#include "./server.h"
#include "common.h"

const uint32_t CONNECTION_QUEUE_LEN = 10U;

server_t* server_init_tcp(const char* addr, const char* port) {
    server_t* srv = calloc(1, sizeof(*srv));

    srv->listen_socket_fd = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);
    if (srv->listen_socket_fd == -1) {
        fprintf(stderr, "[server_init_tcp] Unable to create socket!\n");
        exit(EXIT_FAILURE);
    }

    int setsockopt_yes = 1;
    if (setsockopt(srv->listen_socket_fd, SOL_SOCKET, SO_REUSEADDR, &setsockopt_yes, sizeof(setsockopt_yes)) == -1) {
        fprintf(stderr, "[server_init_tcp] Unable to set SO_REUSEADDR socket option\n");
        exit(EXIT_FAILURE);
    }

    struct sockaddr_in* listen_addr = get_addr(addr, port);

    if (bind(srv->listen_socket_fd, (struct sockaddr*) listen_addr, sizeof(*listen_addr)) == -1) {
        free(listen_addr);
        fprintf(stderr, "[server_init_tcp] Unable to bind\n");
        exit(EXIT_FAILURE);
    }

    free(listen_addr);

    if (listen(srv->listen_socket_fd, CONNECTION_QUEUE_LEN) == -1) {
        fprintf(stderr, "[server_init_tcp] Unable to listen() on a socket\n");
        exit(EXIT_FAILURE);
    }

    struct linger linger_params = {.l_onoff = 1, .l_linger = 1};
    if (setsockopt(srv->listen_socket_fd, SOL_SOCKET, SO_LINGER, &linger_params, sizeof(linger_params)) == -1) {
        fprintf(stderr, "[server_init_tcp] Unable to modify SO_LINGER socket option\n");
        exit(EXIT_FAILURE);
    }

    return srv;
}

void server_shutdown(server_t* srv) {
    if (close(srv->listen_socket_fd) == -1) {
        fprintf(stderr, "[server_shutdown] Unable to close listen socket\n");
        exit(EXIT_FAILURE);
    }
}

conn_t* server_try_accept(server_t* srv) {
    int client_socket_fd = accept(srv->listen_socket_fd, NULL, NULL);
    if (client_socket_fd == -1) {
        if (errno == EAGAIN || errno == EWOULDBLOCK) {
            return NULL;
        }

        fprintf(stderr, "[conn_try_accept] Unable to accept() connection on a socket\n");
        exit(EXIT_FAILURE);
    }

    conn_t* conn = calloc(1, sizeof(*conn));
    conn->conn_socket_fd = client_socket_fd;

    // Разрешаем "зависания сокета" для доотправки данных.

    // Disable Nagle's algorithm:
    int setsockopt_arg = 1;
    if (setsockopt(conn->conn_socket_fd, IPPROTO_TCP, TCP_NODELAY, &setsockopt_arg, sizeof(setsockopt_arg)) == -1) {
        fprintf(stderr, "[conn_try_accept] Unable to enable TCP_NODELAY socket option\n");
        exit(EXIT_FAILURE);
    }

    // Disable corking:
    setsockopt_arg = 0;
    if (setsockopt(conn->conn_socket_fd, IPPROTO_TCP, TCP_CORK, &setsockopt_arg, sizeof(setsockopt_arg)) == -1) {
        fprintf(stderr, "[conn_try_accept] Unable to disable TCP_CORK socket option\n");
        exit(EXIT_FAILURE);
    }

    if (conn_configure_tcpalive(conn) == -1) {
        fprintf(stderr, "[conn_try_accept] Unable to enable TCPALIVE\n");
        exit(EXIT_FAILURE);
    }

    printf("[conn_accept] new connection!\n");
    return conn;
}