"""Unit-Tests Zielrouting, Clock-Sync, zeitgestempelte Aktivierung
(PLAN.md §6.3, §6.4, §6.5)."""

from __future__ import annotations

import pytest
from hms_cluster import (
    ActivationCoordinator,
    ArmState,
    ClockEstimator,
    ClockSample,
    GroupRouter,
    GroupRule,
    ServerGroup,
    TargetKind,
)

# ---------- GroupRouter (§6.3 Bedienmodelle) ----------


@pytest.fixture()
def router() -> GroupRouter:
    r = GroupRouter()
    r.set_node_tags("node-a", frozenset({"stage-left"}))
    r.set_node_tags("node-b", frozenset({"stage-right"}))
    r.set_node_tags("node-c", frozenset({"stage-left", "stage-right"}))
    r.set_node_outputs("node-a", ["out-1"])
    r.set_node_outputs("node-c", ["out-2"])
    return r


def test_resolve_all_targets(router: GroupRouter) -> None:
    assert router.resolve(TargetKind.ALL) == frozenset({"node-a", "node-b", "node-c"})


def test_resolve_single_node(router: GroupRouter) -> None:
    assert router.resolve(TargetKind.NODE, "node-a") == frozenset({"node-a"})
    assert router.resolve(TargetKind.NODE, "unbekannt") == frozenset()


def test_resolve_by_output(router: GroupRouter) -> None:
    assert router.resolve(TargetKind.OUTPUT, "out-2") == frozenset({"node-c"})
    assert router.resolve(TargetKind.OUTPUT, "out-9") == frozenset()


def test_group_rule_selected(router: GroupRouter) -> None:
    router.upsert_group(
        ServerGroup(
            id="g1",
            name="Links",
            rule=GroupRule.SELECTED,
            node_ids=frozenset({"node-a", "unbekannt"}),
        )
    )
    # unbekannte Mitglieder werden still gefiltert, bekannte bleiben
    assert router.resolve(TargetKind.SERVER_GROUP, "g1") == frozenset({"node-a"})


def test_group_rule_tag_query(router: GroupRouter) -> None:
    router.upsert_group(
        ServerGroup(
            id="g2",
            name="Beide Bühnen",
            rule=GroupRule.TAG_QUERY,
            tags=frozenset({"stage-left"}),
        )
    )
    assert router.resolve(TargetKind.SERVER_GROUP, "g2") == frozenset(
        {"node-a", "node-c"}
    )


def test_group_rule_all(router: GroupRouter) -> None:
    router.upsert_group(ServerGroup(id="g3", name="Alle", rule=GroupRule.ALL))
    assert router.resolve(TargetKind.SERVER_GROUP, "g3") == router.resolve(TargetKind.ALL)


def test_preview_matches_resolve(router: GroupRouter) -> None:
    """§17.5: Commit-Vorschau zeigt dieselben Ziele wie der Versand."""
    router.upsert_group(
        ServerGroup(id="g4", name="X", rule=GroupRule.SELECTED, node_ids=frozenset({"node-b"}))
    )
    assert router.preview_targets(TargetKind.SERVER_GROUP, "g4") == router.resolve(
        TargetKind.SERVER_GROUP, "g4"
    )


def test_unknown_group_resolves_empty(router: GroupRouter) -> None:
    assert router.resolve(TargetKind.SERVER_GROUP, "gibts-nicht") == frozenset()


def test_remove_group(router: GroupRouter) -> None:
    router.upsert_group(ServerGroup(id="g", name="Weg"))
    router.remove_group("g")
    assert router.get_group("g") is None


# ---------- ClockEstimator (§6.4 Clock Sync) ----------


def _sample(t0: int, rtt: int, offset: int) -> ClockSample:
    """Probe mit definiertem echtem Offset: node_time = t0 + rtt/2 + offset."""
    node_time = t0 + rtt // 2 + offset
    return ClockSample(t0_ns=t0, t1_ns=t0 + rtt, node_time_ns=node_time)


def test_clock_offset_estimated_from_low_rtt_samples() -> None:
    """Min-Filter: Proben mit Rauschen (hohe RTT) verschieben den Schätzer
    nicht; die niedrigste RTT dominiert (§6.4)."""
    est = ClockEstimator()
    # echter Offset: +5 ms; einige Proben mit Jitter
    est.feed(_sample(0, 1_000_000, 5_000_000))  # 1 ms RTT
    est.feed(_sample(1_000_000, 50_000_000, 30_000_000))  # 50 ms RTT, Jitter
    est.feed(_sample(2_000_000, 2_000_000, 5_500_000))
    est.feed(_sample(3_000_000, 1_500_000, 4_800_000))
    offset = est.offset_ns
    assert offset is not None
    assert 4_000_000 < offset < 6_000_000  # nahe am echten 5 ms


def test_clock_best_rtt_reported() -> None:
    est = ClockEstimator()
    est.feed(_sample(0, 20_000_000, 0))
    est.feed(_sample(1, 5_000_000, 0))
    assert est.rtt_ns == 5_000_000


def test_clock_no_data_returns_none() -> None:
    est = ClockEstimator()
    assert est.offset_ns is None
    assert est.rtt_ns is None
    assert est.drift_ppm is None


def test_clock_drift_estimated_over_time() -> None:
    """Drift: Offset wächst um 100 µs pro Sekunde = 100 ppm (§6.4)."""
    est = ClockEstimator()
    est.feed(_sample(t0=0, rtt=1_000_000, offset=0))
    # 2 s später: 200 µs mehr Offset (200_000 ns) → 100 µs/s = 100 ppm
    est.feed(_sample(t0=2_000_000_000, rtt=1_000_000, offset=200_000))
    drift = est.drift_ppm
    assert drift is not None
    assert 80.0 <= drift <= 120.0  # ~100 ppm


def test_clock_drift_none_below_one_second_window() -> None:
    """Zu kurzes Fenster: Drift ist nicht belastbar (§6.4 Grenze)."""
    est = ClockEstimator()
    est.feed(_sample(0, 1_000_000, 0))
    est.feed(_sample(100_000_000, 1_000_000, 50))  # nur 100 ms Abstand
    assert est.drift_ppm is None


def test_clock_rejects_negative_rtt() -> None:
    with pytest.raises(ValueError, match="negative RTT"):
        ClockEstimator().feed(ClockSample(t0_ns=10, t1_ns=5, node_time_ns=0))


def test_clock_maps_show_time_to_node_time() -> None:
    """§29.1: Showzeit → lokale Monotonic über den Offset."""
    est = ClockEstimator()
    est.feed(_sample(0, 1_000_000, offset=10_000_000))  # +10 ms
    mapped = est.map_show_time(1_000_000_000)
    assert mapped is not None
    assert mapped == 1_010_000_000  # Showzeit + Offset
    # ohne Proben: keine Abbildung möglich
    assert ClockEstimator().map_show_time(0) is None


def test_clock_sample_window_bounded() -> None:
    """Kein unbeschränkter Zustand (§33): Fenster bleibt begrenzt."""
    est = ClockEstimator(max_samples=4)
    for i in range(10):
        est.feed(_sample(i * 1_000_000, 1_000_000, 0))
    assert len(est._samples) <= 4


# ---------- ActivationCoordinator (§6.5) ----------


@pytest.fixture()
def two_node_setup():
    router = GroupRouter()
    router.set_node_tags("node-a", frozenset({"x"}))
    router.set_node_tags("node-b", frozenset({"x"}))
    coord = ActivationCoordinator(router)
    return coord, router


def test_schedule_plans_with_lead_time(two_node_setup) -> None:
    coord, _ = two_node_setup
    planned = coord.schedule("scene-1", now_show_ns=1_000_000_000, lead_ns=200_000_000)
    assert planned.execute_at_show_ns == 1_200_000_000  # §6.4: 100–300 ms Vorlauf
    assert planned.state is ArmState.CREATED


def test_due_requires_all_arms(two_node_setup) -> None:
    """§6.5: Execute nur, wenn ALLE Ziel-Nodes armed; sonst FAILED."""
    coord, _ = two_node_setup
    planned = coord.schedule("scene-1", now_show_ns=0, lead_ns=100)
    coord.acknowledge_arm(planned.command_id, "node-a")
    # Showzeit erreicht, aber node-b fehlt → FAILED, nicht still ausgeführt
    due = coord.due(now_show_ns=1_000_000)
    assert due == []
    assert coord.get(planned.command_id).state is ArmState.FAILED


def test_due_executes_when_all_armed(two_node_setup) -> None:
    coord, _ = two_node_setup
    planned = coord.schedule("scene-1", now_show_ns=0, lead_ns=100)
    coord.acknowledge_arm(planned.command_id, "node-a")
    coord.acknowledge_arm(planned.command_id, "node-b")
    due = coord.due(now_show_ns=1_000_000)
    assert len(due) == 1 and due[0].command_id == planned.command_id
    assert coord.get(planned.command_id).state is ArmState.ARMED


def test_execute_completes_when_all_nodes_report(two_node_setup) -> None:
    coord, _ = two_node_setup
    planned = coord.schedule("scene-1", now_show_ns=0, lead_ns=100)
    coord.acknowledge_arm(planned.command_id, "node-a")
    coord.acknowledge_arm(planned.command_id, "node-b")
    coord.due(now_show_ns=1_000_000)
    # beide Nodes melden ausgeführt (mit Ist-Zeit, §6.5)
    coord.acknowledge_execute(planned.command_id, "node-a")
    assert coord.get(planned.command_id).state is ArmState.ARMED  # noch nicht komplett
    coord.acknowledge_execute(planned.command_id, "node-b")
    assert coord.get(planned.command_id).state is ArmState.EXECUTED


def test_expected_nodes_preview(two_node_setup) -> None:
    """§17.5: Vor dem Commit sichtbar, welche Nodes die Szene erhalten."""
    coord, _ = two_node_setup
    planned = coord.schedule("scene-1", now_show_ns=0, lead_ns=100)
    assert coord.expected_nodes(planned) == frozenset({"node-a", "node-b"})


def test_acknowledge_unknown_command_rejected(two_node_setup) -> None:
    coord, _ = two_node_setup
    with pytest.raises(KeyError):
        coord.acknowledge_arm("gibts-nicht", "node-a")


def test_due_ignores_already_handled(two_node_setup) -> None:
    """Erledigte/gescheiterte Aktivierungen werden nicht erneut geliefert."""
    coord, _ = two_node_setup
    planned = coord.schedule("scene-1", now_show_ns=0, lead_ns=100)
    coord.acknowledge_arm(planned.command_id, "node-a")
    coord.acknowledge_arm(planned.command_id, "node-b")
    coord.due(now_show_ns=1_000_000)  # erstmalig fällig → ARMED
    second = coord.due(now_show_ns=2_000_000)  # erneut aufgerufen: kein Duplikat
    assert second == []


def test_due_before_showtime_returns_empty(two_node_setup) -> None:
    coord, _ = two_node_setup
    coord.schedule("scene-1", now_show_ns=1_000_000_000, lead_ns=200_000_000)
    assert coord.due(now_show_ns=1_100_000_000) == []  # Showzeit noch nicht erreicht