#include "congestion_control.hpp"
#include "VpnPeer.hpp"

CongestionController::CongestionController(const VpnPeer& peer):
    _peer(peer)
{
    _last_seqno = _peer.get_loss_logger().get_cur_seqno();
    _loss_based.bandwidth = 3e5; // 300kBps seems a good value to start with
}

void CongestionController::update_lossbased() {
    const VpnPeer::LossReports& loss_rep = _peer.get_loss_reports();

    uint32_t delta_seqno = loss_rep.last_seqno - loss_rep.prev_seqno;
    unsigned int delta_losses = loss_rep.last_losses - loss_rep.prev_losses;

    double loss_rate = (double)delta_losses / (double)delta_seqno;

    if(loss_rate < 0.02) // FIXME only if the bandwidth is used
        _loss_based.bandwidth *= 1.05;
    else if(loss_rate >= 0.1)
        _loss_based.bandwidth *= (1 - 0.5 * loss_rate);
}

uint64_t CongestionController::get_bandwidth() const {
    return _loss_based.bandwidth;
}