package com.mes.util;

/**
 * 客户端版本号比较，格式 0.0.0 / 0.0.1。
 * 没有点的旧数字（如 1）按 0.0.1 处理。
 */
public final class ClientVersionUtils {

    private ClientVersionUtils() {
    }

    public static int compare(String left, String right) {
        int[] a = parse(left);
        int[] b = parse(right);
        int n = Math.max(a.length, b.length);
        for (int i = 0; i < n; i++) {
            int va = i < a.length ? a[i] : 0;
            int vb = i < b.length ? b[i] : 0;
            if (va != vb) {
                return va < vb ? -1 : 1;
            }
        }
        return 0;
    }

    public static boolean isNewer(String latest, String current) {
        return compare(latest, current) > 0;
    }

    public static String max(String left, String right) {
        if (isBlank(left)) {
            return normalize(right);
        }
        if (isBlank(right)) {
            return normalize(left);
        }
        return compare(left, right) >= 0 ? normalize(left) : normalize(right);
    }

    public static String normalize(String version) {
        if (isBlank(version)) {
            return "0.0.0";
        }
        int[] parts = parse(version);
        return parts[0] + "." + parts[1] + "." + parts[2];
    }

    private static int[] parse(String version) {
        int[] result = new int[] {0, 0, 0};
        if (isBlank(version)) {
            return result;
        }
        String[] parts = version.trim().split("\\.");
        if (parts.length == 1) {
            result[2] = parseInt(parts[0]);
            return result;
        }
        for (int i = 0; i < parts.length && i < 3; i++) {
            result[i] = parseInt(parts[i]);
        }
        return result;
    }

    private static int parseInt(String value) {
        try {
            return Integer.parseInt(value.trim());
        } catch (Exception e) {
            return 0;
        }
    }

    private static boolean isBlank(String value) {
        return value == null || value.trim().length() == 0;
    }
}