#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <fcntl.h>

#define PORT 12345
#define CHUNK_SIZE 1024

void handle_error(const char *msg) {
        perror(msg);
            exit(1);
}

int main()
{
    int server_fd, client_fd, file_fd;
    struct sockaddr_in server_addr, client_addr;
    socklen_t client_len;
    char buffer[CHUNK_SIZE];
    char filename[256];
    ssize_t bytes_read, bytes_sent;
    server_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (server_fd < 0)
    {
        handle_error("Socket creation failed");
    }
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = INADDR_ANY;
    server_addr.sin_port = htons(PORT);
    if (bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0)
    {
         handle_error("Bind failed");
    }
   if (listen(server_fd, 5) < 0)
    {
         handle_error("Listen failed");
    }
    printf("Server listening on port %d...\n", PORT);
    while (1)
    {
        client_len = sizeof(client_addr);
        client_fd = accept(server_fd, (struct sockaddr *)&client_addr, &client_len);
        if (client_fd < 0)
        {
           perror("Accept failed");
           continue;
        }
        printf("Client connected\n");
       // Receive the filename request from the client
       memset(filename, 0, sizeof(filename));
       if (recv(client_fd, filename, sizeof(filename), 0) <= 0)
       {
            perror("Failed to receive filename");
            close(client_fd);
            continue;
        }
       // Open the file requested by the client
        file_fd = open(filename, O_RDONLY);
        if (file_fd < 0)
        {
              perror("File not found");
              close(client_fd);
              continue;
         }
        // Send the file in chunks
          while ((bytes_read = read(file_fd, buffer, CHUNK_SIZE)) > 0) {
          bytes_sent = send(client_fd, buffer, bytes_read, 0);
          if (bytes_sent < 0)
          {
             perror("Send failed");
            close(file_fd);
            close(client_fd);
            break;
          }
        }
       if (bytes_read < 0) {
        perror("File read failed");
      } else {
      printf("File sent successfully\n");
      }
      close(file_fd);
      close(client_fd);
    }
close(server_fd);
return 0;
}