#include <iostream>
#include <fstream>
#include <cstring>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <pthread.h>
#include <string.h>
#include <filesystem>

#ifdef __SWITCH__
#include <switch.h>
#endif

#define PORT 8080
#define BUFFER_SIZE 1024
#define MULTICAST_PORT 8081
#define MULTICAST_GROUP "239.0.0.1"  // Multicast group IP

void sendAck(int sock) {
    const char *ack = "ACK";
    std::cout << "Sending ACK " << std::endl;
    send(sock, ack, strlen(ack), 0);
}

// Функция для получения файла
void receive_file(std::string dirname, int client_socket) {
    char buffer[BUFFER_SIZE] = {0};
    // Receive filename length
    uint32_t filename_len;
    ssize_t bytes_read = read(client_socket, &filename_len, sizeof(filename_len));

    std::cout << "Filename length: " << filename_len << std::endl;

    // Check for end-of-transmission signal
    if (bytes_read <= 0 || filename_len == 0) {
        std::cout << "End of transmission detected." << std::endl;
        pthread_exit(nullptr);
    }

    // Receive filename
    char *filename = new char[filename_len + 1];
    read(client_socket, filename, filename_len);
    filename[filename_len] = '\0';

    std::cout << "Receiving file: " << filename << std::endl;

    // Receive file size
    size_t file_size;
    read(client_socket, &file_size, sizeof(file_size));

    std::cout << "With size: " << file_size << std::endl;
    // Open a file to write the received data
    std::ofstream outfile(dirname + "/" + filename, std::ios::binary);
    delete[] filename; // Clean up filename buffer

    size_t total_bytes_received = 0;
    while (total_bytes_received < file_size) {
        ssize_t bytes_received = read(client_socket, buffer, BUFFER_SIZE);
        std::cout << "bytes received: " << bytes_received << std::endl;
        if (bytes_received <= 0) {
            break;
        }
        outfile.write(buffer, bytes_received);
        total_bytes_received += bytes_received;

        // Send acknowledgment for each chunk received
        sendAck(client_socket);
    }

    std::cout << "File received successfully." << std::endl;
    outfile.close();
}

void *handle_client(void *socket_desc) {
    int client_socket = *(int *)socket_desc;
    free(socket_desc);

    std::cout << "Обработка нового клиента в потоке " << pthread_self() << "\n";

    // Receive directory length
    uint32_t directory_len;
    ssize_t bytes_read = read(client_socket, &directory_len, sizeof(directory_len));

    // Check for end-of-transmission signal
    if (bytes_read <= 0 || directory_len == 0) {
        std::cout << "End of transmission detected." << std::endl;
        pthread_exit(nullptr);
    }

    // Receive filename
    char *dirname = new char[directory_len + 1];
    read(client_socket, dirname, directory_len);
    dirname[directory_len] = '\0';

    std::cout << "Directory name is " << dirname << std::endl;

    if (!std::filesystem::create_directory(dirname)) {
        std::cerr << "Unable to create directory" << std::endl;
        pthread_exit(nullptr);
    }

    // Получаем файлы до тех пор, пока клиент не закроет соединение
    while (true) {
        receive_file(dirname, client_socket);
    }

    close(client_socket);
    pthread_exit(nullptr);
}

void *broadcast_listener(void *) {
    int sockfd;
    struct sockaddr_in servaddr;
    char buffer[BUFFER_SIZE];
    struct ip_mreq group;

    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("socket creation failed");
        pthread_exit(nullptr);
    }

    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(MULTICAST_PORT);

    if (bind(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr))) {
        perror("binding datagram socket");
        close(sockfd);
        pthread_exit(nullptr);
    }

    group.imr_multiaddr.s_addr = inet_addr(MULTICAST_GROUP);
    group.imr_interface.s_addr = htonl(INADDR_ANY);

    if (setsockopt(sockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&group, sizeof(group)) < 0) {
        perror("setsockopt failed");
        close(sockfd);
        pthread_exit(nullptr);
    }

    std::cout << "Broadcast listener started" << std::endl;
    struct sockaddr_in client_addr;
    socklen_t addr_len = sizeof(client_addr);
    while (true) {
        int n = recvfrom(sockfd, buffer, BUFFER_SIZE, 0, (struct sockaddr*)&client_addr, &addr_len);
        if (n < 0) {
            perror("recvfrom failed");
            continue;
        }
        std::cout << buffer << std::endl;
        buffer[n] = '\0';
        if (strcmp(buffer, "DISCOVER_SERVER") == 0) {
            const char *message = "SERVER_HERE";
            sendto(sockfd, message, strlen(message), 0, (const struct sockaddr *)&client_addr, addr_len);
            std::cout << "Server discovery response sent to multicast group" << std::endl;
        }
    }

    close(sockfd);
    pthread_exit(nullptr);
}

int main() {
#ifdef __SWITCH__
    socketInitializeDefault();
    nxlinkStdio();
#endif
    pthread_t broadcast_thread;
    if (pthread_create(&broadcast_thread, nullptr, broadcast_listener, nullptr) < 0) {
        perror("Thread creation failed");
        return 1;
    }

    int server_fd, new_socket;
    struct sockaddr_in address;
    socklen_t addrlen = sizeof(address);

    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
        perror("Socket creation failed");
        exit(EXIT_FAILURE);
    }

    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(PORT);

    if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) < 0) {
        perror("Bind failed");
        close(server_fd);
        exit(EXIT_FAILURE);
    }

    if (listen(server_fd, 3) < 0) {
        perror("Listen failed");
        close(server_fd);
        exit(EXIT_FAILURE);
    }

    std::cout << "Server listening on port " << PORT << std::endl;

    while (true) {
        sockaddr_in client_address;
        socklen_t client_len = sizeof(client_address);
        int client_socket = accept(server_fd, (sockaddr *)&client_address, &client_len);

        if (client_socket < 0) {
            std::cerr << "Ошибка принятия подключения\n";
            continue;
        }

        // Создаем новый поток для обработки клиента
        pthread_t thread_id;
        int *pclient = new (std::nothrow) int(client_socket);
        if (!pclient) {
            std::cerr << "Ошибка выделения памяти\n";
            close(client_socket);
            continue;
        }
        if (pthread_create(&thread_id, nullptr, handle_client, pclient) != 0) {
            std::cerr << "Ошибка создания потока\n";
            delete pclient; // Освобождаем память при ошибке
        } else {
            pthread_detach(thread_id); // Отсоединяем поток, чтобы он мог завершиться самостоятельно
        }
    }

    close(server_fd);
#ifdef __SWITCH__
    socketExit();
#endif
    return 0;
}