根据限制分割消息

/*
 * 思路：
 * 使用Java Stream API，我们可以利用相同的逻辑来实现分割，但通过流处理来简化部分逻辑。
 * 同样的，我们需要计算每个部分的有效信息长度，并判断其可行性。
 */
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

public class MessageSplitterStream {
    public static List<String> splitMessage(String message, int limit) {
        int n = message.length();
        return IntStream.rangeClosed(1, n)
            .mapToObj(b -> {
                int suffixLength = ("<" + b + "/" + b + ">").length();
                int maxPartLength = limit - suffixLength;
                int totalValidLength = maxPartLength * b;
                if (totalValidLength >= n) {
                    int[] currentIndex = {0};
                    return IntStream.rangeClosed(1, b)
                        .mapToObj(a -> {
                            int remainingParts = b - a + 1;
                            int remainingChars = n - currentIndex[0];
                            int partLength = Math.min(maxPartLength, remainingChars - remainingParts + 1);
                            String part = message.substring(currentIndex[0], currentIndex[0] + partLength) + "<" + a + "/" + b + ">";
                            currentIndex[0] += partLength;
                            return part;
                        }).collect(Collectors.toList());
                }
                return new ArrayList<String>();
            }).filter(list -> !list.isEmpty()).findFirst().orElse(new ArrayList<>());
    }
}