#define _GNU_SOURCE
#include <netdb.h>
#include <signal.h>
#include <unistd.h>
#include <unistd.h>
#include <fcntl.h>
#include "ntpclient.h"
#include "thread.h"
#include "sys/time.h"
  
#define NTP_PORT 123  
#define NTP_PACKET_SIZE 48  
  
// 发送NTP请求  
static int sendNTPRequest(NTPClient* client) {  
    client->ntp_packet[0] = 0x1B; // LI = 0, VN = 3, Mode = 3 (client)  
    ssize_t sentBytes = sendto(client->sockfd, client->ntp_packet, NTP_PACKET_SIZE, 0,  
                               &client->server_addr, sizeof(client->server_addr));  
    if (sentBytes < 0) {  
        perror("sendto failed");  
        return -1;  
    }  
    return 0;  
}  
  
// 接收NTP响应  
static int receiveNTPResponse(NTPClient* client) {
    socklen_t len = sizeof(client->server_addr);
    ssize_t receivedBytes = recvfrom(client->sockfd, client->ntp_packet, NTP_PACKET_SIZE, 0,  
                              &client->server_addr, &len);  
    if (receivedBytes < 0) {  
        perror("recvfrom failed");  
        return -1;  
    }  
    return 0;  
}  
  
// 解析NTP响应中的时间  
static time_t parseNTPResponse(const char* ntp_packet) {  
    unsigned int sec_since_1900 = ntohl(((unsigned int *)ntp_packet)[10]);  
    unsigned int frac_sec = ntohl(((unsigned int *)ntp_packet)[11]);  
    double frac = frac_sec * 2.0e-32;  
    return (time_t)(sec_since_1900 - 2208988800U) + (time_t)frac;  
}  

typedef struct {
    char     ip[64];
    uint16_t port;
}ipaddr_t;
static int get_addr(ipaddr_t *addr, struct addrinfo *info)
{
    addr->ip[0] = 0; addr->port = 0;
    if(info->ai_family==AF_INET) {
        struct sockaddr_in* p=(struct sockaddr_in*)(info->ai_addr);
        addr->port = htons(p->sin_port);
        inet_ntop(p->sin_family, &p->sin_addr, addr->ip, sizeof(addr->ip));
    }
    else if(info->ai_family==AF_INET6) {
        struct sockaddr_in6* p=(struct sockaddr_in6*)(info->ai_addr);
        addr->port = htons(p->sin6_port);
        inet_ntop(p->sin6_family, &p->sin6_addr, addr->ip, sizeof(addr->ip));
    }
    else {
        return -1;
    }
    return 0;
}
static void *tmp_thread(void *arg)
{
    ipaddr_t ipa;
    int r,fd=-1,err;
    struct addrinfo hints;
    struct addrinfo *rp;
    NTPClient *pc=(NTPClient*)arg;
    char tmp[32];

    memset(&hints, 0, sizeof hints);
    hints.ai_family   = AF_UNSPEC;
    hints.ai_socktype = SOCK_DGRAM;
    hints.ai_protocol = 0;//IPPROTO_UDP;

    pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
    pthread_testcancel();

    sprintf(tmp, "%d", pc->port);
    printf("___getaddrinfo in\n");
    err = getaddrinfo(pc->server, tmp, &hints, &pc->res);
    if(err){
        printf("___getaddrinfo from %s failed, %s\n", pc->server, gai_strerror(err));
        pthread_exit(NULL);
    }
    printf("___getaddrinfo out\n");

    for(rp=pc->res; rp; rp=rp->ai_next){
        get_addr(&ipa, rp);
        printf("socket to %s:%d ", ipa.ip, ipa.port);

        fd = socket(rp->ai_family, rp->ai_socktype, 0);
        if (fd>=0) {
            pc->sockfd = fd;
            pc->server_addr = *rp->ai_addr;
            printf("ok!\n");
            break;
        }
        printf("failed!\n");
    }
    if(fd>=0) {
        pc->flag = 1;
    }
    else {
        pc->flag = -1;
    }

    pthread_exit(NULL);
}
NTPClient* createNTPClient(const char* ntp_server, int port, int timeout_sec) {  
    NTPClient* client = (NTPClient*)malloc(sizeof(NTPClient));  
    if (!client) {  
        perror("createNTPClient, malloc failed\n");  
        return NULL;  
    } 

    pthread_t tid;
    client->server = (char*)ntp_server;
    client->port = port;
    client->res = NULL;
    client->flag = 0;
    pthread_create(&tid, NULL, tmp_thread, client);
    pthread_detach(tid);
    for(int i=0; i<timeout_sec; i++) {
        if(client->flag) {
            break;
        }
        sleep(1);
    }
    if(client->flag!=1) {
        if(client->flag==0) {
            printf("___getaddrinfo timeout, cancel thread %lu\n", (unsigned long)tid);
            // pthread_cancel(tid);//SIGTERM
            // pthread_join(tid, NULL);
            printf("___cancel ok!\n");
        }
        if(client->res) freeaddrinfo(client->res);
        free(client); return NULL;
    }
    if(client->res) freeaddrinfo(client->res);

    struct timeval tv;
    tv.tv_sec = timeout_sec;
    tv.tv_usec = 0;
    setsockopt(client->sockfd, SOL_SOCKET, SO_RCVTIMEO, (const void*)&tv, sizeof(tv));

    printf("___createNTPClient ok!\n");
  
    return client;  
}  
  
// 销毁NTP客户端实例  
void destroyNTPClient(NTPClient* client) {  
    if (client) {  
        close(client->sockfd);  
        free(client);  
    }  
}  
  
// 从NTP服务器获取当前时间  
int getCurrentTimeFromNTP(NTPClient* client, time_t* current_time) {  
    if (sendNTPRequest(client) < 0) {  
        return -1;  
    }
  
    if (receiveNTPResponse(client) < 0) {  
        return -1;  
    }  
  
    *current_time = parseNTPResponse(client->ntp_packet);  
    return 0;  
}  
  
  
// 根据时间获取星期信息
int getCurrentWeekday(time_t  current_time,char *weekday) {  
    struct tm * timeinfo;  
    timeinfo = localtime(&current_time);  
    if (timeinfo == NULL) {  
        return -1;  
    }  
    
    // 格式化星期几  
    strftime(weekday, 20, "%A", timeinfo); // %A 代表完整的星期名，例如：Sunday 
    
    return 0;
}