"""
Unit tests for pure-logic functions in src/classifier/train.py.

No model checkpoint required. All tests run in milliseconds.
Run: pytest tests/classifier/test_train.py
"""

from src.classifier.model import DOMAIN_LABELS
from src.classifier.train import _build_supplement, _fill, _map_product


# ---------------------------------------------------------------------------
# _map_product
# ---------------------------------------------------------------------------

def test_map_product_exact_banking():
    assert _map_product("Checking or savings account") == "banking"


def test_map_product_exact_cibil():
    assert _map_product("Credit card") == "cibil"


def test_map_product_keyword_fallback_banking():
    assert _map_product("Some new mortgage product") == "banking"


def test_map_product_keyword_fallback_cibil():
    assert _map_product("My credit card debt collection service") == "cibil"


def test_map_product_unknown_returns_none():
    assert _map_product("Exotic product never seen before") is None


def test_map_product_strips_whitespace():
    assert _map_product("  Mortgage  ") == "banking"


# ---------------------------------------------------------------------------
# _build_supplement
# ---------------------------------------------------------------------------

def test_build_supplement_all_six_domains_present():
    import random
    ds = _build_supplement(n_per_class=10, seed=42)
    label_values = set(ds["labels"])
    from src.classifier.model import DOMAIN2ID
    assert label_values == set(DOMAIN2ID.values())


def test_build_supplement_count_per_class():
    from collections import Counter
    ds = _build_supplement(n_per_class=20, seed=42)
    counts = Counter(ds["labels"])
    assert all(c == 20 for c in counts.values()), f"Uneven counts: {counts}"


def test_build_supplement_deterministic():
    ds1 = _build_supplement(n_per_class=10, seed=42)
    ds2 = _build_supplement(n_per_class=10, seed=42)
    assert ds1["text"] == ds2["text"]


def test_build_supplement_no_unfilled_placeholders():
    ds = _build_supplement(n_per_class=10, seed=42)
    placeholders = ["{amount}", "{date}", "{ref}", "{days}"]
    for text in ds["text"]:
        for ph in placeholders:
            assert ph not in text, f"Unfilled placeholder {ph!r} in: {text!r}"