SafeFancyMessage.java

package com.supaham.commons.bukkit.text;

import com.google.common.base.Preconditions;

import org.bukkit.ChatColor;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.annotation.Nonnull;

/**
 * Represents a class that transforms a {@link String} into a {@link FancyMessage}. Useful for
 * fixing multicolor lines.
 *
 * @since 0.2.4
 */
public class SafeFancyMessage {

  private String message;
  private FancyMessage fancyMessage;
  private int currentIndex;

  private final Pattern INCREMENTAL_PATTERN = Pattern.compile(
      "(" + ChatColor.COLOR_CHAR +
      "[0-9a-fk-or])|(\\n)|(?:(https?://[^ ][^ ]*?)(?=[\\.\\?!,;:]?(?:[ \\n]|$)))",
      Pattern.CASE_INSENSITIVE
  );

  /**
   * Converts a {@link String} to to {@link FancyMessage} with minecraft json-chat support.
   *
   * @param message message to convert
   *
   * @return fancy message of {@code message}
   */
  public static FancyMessage from(@Nonnull String message) {
    Preconditions.checkNotNull(message, "message cannot be null.");
    FancyMessage fancyMessage = new FancyMessage();
    new SafeFancyMessage(message, fancyMessage);
    return fancyMessage;
  }

  public SafeFancyMessage(String message, FancyMessage fancyMessage) {
    this.message = message;
    this.fancyMessage = fancyMessage;

    Matcher matcher = INCREMENTAL_PATTERN.matcher(message);
    String match;
    while (matcher.find()) {
      int group = 0;
      while ((match = matcher.group(++group)) == null) {
      }
      appendMessage(matcher.start(group));
      switch (group) {
        case 1: // Color/format group
          ChatColor color = ChatColor.getByChar(match.charAt(1));
          if (color.equals(ChatColor.RESET)) {
            fancyMessage.then();
          } else if (color.isFormat()) {
            fancyMessage.then();
            switch (color) {
              case BOLD:
                fancyMessage.style(ChatColor.BOLD);
                break;
              case ITALIC:
                fancyMessage.style(ChatColor.ITALIC);
                break;
              case STRIKETHROUGH:
                fancyMessage.style(ChatColor.STRIKETHROUGH);
                break;
              case UNDERLINE:
                fancyMessage.style(ChatColor.UNDERLINE);
                break;
              case MAGIC:
                fancyMessage.style(ChatColor.MAGIC);
                break;
              default:
                throw new UnsupportedOperationException("Unexpected ChatColor format " + color);
            }
          } else {
            fancyMessage.then().color(color);
          }
          break;
        case 2: // New line
          fancyMessage.then("\n");
          break;
        case 3: // URL
          appendMessage(matcher.end(group));
          fancyMessage.link(match);
      }
      currentIndex = matcher.end(group);
    }

    if (currentIndex < message.length()) {
      appendMessage(message.length());
    }
  }

  private void appendMessage(int index) {
    if (index <= currentIndex) {
      return;
    }

    String message = this.message.substring(currentIndex, index);
    this.currentIndex = index;
    fancyMessage.append(message);
  }
}