Reimplement Patcher update checking

Closes: #5

Author: C0D3-M4513R

src/main/java/org/kettingpowered/launcher/KettingLauncher.java

@@ -68,9 +68,8 @@ public class KettingLauncher {
     public void init() throws Exception {
         final String mc_version = MCVersion.getMc(args);
         //This cannot get moved past the ensureOneServerAndUpdate call. 
-        //It will cause the just downloaded server to be removed, which causes issues. 
-        //noinspection ConstantValue
-        if (false) { //todo: patcher update checking
+        //It will cause the just downloaded server to be removed, which causes issues.
+        if (Patcher.checkUpdateNeeded()) {
             if (Main.DEBUG) System.out.println("Patcher needs updating.");
             //prematurely delete files to prevent errors
             FileUtils.deleteDir(KettingFiles.NMS_BASE_DIR);
@@ -147,7 +146,6 @@ else if(versions.size() > 1) {
             }
             serverVersion = parsedServerVersions.get(0);
         }
-        //todo: Server version is populated here. We could theoretically do what used to be the patched invalidation check here. 
         if (args.enableServerUpdator() || needsDownload) {
             final String mc_minecraft_forge = String.format("%s-%s-%s", mc_mmp, serverVersion.t1(), serverVersion.t2());
             final File forgeDir = new File(KettingFiles.KETTINGSERVER_FORGE_DIR,mc_minecraft_forge);
@@ -162,8 +160,12 @@ else if(versions.size() > 1) {
                 final MavenArtifact installerJsonArtifact = new MavenArtifact(KettingConstants.KETTINGSERVER_GROUP, Main.FORGE_SERVER_ARTIFACT_ID, mc_minecraft_forge, Optional.of("installscript"), Optional.of("json"));
                 final MavenArtifact kettingLibsArtifact = new MavenArtifact(KettingConstants.KETTINGSERVER_GROUP, Main.FORGE_SERVER_ARTIFACT_ID, mc_minecraft_forge, Optional.of("ketting-libraries"), Optional.of("txt"));
                 final MavenArtifact universalJarArtifact = new MavenArtifact(KettingConstants.KETTINGSERVER_GROUP, Main.FORGE_SERVER_ARTIFACT_ID, mc_minecraft_forge, Optional.of("universal"), Optional.of("jar"));
-                
-                serverBinPatchesArtifact.downloadDependencyAndHash();
+
+                //noinspection ResultOfMethodCallIgnored
+                KettingFiles.SERVER_LZMA.getParentFile().mkdirs();
+                //noinspection ResultOfMethodCallIgnored
+                KettingFiles.SERVER_LZMA.delete();
+                if (!serverBinPatchesArtifact.downloadDependencyAndHash().renameTo(KettingFiles.SERVER_LZMA)) System.err.println("An error occurred, whilst moving Server Binary Patches to it's correct location. There might be errors Patching!");
                 installerJsonArtifact.downloadDependencyAndHash();
                 kettingLibsArtifact.downloadDependencyAndHash();
                 universalJarArtifact.downloadDependencyAndHash();
@@ -205,7 +207,7 @@ void launch() throws Exception {
         Libraries.downloadMcp();
 
 
-        new Patcher(); //todo: patcher update checking 
+        if (Patcher.checkUpdateNeeded()) new Patcher();
 
         System.out.println("Launching Ketting...");
         final List<String> arg_list = new ArrayList<>(args.args());

src/main/java/org/kettingpowered/launcher/Patcher.java

@@ -11,14 +11,19 @@
 import org.kettingpowered.ketting.internal.KettingFileVersioned;
 import org.kettingpowered.ketting.internal.KettingFiles;
 import org.kettingpowered.launcher.betterui.BetterUI;
+import org.kettingpowered.launcher.internal.utils.Hash;
 import org.kettingpowered.launcher.internal.utils.NetworkUtils;
 import org.kettingpowered.launcher.utils.Processors;
 
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.FileReader;
+import java.io.FileWriter;
 import java.io.IOException;
 import java.io.PrintStream;
+import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -32,7 +37,7 @@ public class Patcher {
     private final PrintStream out = System.out;
     private PrintStream log;
 
-    public Patcher() throws IOException {
+    public Patcher() throws IOException, NoSuchAlgorithmException {
         downloadServer();
         readInstallScript();
         prepareTokens();
@@ -119,7 +124,7 @@ private void prepareTokens() {
         tokens.put("{BINPATCH}", KettingFiles.SERVER_LZMA.getAbsolutePath());
     }
 
-    private void readAndExecuteProcessors() throws IOException {
+    private void readAndExecuteProcessors() throws IOException, NoSuchAlgorithmException {
         final File logFile = KettingFiles.PATCHER_LOGS;
         if (!logFile.exists()) {
             try {
@@ -182,6 +187,43 @@ public void write(int b) {
                 }
             });
         }
+        writeStoredHashes();
+    }
+    private static void writeStoredHashes() throws IOException, NoSuchAlgorithmException {
+        try (BufferedWriter writer = new BufferedWriter(new FileWriter(KettingFiles.STORED_HASHES))){
+            writer
+                    .append("installJson=")
+                    .append(Hash.getHash(KettingFileVersioned.FORGE_INSTALL_JSON, "SHA3-512"))
+                    .append("\nserverLzma=")
+                    .append(Hash.getHash(KettingFiles.SERVER_LZMA, "SHA3-512"))
+                    .append("\nserver=")
+                    .append(Hash.getHash(KettingFileVersioned.SERVER_JAR, "SHA3-512"));
+        }
+    }
+    public static boolean checkUpdateNeeded() {
+        if (!KettingFiles.STORED_HASHES.exists()) return true;
+        try (BufferedReader reader = new BufferedReader(new FileReader(KettingFiles.STORED_HASHES))){
+            return !reader.lines()
+                    .allMatch(string -> {
+                        String[] args = string.split("=");
+                        String value = args[1].trim();
+                        try {
+                            return switch (args[0].trim()) {
+                                case "installJson" ->
+                                        value.equals(Hash.getHash(KettingFileVersioned.FORGE_INSTALL_JSON, "SHA3-512"));
+                                case "serverLzma" ->
+                                        value.equals(Hash.getHash(KettingFiles.SERVER_LZMA, "SHA3-512"));
+                                case "server" ->
+                                    value.equals(Hash.getHash(KettingFileVersioned.SERVER_JAR, "SHA3-512"));
+                                default -> false;
+                            };
+                        } catch (NoSuchAlgorithmException | IOException e) {
+                            return false;
+                        }
+                    });
+        }catch (Exception ignored) {
+            return true;
+        }
     }
 
     private void mute() {

src/main/java/org/kettingpowered/launcher/internal/utils/Hash.java

@@ -1,6 +1,8 @@
 package org.kettingpowered.launcher.internal.utils;
 
 
+import org.kettingpowered.launcher.KettingLauncher;
+
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -21,7 +23,7 @@ public static String getHash(File file, String algorithm) throws NoSuchAlgorithm
     public static String getHash(InputStream stream, String algorithm) throws NoSuchAlgorithmException, IOException {
         MessageDigest digest = MessageDigest.getInstance(algorithm);
 
-        byte[] buffer = new byte[1024];
+        byte[] buffer = new byte[KettingLauncher.BufferSize];
         int total;
         while ((total = stream.read(buffer)) != -1) {
             digest.update(buffer, 0, total);