Process URLs as clickable. Adds BUKKIT-4917

In Minecraft 1.7, URL processing was removed from the client while the
server gained the ability to designate a URL to be launched in response to
clicking text. However, this functionality is not implemented in the
vanilla server. This commit adds that functionality to messages sent to
the client, processing URLs as clickable.

Additionally, char array iteration is replaced with regex.

src/main/java/org/bukkit/craftbukkit/util/CraftChatMessage.java

@@ -3,23 +3,28 @@ package org.bukkit.craftbukkit.util;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
+import net.minecraft.server.ChatClickable;
 import net.minecraft.server.ChatComponentText;
 import net.minecraft.server.ChatModifier;
 import net.minecraft.server.EnumChatFormat;
+import net.minecraft.server.EnumClickAction;
 import net.minecraft.server.IChatBaseComponent;
 
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableMap.Builder;
 
 public final class CraftChatMessage {
-    private static class FromString {
+    private static class StringMessage {
         private static final Map<Character, EnumChatFormat> formatMap;
+        private static final Pattern INCREMENTAL_PATTERN = Pattern.compile("(" + String.valueOf(org.bukkit.ChatColor.COLOR_CHAR) + "[0-9a-fk-or])|(\\n)|(?:(https?://[^ ][^ ]*?)(?=[\\.\\?!,;:]?(?:[ \\n]|$)))", Pattern.CASE_INSENSITIVE);
 
         static {
             Builder<Character, EnumChatFormat> builder = ImmutableMap.builder();
             for (EnumChatFormat format : EnumChatFormat.values()) {
-                builder.put(format.getChar(), format);
+                builder.put(Character.toLowerCase(format.getChar()), format);
             }
             formatMap = builder.build();
         }
@@ -27,25 +32,29 @@ public final class CraftChatMessage {
         private final List<IChatBaseComponent> list = new ArrayList<IChatBaseComponent>();
         private IChatBaseComponent currentChatComponent = new ChatComponentText("");
         private ChatModifier modifier = new ChatModifier();
-        private StringBuilder builder = new StringBuilder();
         private final IChatBaseComponent[] output;
+        private int currentIndex;
+        private final String message;
 
-        private FromString(String message) {
+        private StringMessage(String message) {
+            this.message = message;
             if (message == null) {
                 output = new IChatBaseComponent[] { currentChatComponent };
                 return;
             }
             list.add(currentChatComponent);
 
-            EnumChatFormat format = null;
-
-            for (int i = 0; i < message.length(); i++) {
-                char currentChar = message.charAt(i);
-                if (currentChar == '\u00A7' && (i < (message.length() - 1)) && (format = formatMap.get(message.charAt(i + 1))) != null) {
-                    if (builder.length() > 0) {
-                        appendNewComponent();
-                    }
-
+            Matcher matcher = INCREMENTAL_PATTERN.matcher(message);
+            String match = null;
+            while (matcher.find()) {
+                int groupId = 0;
+                while ((match = matcher.group(++groupId)) == null) {
+                    // NOOP
+                }
+                appendNewComponent(matcher.start(groupId));
+                switch (groupId) {
+                case 1:
+                    EnumChatFormat format = formatMap.get(match.toLowerCase().charAt(1));
                     if (format == EnumChatFormat.RESET) {
                         modifier = new ChatModifier();
                     } else if (format.isFormat()) {
@@ -71,27 +80,31 @@ public final class CraftChatMessage {
                     } else { // Color resets formatting
                         modifier = new ChatModifier().setColor(format);
                     }
-                    i++;
-                } else if (currentChar == '\n') {
-                    if (builder.length() > 0) {
-                        appendNewComponent();
-                    }
+                    break;
+                case 2:
                     currentChatComponent = null;
-                } else {
-                    builder.append(currentChar);
+                    break;
+                case 3:
+                    modifier.a(new ChatClickable(EnumClickAction.OPEN_URL, match)); // Should be setChatClickable
+                    appendNewComponent(matcher.end(groupId));
+                    modifier.a((ChatClickable) null);
                 }
+                currentIndex = matcher.end(groupId);
             }
 
-            if (builder.length() > 0) {
-                appendNewComponent();
+            if (currentIndex < message.length()) {
+                appendNewComponent(message.length());
             }
 
             output = list.toArray(new IChatBaseComponent[0]);
         }
 
-        private void appendNewComponent() {
-            IChatBaseComponent addition = new ChatComponentText(builder.toString()).setChatModifier(modifier);
-            builder = new StringBuilder();
+        private void appendNewComponent(int index) {
+            if (index <= currentIndex) {
+                return;
+            }
+            IChatBaseComponent addition = new ChatComponentText(message.substring(currentIndex, index)).setChatModifier(modifier);
+            currentIndex = index;
             modifier = modifier.clone();
             if (currentChatComponent == null) {
                 currentChatComponent = new ChatComponentText("");
@@ -106,7 +119,7 @@ public final class CraftChatMessage {
     }
 
     public static IChatBaseComponent[] fromString(String message) {
-        return new FromString(message).getOutput();
+        return new StringMessage(message).getOutput();
     }
 
     private CraftChatMessage() {