Fix suggestion argument splitting

Author: vaperion

bukkit/src/main/java/me/vaperion/blade/bukkit/container/BukkitContainer.java

@@ -394,10 +394,10 @@ public void tabComplete(@NotNull CommandSender sender,
             if (!node.isStub()) {
                 // Found exact command, we can suggest arguments here.
 
-                String[] args = removePrefix(
+                String[] args = splitSuggestionArguments(removePrefix(
                     removeCommandQualifier(commandLine),
                     node.matchedLabelOr("")
-                ).split(" ");
+                ));
 
                 if (!platformTypes.contains(SuggestionType.ARGUMENTS)) {
                     // Platform doesn't support argument suggestions.
@@ -428,7 +428,7 @@ public void tabComplete(@NotNull CommandSender sender,
                 return;
             }
 
-            String[] args = removeCommandQualifier(commandLine).split(" ");
+            String[] args = splitSuggestionArguments(removeCommandQualifier(commandLine));
 
             Context context = new Context(
                 blade,

core/src/main/java/me/vaperion/blade/util/BladeHelper.java

@@ -119,6 +119,23 @@ static String mergeLabelWithArgs(@NotNull String label,
             : label + " " + args;
     }
 
+    @NotNull
+    static String[] splitSuggestionArguments(@NotNull String input) {
+        int start = 0;
+
+        while (start < input.length() && input.charAt(start) == ' ') {
+            start++;
+        }
+
+        input = input.substring(start);
+
+        if (input.isEmpty()) {
+            return new String[]{ "" };
+        }
+
+        return input.split(" ", -1);
+    }
+
     @NotNull
     static String removePrefix(@NotNull String input,
                                @NotNull String prefix) {

core/src/test/java/me/vaperion/blade/BladeHelperTest.java

@@ -0,0 +1,38 @@
+package me.vaperion.blade;
+
+import me.vaperion.blade.util.BladeHelper;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class BladeHelperTest {
+
+    @Test
+    public void suggestionArgumentsPreserveTrailingEmptyArgument() {
+        Assertions.assertArrayEquals(
+            new String[]{ "server", "" },
+            BladeHelper.splitSuggestionArguments("server ")
+        );
+    }
+
+    @Test
+    public void suggestionArgumentsPreserveEmptyArgument() {
+        Assertions.assertArrayEquals(
+            new String[]{ "" },
+            BladeHelper.splitSuggestionArguments("")
+        );
+
+        Assertions.assertArrayEquals(
+            new String[]{ "" },
+            BladeHelper.splitSuggestionArguments(" ")
+        );
+    }
+
+    @Test
+    public void suggestionArgumentsIgnoreLeadingSeparatorFromRemovedLabel() {
+        Assertions.assertArrayEquals(
+            new String[]{ "remove" },
+            BladeHelper.splitSuggestionArguments(" remove")
+        );
+    }
+
+}

fabric-legacy/src/main/java/me/vaperion/blade/fabric/container/FabricContainer.java

@@ -249,10 +249,10 @@ public void suggest(@NotNull CommandContext<CommandSourceStack> ctx,
             if (!node.isStub()) {
                 // Found exact command, we can suggest arguments here.
 
-                String[] args = removePrefix(
+                String[] args = splitSuggestionArguments(removePrefix(
                     removeCommandQualifier(ctx.getInput()),
                     node.matchedLabelOr("")
-                ).split(" ");
+                ));
 
                 Context context = new Context(
                     blade,
@@ -273,7 +273,7 @@ public void suggest(@NotNull CommandContext<CommandSourceStack> ctx,
 
             // Only found command stub - suggest subcommands.
 
-            String[] args = removeCommandQualifier(ctx.getInput()).split(" ");
+            String[] args = splitSuggestionArguments(removeCommandQualifier(ctx.getInput()));
 
             Context context = new Context(
                 blade,

fabric/src/main/java/me/vaperion/blade/fabric/container/FabricContainer.java

@@ -249,10 +249,10 @@ public void suggest(@NotNull CommandContext<CommandSourceStack> ctx,
             if (!node.isStub()) {
                 // Found exact command, we can suggest arguments here.
 
-                String[] args = removePrefix(
+                String[] args = splitSuggestionArguments(removePrefix(
                     removeCommandQualifier(ctx.getInput()),
                     node.matchedLabelOr("")
-                ).split(" ");
+                ));
 
                 Context context = new Context(
                     blade,
@@ -273,7 +273,7 @@ public void suggest(@NotNull CommandContext<CommandSourceStack> ctx,
 
             // Only found command stub - suggest subcommands.
 
-            String[] args = removeCommandQualifier(ctx.getInput()).split(" ");
+            String[] args = splitSuggestionArguments(removeCommandQualifier(ctx.getInput()));
 
             Context context = new Context(
                 blade,

minestom/src/main/java/me/vaperion/blade/minestom/container/MinestomContainer.java

@@ -372,14 +372,4 @@ private String normalizeCompletionInput(@NotNull String input) {
         return input.replace(MINESTOM_COMPLETION_PLACEHOLDER, ' ');
     }
 
-    @NotNull
-    private String[] splitSuggestionArguments(@NotNull String input) {
-        input = input.stripLeading();
-
-        if (input.isEmpty()) {
-            return new String[0];
-        }
-
-        return input.split(" ", -1);
-    }
 }

velocity/src/main/java/me/vaperion/blade/velocity/container/VelocityContainer.java

@@ -232,7 +232,7 @@ public void execute(Invocation invocation) {
     @Override
     public List<String> suggest(Invocation invocation) {
         CommandSource sender = invocation.source();
-        String[] args = invocation.arguments().split(" ");
+        String[] args = splitSuggestionArguments(invocation.arguments());
         String label = invocation.alias();
 
         if (!blade.configuration().tabCompleter().isDefault())