"""Self-check for the AI cost function: rates per million tokens, thinking bills as output,
long-context rates above the threshold, and an unknown model is an error, never zero."""
import importlib.util
from pathlib import Path

import pytest

SRC = Path(__file__).resolve().parents[1] / "skills" / "rpa-dashboard-ai" / "templates" / "web" / "pricing.py"
spec = importlib.util.spec_from_file_location("pricing", SRC)
pricing = importlib.util.module_from_spec(spec)
spec.loader.exec_module(pricing)

TABLE = {
    "flat-model": {"input": 0.30, "output": 2.50},
    "long-model": {"input": 1.25, "output": 10.00, "long_threshold": 200_000, "input_long": 2.50, "output_long": 15.00},
}


@pytest.fixture(autouse=True)
def table(monkeypatch):
    monkeypatch.setattr(pricing, "PRICING", TABLE)


def test_normal_call_prices_input_and_output_per_million():
    # 1M in at 0.30 + 0.2M out at 2.50 = 0.30 + 0.50
    assert pricing.cost_for_call("flat-model", 1_000_000, 200_000) == pytest.approx(0.80)


def test_thinking_tokens_bill_at_the_output_rate():
    # 0.1M in at 0.30 + (0.1M out + 0.3M thinking) at 2.50 = 0.03 + 1.00
    assert pricing.cost_for_call("flat-model", 100_000, 100_000, 300_000) == pytest.approx(1.03)


def test_long_context_rates_apply_above_the_threshold_only():
    # at the threshold: 0.2M at 1.25 + 0.1M at 10 = 0.25 + 1.00
    assert pricing.cost_for_call("long-model", 200_000, 100_000) == pytest.approx(1.25)
    # above it: 0.4M at 2.50 + 0.1M at 15 = 1.00 + 1.50
    assert pricing.cost_for_call("long-model", 400_000, 100_000) == pytest.approx(2.50)


def test_unknown_model_raises_and_names_the_known_models():
    with pytest.raises(ValueError) as e:
        pricing.cost_for_call("mystery-model", 1000, 1000)
    assert "mystery-model" in str(e.value)
    assert "flat-model" in str(e.value) and "long-model" in str(e.value)


def test_bundled_table_records_its_source_and_as_of_date():
    assert pricing.PRICING_SOURCE.startswith("https://")
    assert len(pricing.PRICING_AS_OF) == 10 and pricing.PRICING_AS_OF[4] == "-"