"""Tests for the Learn-phase "wow" additions to DE round 2
(dee.server._de_round2_library): pool_deltas (the before/after re-rank +
plain-language reasons) and global_prior (cross-user aggregate surfacing).

Exercises the real top_percentile_pool / evolve / variants_to_dataframe /
active_learning / aggregate pipeline on a tiny synthetic pool — only the ESM-2
scorer itself and the stored cross-user aggregate are mocked, so this proves
the new wiring (not just the isolated math already covered by
test_active_learning.py / test_aggregate.py)."""
import pandas as pd
import pytest

from dee import server
from dee.core.aggregate import GlobalPrior

_SETTINGS = {
    "model": "small", "host": "e_coli", "percentile": 85.0, "k": 5,
    "min_mutations": 1, "max_mutations": 2, "restarts": 1, "steps": 50, "seed": 1,
}


def _fake_scores_df(n=5):
    # wt_aa is always 'A' -> labels are A1G, A2G, ... A5G.
    return pd.DataFrame({
        "position": list(range(n)), "wt_aa": ["A"] * n, "mut_aa": ["G"] * n,
        "delta_ll": [float(i) - 2 for i in range(n)],   # -2, -1, 0, 1, 2
    })


def _label(i):
    return f"A{i + 1}G"


@pytest.fixture(autouse=True)
def _mock_scorer(monkeypatch):
    monkeypatch.setattr(server._scoring, "get_scorer", lambda *a, **kw: "the-scorer")
    monkeypatch.setattr(server._scoring, "score_guarded",
                        lambda scorer, protein: _fake_scores_df())
    monkeypatch.setattr(server, "top_percentile_pool", lambda df, percentile: df)


def test_pool_deltas_shape_sorted_and_reasoned_when_learned(monkeypatch):
    monkeypatch.setattr(server, "_load_global_prior",
                        lambda: GlobalPrior(effects={}, n_users={}, n_obs={}))
    # Enough varied measurements to clear MIN_MEASUREMENTS with real spread.
    measurements = [
        ([_label(0)], 1.0), ([_label(1)], 3.0), ([_label(2)], 5.0),
        ([_label(3)], 7.0), ([_label(4)], 9.0),
    ]
    rows, info = server._de_round2_library("A" * 5, _SETTINGS, measurements)

    assert info["learned"] is True
    deltas = info["pool_deltas"]
    assert 1 <= len(deltas) <= server._POOL_DELTAS_MAX
    # Sorted descending by adjusted_score.
    scores = [d["adjusted_score"] for d in deltas]
    assert scores == sorted(scores, reverse=True)
    for d in deltas:
        assert set(d.keys()) == {"label", "prior_score", "adjusted_score",
                                  "delta", "n_measured", "reason"}
        assert isinstance(d["reason"], str) and d["reason"]
        assert d["delta"] == pytest.approx(d["adjusted_score"] - d["prior_score"])
    # Every measured mutation should show n_measured >= 1.
    measured_labels = {_label(i) for i in range(5)}
    assert all(d["n_measured"] >= 1 for d in deltas if d["label"] in measured_labels)
    assert rows  # a real variant table came back


def test_pool_deltas_all_zero_delta_when_not_enough_signal(monkeypatch):
    monkeypatch.setattr(server, "_load_global_prior",
                        lambda: GlobalPrior(effects={}, n_users={}, n_obs={}))
    # Only 1 measurement — below MIN_MEASUREMENTS -> honest fallback, no change.
    rows, info = server._de_round2_library("A" * 5, _SETTINGS, [([_label(0)], 3.0)])
    assert info["learned"] is False
    assert all(d["delta"] == 0.0 for d in info["pool_deltas"])
    assert rows


def test_global_prior_absent_reports_not_applied(monkeypatch):
    monkeypatch.setattr(server, "_load_global_prior",
                        lambda: GlobalPrior(effects={}, n_users={}, n_obs={}))
    _, info = server._de_round2_library("A" * 5, _SETTINGS, [([_label(0)], 3.0)])
    assert info["global_prior"] == {"applied": False, "substitution_types": 0}


def test_global_prior_present_blends_and_reports_applied(monkeypatch):
    # A field-wide prior that says A>G substitutions tend to be strongly
    # favorable — should nudge prior_score upward vs the no-prior case, and
    # be honestly reported (substitution_types == 1, the one key present).
    gp = GlobalPrior(effects={("A", "G"): 2.0}, n_users={("A", "G"): 5}, n_obs={("A", "G"): 12})
    monkeypatch.setattr(server, "_load_global_prior", lambda: gp)
    _, info = server._de_round2_library("A" * 5, _SETTINGS, [([_label(0)], 3.0)])
    assert info["global_prior"] == {"applied": True, "substitution_types": 1}
    # Not enough measurements to learn, but the global-prior nudge still shows
    # up in prior_score (baseline moved even though round 2 fell back).
    unpatched_gp = GlobalPrior(effects={}, n_users={}, n_obs={})
    monkeypatch.setattr(server, "_load_global_prior", lambda: unpatched_gp)
    _, info_no_gp = server._de_round2_library("A" * 5, _SETTINGS, [([_label(0)], 3.0)])
    by_label = {d["label"]: d["prior_score"] for d in info["pool_deltas"]}
    by_label_no_gp = {d["label"]: d["prior_score"] for d in info_no_gp["pool_deltas"]}
    assert by_label[_label(0)] > by_label_no_gp[_label(0)]


def test_round2_route_exposes_pool_deltas_and_global_prior(monkeypatch):
    import types

    app = server.create_app()
    app.config.update(TESTING=True)
    client = app.test_client()
    monkeypatch.setattr(server._auth, "get_auth",
                        lambda: types.SimpleNamespace(anonymous=False, user_id="u1",
                                                      email="x@y.z", plan="free"))
    monkeypatch.setattr(server._auth, "cleanup_expired_de_outcomes_async", lambda uid: None)
    monkeypatch.setattr(server, "_load_global_prior",
                        lambda: GlobalPrior(effects={}, n_users={}, n_obs={}))

    r = client.post("/api/de/round2", json={
        "wt_protein": "A" * 5,
        "measurements": [
            {"mutations": _label(0), "measured_value": 1.0},
            {"mutations": _label(1), "measured_value": 3.0},
            {"mutations": _label(2), "measured_value": 5.0},
            {"mutations": _label(3), "measured_value": 7.0},
        ],
        "settings": _SETTINGS,
    })
    assert r.status_code == 200
    body = r.get_json()
    assert body["ok"] is True
    assert body["round"] == 2
    assert "pool_deltas" in body["surrogate"]
    assert "global_prior" in body["surrogate"]
    # New: round 2 carries the epistasis-in-the-loop block and per-variant
    # confidence. (The string-scorer fixture has no log_probs, so the
    # interaction re-rank degrades gracefully to applied=False — the point of
    # this assertion is that the WIRING is present and never crashes the run.)
    assert "epistasis" in body["surrogate"]
    assert set(body["surrogate"]["epistasis"]) == {"applied", "n_clash", "n_analyzed"}
    non_wt = [v for v in body["variants"] if v.get("Variant_ID") != "WT"]
    assert non_wt and all("Confidence" in v for v in non_wt)


def test_result_route_defaults_global_prior_when_never_set():
    app = server.create_app()
    app.config.update(TESTING=True)
    client = app.test_client()
    job = server.JobState(job_id="j1", status="done", wt_identifier="WT",
                          wt_protein="ACDEFG", variants=[])
    with server._JOBS_LOCK:
        server._JOBS["j1"] = job
    r = client.get("/api/result/j1")
    assert r.status_code == 200
    assert r.get_json()["global_prior"] == {"applied": False, "substitution_types": 0}


def test_result_route_surfaces_global_prior_when_set():
    app = server.create_app()
    app.config.update(TESTING=True)
    client = app.test_client()
    job = server.JobState(job_id="j2", status="done", wt_identifier="WT",
                          wt_protein="ACDEFG", variants=[],
                          global_prior_info={"applied": True, "substitution_types": 7})
    with server._JOBS_LOCK:
        server._JOBS["j2"] = job
    r = client.get("/api/result/j2")
    assert r.status_code == 200
    assert r.get_json()["global_prior"] == {"applied": True, "substitution_types": 7}