#include "netlinkhandler.h"
#include <sys/socket.h>
#include <linux/netlink.h>
#include <unistd.h>
#include <cstring>
#include <QDebug>

NetlinkHandler::NetlinkHandler(QObject *parent) : QObject(parent) {}

NetlinkHandler::~NetlinkHandler()
{
    closeSocket();
}

bool NetlinkHandler::init(int protocol)
{
    LOG_DEBUG("protoal is %d",protocol);
    if (!createSocket(protocol)) {
        emit errorOccurred("Failed to create netlink socket");
        return false;
    }

    m_notifier = new QSocketNotifier(m_sock, QSocketNotifier::Read, this);
    connect(m_notifier, &QSocketNotifier::activated, this, &NetlinkHandler::onSocketReadyRead);

    return true;
}

bool NetlinkHandler::createSocket(int protocol)
{
    m_sock = socket(AF_NETLINK, SOCK_RAW, protocol);
    if (m_sock < 0) return false;

    sockaddr_nl local = {};
    local.nl_family = AF_NETLINK;
    local.nl_pid = getpid(); // 用户态PID
    local.nl_groups = 0;

    if (bind(m_sock, reinterpret_cast<sockaddr*>(&local), sizeof(local)) < 0) {
        close(m_sock);
        return false;
    }
    return true;
}

void NetlinkHandler::closeSocket()
{
    if (m_sock >= 0) {
        ::close(m_sock);
        m_sock = -1;
    }
}

bool NetlinkHandler::sendMessage(const QByteArray &msg)
{
    if (m_sock < 0) return false;

    struct nlmsghdr *nlh;
    struct sockaddr_nl kernel = {};
    struct iovec iov;
    struct msghdr message = {};

    char buffer[4096] = {};

    nlh = reinterpret_cast<struct nlmsghdr*>(buffer);
    nlh->nlmsg_len = NLMSG_LENGTH(msg.size());
    nlh->nlmsg_pid = getpid();
    nlh->nlmsg_flags = 0;

    memcpy(NLMSG_DATA(nlh), msg.data(), msg.size());

    kernel.nl_family = AF_NETLINK;

    iov.iov_base = nlh;
    iov.iov_len = nlh->nlmsg_len;

    message.msg_name = &kernel;
    message.msg_namelen = sizeof(kernel);
    message.msg_iov = &iov;
    message.msg_iovlen = 1;

    return sendmsg(m_sock, &message, 0) >= 0;
}

void NetlinkHandler::onSocketReadyRead()
{
    char buffer[4096] = {};
    int len = recv(m_sock, buffer, sizeof(buffer), 0);
    if (len < 0) {
        emit errorOccurred("recv failed");
        return;
    }

    struct nlmsghdr *nlh = reinterpret_cast<struct nlmsghdr*>(buffer);
    if (NLMSG_OK(nlh, len)) {
        QByteArray data(reinterpret_cast<char*>(NLMSG_DATA(nlh)), nlh->nlmsg_len - NLMSG_HDRLEN);
        emit messageReceived(data);
    }
}