import pytest
import statistics
from queue_separation import main

@pytest.fixture
def sample_jobs():
    # Mix aus regulären und Hotspot-Jobs
    jobs = [
        {"id": i, "runtime": 1.0 + i * 0.1, "queue": "main" if i % 3 else "hotspot"}
        for i in range(1, 31)
    ]
    return jobs


def test_simulate_queue_separation_structure(sample_jobs):
    main_queue = [j for j in sample_jobs if j["queue"] == "main"]
    hotspot_queue = [j for j in sample_jobs if j["queue"] == "hotspot"]

    result = main.simulate_queue_separation(
        jobs=sample_jobs, hotspot_queue=hotspot_queue, main_queue=main_queue
    )

    # Strukturvalidierung
    assert isinstance(result, dict), "Simulationsergebnis muss ein Dict sein"
    for field in ("retry_tail_p99", "bandwidth", "hotspot_percentage"):
        assert field in result, f"Fehlendes Feld {field} in PerformanceMetrics"
        assert isinstance(result[field], (float, int)), f"{field} muss numerisch sein"


def test_simulation_value_ranges(sample_jobs):
    main_queue = [j for j in sample_jobs if j["queue"] == "main"]
    hotspot_queue = [j for j in sample_jobs if j["queue"] == "hotspot"]

    result = main.simulate_queue_separation(
        jobs=sample_jobs, hotspot_queue=hotspot_queue, main_queue=main_queue
    )

    # Werte sollen in plausiblen Bereichen liegen
    assert 0.0 <= result["retry_tail_p99"] <= 100.0, "retry_tail_p99 außerhalb des Bereichs"
    assert result["bandwidth"] > 0, "Bandbreite sollte positiv sein"
    assert 0.0 <= result["hotspot_percentage"] <= 1.0, "Hotspot-Prozentsatz außerhalb des Bereichs"


def test_tail_latency_increases_with_hotspots(sample_jobs):
    # Weniger Hotspots -> bessere Performance erwartet
    main_queue = [j for j in sample_jobs if j["queue"] == "main"]
    hotspot_queue = [j for j in sample_jobs if j["queue"] == "hotspot"]

    results_low_hotspot = main.simulate_queue_separation(
        jobs=sample_jobs[:10], hotspot_queue=hotspot_queue[:1], main_queue=main_queue[:9]
    )

    results_high_hotspot = main.simulate_queue_separation(
        jobs=sample_jobs, hotspot_queue=hotspot_queue + main_queue[:5], main_queue=main_queue[5:]
    )

    assert (
        results_high_hotspot["retry_tail_p99"] >= results_low_hotspot["retry_tail_p99"]
    ), "Mehr Hotspots sollten höhere Tail-Latenz erzeugen"
    assert results_high_hotspot["bandwidth"] >= 0 and results_low_hotspot["bandwidth"] >= 0


def test_invalid_input_handling():
    # Ungültiger Input sollte Exception oder Validation Error werfen
    invalid_jobs = [{"runtime": "fast", "queue": 123}]  # Typfehler
    with pytest.raises((AssertionError, TypeError, ValueError)):
        main.simulate_queue_separation(
            jobs=invalid_jobs, hotspot_queue=[], main_queue=[]
        )