From d9c2af035ac2edb68bc8b6a1f94b7c772c3509c8 Mon Sep 17 00:00:00 2001
From: Keuin <keuinx@gmail.com>
Date: Sun, 2 Aug 2020 18:31:50 +0800
Subject: Refactor & object tree impl. stage 1

---
 .../util/backup/BackupNameSuggestionProvider.java  | 77 ++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 src/main/java/com/keuin/kbackupfabric/util/backup/BackupNameSuggestionProvider.java

(limited to 'src/main/java/com/keuin/kbackupfabric/util/backup/BackupNameSuggestionProvider.java')

diff --git a/src/main/java/com/keuin/kbackupfabric/util/backup/BackupNameSuggestionProvider.java b/src/main/java/com/keuin/kbackupfabric/util/backup/BackupNameSuggestionProvider.java
new file mode 100644
index 0000000..4639e99
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/util/backup/BackupNameSuggestionProvider.java
@@ -0,0 +1,77 @@
+package com.keuin.kbackupfabric.util.backup;
+
+import com.mojang.brigadier.suggestion.SuggestionProvider;
+import com.mojang.brigadier.suggestion.Suggestions;
+import com.mojang.brigadier.suggestion.SuggestionsBuilder;
+import net.minecraft.server.command.ServerCommandSource;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+import java.util.concurrent.CompletableFuture;
+
+public class BackupNameSuggestionProvider {
+
+    private static final List<String> candidateCacheList = new ArrayList<>();
+    private static final Object syncSetDirectory = new Object();
+    private static final Object syncCache = new Object();
+    private static final long CACHE_TTL = 8000;
+    private static String backupSaveDirectory;
+    private static long cacheUpdateTime = 0;
+
+    public static void setBackupSaveDirectory(String backupSaveDirectory) {
+        synchronized (syncSetDirectory) {
+            BackupNameSuggestionProvider.backupSaveDirectory = backupSaveDirectory;
+        }
+        // Immediately perform an update
+        updateCandidateList();
+    }
+
+    public static void updateCandidateList() {
+        synchronized (syncCache) {
+            try {
+                File file = new File(backupSaveDirectory);
+                candidateCacheList.clear();
+                File[] files = file.listFiles();
+                if (files == null)
+                    return;
+                for (File f : files)
+                    candidateCacheList.add(BackupFilesystemUtil.getBackupName(f.getName()));
+                cacheUpdateTime = System.currentTimeMillis();
+            } catch (NullPointerException ignored) {
+            }
+        }
+    }
+
+//    private static void updateCandidateList(Collection<String> stringCollection) {
+//        candidateList.clear();
+//        candidateList.addAll(stringCollection);
+//    }
+
+    public static SuggestionProvider<ServerCommandSource> getProvider() {
+        return (context, builder) -> getCompletableFuture(builder);
+    }
+
+    private static CompletableFuture<Suggestions> getCompletableFuture(SuggestionsBuilder builder) {
+        if (isCacheExpired())
+            updateCandidateList();
+        String remaining = builder.getRemaining().toLowerCase(Locale.ROOT);
+        synchronized (syncCache) {
+            if (candidateCacheList.isEmpty()) { // If the list is empty then return no suggestions
+                return Suggestions.empty(); // No suggestions
+            }
+
+            for (String string : candidateCacheList) { // Iterate through the supplied list
+                if (string.toLowerCase(Locale.ROOT).startsWith(remaining)) {
+                    builder.suggest(string); // Add every single entry to suggestions list.
+                }
+            }
+        }
+        return builder.buildFuture(); // Create the CompletableFuture containing all the suggestions
+    }
+
+    private static boolean isCacheExpired() {
+        return System.currentTimeMillis() - cacheUpdateTime > CACHE_TTL || cacheUpdateTime == 0;
+    }
+}
-- 
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