import random

from gausse.components.database import ComponentDatabase
from gausse.optim.objective import compute_cost_rub, decoded_summary, evaluate
from gausse.optim.search_space import SearchBounds, decode, sample_genome

DB = ComponentDatabase.load()
BOUNDS = SearchBounds()


def test_evaluate_feasible_genome_has_fitness_equal_efficiency():
    rng = random.Random(2)
    found_feasible = False
    for _ in range(50):
        genome = sample_genome(DB, BOUNDS, rng)
        result = evaluate(genome, DB, BOUNDS)
        if result.feasible:
            found_feasible = True
            assert result.fitness == result.efficiency
            # КПД <= 1 всегда; может быть СЛЕГКА отрицательным: трение о трубку
            # за время разряда может съесть больше, чем слабая катушка добавила
            assert -0.01 <= result.efficiency <= 1.0
            assert result.cost_rub > 0
            break
    assert found_feasible, "ни один из 50 случайных геномов не оказался реализуемым"


def test_evaluate_infeasible_genome_has_negative_fitness_and_reason():
    rng = random.Random(9)
    genome = sample_genome(DB, BOUNDS, rng)
    # индукционный датчик требует скорости >= порог/чувствительность = 5 м/с,
    # а старт по умолчанию 3 м/с -- первая ступень обязана провалиться
    inductive_idx = next(i for i, s in enumerate(DB.sensors) if s.kind == "inductive")
    genome.stages[0].sensor_idx = inductive_idx
    result = evaluate(genome, DB, BOUNDS)
    assert not result.feasible
    assert result.fitness < 0
    assert result.reason is not None
    assert result.failed_stage_index == 0


def test_compute_cost_rub_is_positive_and_scales_with_stage_count():
    rng = random.Random(4)
    genome = sample_genome(DB, BOUNDS, rng)
    config, _, _ = decode(genome, DB, BOUNDS)
    cost = compute_cost_rub(config, DB)
    assert cost > 0

    genome.stages.append(genome.stages[0])
    genome.inter_stage_gaps_m.append(0.05)
    config2, _, _ = decode(genome, DB, BOUNDS)
    cost2 = compute_cost_rub(config2, DB)
    assert cost2 > cost


def test_decoded_summary_uses_real_part_numbers():
    rng = random.Random(6)
    genome = sample_genome(DB, BOUNDS, rng)
    summary = decoded_summary(genome, DB)
    assert len(summary["stages"]) == len(genome.stages)
    real_wire_ids = {w.part_id for w in DB.wires}
    assert all(s["wire"] in real_wire_ids for s in summary["stages"])