"""Unit tests for eval.instruct_check (T4.2) — CPU helpers only.

The model-driven ``evaluate`` path is exercised live in M4 exit validation.
"""
import json
import os
import tempfile

import pytest

from tsmm.eval.instruct_check import (
    CATEGORIES,
    _forecast_list,
    load_by_category,
)


def _write_eval(tmpdir, rows):
    path = os.path.join(tmpdir, "eval.jsonl")
    with open(path, "w") as f:
        for r in rows:
            f.write(json.dumps(r) + "\n")
    return path


def test_load_by_category_buckets_and_caps(tmp_path):
    rows = []
    for cat in CATEGORIES:
        for i in range(5):
            rows.append({"category": cat, "series": [[1.0]], "answer": "x", "labels": [0]})
    # plus an unknown-category row that must be ignored
    rows.append({"category": "mystery", "series": [[1.0]], "answer": "x"})
    path = _write_eval(str(tmp_path), rows)
    out = load_by_category(path, per_cat=3, seed=0)
    assert set(out.keys()) == set(CATEGORIES)
    for cat in CATEGORIES:
        assert len(out[cat]) == 3
    assert "mystery" not in out


def test_load_by_category_deterministic_with_seed(tmp_path):
    rows = [{"category": "anomaly", "series": [[float(i)]], "answer": str(i), "labels": [0]}
            for i in range(20)]
    path = _write_eval(str(tmp_path), rows)
    a = load_by_category(path, per_cat=5, seed=42)
    b = load_by_category(path, per_cat=5, seed=42)
    assert [s["answer"] for s in a["anomaly"]] == [s["answer"] for s in b["anomaly"]]
    # different seed → (very likely) different selection
    c = load_by_category(path, per_cat=5, seed=7)
    assert [s["answer"] for s in a["anomaly"]] != [s["answer"] for s in c["anomaly"]]


def test_load_by_category_handles_short_pool(tmp_path):
    rows = [{"category": "event", "series": [[1.0]], "answer": "x"} for _ in range(2)]
    path = _write_eval(str(tmp_path), rows)
    out = load_by_category(path, per_cat=10, seed=0)
    assert len(out["event"]) == 2
    # missing categories are empty lists, not errors
    assert out["anomaly"] == []


def test_load_by_category_skips_blank_lines(tmp_path):
    path = os.path.join(str(tmp_path), "eval.jsonl")
    with open(path, "w") as f:
        f.write(json.dumps({"category": "anomaly", "series": [[1.0]], "answer": "x"}) + "\n")
        f.write("\n")
        f.write("   \n")
        f.write(json.dumps({"category": "anomaly", "series": [[2.0]], "answer": "y"}) + "\n")
    out = load_by_category(path, per_cat=5, seed=0)
    assert len(out["anomaly"]) == 2


def test_forecast_list_from_nested_json():
    ref = json.dumps({"forecast": [[1.0, 2.0, 3.0]]})
    assert _forecast_list(ref) == [1.0, 2.0, 3.0]


def test_forecast_list_from_flat_json():
    ref = json.dumps({"forecast": [4.0, 5.0]})
    assert _forecast_list(ref) == [4.0, 5.0]


def test_forecast_list_accepts_dict_input():
    assert _forecast_list({"forecast": [[1.0, 2.0]]}) == [1.0, 2.0]


def test_forecast_list_returns_empty_on_garbage():
    assert _forecast_list("not json") == []
    assert _forecast_list(json.dumps({"no_forecast": 1})) == []
    assert _forecast_list("") == []
    assert _forecast_list(None) == []