#include <cstdio>
#include <netdb.h>
#include <netinet/in.h>
#include <string>
#include <sys/socket.h>
#include <unistd.h>
#include <unordered_map>

#include <openssl/ssl.h>

std::unordered_map<std::string, std::string> key_value_database;

int main(int argc, char **argv) {
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <port>\n", argv[0]);
        return 1;
    }

    int serv = socket(AF_INET, SOCK_STREAM, 0);

    const int one = 1;
    setsockopt(serv, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));

    sockaddr_in sa = {};
    sa.sin_family = AF_INET;
    sa.sin_port = htons(atoi(argv[1]));

    if (bind(serv, (sockaddr *)&sa, sizeof(sa))) {
        perror("bind failed");
        return 1;
    }

    listen(serv, 1);

    while (1) {
        sockaddr_in ca;
        socklen_t l = sizeof(ca);
        int cli = accept(serv, (sockaddr *)&ca, &l);

        char clientName[NI_MAXHOST], clientPort[NI_MAXSERV];
        getnameinfo((sockaddr *)&ca, l, clientName, NI_MAXHOST, clientPort, NI_MAXSERV, 0);
        printf("New client [%s:%s]\n", clientName, clientPort);

        while (1) {
            char request[1025]{};
            int count = read(cli, request, 1024);
            if (count <= 0)
                break;
            if (request[count - 1] == '\n')
                request[count - 1] = '\0';
            if (!strlen(request))
                continue;

            char *firstSpace = strchr(request, ' ');
            if (firstSpace != nullptr) {
                *firstSpace = '\0';
                char *key = request;
                char *value = firstSpace + 1;
                key_value_database[key] = value;
                printf("[%s:%s] assigned to '%s' value '%s'\n", clientName, clientPort, key, value);
            } else {
                char *key = request;
                std::string value;
                if (key_value_database.count(key))
                    value = key_value_database[key];
                else
                    value = "(null)";
                std::string response = std::string("[") + key + "] " + value + "\n";
                write(cli, response.data(), response.length());
                printf("[%s:%s] read from '%s' value '%s'\n", clientName, clientPort, key, value.data());
            }
        }

        printf("Client [%s:%s] gone\n", clientName, clientPort);

        shutdown(cli, SHUT_RDWR);
        close(cli);
    }
}