import email
from email.message import EmailMessage

import pytest
from unittest import mock

from projektmatch import mailer


def fake_conn():
    conn = mock.Mock()
    conn.uid.return_value = ("OK", [b"3 7"])
    conn.list.return_value = ("OK", [
        b'(\\HasNoChildren) "." "INBOX"',
        b'(\\HasNoChildren \\Trash) "." "Trash"'])
    return conn


def test_unchecked_uids_search():
    box = mailer.MailBox("u", "p", conn=fake_conn())
    assert box.unchecked_uids() == ["3", "7"]
    box.conn.uid.assert_called_with("SEARCH", None,
                                    "UNKEYWORD $ProjektChecked")


def test_flag_checked():
    box = mailer.MailBox("u", "p", conn=fake_conn())
    box.flag_checked("3")
    box.conn.uid.assert_called_with("STORE", "3", "+FLAGS",
                                    "($ProjektChecked)")


def test_trash_folder_by_special_use():
    box = mailer.MailBox("u", "p", conn=fake_conn())
    assert box.trash_folder() == "Trash"


def test_move_uses_move_then_fallback():
    conn = fake_conn()
    box = mailer.MailBox("u", "p", conn=conn)
    conn.uid.return_value = ("OK", [b""])
    box.move_to_trash("3")
    assert conn.uid.call_args_list[-1].args[:2] == ("MOVE", "3")
    conn.uid.side_effect = [("NO", [b""]), ("OK", [b""]), ("OK", [b""])]
    box.move_to_trash("4")
    assert conn.expunge.called


def test_fetch_raises_on_no_response():
    conn = fake_conn()
    conn.uid.return_value = ("NO", [None])
    box = mailer.MailBox("u", "p", conn=conn)
    with pytest.raises(RuntimeError):
        box.fetch("3")


def test_fetch_raises_on_malformed_ok_response():
    conn = fake_conn()
    conn.uid.return_value = ("OK", [None])
    box = mailer.MailBox("u", "p", conn=conn)
    with pytest.raises(RuntimeError):
        box.fetch("3")


def test_send_mail_starttls():
    with mock.patch("projektmatch.mailer.smtplib.SMTP") as smtp, \
            mock.patch("projektmatch.mailer.append_sent") as append_sent:
        server = smtp.return_value.__enter__.return_value
        mailer.send_mail("u@x", "pw", "to@x", "Subj", "Body")
    server.starttls.assert_called_once()
    server.login.assert_called_once_with("u@x", "pw")
    msg = server.send_message.call_args.args[0]
    assert msg["Subject"] == "Subj" and msg["To"] == "to@x"
    assert msg["Date"]
    assert msg["Message-ID"].endswith("@destengs.com>")
    append_sent.assert_called_once_with("u@x", "pw", msg)


def test_send_mail_survives_append_failure():
    with mock.patch("projektmatch.mailer.smtplib.SMTP") as smtp, \
            mock.patch("projektmatch.mailer.append_sent",
                        side_effect=OSError("imap down")):
        mailer.send_mail("u@x", "pw", "to@x", "Subj", "Body")


def test_ensure_alive_keeps_healthy_connection():
    conn = fake_conn()
    conn.noop.return_value = ("OK", [b""])
    box = mailer.MailBox("u", "p", conn=conn)
    box.ensure_alive()
    assert box.conn is conn
    conn.noop.assert_called_once()


def test_ensure_alive_reconnects_on_dead_connection():
    conn = fake_conn()
    conn.noop.side_effect = OSError("connection closed")
    box = mailer.MailBox("u", "p", conn=conn)
    fresh = fake_conn()
    with mock.patch("projektmatch.mailer.imaplib.IMAP4_SSL",
                    return_value=fresh):
        box.ensure_alive()
    assert box.conn is fresh
    fresh.login.assert_called_once_with("u", "p")
    fresh.select.assert_called_once_with("INBOX")


def test_append_sent_uses_special_use_folder():
    conn = mock.Mock()
    conn.list.return_value = ("OK", [
        b'(\\HasNoChildren) "." "INBOX"',
        b'(\\HasNoChildren \\Sent) "." "Sent"'])
    msg = EmailMessage()
    msg["Subject"] = "Subj"
    msg.set_content("Body")

    mailer.append_sent("u@x", "pw", msg, conn=conn)

    args = conn.append.call_args.args
    assert args[0] == "Sent"
    assert "\\Seen" in args[1]
    assert args[3] == msg.as_bytes()
    conn.login.assert_not_called()
    conn.logout.assert_not_called()