Add Did You Mean Suggestion for Mistyped Commands

Author: devBitt

src/main/java/com/mycmd/App.java

@@ -36,6 +36,14 @@ public static void main(String[] args) {
                 }
             } else {
                 System.out.println("'" + cmd + "' is not recognized as an internal or external command.");
+                // Suggest closest command
+                List<String> validCommands = new ArrayList<>(commands.keySet());
+                String suggestion = StringUtils.findClosest(cmd, validCommands);
+                if (suggestion != null && !suggestion.equals(cmd)) {
+                    System.out.println("'" + cmd + "' is not recognized as an internal or external command. Did you mean '" + suggestion + "'?");
+                } else {
+                    System.out.println("'" + cmd + "' is not recognized as an internal or external command.");
+                }
             }
         }
     }

src/main/java/com/mycmd/StringUtils.java

@@ -0,0 +1,37 @@
+package com.mycmd;
+
+import java.util.List;
+
+public class StringUtils {
+    // Compute Levenshtein distance between two strings
+    public static int levenshtein(String a, String b) {
+        int[] costs = new int[b.length() + 1];
+        for (int j = 0; j < costs.length; j++) {
+            costs[j] = j;
+        }
+        for (int i = 1; i <= a.length(); i++) {
+            costs[0] = i;
+            int nw = i - 1;
+            for (int j = 1; j <= b.length(); j++) {
+                int cj = Math.min(1 + Math.min(costs[j], costs[j - 1]), a.charAt(i - 1) == b.charAt(j - 1) ? nw : nw + 1);
+                nw = costs[j];
+                costs[j] = cj;
+            }
+        }
+        return costs[b.length()];
+    }
+
+    // Find the closest string from a list
+    public static String findClosest(String input, List<String> candidates) {
+        String closest = null;
+        int minDist = Integer.MAX_VALUE;
+        for (String candidate : candidates) {
+            int dist = levenshtein(input, candidate);
+            if (dist < minDist) {
+                minDist = dist;
+                closest = candidate;
+            }
+        }
+        return closest;
+    }
+}