#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <netinet/in.h>
#include <pthread.h>
#include <arpa/inet.h>

void *client_thread(void *vptr) {
  int fd = *((int *)vptr);

  while(1) {
    // accept any message
    unsigned char buffer[4097];
    ssize_t len = recv(fd, buffer, sizeof(buffer)-1, 0);
    if (len <= 0) {
      printf("client %d disconnected\n", fd);
      break;
    }

    // print it out
    buffer[len] = '\0';

    printf("[%d] recv() binary:", fd);
    for(ssize_t i = 0; i < len; i+=1) printf(" %02x", buffer[i]);
    printf("\n");

    printf("[%d] recv(): %s\n", fd, buffer);



    // send "I got it" back
    sprintf(buffer, "recv()ed %ld bytes\n", len);
    send(fd, buffer, strlen(buffer), 0); // to do: check return value
  }

  return NULL;
}

int main(int argc, char *argv[]) {
  if (argc != 2) {
    printf("Usage: %s <port>\n", argv[0]);
    return 1;
  }
  int port = atoi(argv[1]);
  printf("Binding to port %d. Visit http://localhost:%d/ to interact with your server!\n", port, port);

  // socket:
  int sockfd = socket(AF_INET, SOCK_STREAM, 0);

  // bind:
  struct sockaddr_in server_addr, client_address;
  memset(&server_addr, 0x00, sizeof(server_addr));
  server_addr.sin_family = AF_INET;
  server_addr.sin_addr.s_addr = INADDR_ANY;
  server_addr.sin_port = htons(port);  
  bind(sockfd, (const struct sockaddr *)&server_addr, sizeof(server_addr));

  // listen:
  listen(sockfd, 10);

  // accept:
  socklen_t client_addr_len;
  while (1) {
    int *fd = malloc(sizeof(int));
    client_addr_len = sizeof(struct sockaddr_in);
    *fd = accept(sockfd, (struct sockaddr *)&client_address, &client_addr_len);
    printf("Client connected from %s (fd=%d)\n", inet_ntoa(client_address.sin_addr), *fd);

    pthread_t tid;
    pthread_create(&tid, NULL, client_thread, fd);
    pthread_detach(tid);
  }

  return 0;
}