"""enc:v2 envelope encryption (H4): roundtrip, legacy v1 compat, format checks."""
import base64
import hashlib

import pytest
from cryptography.fernet import Fernet

from app.services import crypto


@pytest.fixture(autouse=True)
def _kek(monkeypatch):
    monkeypatch.setattr(crypto.settings, "encryption_key", "k" * 64)
    # Reset module caches so each test derives from the patched KEK.
    crypto._fernet_v1 = None
    crypto._fernet_v2_cache.clear()
    crypto._encrypt_salt = None
    yield
    crypto._fernet_v1 = None
    crypto._fernet_v2_cache.clear()
    crypto._encrypt_salt = None


def test_v2_roundtrip():
    blob = crypto.encrypt_api_key("0x" + "ab" * 32)
    assert blob.startswith(crypto.ENC_PREFIX_V2)
    assert crypto.decrypt_api_key(blob) == "0x" + "ab" * 32
    assert crypto.is_current_format(blob)
    # Fits the hl_api_key String(256) column.
    assert len(blob) <= 256


def test_v1_blob_still_decrypts():
    # Build a v1 blob exactly the way the legacy code did.
    digest = hashlib.sha256(("k" * 64).encode()).digest()
    f = Fernet(base64.urlsafe_b64encode(digest))
    blob = crypto.ENC_PREFIX_V1 + f.encrypt(b"secret-key").decode()
    assert not crypto.is_current_format(blob)
    assert crypto.decrypt_api_key(blob) == "secret-key"


def test_wrong_kek_raises(monkeypatch):
    blob = crypto.encrypt_api_key("topsecret")
    monkeypatch.setattr(crypto.settings, "encryption_key", "x" * 64)
    crypto._fernet_v2_cache.clear()
    with pytest.raises(RuntimeError):
        crypto.decrypt_api_key(blob)


def test_malformed_v2_raises():
    with pytest.raises(RuntimeError):
        crypto.decrypt_api_key(crypto.ENC_PREFIX_V2 + "no-salt-separator")


def test_plaintext_refused_in_production(monkeypatch):
    monkeypatch.setattr(crypto.settings, "environment", "production")
    with pytest.raises(RuntimeError):
        crypto.decrypt_api_key("raw-plaintext-key")