"""Credential assignments stay configurable without importing live services."""
import ast
import os
from pathlib import Path
import secrets
import unittest
from unittest.mock import patch

ROOT = Path(__file__).resolve().parents[1]
MAPPINGS = (
    ('bot-utility/for_admin_komari_agent.py', 'KOMARI_PASSWORD', 'KOMARI_PASSWORD'),
    ('bot-utility/pixiv.py', 'CF_PASSWORD', 'PIXIV_CF_PASSWORD'),
    ('mail-bridge/mailWeb.py', 'HMAIL_ADMIN_PASSWORD', 'HMAIL_ADMIN_PASSWORD'),
    ('mail-bridge/mailWeb.py', 'REGISTER_AUTH_CODE', 'MAIL_REGISTER_AUTH_CODE'),
    ('mail-bridge/mailWeb.py', 'app.secret_key', 'MAIL_FLASK_SECRET_KEY'),
)


def expression(relative, target):
    tree = ast.parse((ROOT / relative).read_text(encoding='utf-8'))
    for node in tree.body:
        if isinstance(node, ast.Assign) and any(ast.unparse(t) == target for t in node.targets):
            return ast.Expression(node.value)
    raise AssertionError('Credential assignment missing: ' + target)


class EnvironmentCredentialTests(unittest.TestCase):
    def test_each_credential_comes_from_its_environment_variable(self):
        for path, target, env in MAPPINGS:
            with self.subTest(target=target), patch.dict(os.environ, {env: 'temporary-unit-test-value'}):
                value = eval(compile(expression(path, target), '<credential-assignment>', 'eval'),
                             {'os': os, 'secrets': secrets})
                self.assertEqual(value, 'temporary-unit-test-value')

    def test_missing_passwords_default_empty_not_embedded_credentials(self):
        for path, target, _ in MAPPINGS[:-1]:
            with self.subTest(target=target), patch.dict(os.environ, {}, clear=True):
                value = eval(compile(expression(path, target), '<credential-assignment>', 'eval'),
                             {'os': os, 'secrets': secrets})
                self.assertEqual(value, '')

    def test_unconfigured_flask_key_is_ephemeral_not_shared(self):
        path, target, _ = MAPPINGS[-1]
        with patch.dict(os.environ, {}, clear=True):
            code = compile(expression(path, target), '<credential-assignment>', 'eval')
            one = eval(code, {'os': os, 'secrets': secrets})
            two = eval(code, {'os': os, 'secrets': secrets})
        self.assertTrue(one)
        self.assertNotEqual(one, two)


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