Create basic outline of command mapper

src/main/java/fr/xephi/authme/command/CommandMapper.java

@@ -0,0 +1,80 @@
+package fr.xephi.authme.command;
+
+import fr.xephi.authme.util.CollectionUtils;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Class responsible for mapping incoming arguments to a {@link CommandDescription}.
+ */
+public class CommandMapper {
+
+    /**
+     * Map incoming command parts to an actual command.
+     *
+     * @param parts The parts to process
+     * @return The generated result
+     */
+    public FoundCommandResult mapPartsToCommand(final List<String> parts) {
+        if (CollectionUtils.isEmpty(parts)) {
+            return null; // TODO pass on the information that the base could not be mapped
+        }
+
+        CommandDescription base = getBaseCommand(parts.get(0));
+        if (base == null) {
+            return null; // TODO Pass on the information that base could not be mapped
+        }
+
+        //List<String> labels = CollectionUtils.getRange(parts, 0, 1);
+        List<String> remaining = parts.subList(1, parts.size());
+
+        // Prefer labels: /register help goes to "Help command", not "Register command" with 'help'
+        CommandDescription childCommand = returnSuitableChild(base, remaining);
+        if (childCommand != null) {
+            // return childcommand: it's valid...
+        }
+
+        // No child command found, check if parent is suitable
+        if (isSuitableArgumentCount(base, remaining.size())) {
+            // return base... it's valid
+        }
+
+        // TODO: We don't have a suitable command for the given parts, so find the most similar one
+        return null;
+
+    }
+
+    private static boolean isSuitableArgumentCount(CommandDescription command, int argumentCount) {
+        int minArgs = CommandUtils.getMinNumberOfArguments(command);
+        int maxArgs = CommandUtils.getMaxNumberOfArguments(command);
+
+        return argumentCount >= minArgs && argumentCount <= maxArgs;
+    }
+
+    // Is the given command a suitable match for the given parts? parts is for example [changepassword, newpw, newpw]
+    public CommandDescription returnSuitableChild(CommandDescription baseCommand, List<String> parts) {
+        // TODO: Validate list + make case-insensitive
+        final String label = parts.get(0).toLowerCase();
+        final int argumentCount = parts.size() - 1;
+
+        List<String> args = parts.subList(1, parts.size());
+        for (CommandDescription child : baseCommand.getChildren()) {
+            if (child.getLabels().contains(label) && isSuitableArgumentCount(child, argumentCount)) {
+                return child;
+            }
+        }
+        return null;
+    }
+
+    public CommandDescription getBaseCommand(String label) {
+        String baseLabel = label.toLowerCase();
+        for (CommandDescription command : CommandInitializer.getBaseCommands()) {
+            if (command.getLabels().contains(baseLabel)) {
+                return command;
+            }
+        }
+        return null;
+    }
+
+}