import random

import pytest

from gausse.components.database import ComponentDatabase
from gausse.components.schema import CapacitorBank, CapacitorSpec
from gausse.optim.objective import build_detail
from gausse.optim.search_space import SearchBounds, decode, sample_genome
from gausse.sim.coilgun import run_coilgun

BASE = CapacitorSpec(
    part_number="c-base", capacitance_uf=100.0, voltage_v=400.0, esr_ohm=0.2,
    max_current_a=20.0, price=150.0, source="test",
)


def test_series_multiplies_voltage_and_divides_capacitance():
    bank = CapacitorBank.from_spec(BASE, n_series=3, n_parallel=1)
    assert bank.voltage_v == pytest.approx(1200.0)          # 400 * 3
    assert bank.capacitance_uf == pytest.approx(100.0 / 3)  # C / 3
    assert bank.esr_ohm == pytest.approx(0.6)               # ESR * 3
    assert bank.count == 3
    assert bank.price == pytest.approx(450.0)               # 150 * 3


def test_parallel_multiplies_capacitance_current_and_divides_esr():
    bank = CapacitorBank.from_spec(BASE, n_series=1, n_parallel=4)
    assert bank.capacitance_uf == pytest.approx(400.0)      # C * 4
    assert bank.voltage_v == pytest.approx(400.0)           # без изменения
    assert bank.esr_ohm == pytest.approx(0.05)              # ESR / 4
    assert bank.max_current_a == pytest.approx(80.0)        # 20 * 4 -- вот "на силу тока"
    assert bank.count == 4


def test_series_parallel_combination():
    bank = CapacitorBank.from_spec(BASE, n_series=2, n_parallel=3)
    assert bank.voltage_v == pytest.approx(800.0)
    assert bank.capacitance_uf == pytest.approx(100.0 * 3 / 2)
    assert bank.esr_ohm == pytest.approx(0.2 * 2 / 3)
    assert bank.count == 6
    assert bank.price == pytest.approx(150.0 * 6)


def test_energy_scales_with_bank():
    single = CapacitorBank.from_spec(BASE, 1, 1)
    bank = CapacitorBank.from_spec(BASE, 2, 2)  # V×2, C×1 (2 series, 2 parallel => C*2/2=C)
    e_single = 0.5 * (single.capacitance_uf * 1e-6) * single.voltage_v**2
    e_bank = 0.5 * (bank.capacitance_uf * 1e-6) * bank.voltage_v**2
    # тот же C, но вдвое большее напряжение -> вчетверо больше энергии
    assert e_bank == pytest.approx(4 * e_single)


def test_decoded_record_contains_capacitor_bank_composition():
    db = ComponentDatabase.load()
    bounds = SearchBounds()
    rng = random.Random(1)
    genome = sample_genome(db, bounds, rng)
    config, ix, iv = decode(genome, db, bounds)
    result = run_coilgun(config)
    detail = build_detail(config, result, db, ix, iv)
    bank = detail["stages"][0]["capacitor_bank"]
    assert set(bank) >= {"base_part", "n_series", "n_parallel", "count", "total_voltage_rating_v", "max_current_a"}
    assert bank["count"] == bank["n_series"] * bank["n_parallel"]
    # база должна быть реальной деталью
    assert bank["base_part"] in {c.part_number for c in db.capacitors}


def test_genome_carries_series_parallel_and_they_vary():
    db = ComponentDatabase.load()
    bounds = SearchBounds()
    rng = random.Random(5)
    series_vals, parallel_vals = set(), set()
    for _ in range(40):
        g = sample_genome(db, bounds, rng)
        for st in g.stages:
            assert bounds.cap_series_min <= st.cap_series <= bounds.cap_series_max
            assert bounds.cap_parallel_min <= st.cap_parallel <= bounds.cap_parallel_max
            series_vals.add(st.cap_series)
            parallel_vals.add(st.cap_parallel)
    assert len(series_vals) > 1 and len(parallel_vals) > 1