"""Feature-flag isolation: flags control INSTALLED_APPS membership and deps."""

import ast
from pathlib import Path

from django.apps import apps
from django.core.exceptions import ImproperlyConfigured
from django.test import SimpleTestCase, TestCase
from django.urls import reverse


def _read_settings_source() -> str:
    return (Path(__file__).resolve().parent.parent / "client_site/settings/base.py").read_text()


class FeatureFlagSettingsTests(SimpleTestCase):
    def test_optional_apps_are_gated_in_settings(self):
        src = _read_settings_source()
        self.assertIn("FEATURE_EMAIL_SMS", src)
        self.assertIn("FEATURE_DIRECT_MAIL", src)
        self.assertIn("FEATURE_BLOG", src)
        self.assertIn("FEATURE_PAYMENTS", src)
        self.assertIn("FEATURE_SOCIAL", src)
        self.assertIn("FEATURE_SOCIAL_AI", src)
        self.assertIn("email_sms.apps.EmailSmsConfig", src)
        self.assertIn("directmail.apps.DirectmailConfig", src)
        self.assertIn("blog.apps.BlogConfig", src)
        self.assertIn("payments.apps.PaymentsConfig", src)
        self.assertIn("social_ai.apps.SocialAiConfig", src)

    def test_payments_requires_email_sms_in_source(self):
        src = _read_settings_source()
        self.assertIn("FEATURE_PAYMENTS requires FEATURE_EMAIL_SMS", src)
        self.assertIn("FEATURE_SOCIAL_AI requires FEATURE_SOCIAL", src)


class AlwaysOnImportIsolationTests(SimpleTestCase):
    """Always-on modules must not import optional apps at module level."""

    OPTIONAL = {
        "email_sms",
        "directmail",
        "blog",
        "payments",
        "social",
        "social_ai",
    }

    ALWAYS_ON = [
        "dashboard/views.py",
        "public/views.py",
        "core/management/commands/dispatch_due.py",
        "client_site/urls.py",
    ]

    def test_no_module_level_optional_imports(self):
        root = Path(__file__).resolve().parent.parent
        for rel in self.ALWAYS_ON:
            path = root / rel
            tree = ast.parse(path.read_text())
            for node in ast.walk(tree):
                if isinstance(node, ast.ImportFrom) and node.module:
                    top = node.module.split(".")[0]
                    # Allow inside functions — ast.ImportFrom at module body only
                if isinstance(node, (ast.Import, ast.ImportFrom)):
                    pass
            # Check only top-level
            for node in tree.body:
                if isinstance(node, ast.Import):
                    for alias in node.names:
                        top = alias.name.split(".")[0]
                        self.assertNotIn(top, self.OPTIONAL, f"{rel} imports {alias.name}")
                if isinstance(node, ast.ImportFrom) and node.module:
                    top = node.module.split(".")[0]
                    self.assertNotIn(top, self.OPTIONAL, f"{rel} imports {node.module}")


class InstalledOptionalAppsTests(TestCase):
    """Dev defaults install optional apps so the template is a working seed."""

    def test_dev_installs_catalog_apps(self):
        labels = {c.label for c in apps.get_app_configs()}
        for label in ("email_sms", "directmail", "blog", "payments", "social", "social_ai"):
            self.assertIn(label, labels)

    def test_optional_urls_resolve_when_installed(self):
        self.assertTrue(reverse("email_sms:campaign_list").startswith("/portal/messaging/"))
        self.assertTrue(reverse("directmail:postcard_designer").startswith("/portal/direct-mail/"))
        self.assertTrue(reverse("blog:list").startswith("/blog/"))
        self.assertTrue(reverse("payments:invoice_list").startswith("/portal/payments/"))
        self.assertTrue(reverse("social:composer").startswith("/portal/social/"))
        self.assertTrue(reverse("social_ai:generate").startswith("/portal/social/api/generate/"))