"""Tests for bandwidth estimator."""

import time

import pytest


class TestBandwidthEstimator:
    def test_initial_rates_are_zero(self):
        from i2p_streaming.bandwidth import BandwidthEstimator
        bw = BandwidthEstimator()
        assert bw.send_bps() == 0.0
        assert bw.recv_bps() == 0.0

    def test_record_sent_increases_send_rate(self):
        from i2p_streaming.bandwidth import BandwidthEstimator
        bw = BandwidthEstimator(window_ms=1000)
        bw.record_sent(1000)
        assert bw.send_bps() > 0.0

    def test_record_received_increases_recv_rate(self):
        from i2p_streaming.bandwidth import BandwidthEstimator
        bw = BandwidthEstimator(window_ms=1000)
        bw.record_received(1000)
        assert bw.recv_bps() > 0.0

    def test_send_and_recv_are_independent(self):
        from i2p_streaming.bandwidth import BandwidthEstimator
        bw = BandwidthEstimator()
        bw.record_sent(5000)
        assert bw.send_bps() > 0.0
        assert bw.recv_bps() == 0.0

    def test_multiple_records_accumulate(self):
        from i2p_streaming.bandwidth import BandwidthEstimator
        bw = BandwidthEstimator(window_ms=5000)
        bw.record_sent(100)
        first = bw.send_bps()
        bw.record_sent(100)
        second = bw.send_bps()
        assert second >= first

    def test_ema_smoothing(self):
        """EMA should smooth out spikes over time."""
        from i2p_streaming.bandwidth import BandwidthEstimator
        bw = BandwidthEstimator(window_ms=1000)
        # Record a large spike
        bw.record_sent(10000)
        spike_rate = bw.send_bps()
        # Wait a bit then record small amounts — rate should decrease
        time.sleep(0.05)
        for i in range(10):
            time.sleep(0.01)
            bw.record_sent(10)
        after_small = bw.send_bps()
        # After many small records with real elapsed time, rate should drop
        assert after_small < spike_rate

    def test_custom_window_size(self):
        from i2p_streaming.bandwidth import BandwidthEstimator
        bw = BandwidthEstimator(window_ms=500)
        bw.record_sent(1000)
        assert bw.send_bps() > 0.0

    def test_zero_bytes_recorded(self):
        from i2p_streaming.bandwidth import BandwidthEstimator
        bw = BandwidthEstimator()
        bw.record_sent(0)
        # Should not error, rate should be 0
        assert bw.send_bps() == 0.0