add ip change notification and refine sender display

tests/test_smtp.py

@@ -5,7 +5,13 @@ import smtplib
 from fastapi.testclient import TestClient
 
 from app.config import Settings
-from app.services.email import EmailDeliveryError, get_smtp_config, is_smtp_ready, send_smtp_test_email
+from app.services.email import (
+    EmailDeliveryError,
+    get_smtp_config,
+    is_smtp_ready,
+    send_public_ip_changed_email,
+    send_smtp_test_email,
+)
 
 
 def _extract_csrf_token(html: str) -> str:
@@ -43,6 +49,7 @@ def _smtp_settings(**overrides) -> Settings:
         "smtp_port": 587,
         "smtp_username": "smtp-user",
         "smtp_password": "super-secret-password",
+        "smtp_from_name": "Home Automation",
         "smtp_from_address": "sender@example.com",
         "smtp_to_address": "recipient@example.com",
         "smtp_use_starttls": True,
@@ -60,6 +67,7 @@ def test_get_smtp_config_reads_runtime_values() -> None:
     assert smtp_config.port == 2525
     assert smtp_config.username == "smtp-user"
     assert smtp_config.password == "super-secret-password"
+    assert smtp_config.from_name == "Home Automation"
     assert smtp_config.from_address == "sender@example.com"
     assert smtp_config.to_address == "recipient@example.com"
     assert smtp_config.use_starttls is False
@@ -96,11 +104,13 @@ def test_send_smtp_test_email_success(monkeypatch) -> None:
             sent["username"] = username
             sent["password"] = password
 
-        def send_message(self, message):
+        def send_message(self, message, from_addr=None, to_addrs=None):
             sent["subject"] = message["Subject"]
             sent["from"] = message["From"]
             sent["to"] = message["To"]
             sent["body"] = message.get_content()
+            sent["envelope_from"] = from_addr
+            sent["envelope_to"] = to_addrs
 
     monkeypatch.setattr("app.services.email.smtplib.SMTP", FakeSMTP)
 
@@ -113,8 +123,10 @@ def test_send_smtp_test_email_success(monkeypatch) -> None:
     assert sent["username"] == "smtp-user"
     assert sent["password"] == "super-secret-password"
     assert sent["subject"] == "Home Automation SMTP Test"
-    assert sent["from"] == "sender@example.com"
+    assert sent["from"] == "Home Automation <sender@example.com>"
     assert sent["to"] == "recipient@example.com"
+    assert sent["envelope_from"] == "sender@example.com"
+    assert sent["envelope_to"] == ["recipient@example.com"]
     assert "This is a test email" in sent["body"]
 
 
@@ -140,8 +152,10 @@ def test_send_smtp_test_email_does_not_require_smtp_enabled(monkeypatch) -> None
         def login(self, username, password):
             return None
 
-        def send_message(self, message):
+        def send_message(self, message, from_addr=None, to_addrs=None):
             sent["subject"] = message["Subject"]
+            sent["from"] = message["From"]
+            sent["envelope_from"] = from_addr
 
     monkeypatch.setattr("app.services.email.smtplib.SMTP", FakeSMTP)
 
@@ -149,6 +163,8 @@ def test_send_smtp_test_email_does_not_require_smtp_enabled(monkeypatch) -> None
 
     assert sent["host"] == "smtp.example.com"
     assert sent["subject"] == "Home Automation SMTP Test"
+    assert sent["from"] == "Home Automation <sender@example.com>"
+    assert sent["envelope_from"] == "sender@example.com"
 
 
 def test_send_smtp_test_email_failure_sanitizes_password(monkeypatch) -> None:
@@ -178,6 +194,53 @@ def test_send_smtp_test_email_failure_sanitizes_password(monkeypatch) -> None:
         assert "[redacted]" in str(exc)
 
 
+def test_send_public_ip_changed_email_contains_expected_english_content(monkeypatch) -> None:
+    sent = {}
+
+    class FakeSMTP:
+        def __init__(self, host, port, timeout):
+            sent["host"] = host
+
+        def __enter__(self):
+            return self
+
+        def __exit__(self, exc_type, exc, tb):
+            return None
+
+        def ehlo(self):
+            return None
+
+        def starttls(self):
+            return None
+
+        def login(self, username, password):
+            return None
+
+        def send_message(self, message, from_addr=None, to_addrs=None):
+            sent["subject"] = message["Subject"]
+            sent["body"] = message.get_content()
+            sent["from"] = message["From"]
+            sent["envelope_from"] = from_addr
+
+    monkeypatch.setattr("app.services.email.smtplib.SMTP", FakeSMTP)
+
+    send_public_ip_changed_email(
+        _smtp_settings(),
+        previous_ipv4="203.0.113.10",
+        current_ipv4="198.51.100.25",
+        detected_at=__import__("datetime").datetime(2026, 4, 29, 10, 0, tzinfo=__import__("datetime").UTC),
+    )
+
+    assert sent["subject"] == "Public IP changed"
+    assert sent["from"] == "Home Automation <sender@example.com>"
+    assert sent["envelope_from"] == "sender@example.com"
+    assert "Your public IPv4 address has changed." in sent["body"]
+    assert "Previous IP: 203.0.113.10" in sent["body"]
+    assert "Current IP: 198.51.100.25" in sent["body"]
+    assert "Detected at: 2026-04-29 10:00:00 UTC" in sent["body"]
+    assert "update the trusted IP manually" in sent["body"]
+
+
 def test_config_update_does_not_clear_existing_smtp_password(
     client: TestClient, test_database_urls
 ) -> None: