#include <stdlib.h>
#include <iostream>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <netinet/in.h>

#define MAX_SIZE 1024

using namespace std;

bool write_fully(int fd, const char *buffer, ssize_t count) {
    const char *ptr = buffer;
    const char *end = buffer + count;
    while (ptr != end) {
    ssize_t written = write(fd, (void*) ptr, end - ptr);
    if (written == -1) {
        return false;
    }
    ptr += written;
    }
    return true;
}

void server_for_connection(int socket_fd) {
    int read_count;
    char request_buf[MAX_SIZE];
    while (1) {
    read_count = read(socket_fd, (void*) request_buf, MAX_SIZE);
    if (read_count == 0) {
        return; // EOF
    } else if (read_count == -1) {
        cerr << "read: " << strerror(errno) << endl;
        return;
    }

    string response = string(request_buf, read_count);

    cout << "read: " << response;

    if (response.substr(0,4).find("USER") != string::npos) {
        string acceptedUser = "230 Welcome!!!\n";
        const char* acceptedCstr = acceptedUser.c_str();
        send(socket_fd, acceptedCstr, strlen(acceptedCstr), 0);
    }

    if (false == write_fully(socket_fd, request_buf, read_count)) {
        cerr << "write: " << strerror(errno) << endl;
        return;
    }
    }
}

int main(int argc, char** argv) {
    if (argc < 2) {
        std::cerr << "Usage: " << argv[0] << " PORT-NUMBER" << std::endl;
        return 1;
    }

    const char *portname = argv[1];
    string stringMsg = "220 Please reply.\n";
    const char* exampleMsg = stringMsg.c_str();
    socklen_t socksize = sizeof(struct sockaddr_in);

    struct sockaddr_in addr_dest;
    struct sockaddr_in addr;

    addr.sin_family = AF_INET;
    inet_pton(AF_INET, "127.0.0.1", &(addr.sin_addr.s_addr));
//    addr.sin_addr.s_addr = INADDR_ANY;
    addr.sin_port = htons(atoi(portname));

    int server_socket_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

    if (bind(server_socket_fd, (struct sockaddr*) &addr, sizeof(addr)) < 0) {
    cout << "Error with binding!!!" << endl;
    return 1;
    }

    listen(server_socket_fd, 1);
    int client_socket_fd = accept(server_socket_fd, (struct sockaddr*) &addr_dest, &socksize);

    while(client_socket_fd) {
    printf("Connection from: %s\n", inet_ntoa(addr.sin_addr));
    send(client_socket_fd, exampleMsg, strlen(exampleMsg), 0);

    server_for_connection(client_socket_fd);

    close(client_socket_fd);
    client_socket_fd = accept(server_socket_fd, (struct sockaddr*) &addr_dest, &socksize);
    }

    close(server_socket_fd);


//    std::cout << "Code to bind to 127.0.0.1 port " << portname
//              << " and listen for connections unimplemented." << std::endl;
    return 0;
}