#include <iostream>
#include <vector>
#include <queue>

using namespace std;

class SlidingWindow {
private:
    int window_size;
    int total_frames;
    vector<int> sent_frames; // queue of sent frames
    int next_frame_to_send; // index of the next frame to send
    int next_frame_to_receive; // index of the next frame to receive

public:
  SlidingWindow(int window_size, int total_frames) {
    this->window_size = window_size;
    this->total_frames = total_frames;
    this->next_frame_to_send = 0;
    this->next_frame_to_receive = 0;
  }

    // send a frame
    void send_frame() {
        if (sent_frames.size() < window_size && next_frame_to_send < total_frames) {
            sent_frames.push_back(next_frame_to_send);
            next_frame_to_send++;
            cout << "Sent frame " << sent_frames.back() << endl;
        } else {
            cout << "Window is full. Waiting before sending next frames." << endl;
        }
    }

    // receive a frame
    void receive_frame(int frame_number) {
        if (frame_number == next_frame_to_receive) {
            next_frame_to_receive++;
            cout << "Received frame " << frame_number << endl;
        } else {
            cout << "Received frame " << frame_number << ", but expected frame " << next_frame_to_receive << endl;
        }

        // remove acknowledged frames from the sent_frames queue
        while (!sent_frames.empty() && sent_frames.front() <= next_frame_to_receive - 1) {
            sent_frames.erase(sent_frames.begin());
        }
    }

    bool all_frames_sent() {
        return next_frame_to_send == total_frames;
    }

    bool all_frames_received() {
        return next_frame_to_receive == total_frames;
    }
};

int main() {
    int window_size, total_frames;
    cout << "Enter the window size:\t";
    cin >> window_size;
    cout << "Enter the total number of frames:\t";
    cin >> total_frames;

    SlidingWindow window(window_size, total_frames);

    while (!window.all_frames_sent() || !window.all_frames_received()) {
        window.send_frame();

        // simulate receiving frames
        for (int i = 0; i < rand() % 3; i++) {
            int frame_number = rand() % total_frames;
            window.receive_frame(frame_number);
        }
    }
    cout << "All frames sent and received successfully!" << endl;

    return 0;
}