#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <spawn.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>

bool ports[999];

int start_server(int* socket_fd) {
    struct sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(1337);
    server_addr.sin_addr.s_addr = INADDR_ANY;

    printf("[Host] Starting Server\n");
    *socket_fd = socket(AF_INET, SOCK_STREAM, 0);
    int bound = bind(*socket_fd, (struct sockaddr*)&server_addr, sizeof(server_addr));
    if(bound < 0) {
        printf("[Host] Bind Error: %s (%d)\n", strerror(errno), errno);
        return 1;
    }
    listen(*socket_fd, 5);
    return 0;
}

void start_worker(int port) {
    char portStr[6];
    sprintf(portStr, "%d", port);
    char *argv[] = {"./worker", portStr, NULL};
    extern char **environ;

    pid_t pid;
    posix_spawn(&pid, "./worker", NULL, NULL,  argv, environ);
}

int assign_workers(int* socket_fd) {
    while(true) {
        struct sockaddr_in client_addr;
        int client_size = sizeof(client_addr);
        int client_sock = accept(*socket_fd, (struct sockaddr*)&client_addr, &client_size); 

        char buffer[5];
        int bytes_received;
        bytes_received = recv(client_sock, buffer, sizeof(buffer), 0);
        if(bytes_received < 0 || bytes_received == 0) {
            continue;
        }

        if(buffer[0] == 0x0) { // Get Port
            for(int i = 0; i < sizeof(ports); i++) {
                if(!ports[i]) {
                    int port = 11000+i;
                    printf("[Host] Assigning port %i to worker\n", port);
                    char buff[sizeof(int)];
                    memcpy(buff, &port, sizeof(int));
                    write(client_sock, buff, sizeof(buff));
                    start_worker(port);
                    ports[i] = true;
                    shutdown(client_sock, SHUT_RDWR);
                    close(client_sock);
                    break;
                }
            }
        } else if(buffer[0] == 0x1) { // Remove Worker
            u_int32_t port;
            memcpy(&port, buffer+1, sizeof(u_int32_t));
            port = ntohl(port);
            printf("[Host] Unassigning port %i\n", port);
            ports[abs(11000-port)] = false;
            shutdown(client_sock, SHUT_RDWR);
            close(client_sock);
        }
    }
    return 0;
}

int main() {
    int* socket_fd;
    start_server(socket_fd);
    assign_workers(socket_fd);
    return 0;
}