"""Unit tests for mailer.py's SMTP call shape (#18). Calls _send_now directly
rather than going through the background-thread queue, so assertions are
synchronous -- the queue itself is just plumbing, already covered indirectly
by app.py's identical Sheets-mirror pattern.
"""
from email.message import EmailMessage

import pytest

import mailer


class _FakeSMTP:
    sent = []
    login_calls = []

    def __init__(self, host, port, timeout=None):
        self.host = host
        self.port = port

    def __enter__(self):
        return self

    def __exit__(self, *exc):
        return False

    def starttls(self):
        pass

    def login(self, username, password):
        _FakeSMTP.login_calls.append((username, password))

    def send_message(self, msg):
        _FakeSMTP.sent.append(msg)


@pytest.fixture(autouse=True)
def _reset_fake_smtp():
    _FakeSMTP.sent = []
    _FakeSMTP.login_calls = []
    yield


def _msg(to="alice@example.com"):
    msg = EmailMessage()
    msg["Subject"] = "Terminbestätigung"
    msg["From"] = "noreply@example.com"
    msg["To"] = to
    msg.set_content("<p>hi</p>", subtype="html")
    return msg


def test_send_now_skips_when_smtp_host_not_configured(monkeypatch):
    monkeypatch.setattr(mailer, "SMTP_HOST", "")
    monkeypatch.setattr(mailer, "smtplib", type("m", (), {"SMTP": _FakeSMTP}))
    mailer._send_now(_msg())
    assert _FakeSMTP.sent == []


def test_send_now_sends_via_smtp_when_configured(monkeypatch):
    monkeypatch.setattr(mailer, "SMTP_HOST", "smtp.example.com")
    monkeypatch.setattr(mailer, "SMTP_PORT", 587)
    monkeypatch.setattr(mailer, "SMTP_USERNAME", "")
    monkeypatch.setattr(mailer, "smtplib", type("m", (), {"SMTP": _FakeSMTP}))
    msg = _msg()
    mailer._send_now(msg)
    assert _FakeSMTP.sent == [msg]
    assert _FakeSMTP.login_calls == []


def test_send_now_logs_in_when_username_configured(monkeypatch):
    monkeypatch.setattr(mailer, "SMTP_HOST", "smtp.example.com")
    monkeypatch.setattr(mailer, "SMTP_USERNAME", "mailer")
    monkeypatch.setattr(mailer, "SMTP_PASSWORD", "secret")
    monkeypatch.setattr(mailer, "smtplib", type("m", (), {"SMTP": _FakeSMTP}))
    mailer._send_now(_msg())
    assert _FakeSMTP.login_calls == [("mailer", "secret")]


def test_send_email_builds_html_message_and_enqueues(monkeypatch):
    captured = []
    monkeypatch.setattr(mailer._queue, "put", lambda m: captured.append(m))
    mailer.send_email("bob@example.com", "Subject line", "<p>body</p>",
                       from_addr="noreply@custom.example")
    assert len(captured) == 1
    msg = captured[0]
    assert msg["To"] == "bob@example.com"
    assert msg["Subject"] == "Subject line"
    assert msg["From"] == "noreply@custom.example"
    assert msg.get_content_type() == "text/html"


def test_send_email_defaults_from_addr_to_fallback(monkeypatch):
    captured = []
    monkeypatch.setattr(mailer._queue, "put", lambda m: captured.append(m))
    monkeypatch.setattr(mailer, "MAIL_FALLBACK_FROM", "noreply@mivanchenko.de")
    mailer.send_email("bob@example.com", "Subject", "<p>body</p>")
    assert captured[0]["From"] == "noreply@mivanchenko.de"