"""Tests for metrics trackers and helpers."""

from s5p.metrics import LatencyTracker, Metrics, RateTracker, _human_bytes

# -- LatencyTracker ----------------------------------------------------------


class TestLatencyTracker:
    """Test latency sample collection and percentile stats."""

    def test_empty(self):
        lt = LatencyTracker()
        assert lt.count == 0
        assert lt.stats() is None

    def test_single(self):
        lt = LatencyTracker()
        lt.record(0.1)
        s = lt.stats()
        assert s is not None
        assert s["count"] == 1
        assert s["min"] == s["max"] == s["avg"] == s["p50"]

    def test_percentiles(self):
        lt = LatencyTracker()
        # 100 evenly spaced samples: 0.001, 0.002, ..., 0.100
        for i in range(1, 101):
            lt.record(i / 1000)
        s = lt.stats()
        assert s["count"] == 100
        assert s["min"] == 1.0          # 0.001s = 1.0ms
        assert s["max"] == 100.0        # 0.100s = 100.0ms
        assert 49.0 <= s["avg"] <= 52.0
        assert 50.0 <= s["p50"] <= 52.0
        assert 95.0 <= s["p95"] <= 97.0
        assert 99.0 <= s["p99"] <= 101.0

    def test_bounded(self):
        lt = LatencyTracker(maxlen=5)
        for i in range(10):
            lt.record(i / 100)
        assert lt.count == 5
        s = lt.stats()
        # only the last 5 samples remain: 0.05..0.09
        assert s["min"] == 50.0
        assert s["max"] == 90.0

    def test_milliseconds(self):
        lt = LatencyTracker()
        lt.record(0.5)  # 500ms
        s = lt.stats()
        assert s["min"] == 500.0
        assert s["max"] == 500.0


# -- RateTracker -------------------------------------------------------------


class TestRateTracker:
    """Test rolling window event rate calculation."""

    def test_empty(self):
        rt = RateTracker()
        assert rt.rate() == 0.0

    def test_single(self):
        rt = RateTracker()
        rt.record()
        assert rt.rate() == 0.0

    def test_known_rate(self):
        rt = RateTracker()
        # 11 events at 0.1s intervals = 10/1.0 = 10.0/s
        for i in range(11):
            rt.record(now=100.0 + i * 0.1)
        assert abs(rt.rate() - 10.0) < 0.01

    def test_bounded(self):
        rt = RateTracker(maxlen=5)
        for i in range(10):
            rt.record(now=float(i))
        # only last 5 events: t=5..9, span=4, rate=4/4=1.0
        assert abs(rt.rate() - 1.0) < 0.01

    def test_zero_span(self):
        rt = RateTracker()
        rt.record(now=1.0)
        rt.record(now=1.0)
        assert rt.rate() == 0.0


# -- Metrics -----------------------------------------------------------------


class TestMetrics:
    """Test Metrics aggregation and output."""

    def test_to_dict_includes_rate_and_latency(self):
        m = Metrics()
        m.connections = 10
        m.conn_rate.record(now=0.0)
        m.conn_rate.record(now=1.0)
        m.latency.record(0.2)
        m.latency.record(0.3)
        d = m.to_dict()
        assert "rate" in d
        assert isinstance(d["rate"], float)
        assert "latency" in d
        assert d["latency"] is not None
        assert d["latency"]["count"] == 2

    def test_to_dict_latency_none_when_empty(self):
        m = Metrics()
        d = m.to_dict()
        assert d["latency"] is None
        assert d["rate"] == 0.0

    def test_summary_includes_rate(self):
        m = Metrics()
        m.conn_rate.record(now=0.0)
        m.conn_rate.record(now=1.0)
        s = m.summary()
        assert "rate=" in s
        assert "/s" in s

    def test_summary_includes_latency(self):
        m = Metrics()
        m.latency.record(0.2)
        s = m.summary()
        assert "p50=" in s
        assert "p95=" in s

    def test_summary_no_latency_when_empty(self):
        m = Metrics()
        s = m.summary()
        assert "p50=" not in s
        assert "p95=" not in s

    def test_listener_latency(self):
        m = Metrics()
        m.get_listener_latency("0.0.0.0:1080").record(0.5)
        m.get_listener_latency("0.0.0.0:1080").record(0.6)
        m.get_listener_latency("0.0.0.0:1081").record(0.1)
        d = m.to_dict()
        assert "listener_latency" in d
        assert "0.0.0.0:1080" in d["listener_latency"]
        assert "0.0.0.0:1081" in d["listener_latency"]
        assert d["listener_latency"]["0.0.0.0:1080"]["count"] == 2
        assert d["listener_latency"]["0.0.0.0:1081"]["count"] == 1

    def test_listener_latency_empty(self):
        m = Metrics()
        d = m.to_dict()
        assert d["listener_latency"] == {}


# -- _human_bytes ------------------------------------------------------------


class TestHumanBytes:
    """Test byte count formatting."""

    def test_bytes(self):
        assert _human_bytes(0) == "0B"
        assert _human_bytes(512) == "512B"

    def test_kilobytes(self):
        assert _human_bytes(1024) == "1.0K"
        assert _human_bytes(1536) == "1.5K"

    def test_megabytes(self):
        assert _human_bytes(1024 * 1024) == "1.0M"

    def test_gigabytes(self):
        assert _human_bytes(1024**3) == "1.0G"

    def test_terabytes(self):
        assert _human_bytes(1024**4) == "1.0T"

    def test_petabytes(self):
        assert _human_bytes(1024**5) == "1.0P"