"""CPU-only expected-red contract for autonomous Flow-encoder rounds.

Expected public API (specified before implementation)::

    from music3lab.autonomous import (
        AutonomousController, Candidate, EvaluationSuite, PromotionPolicy,
        Registry,
    )

This contract deliberately covers only continuous Flow-encoder waveform
reconstruction. It neither asserts nor implies Music 3 token extraction,
composition, style transfer, or native-token generation.
"""
from __future__ import annotations

from pathlib import Path

import pytest

from music3lab.autonomous import (
    AutonomousController,
    Candidate,
    EvaluationSuite,
    PromotionPolicy,
    Registry,
)


USER22 = tuple(f"user22-{index:02d}" for index in range(22))


def _suite() -> EvaluationSuite:
    return EvaluationSuite.freeze(
        train=tuple(f"train-{index:02d}" for index in range(8)),
        validation=tuple(f"validation-{index:02d}" for index in range(6)),
        public=tuple(f"public-{index:02d}" for index in range(6)),
        sealed=tuple(f"sealed-{index:02d}" for index in range(6)),
        excluded_sources=USER22,
    )


def _controller(tmp_path: Path) -> tuple[AutonomousController, Registry]:
    registry = Registry(tmp_path / "registry")
    registry.register_champion(
        Candidate(name="base", artifact_sha256="a" * 64, kind="flow_encoder")
    )
    policy = PromotionPolicy(
        bootstrap_samples=200,
        seed=41,
        protected_regression_limit=0.0,
        teacher_regression_limit=0.05,
    )
    return AutonomousController(registry=registry, policy=policy), registry


def _metrics(*, train: float, validation: float, public: float, sealed: float, teacher: float = 1.0, technical: float = 1.0, protected: float = 1.0) -> dict[str, tuple[float, ...]]:
    return {
        "train": (train,) * 8,
        "validation": (validation,) * 6,
        "public": (public,) * 6,
        "sealed": (sealed,) * 6,
        "teacher": (teacher,) * 6,
        "technical": (technical,) * 6,
        "protected": (protected,) * 6,
    }


def test_frozen_source_exclusive_suite_excludes_user22_and_is_immutable() -> None:
    suite = _suite()

    assert suite.splits == ("train", "validation", "public", "sealed")
    assert not set(USER22) & set().union(*suite.source_ids_by_split.values())
    assert len(set().union(*suite.source_ids_by_split.values())) == 26
    with pytest.raises((AttributeError, TypeError, ValueError)):
        suite.source_ids_by_split["train"] += ("leak",)


def test_challenger_selection_uses_validation_then_independent_public_and_sealed_metrics(tmp_path: Path) -> None:
    controller, registry = _controller(tmp_path)
    suite = _suite()
    baseline = _metrics(train=1.0, validation=1.0, public=1.0, sealed=1.0)
    winner = Candidate(name="real-latent-calibration", artifact_sha256="b" * 64, kind="flow_encoder")
    weaker = Candidate(name="weaker-validation", artifact_sha256="c" * 64, kind="flow_encoder")

    report = controller.run_round(
        suite=suite,
        baseline=baseline,
        challengers={
            winner: _metrics(train=0.80, validation=0.60, public=0.70, sealed=0.70),
            weaker: _metrics(train=0.10, validation=0.70, public=0.01, sealed=0.01),
        },
    )

    assert report.validation_winner == winner.artifact_sha256
    assert report.decision == "PROMOTE"
    assert registry.champion().artifact_sha256 == winner.artifact_sha256
    assert report.selection_split == "validation"
    assert report.independent_splits == ("public", "sealed")


def test_zero_latent_challenger_is_automatically_rejected(tmp_path: Path) -> None:
    controller, registry = _controller(tmp_path)
    baseline_hash = registry.champion().artifact_sha256
    zero = Candidate(
        name="zero-latent",
        artifact_sha256="d" * 64,
        kind="flow_encoder",
        metadata={"latent_strategy": "zero"},
    )

    report = controller.run_round(
        suite=_suite(),
        baseline=_metrics(train=1.0, validation=1.0, public=1.0, sealed=1.0),
        challengers={zero: _metrics(train=1.2, validation=1.4, public=1.5, sealed=1.5)},
    )

    assert report.decision == "REJECT"
    assert "zero-latent" in report.rejected[zero.artifact_sha256].reasons
    assert registry.champion().artifact_sha256 == baseline_hash


def test_train_lookup_overfit_rolls_back_without_champion_pointer_or_hash_change(tmp_path: Path) -> None:
    controller, registry = _controller(tmp_path)
    baseline = registry.champion()
    lookup = Candidate(name="train-lookup", artifact_sha256="e" * 64, kind="flow_encoder")

    report = controller.run_round(
        suite=_suite(),
        baseline=_metrics(train=1.0, validation=1.0, public=1.0, sealed=1.0),
        challengers={lookup: _metrics(train=0.0, validation=0.60, public=1.20, sealed=1.30)},
    )

    assert report.decision == "ROLLBACK"
    assert report.rejected[lookup.artifact_sha256].rollback is True
    assert registry.champion().name == baseline.name
    assert registry.champion().artifact_sha256 == baseline.artifact_sha256


def test_promotion_requires_positive_bootstrap_ci_and_all_non_regression_gates(tmp_path: Path) -> None:
    controller, registry = _controller(tmp_path)
    candidate = Candidate(name="candidate", artifact_sha256="f" * 64, kind="flow_encoder")
    baseline = _metrics(train=1.0, validation=1.0, public=1.0, sealed=1.0)

    rejected = controller.run_round(
        suite=_suite(), baseline=baseline,
        challengers={candidate: _metrics(train=0.7, validation=0.7, public=0.7, sealed=0.7, teacher=1.2)},
    )
    assert rejected.decision == "REJECT"
    assert "teacher" in rejected.rejected[candidate.artifact_sha256].reasons

    accepted = controller.run_round(
        suite=_suite(), baseline=baseline,
        challengers={candidate: _metrics(train=0.7, validation=0.7, public=0.7, sealed=0.7, teacher=1.01, technical=0.99, protected=1.0)},
    )
    assert accepted.decision == "PROMOTE"
    assert all(interval[0] > 0 for interval in accepted.bootstrap_ci.values())
    assert registry.champion().artifact_sha256 == candidate.artifact_sha256


def test_registry_contains_complete_base_champion_challenger_and_rejected_audit_rows(tmp_path: Path) -> None:
    controller, registry = _controller(tmp_path)
    good = Candidate(name="good", artifact_sha256="1" * 64, kind="flow_encoder")
    bad = Candidate(name="bad", artifact_sha256="2" * 64, kind="flow_encoder")
    report = controller.run_round(
        suite=_suite(), baseline=_metrics(train=1.0, validation=1.0, public=1.0, sealed=1.0),
        challengers={
            good: _metrics(train=0.7, validation=0.7, public=0.7, sealed=0.7),
            bad: _metrics(train=0.1, validation=0.8, public=1.2, sealed=1.2),
        },
    )

    rows = registry.audit_rows(round_id=report.round_id)
    assert {row.role for row in rows} == {"base", "champion", "challenger", "rejected"}
    assert {row.artifact_sha256 for row in rows} >= {"a" * 64, good.artifact_sha256, bad.artifact_sha256}
    assert all(row.suite_sha256 == _suite().sha256 for row in rows)