laminar 0.5.0

use std::time::Instant;

use crate::{
    net::{NetworkQuality, RttMeasurer},
    sequence_buffer::{CongestionData, SequenceBuffer},
    Config,
};

/// Keeps track of congestion information.
pub struct CongestionHandler {
    rtt_measurer: RttMeasurer,
    congestion_data: SequenceBuffer<CongestionData>,
    _quality: NetworkQuality,
}

impl CongestionHandler {
    /// Constructs a new `CongestionHandler` which you can use for keeping track of congestion information.
    pub fn new(config: &Config) -> CongestionHandler {
        CongestionHandler {
            rtt_measurer: RttMeasurer::new(config),
            congestion_data: SequenceBuffer::with_capacity(<u16>::max_value()),
            _quality: NetworkQuality::Good,
        }
    }

    /// Processes incoming sequence number.
    ///
    /// This will calculate the RTT-time and smooth down the RTT-value to prevent uge RTT-spikes.
    pub fn process_incoming(&mut self, incoming_seq: u16) {
        let congestion_data = self.congestion_data.get_mut(incoming_seq);
        self.rtt_measurer.calculate_rrt(congestion_data);
    }

    /// Processes outgoing sequence number.
    ///
    /// This will insert an entry which is used for keeping track of the sending time.
    /// Once we process incoming sequence numbers we can calculate the `RTT` time.
    pub fn process_outgoing(&mut self, seq: u16, time: Instant) {
        self.congestion_data
            .insert(seq, CongestionData::new(seq, time));
    }
}

#[cfg(test)]
mod test {
    use std::time::Instant;

    use crate::infrastructure::CongestionHandler;
    use crate::Config;

    #[test]
    fn congestion_entry_created() {
        let mut congestion_handler = CongestionHandler::new(&Config::default());

        congestion_handler.process_outgoing(1, Instant::now());

        assert_eq!(congestion_handler.congestion_data.exists(1), true);
    }

    #[test]
    fn rtt_value_is_updated() {
        let mut congestion_handler = CongestionHandler::new(&Config::default());

        assert_eq!(
            congestion_handler.rtt_measurer.get_rtt().abs() < std::f32::EPSILON,
            true
        );
        congestion_handler.process_outgoing(1, Instant::now());
        congestion_handler.process_incoming(1);
        assert_eq!(congestion_handler.rtt_measurer.get_rtt() != 0., true);
    }
}