#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <unistd.h>

#include <openssl/ssl.h>

int main(int argc, char **argv) {
    SSL_CTX *ctx = SSL_CTX_new(TLS_server_method());
    
    SSL_CTX_use_certificate_chain_file(ctx, "chain.pem")                        == 1 || fprintf(stderr, "problem with chain.pem\n");
    //SSL_CTX_use_certificate_file(ctx, "server.crt", SSL_FILETYPE_PEM)         == 1 || fprintf(stderr, "problem with server.crt\n");
    SSL_CTX_use_PrivateKey_file(ctx, "server.key", SSL_FILETYPE_PEM)            == 1 || fprintf(stderr, "problem with server.key\n");
    
    struct sockaddr_in sa = {0};
    sa.sin_family = AF_INET;
    sa.sin_addr.s_addr = INADDR_ANY;
    sa.sin_port = htons(atoi(argv[1]));

    int sfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    bind(sfd, (struct sockaddr *)&sa, sizeof(sa))                               == 0 || fprintf(stderr, "problem with bind\n");
    listen(sfd, 10);
    
    while (1) {
        int cfd = accept(sfd, NULL, NULL);
        
        SSL *ssl = SSL_new(ctx);
        SSL_set_fd(ssl, cfd);
        
        SSL_accept(ssl);
        
        char buf[1024];
        SSL_read(ssl, buf, sizeof(buf));
        
        SSL_write(ssl, "Welcome to the SSL/TLS server!\n", 31);
        
        SSL_shutdown(ssl);
        SSL_free(ssl);
        close(cfd);
    }
}