#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netdb.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

bool has_internet() {
    int ret;
    
    // https://www.man7.org/linux/man-pages/man3/getaddrinfo.3.html
    struct addrinfo hints;
    memset(&hints, 0, sizeof(hints));
    hints.ai_family = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_flags = 0;
    hints.ai_protocol = 0;
    struct addrinfo *res, *rp;
    ret = getaddrinfo("hopeless-cloud.xyz", "80", 0, &res);
    if (ret != 0) {
        // fprintf(stderr, "Couldn't getaddrinfo()\n");
        return false;
    }
    int sockfd;
    for (rp = res; rp != NULL; rp = rp->ai_next) {
        // https://www.man7.org/linux/man-pages/man2/socket.2.html
        sockfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
        if (sockfd == -1) { continue; }
        
        // https://www.man7.org/linux/man-pages/man2/connect.2.html
        if (connect(sockfd, rp->ai_addr, rp->ai_addrlen) == 0) { break; }
        
        close(sockfd);
    }
    freeaddrinfo(res);
    if (rp == NULL) {
        // fprintf(stderr, "Couldn't connect socket\n");
        return false;
    }
    
    // https://www.man7.org/linux/man-pages/man2/write.2.html
    char *req_msg = "GET / HTTP/1.1\r\n\r\n";
    if (write(sockfd, req_msg, strlen(req_msg)) != strlen(req_msg)) {
        // fprintf(stderr, "Couldn't fully write to socket\n");
        return false;
    }
    
    // https://www.man7.org/linux/man-pages/man2/recv.2.html
    size_t count = 1000000;
    char buf[count];
    if (recv(sockfd, buf, count-1, MSG_WAITALL) == -1 ) {
        // fprintf(stderr, "Couldn't read from socket\n");
        return false;
    }
    // printf("%s\n", buf);
    close(sockfd);
    return true;
}

int main() {
    if (has_internet()) {
        // printf("has internet\n");
        return 0;
    } else {
        // printf("no internet\n");
        return 1;
    }
}