.getPlayerManager());
 
+        // Initialize backup manager server reference
+        KBCommands.setServer(server);
+
         // Update backup suggestion list
         BackupNameSuggestionProvider.setBackupSaveDirectory(BackupFilesystemUtil.getBackupSaveDirectory(server).getPath());
 
@@ -64,7 +67,7 @@ public final class KBPluginEvents implements ModInitializer, ServerStartCallback
                 MetadataHolder.setMetadata(metadata);
                 PrintUtil.info("Restored world from a previous backup:");
                 PrintUtil.info("Backup Name: " + metadata.getBackupName());
-                PrintUtil.info("Create Time: " + (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")).format(new Date(metadata.getBackupTime())));
+                PrintUtil.info("Create Time: " + DateUtil.fromEpochMillis(metadata.getBackupTime()));
 
                 // Delete metadata file
                 if (!metadataFile.delete()) {
diff --git a/src/main/java/com/keuin/kbackupfabric/backup/incremental/manager/IncrementalBackupStorageManager.java b/src/main/java/com/keuin/kbackupfabric/backup/incremental/manager/IncrementalBackupStorageManager.java
index ff75d8c..0b15a84 100644
--- a/src/main/java/com/keuin/kbackupfabric/backup/incremental/manager/IncrementalBackupStorageManager.java
+++ b/src/main/java/com/keuin/kbackupfabric/backup/incremental/manager/IncrementalBackupStorageManager.java
@@ -18,6 +18,9 @@ import java.util.logging.Logger;
 
 import static org.apache.commons.io.FileUtils.forceDelete;
 
+/**
+ * Managing the base storing all collection objects.
+ */
 public class IncrementalBackupStorageManager {
 
     private final Path backupStorageBase;
diff --git a/src/main/java/com/keuin/kbackupfabric/ui/BackupInfo.java b/src/main/java/com/keuin/kbackupfabric/ui/BackupInfo.java
new file mode 100644
index 0000000..cf537f9
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/ui/BackupInfo.java
@@ -0,0 +1,34 @@
+package com.keuin.kbackupfabric.ui;
+
+import com.keuin.kbackupfabric.operation.backup.method.ConfiguredBackupMethod;
+import com.keuin.kbackupfabric.util.DateUtil;
+import net.minecraft.server.MinecraftServer;
+
+import java.time.LocalDateTime;
+
+/**
+ * Used in UI part. Holds necessary information for displaying a backup.
+ */
+public interface BackupInfo {
+    String getName();
+
+    LocalDateTime getCreationTime();
+
+    long getSizeBytes();
+
+    String getType();
+
+    default String getCanonicalName() {
+        return getName() + "-" + DateUtil.getString(getCreationTime());
+    }
+
+    ConfiguredBackupMethod createConfiguredBackupMethod(MinecraftServer server);
+
+    /**
+     * This is depreciated. But eliminating all usages needs to refactor the UI code.
+     *
+     * @return the backup file name.
+     */
+    @Deprecated
+    String getBackupFileName();
+}
\ No newline at end of file
diff --git a/src/main/java/com/keuin/kbackupfabric/ui/BackupManager.java b/src/main/java/com/keuin/kbackupfabric/ui/BackupManager.java
new file mode 100644
index 0000000..abd7d5b
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/ui/BackupManager.java
@@ -0,0 +1,64 @@
+package com.keuin.kbackupfabric.ui;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Iterator;
+
+/**
+ * Holding all types of backups for the user interaction logic.
+ */
+public class BackupManager {
+
+    private final File backupStorageDirectory;
+
+    public BackupManager(File backupStorageDirectory) {
+        this.backupStorageDirectory = backupStorageDirectory;
+    }
+
+    public BackupManager(String backupStorageDirectory) {
+        this.backupStorageDirectory = new File(backupStorageDirectory);
+    }
+
+    /**
+     * Get available backups in the disk.
+     *
+     * @return all backups.
+     */
+    public Iterable<BackupInfo> getAllBackups() {
+        return new Iterable<BackupInfo>() {
+            @NotNull
+            @Override
+            public Iterator<BackupInfo> iterator() {
+                return new Iterator<BackupInfo>() {
+                    private final Iterator<File> fileIterator = Arrays.stream(backupStorageDirectory.listFiles()).filter(file -> {
+                        String name = file.getName().toLowerCase();
+                        return name.endsWith(".zip") || name.endsWith(".kbi");
+                    }).iterator();
+
+                    @Override
+                    public boolean hasNext() {
+                        return fileIterator.hasNext();
+                    }
+
+                    @Override
+                    public BackupInfo next() {
+                        try {
+                            File backupFile = fileIterator.next();
+                            String fileName = backupFile.getName().toLowerCase();
+                            if (fileName.endsWith(".zip"))
+                                return PrimitiveBackupInfo.fromFile(backupFile);
+                            if (fileName.endsWith(".kbi"))
+                                return IncrementalBackupInfo.fromFile(backupFile);
+                            throw new RuntimeException("Invalid backup file extname");
+                        } catch (IOException e) {
+                            throw new RuntimeException(e);
+                        }
+                    }
+                };
+            }
+        };
+    }
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/ui/IncrementalBackupInfo.java b/src/main/java/com/keuin/kbackupfabric/ui/IncrementalBackupInfo.java
new file mode 100644
index 0000000..89d7fbf
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/ui/IncrementalBackupInfo.java
@@ -0,0 +1,68 @@
+package com.keuin.kbackupfabric.ui;
+
+import com.keuin.kbackupfabric.backup.incremental.serializer.IncBackupInfoSerializer;
+import com.keuin.kbackupfabric.backup.incremental.serializer.SavedIncrementalBackup;
+import com.keuin.kbackupfabric.operation.backup.method.ConfiguredBackupMethod;
+import net.minecraft.server.MinecraftServer;
+
+import java.io.File;
+import java.io.IOException;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+
+/**
+ * Used in UI part.
+ */
+public class IncrementalBackupInfo implements BackupInfo {
+    private final String name;
+    private final LocalDateTime creationTime;
+    private final long sizeBytes;
+    private final String fileName;
+
+    private IncrementalBackupInfo(String name, LocalDateTime creationTime, long sizeBytes, String fileName) {
+        this.name = name;
+        this.creationTime = creationTime;
+        this.sizeBytes = sizeBytes;
+        this.fileName = fileName;
+    }
+
+    public static IncrementalBackupInfo fromFile(File indexFile) throws IOException {
+        SavedIncrementalBackup info = IncBackupInfoSerializer.fromFile(indexFile);
+        return new IncrementalBackupInfo(
+                info.getBackupName(),
+                info.getBackupTime().withZoneSameInstant(ZoneId.systemDefault()).toLocalDateTime(),
+                info.getTotalSizeBytes(),
+                indexFile.getName()
+        );
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public LocalDateTime getCreationTime() {
+        return creationTime;
+    }
+
+    @Override
+    public long getSizeBytes() {
+        return sizeBytes;
+    }
+
+    @Override
+    public String getType() {
+        return "Incremental";
+    }
+
+    @Override
+    public ConfiguredBackupMethod createConfiguredBackupMethod(MinecraftServer server) {
+        throw new RuntimeException("not implemented");
+    }
+
+    @Override
+    public String getBackupFileName() {
+        return fileName;
+    }
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/KBCommands.java b/src/main/java/com/keuin/kbackupfabric/ui/KBCommands.java
index fe5ea7f..87f667d 100644
--- a/src/main/java/com/keuin/kbackupfabric/KBCommands.java
+++ b/src/main/java/com/keuin/kbackupfabric/ui/KBCommands.java
@@ -1,8 +1,6 @@
-package com.keuin.kbackupfabric;
+package com.keuin.kbackupfabric.ui;
 
 import com.keuin.kbackupfabric.backup.BackupFilesystemUtil;
-import com.keuin.kbackupfabric.backup.incremental.serializer.IncBackupInfoSerializer;
-import com.keuin.kbackupfabric.backup.incremental.serializer.SavedIncrementalBackup;
 import com.keuin.kbackupfabric.backup.name.IncrementalBackupFileNameEncoder;
 import com.keuin.kbackupfabric.backup.name.PrimitiveBackupFileNameEncoder;
 import com.keuin.kbackupfabric.backup.suggestion.BackupNameSuggestionProvider;
@@ -21,14 +19,11 @@ import com.mojang.brigadier.context.CommandContext;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.command.ServerCommandSource;
 
-import java.io.File;
 import java.io.IOException;
 import java.time.LocalDateTime;
 import java.util.ArrayList;
-import java.util.Arrays;
+import java.util.Comparator;
 import java.util.List;
-import java.util.Objects;
-import java.util.function.Function;
 
 import static com.keuin.kbackupfabric.backup.BackupFilesystemUtil.*;
 import static com.keuin.kbackupfabric.util.PrintUtil.*;
@@ -41,12 +36,35 @@ public final class KBCommands {
     private static final String DEFAULT_BACKUP_NAME = "noname";
     private static boolean notifiedPreviousRestoration = false;
 
+    // don't access it directly
+    private static MinecraftServer server;
+    private static BackupManager backupManager;
+    private static final Object managerCreatorLock = new Object();
+
     //private static final Logger LOGGER = LogManager.getLogger();
 
-    private static final List<String> backupFileNameList = new ArrayList<>(); // index -> backupName
+    private static final List<BackupInfo> backupList = new ArrayList<>(); // index -> backupName
     private static Invokable pendingOperation = null;
     //private static BackupMethod activatedBackupMethod = new PrimitiveBackupMethod(); // The backup method we currently using
 
+    public static void setServer(MinecraftServer server) {
+        KBCommands.server = server;
+    }
+
+    private static MinecraftServer getServer() {
+        if (server != null)
+            return server;
+        throw new IllegalStateException("server is not initialized.");
+    }
+
+    private static BackupManager getBackupManager() {
+        synchronized (managerCreatorLock) {
+            if (backupManager == null)
+                backupManager = new BackupManager(getBackupSaveDirectory(getServer()));
+            return backupManager;
+        }
+    }
+
     /**
      * Print the help menu.
      *
@@ -75,11 +93,24 @@ public final class KBCommands {
         if (MetadataHolder.hasMetadata() && !notifiedPreviousRestoration) {
             // Output metadata info
             notifiedPreviousRestoration = true;
-            msgStress(context, "Restored from backup " + MetadataHolder.getMetadata().getBackupName());
+            msgStress(context, "Restored from backup "
+                    + MetadataHolder.getMetadata().getBackupName() + " (created at " +
+                    DateUtil.fromEpochMillis(MetadataHolder.getMetadata().getBackupTime())
+                    + ")");
         }
         return statCode;
     }
 
+    private static void updateBackupList() {
+        synchronized (backupList) {
+            backupList.clear();
+            List<BackupInfo> list = new ArrayList<>();
+            getBackupManager().getAllBackups().forEach(list::add);
+            list.sort(Comparator.comparing(BackupInfo::getCreationTime).reversed());
+            backupList.addAll(list);
+        }
+    }
+
     /**
      * List all existing backups.
      *
@@ -91,47 +122,73 @@ public final class KBCommands {
         //       that's enough.
         // TODO: Show real name and size and etc info for incremental backup
         // TODO: Show concrete info from metadata for `.zip` backup
-        MinecraftServer server = context.getSource().getMinecraftServer();
+//        MinecraftServer server = context.getSource().getMinecraftServer();
         // TODO: refactor this to use {@link ObjectCollectionSerializer#fromDirectory}
-        File[] files = getBackupSaveDirectory(server).listFiles(
-                (dir, name) -> dir.isDirectory() &&
-                        (name.toLowerCase().endsWith(".zip") && name.toLowerCase().startsWith(getBackupFileNamePrefix())
-                                || name.toLowerCase().endsWith(".kbi"))
-        );
-
-        Function<File, String> backupInformationProvider = file -> {
-            Objects.requireNonNull(file);
-            if (file.getName().toLowerCase().endsWith(".zip"))
-                return getPrimitiveBackupInformationString(file.getName(), file.length());
-                // TODO: refactor this to use {@link ObjectCollectionSerializer#fromDirectory}
-            else if (file.getName().toLowerCase().endsWith(".kbi"))
-                return getIncrementalBackupInformationString(file);
-            return file.getName();
-        };
-
-        synchronized (backupFileNameList) {
-            backupFileNameList.clear();
-            if (files != null) {
-                if (files.length != 0) {
-                    msgInfo(context, "Available backups: (file is not checked, manipulation may affect this plugin)");
-                } else {
-                    msgInfo(context, "There are no available backups. To make a new backup, run /kb backup.");
-                }
-                int i = 0;
-                for (File file : files) {
-                    ++i;
-                    String backupFileName = file.getName();
-                    msgInfo(context, String.format("[%d] %s", i, backupInformationProvider.apply(file)));
-                    backupFileNameList.add(backupFileName);
-                }
-            } else {
-                msgErr(context, "Error: failed to list files in backup folder.");
+//        File[] files = getBackupSaveDirectory(server).listFiles(
+//                (dir, name) -> dir.isDirectory() &&
+//                        (name.toLowerCase().endsWith(".zip") && name.toLowerCase().startsWith(getBackupFileNamePrefix())
+//                                || name.toLowerCase().endsWith(".kbi"))
+//        );
+
+//        Function<File, String> backupInformationProvider = file -> {
+//            Objects.requireNonNull(file);
+//            if (file.getName().toLowerCase().endsWith(".zip"))
+//                return getPrimitiveBackupInformationString(file.getName(), file.length());
+//                // TODO: refactor this to use {@link ObjectCollectionSerializer#fromDirectory}
+//            else if (file.getName().toLowerCase().endsWith(".kbi"))
+//                return getIncrementalBackupInformationString(file);
+//            return file.getName();
+//        };
+
+        updateBackupList();
+        synchronized (backupList) {
+            if (backupList.isEmpty())
+                msgInfo(context, "There is no backup available. To make a new backup, use `/kb backup`.");
+            else
+                msgInfo(context, "Available backups:");
+            for (int i = backupList.size() - 1; i >= 0; --i) {
+                BackupInfo info = backupList.get(i);
+                printBackupInfo(context, info, i);
             }
+//            if (files != null) {
+//                if (files.length != 0) {
+//                    msgInfo(context, "Available backups: (file is not checked, manipulation may affect this plugin)");
+//                } else {
+//                    msgInfo(context, "There are no available backups. To make a new backup, run /kb backup.");
+//                }
+//                int i = 0;
+//                for (File file : files) {
+//                    ++i;
+//                    String backupFileName = file.getName();
+//                    msgInfo(context, String.format("[%d] %s", i, backupInformationProvider.apply(file)));
+//                    backupFileNameList.add(backupFileName);
+//                }
+//            } else {
+//                msgErr(context, "Error: failed to list files in backup folder.");
+//            }
         }
         return SUCCESS;
     }
 
     /**
+     * Print backup information.
+     *
+     * @param context the context.
+     * @param info    the info.
+     * @param i       the index, starting from 0.
+     */
+    private static void printBackupInfo(CommandContext<ServerCommandSource> context, BackupInfo info, int i) {
+        msgInfo(context, String.format(
+                "[%d] (%s) %s (%s) %s",
+                i + 1,
+                info.getType(),
+                info.getName(),
+                DateUtil.getPrettyString(info.getCreationTime()),
+                (info.getSizeBytes() > 0) ? BackupFilesystemUtil.getFriendlyFileSizeString(info.getSizeBytes()) : ""
+        ));
+    }
+
+    /**
      * Backup with context parameter backupName.
      *
      * @param context the context.
@@ -245,7 +302,6 @@ public final class KBCommands {
 
             // Detect backup type
 
-
             // Update pending task
             //pendingOperation = AbstractConfirmableOperation.createRestoreOperation(context, backupName);
 //        File backupFile = new File(getBackupSaveDirectory(server), getBackupFileName(backupName));
@@ -365,29 +421,32 @@ public final class KBCommands {
         // FIXME: This breaks after adding incremental backup
         try {
             // List all backups
-            MinecraftServer server = context.getSource().getMinecraftServer();
-            List<File> files = Arrays.asList(Objects.requireNonNull(getBackupSaveDirectory(server).listFiles()));
-            files.removeIf(f -> !f.getName().startsWith(BackupFilesystemUtil.getBackupFileNamePrefix()));
-            files.sort((x, y) -> (int) (BackupFilesystemUtil.getBackupTimeFromBackupFileName(y.getName()) - BackupFilesystemUtil.getBackupTimeFromBackupFileName(x.getName())));
-            File prevBackupFile = files.get(0);
-            String backupFileName = prevBackupFile.getName();
-            int i;
-            synchronized (backupFileNameList) {
-                i = backupFileNameList.indexOf(backupFileName);
-                if (i == -1) {
-                    backupFileNameList.add(backupFileName);
-                    i = backupFileNameList.size();
+            updateBackupList();
+//            MinecraftServer server = context.getSource().getMinecraftServer();
+//            List<File> files = Arrays.asList(Objects.requireNonNull(getBackupSaveDirectory(server).listFiles()));
+//            files.removeIf(f -> !f.getName().startsWith(BackupFilesystemUtil.getBackupFileNamePrefix()));
+//            files.sort((x, y) -> (int) (BackupFilesystemUtil.getBackupTimeFromBackupFileName(y.getName()) - BackupFilesystemUtil.getBackupTimeFromBackupFileName(x.getName())));
+//            File prevBackupFile = files.get(0);
+//            String backupFileName = prevBackupFile.getName();
+//            int i;
+//            synchronized (backupList) {
+//                i = backupList.indexOf(backupFileName);
+//                if (i == -1) {
+//                    backupList.add(backupFileName);
+//                    i = backupList.size();
+//                } else {
+//                    ++i;
+//                }
+//            }
+            synchronized (backupList) {
+                if (!backupList.isEmpty()) {
+                    BackupInfo info = backupList.get(0);
+                    msgInfo(context, "The most recent backup:");
+                    printBackupInfo(context, info, 0);
                 } else {
-                    ++i;
+                    msgInfo(context, "There is no backup available.");
                 }
             }
-            msgInfo(context, String.format(
-                    "The most recent backup: [%d] %s",
-                    i,
-                    getPrimitiveBackupInformationString(backupFileName, prevBackupFile.length())
-            ));
-        } catch (NullPointerException e) {
-            msgInfo(context, "There are no backups available.");
         } catch (SecurityException ignored) {
             msgErr(context, "Failed to read file.");
             return FAILED;
@@ -395,26 +454,26 @@ public final class KBCommands {
         return SUCCESS;
     }
 
-    private static String getPrimitiveBackupInformationString(String backupFileName, long backupFileSizeBytes) {
-        return String.format(
-                "(ZIP) %s , size: %s",
-                PrimitiveBackupFileNameEncoder.INSTANCE.decode(backupFileName),
-                getFriendlyFileSizeString(backupFileSizeBytes)
-        );
-    }
+//    private static String getPrimitiveBackupInformationString(String backupFileName, long backupFileSizeBytes) {
+//        return String.format(
+//                "(ZIP) %s , size: %s",
+//                PrimitiveBackupFileNameEncoder.INSTANCE.decode(backupFileName),
+//                getFriendlyFileSizeString(backupFileSizeBytes)
+//        );
+//    }
 
-    private static String getIncrementalBackupInformationString(File backupFile) {
-        try {
-            SavedIncrementalBackup info = IncBackupInfoSerializer.fromFile(backupFile);
-            return "(Incremental) " + info.getBackupName()
-                    + ", " + DateUtil.getString(info.getBackupTime())
-                    + ((info.getTotalSizeBytes() > 0) ?
-                    (" size: " + BackupFilesystemUtil.getFriendlyFileSizeString(info.getTotalSizeBytes())) : "");
-        } catch (IOException e) {
-            e.printStackTrace();
-            return "(Incremental) " + backupFile.getName();
-        }
-    }
+//    private static String getIncrementalBackupInformationString(File backupFile) {
+//        try {
+//            SavedIncrementalBackup info = IncBackupInfoSerializer.fromFile(backupFile);
+//            return "(Incremental) " + info.getBackupName()
+//                    + ", " + DateUtil.getString(info.getBackupTime())
+//                    + ((info.getTotalSizeBytes() > 0) ?
+//                    (" size: " + BackupFilesystemUtil.getFriendlyFileSizeString(info.getTotalSizeBytes())) : "");
+//        } catch (IOException e) {
+//            e.printStackTrace();
+//            return "(Incremental) " + backupFile.getName();
+//        }
+//    }
 
 //    /**
 //     * Select the backup method we use.
@@ -444,8 +503,8 @@ public final class KBCommands {
             if (backupName.matches("[0-9]*")) {
                 // If numeric input
                 int index = Integer.parseInt(backupName) - 1;
-                synchronized (backupFileNameList) {
-                    return backupFileNameList.get(index); // Replace input number with real backup file name.
+                synchronized (backupList) {
+                    return backupList.get(index).getBackupFileName(); // Replace input number with real backup file name.
                 }
             }
         } catch (NumberFormatException | IndexOutOfBoundsException ignored) {
diff --git a/src/main/java/com/keuin/kbackupfabric/ui/PrimitiveBackupInfo.java b/src/main/java/com/keuin/kbackupfabric/ui/PrimitiveBackupInfo.java
new file mode 100644
index 0000000..8cca8d2
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/ui/PrimitiveBackupInfo.java
@@ -0,0 +1,78 @@
+package com.keuin.kbackupfabric.ui;
+
+import com.keuin.kbackupfabric.backup.name.BackupFileNameEncoder;
+import com.keuin.kbackupfabric.backup.name.PrimitiveBackupFileNameEncoder;
+import com.keuin.kbackupfabric.operation.backup.method.ConfiguredBackupMethod;
+import com.keuin.kbackupfabric.util.FilesystemUtil;
+import net.minecraft.server.MinecraftServer;
+
+import java.io.File;
+import java.time.LocalDateTime;
+
+/**
+ * Used in UI part.
+ */
+public class PrimitiveBackupInfo implements BackupInfo {
+    private final String name;
+    private final LocalDateTime creationTime;
+    private final long sizeBytes;
+    private final String fileName;
+
+    @Deprecated
+    private PrimitiveBackupInfo(String name, LocalDateTime creationTime, long sizeBytes) {
+        this.name = name;
+        this.creationTime = creationTime;
+        this.sizeBytes = sizeBytes;
+        this.fileName = PrimitiveBackupFileNameEncoder.INSTANCE.encode(name, creationTime);
+    }
+
+    private PrimitiveBackupInfo(String fileName, long sizeBytes) {
+        this.fileName = fileName;
+        BackupFileNameEncoder.BackupBasicInformation info = PrimitiveBackupFileNameEncoder.INSTANCE.decode(fileName);
+        if (info == null)
+            throw new IllegalArgumentException("Invalid file name.");
+        this.name = info.customName;
+        this.creationTime = info.time;
+        this.sizeBytes = sizeBytes;
+    }
+
+    public static PrimitiveBackupInfo fromFile(File zipFile) {
+        // TODO: fix this, use metadata file instead
+//        fileName = zipFile.getName();
+//        BackupFileNameEncoder.BackupBasicInformation info = PrimitiveBackupFileNameEncoder.INSTANCE.decode(fileName);
+//        if (info == null)
+//            throw new IllegalArgumentException("Invalid file name.");
+//        return new PrimitiveBackupInfo(info.customName, info.time, FilesystemUtil.getFileSizeBytes(zipFile));
+        return new PrimitiveBackupInfo(zipFile.getName(), FilesystemUtil.getFileSizeBytes(zipFile));
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public LocalDateTime getCreationTime() {
+        return creationTime;
+    }
+
+    @Override
+    public long getSizeBytes() {
+        return sizeBytes;
+    }
+
+    @Override
+    public String getType() {
+        return "ZIP";
+    }
+
+    @Override
+    public ConfiguredBackupMethod createConfiguredBackupMethod(MinecraftServer server) {
+        throw new RuntimeException("not implemented");
+    }
+
+    @Override
+    public String getBackupFileName() {
+        return null;
+    }
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/util/DateUtil.java b/src/main/java/com/keuin/kbackupfabric/util/DateUtil.java
index b101cfd..7111347 100644
--- a/src/main/java/com/keuin/kbackupfabric/util/DateUtil.java
+++ b/src/main/java/com/keuin/kbackupfabric/util/DateUtil.java
@@ -1,13 +1,18 @@
 package com.keuin.kbackupfabric.util;
 
+import java.text.SimpleDateFormat;
 import java.time.LocalDateTime;
 import java.time.ZoneId;
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
 import java.time.format.DateTimeFormatter;
+import java.util.Date;
 
 public class DateUtil {
+
     private static final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd_HH-mm-ss");
+    private static final SimpleDateFormat outFormatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+    private static final DateTimeFormatter prettyFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
 
     public static String getString(LocalDateTime localDateTime) {
         return localDateTime.format(formatter);
@@ -28,4 +33,12 @@ public class DateUtil {
     public static LocalDateTime toLocalDateTime(String timeString) {
         return LocalDateTime.parse(timeString, formatter);
     }
+
+    public static String fromEpochMillis(long epochMillis) {
+        return outFormatter.format(new Date(epochMillis));
+    }
+
+    public static String getPrettyString(LocalDateTime localDateTime) {
+        return prettyFormatter.format(localDateTime);
+    }
 }
diff --git a/src/main/java/com/keuin/kbackupfabric/util/FilesystemUtil.java b/src/main/java/com/keuin/kbackupfabric/util/FilesystemUtil.java
index f245cff..bccd403 100644
--- a/src/main/java/com/keuin/kbackupfabric/util/FilesystemUtil.java
+++ b/src/main/java/com/keuin/kbackupfabric/util/FilesystemUtil.java
@@ -15,19 +15,22 @@ public class FilesystemUtil {
      */
     public static long getFileSizeBytes(String parentDirectory, String fileName) {
         long fileSize = -1;
-        try{
+        try {
             File backupZipFile = new File(parentDirectory, fileName);
             fileSize = backupZipFile.length();
-        } catch (SecurityException ignored){
+        } catch (SecurityException ignored) {
         }
         return fileSize;
     }
 
     public static long getFileSizeBytes(String filePath) {
+        return getFileSizeBytes(new File(filePath));
+    }
+
+    public static long getFileSizeBytes(File file) {
         long fileSize = -1;
         try {
-            File backupZipFile = new File(filePath);
-            fileSize = backupZipFile.length();
+            fileSize = file.length();
         } catch (SecurityException ignored) {
         }
         return fileSize;