"""Offline behavior and precision checks for native ETH amounts."""

import unittest
from decimal import Decimal, localcontext

from core import CryptoHubError, InvalidAmountError
from eth import WEI_PER_ETH, eth_to_wei, wei_to_eth


class EthUnitsTest(unittest.TestCase):
    def test_exact_conversions(self):
        for eth, wei in [("0", 0), ("1", WEI_PER_ETH), ("0.1", 10**17),
                         ("0.000000000000000001", 1), ("1.0000000000000000000", WEI_PER_ETH)]:
            with self.subTest(eth=eth):
                self.assertEqual(eth_to_wei(eth), wei)
                self.assertEqual(eth_to_wei(Decimal(eth)), wei)
                self.assertEqual(wei_to_eth(wei), Decimal(eth))

    def test_invalid_eth_is_rejected(self):
        for amount in [0.1, True, 1, None, "", "invalid", "-1", "NaN", "sNaN",
                       "Infinity", "-Infinity", "0.0000000000000000001"]:
            with self.subTest(amount=amount):
                with self.assertRaises(InvalidAmountError):
                    eth_to_wei(amount)

    def test_invalid_wei_is_rejected(self):
        for amount in [-1, True, False, 1.0, "1", Decimal("1"), None]:
            with self.subTest(amount=amount):
                with self.assertRaises(InvalidAmountError):
                    wei_to_eth(amount)

    def test_large_amount_round_trip_ignores_decimal_precision(self):
        wei = 123456789012345678901234567890123456789
        expected = Decimal("123456789012345678901.234567890123456789")
        with localcontext() as context:
            context.prec = 6
            self.assertEqual(wei_to_eth(wei), expected)
            self.assertEqual(eth_to_wei(expected), wei)
            self.assertEqual(eth_to_wei(wei_to_eth(wei)), wei)

    def test_invalid_amount_is_public_library_error(self):
        self.assertIsInstance(InvalidAmountError("invalid"), CryptoHubError)


if __name__ == "__main__":
    unittest.main()