import json
from decimal import Decimal

import pytest

from app import crypto, journal
from app.models import SCHEMA_VERSION, Document
from app.storage import Vault, content_hash, migrate


def test_create_and_reopen(tmp_path):
    path = tmp_path / "vault.fmdb"
    vault = Vault.create(path, "pw")
    journal.create_product(vault, "Булка с маком", cost_price=20, retail_price=35)
    vault.save()

    reopened = Vault.open(path, "pw")
    assert [p.name for p in reopened.doc.products] == ["Булка с маком"]
    assert reopened.doc.products[0].cost_price == Decimal("20.00")


def test_open_with_wrong_password(tmp_path):
    path = tmp_path / "vault.fmdb"
    Vault.create(path, "pw")
    with pytest.raises(crypto.WrongPassword):
        Vault.open(path, "nope")


def test_create_refuses_to_clobber(tmp_path):
    path = tmp_path / "vault.fmdb"
    Vault.create(path, "pw")
    with pytest.raises(crypto.VaultError):
        Vault.create(path, "other")


def test_save_skips_write_when_nothing_changed(tmp_path):
    """Главная защита от мусорных коммитов в git.

    Шифртекст каждый раз новый, поэтому решение «писать или нет» принимается
    по хешу открытых данных, а не по байтам файла.
    """
    path = tmp_path / "vault.fmdb"
    vault = Vault.create(path, "pw")
    journal.create_product(vault, "Булка", cost_price=10, retail_price=20)

    assert vault.save() is True
    assert vault.save() is False
    assert vault.save() is False


def test_save_detects_real_change(tmp_path):
    vault = Vault.create(tmp_path / "vault.fmdb", "pw")
    vault.save()
    journal.create_product(vault, "Булка", cost_price=10, retail_price=20)
    assert vault.is_dirty is True
    assert vault.save() is True
    assert vault.is_dirty is False


def test_freshly_opened_vault_is_not_dirty(tmp_path):
    """Иначе каждое открытие программы порождало бы коммит на пустом месте."""
    path = tmp_path / "vault.fmdb"
    vault = Vault.create(path, "pw")
    journal.create_product(vault, "Булка", cost_price=10, retail_price=20)
    vault.save()

    reopened = Vault.open(path, "pw")
    assert reopened.is_dirty is False
    assert reopened.save() is False


def test_content_hash_ignores_key_order():
    assert content_hash({"a": 1, "b": 2}) == content_hash({"b": 2, "a": 1})


def test_change_password(tmp_path):
    path = tmp_path / "vault.fmdb"
    vault = Vault.create(path, "old")
    journal.create_product(vault, "Булка", cost_price=10, retail_price=20)
    vault.save()

    vault.change_password("new")
    with pytest.raises(crypto.WrongPassword):
        Vault.open(path, "old")
    assert Vault.open(path, "new").doc.products[0].name == "Булка"


def test_atomic_write_leaves_backup(tmp_path):
    path = tmp_path / "vault.fmdb"
    vault = Vault.create(path, "pw")
    journal.create_product(vault, "Булка", cost_price=10, retail_price=20)
    vault.save()

    assert path.with_suffix(".fmdb.bak").exists()
    assert not path.with_suffix(".fmdb.tmp").exists()


def test_decimals_survive_round_trip(tmp_path):
    """Деньги ходят через строки, поэтому копейки не должны разъезжаться."""
    path = tmp_path / "vault.fmdb"
    vault = Vault.create(path, "pw")
    journal.create_product(vault, "Булка", cost_price="33.33", retail_price="66.67")
    vault.save()

    product = Vault.open(path, "pw").doc.products[0]
    assert product.cost_price == Decimal("33.33")
    assert product.retail_price == Decimal("66.67")


def test_export_plain_json(tmp_path):
    vault = Vault.create(tmp_path / "vault.fmdb", "pw")
    journal.create_product(vault, "Булка с маком", cost_price=20, retail_price=35)

    out = vault.export_plain_json(tmp_path / "export.json")
    data = json.loads(out.read_text(encoding="utf-8"))
    assert data["products"][0]["name"] == "Булка с маком"


def test_migration_adds_journal():
    raw = migrate({"schema_version": 0, "products": []})
    assert raw["schema_version"] == SCHEMA_VERSION
    assert raw["journal"] == []


def test_migration_adds_packaging_without_changing_behaviour():
    """Старая база должна открыться так, будто всё записано в базовых единицах."""
    raw = migrate(
        {
            "schema_version": 1,
            "products": [{"id": "p_1", "name": "Печенье", "unit": "шт", "cost_price": "20"}],
            "batches": [
                {
                    "id": "b_1", "number": 1, "date": "2026-08-01", "due_date": "2026-08-15",
                    "lines": [{"product_id": "p_1", "qty": "10", "unit_cost": "20"}],
                }
            ],
            "sales": [
                {
                    "id": "s_1", "date": "2026-08-02", "kind": "retail",
                    "lines": [{"product_id": "p_1", "qty": "3", "unit_price": "30"}],
                }
            ],
        }
    )

    assert raw["schema_version"] == SCHEMA_VERSION
    assert raw["products"][0]["packs"] == []
    assert raw["batches"][0]["lines"][0] == {
        "product_id": "p_1", "qty": "10", "unit_cost": "20", "uom": "", "uom_size": "1"
    }

    doc = Document.from_dict(raw)
    assert doc.batches[0].lines[0].base_qty == Decimal("10.000")
    assert doc.batches[0].lines[0].base_unit_cost == Decimal("20.00")
    assert doc.sales[0].lines[0].base_unit_price == Decimal("30.00")


def test_future_schema_refuses_to_open():
    with pytest.raises(crypto.UnsupportedFormat, match="новой версией"):
        migrate({"schema_version": 999})


def test_corrupted_json_inside_valid_encryption(tmp_path):
    """GCM подтвердил целостность, но внутри не JSON — сообщаем внятно."""
    path = tmp_path / "vault.fmdb"
    path.write_bytes(crypto.encrypt(b"not json at all", "pw"))
    with pytest.raises(crypto.VaultError, match="повреждено"):
        Vault.open(path, "pw")