// Experiment 11: TCP client-server program to transfer a file from client to server
// CLIENT side - sends the file
// Compile: gcc 11_tcp_file_client.c -o fileclient
// Run    : ./fileclient <filename>
//          ./fileclient sample.txt

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

#define PORT 7777
#define BUF  1024

int main(int argc, char *argv[]) {
    if (argc != 2) {
        printf("Usage: %s <filename>\n", argv[0]);
        return 1;
    }

    int sock;
    struct sockaddr_in serv_addr;
    char buffer[BUF];

    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) { perror("socket"); exit(1); }

    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port   = htons(PORT);
    inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr);

    if (connect(sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0) {
        perror("connect"); exit(1);
    }
    printf("Connected to server.\n");

    FILE *fp = fopen(argv[1], "rb");
    if (!fp) { perror("fopen"); exit(1); }

    int n;
    while ((n = fread(buffer, 1, BUF, fp)) > 0) {
        if (send(sock, buffer, n, 0) < 0) {
            perror("send"); break;
        }
    }

    fclose(fp);
    printf("File '%s' sent successfully.\n", argv[1]);

    close(sock);
    return 0;
}