"""Unit-Tests Parameter-Engine (PLAN.md §11)."""

from __future__ import annotations

import uuid

import pytest
from hms_parameter import ParameterEngine, layer_opacity_path, master_intensity_path
from hms_parameter.engine import ControlSource, MergeMode, RevisionConflict


@pytest.fixture()
def path() -> str:
    return layer_opacity_path(str(uuid.uuid4()), str(uuid.uuid4()))


def test_invalid_path_rejected() -> None:
    engine = ParameterEngine()
    with pytest.raises(ValueError, match="invalid parameter path"):
        engine.set_value("composition/not-a-uuid/layer/x/opacity", 1.0, ControlSource.WEB)
    with pytest.raises(ValueError, match="invalid parameter path"):
        engine.set_value("../escape", 1.0, ControlSource.WEB)


def test_nan_and_infinity_rejected(path: str) -> None:
    engine = ParameterEngine()
    with pytest.raises(ValueError, match="finite"):
        engine.set_value(path, float("nan"), ControlSource.WEB)
    with pytest.raises(ValueError, match="finite"):
        engine.set_value(path, float("inf"), ControlSource.WEB)


def test_higher_priority_wins(path: str) -> None:
    engine = ParameterEngine()
    engine.set_value(path, 0.5, ControlSource.WEB)
    assert engine.effective_value(path) == pytest.approx(0.5)
    engine.set_value(path, 0.9, ControlSource.CONSOLE)
    assert engine.effective_value(path) == pytest.approx(0.9)  # Pult überstimmt Web
    engine.set_value(path, 0.0, ControlSource.SAFETY)
    assert engine.effective_value(path) == pytest.approx(0.0)  # Blackout überstimmt alles


def test_lower_priority_cannot_displace_higher(path: str) -> None:
    engine = ParameterEngine()
    engine.set_value(path, 0.9, ControlSource.CONSOLE)
    engine.set_value(path, 0.1, ControlSource.WEB)  # niedrigere Priorität
    assert engine.effective_value(path) == pytest.approx(0.9)  # CONSOLE bleibt wirksam
    assert engine.current_source(path) is ControlSource.CONSOLE


def test_release_falls_back_to_lower_priority(path: str) -> None:
    engine = ParameterEngine()
    engine.set_value(path, 0.2, ControlSource.WEB)
    engine.set_value(path, 0.8, ControlSource.CONSOLE)
    engine.release(path, ControlSource.CONSOLE)
    assert engine.effective_value(path) == pytest.approx(0.2)  # Web übernimmt wieder
    engine.release(path, ControlSource.WEB)
    assert engine.current_source(path) is None


def test_revision_increments_on_set_and_release(path: str) -> None:
    engine = ParameterEngine()
    r0 = engine.revision
    r1 = engine.set_value(path, 0.5, ControlSource.WEB)
    r2 = engine.set_value(path, 0.6, ControlSource.WEB)
    r3 = engine.release(path, ControlSource.WEB)
    assert (r1, r2, r3) == (r0 + 1, r0 + 2, r0 + 3)


def test_optimistic_locking_revision_conflict(path: str) -> None:
    engine = ParameterEngine()
    engine.set_value(path, 0.5, ControlSource.WEB)
    with pytest.raises(RevisionConflict):
        engine.set_value(path, 0.6, ControlSource.WEB, expected_revision=engine.revision + 5)
    engine.set_value(path, 0.6, ControlSource.WEB, expected_revision=engine.revision)


def test_snapshot_is_atomic_and_readonly(path: str) -> None:
    engine = ParameterEngine()
    engine.set_value(path, 0.42, ControlSource.WEB)
    snap = engine.snapshot()
    assert snap.get(path) == pytest.approx(0.42)
    assert snap.revision == engine.revision
    values = snap.as_dict()
    values[path] = 99.0  # Manipulation der Kopie darf Snapshot nicht ändern
    assert snap.get(path) == pytest.approx(0.42)
    # Änderung nach dem Snapshot erscheint nicht im alten Snapshot (§11.4)
    engine.set_value(path, 0.9, ControlSource.WEB)
    assert snap.get(path) == pytest.approx(0.42)


def test_defaults_in_snapshot_without_override() -> None:
    engine = ParameterEngine()
    master = master_intensity_path()
    engine.set_default(master, 1.0)
    snap = engine.snapshot()
    assert snap.get(master) == pytest.approx(1.0)
    assert engine.effective_value(master) == pytest.approx(1.0)


def test_htp_mode_takes_maximum(path: str) -> None:
    engine = ParameterEngine(merge_mode=MergeMode.HTP)
    engine.set_value(path, 0.9, ControlSource.WEB)
    engine.set_value(path, 0.1, ControlSource.WEB)
    assert engine.effective_value(path) == pytest.approx(0.9)  # HTP: Maximum bleibt