email-connect/tests/test_transactional.py

import io
import json
import smtplib

import pytest

from email_connect.transactional import (
    ProviderError,
    SMTPProvider,
    SQLiteDeliveryStore,
    TransactionalApplication,
)


class Provider:
    def __init__(self):
        self.calls = []

    def send(self, *args):
        self.calls.append(args)
        return "message:1"


class FailingProvider:
    def __init__(self, error: ProviderError):
        self.error = error
        self.calls = 0

    def send(self, *args):
        self.calls += 1
        raise self.error


def event(event_id="evt-1", typ="family_member.invited", email="person@example.test"):
    return {
        "id": event_id,
        "type": typ,
        "source": "user-engine",
        "data": {"primary_email": email, "invitation_id": "inv-1"},
    }


def invoke(app, payload, token="opaque", key=None, path="/v1/send"):
    raw = json.dumps(payload).encode()
    result = {}
    env = {
        "PATH_INFO": path,
        "REQUEST_METHOD": "POST",
        "CONTENT_LENGTH": str(len(raw)),
        "wsgi.input": io.BytesIO(raw),
        "HTTP_AUTHORIZATION": f"Bearer {token}",
    }
    if path == "/v1/send":
        env["HTTP_IDEMPOTENCY_KEY"] = key if key is not None else payload.get("id", "evt-1")
    body = b"".join(app(env, lambda s, h: result.update(status=s)))
    return result["status"], json.loads(body)


def test_sends_fixed_template_once(tmp_path):
    provider = Provider()
    app = TransactionalApplication(
        SQLiteDeliveryStore(str(tmp_path / "mail.db")), provider, "opaque", "https://users.example"
    )
    status, body = invoke(app, event())
    assert status.startswith("202")
    assert body["evidence_ceiling"] == "provider_accepted"
    assert body["event_id"] == "evt-1"
    assert invoke(app, event())[1]["status"] == "duplicate"
    assert len(provider.calls) == 1 and "/invitations/inv-1" in provider.calls[0][2]


def test_rejects_auth_recipient_template_and_key(tmp_path):
    app = TransactionalApplication(
        SQLiteDeliveryStore(str(tmp_path / "mail.db")), Provider(), "opaque", "https://users.example"
    )
    assert invoke(app, event(), token="bad")[0].startswith("401")
    bad = event()
    bad["data"]["primary_email"] = "bad\n@example.test"
    assert invoke(app, bad)[1]["error"] == "invalid_recipient"
    bad = event()
    bad["type"] = "arbitrary.send"
    assert invoke(app, bad)[1]["error"] == "template_not_allowed"
    assert invoke(app, event(), key="other")[1]["error"] == "idempotency_key_mismatch"


def test_resend_is_separate_event_and_sends_again(tmp_path):
    provider = Provider()
    app = TransactionalApplication(
        SQLiteDeliveryStore(str(tmp_path / "mail.db")), provider, "opaque", "https://users.example"
    )
    assert invoke(app, event("evt-1", "family_member.invited"))[0].startswith("202")
    status, body = invoke(app, event("evt-2", "family_invitation.resent"))
    assert status.startswith("202") and body["status"] == "accepted"
    assert len(provider.calls) == 2


def test_suppression_blocks_send(tmp_path):
    store = SQLiteDeliveryStore(str(tmp_path / "mail.db"))
    store.suppress("person@example.test", "complaint")
    provider = Provider()
    app = TransactionalApplication(store, provider, "opaque", "https://users.example")
    status, body = invoke(app, event())
    assert status.startswith("400")
    assert body["error"] == "recipient_suppressed"
    assert provider.calls == []


def test_provider_timeout_temporary_and_permanent_are_redacted(tmp_path):
    cases = [
        (ProviderError("provider_timeout", retryable=True), "503", True),
        (ProviderError("temporary_deferral", retryable=True), "503", True),
        (ProviderError("permanent_rejection", retryable=False), "422", False),
        (ProviderError("provider_unavailable", retryable=True), "503", True),
    ]
    for err, code_prefix, retryable in cases:
        app = TransactionalApplication(
            SQLiteDeliveryStore(str(tmp_path / f"{err.code}.db")),
            FailingProvider(err),
            "opaque",
            "https://users.example",
        )
        status, body = invoke(app, event(event_id=f"evt-{err.code}"))
        assert status.startswith(code_prefix), (err.code, status, body)
        assert body["error"] == err.code
        assert body["retryable"] is retryable
        # Diagnostics must stay redacted: no SMTP host, password, or exception text.
        blob = json.dumps(body)
        assert "smtp" not in blob.lower()
        assert "password" not in blob.lower()
        assert "exception" not in blob.lower()


def test_smtp_provider_maps_recipient_refused_to_permanent():
    class Boom(smtplib.SMTP):
        def __init__(self, *a, **k):
            pass

        def __enter__(self):
            return self

        def __exit__(self, *a):
            return False

        def starttls(self):
            return None

        def login(self, *a):
            return None

        def send_message(self, msg):
            raise smtplib.SMTPRecipientsRefused({"x@y.z": (550, b"user unknown")})

    import email_connect.transactional as mod

    original = mod.smtplib.SMTP
    mod.smtplib.SMTP = Boom
    try:
        provider = mod.SMTPProvider("smtp.example", 587, "u", "p", "from@example")
        try:
            provider.send("x@y.z", "s", "b")
            assert False, "expected ProviderError"
        except ProviderError as exc:
            assert exc.code == "permanent_rejection" and exc.retryable is False
    finally:
        mod.smtplib.SMTP = original


def test_registration_verification_is_digest_only_and_single_use(tmp_path):
    provider = Provider()
    store = SQLiteDeliveryStore(str(tmp_path / "mail.db"))
    app = TransactionalApplication(store, provider, "opaque", "https://users.example")
    request = {
        "registration_id": "reg-1",
        "normalized_email": "person@example.test",
        "preferred_username": "person",
        "client_id": "coulomb-social",
        "tenant": "tenant:coulomb",
        "correlation_id": "corr-1",
    }
    raw = json.dumps(request).encode()
    result = {}
    response = json.loads(
        b"".join(
            app(
                {
                    "PATH_INFO": "/v1/registration-verifications",
                    "REQUEST_METHOD": "POST",
                    "CONTENT_LENGTH": str(len(raw)),
                    "wsgi.input": io.BytesIO(raw),
                    "HTTP_AUTHORIZATION": "Bearer opaque",
                },
                lambda s, h: result.update(status=s),
            )
        )
    )
    assert result["status"].startswith("202") and response["accepted"]
    text = provider.calls[0][2]
    handle = text.split("handle=", 1)[1].splitlines()[0]
    stored = store.db.execute("SELECT handle_hash FROM verifications").fetchone()[0]
    assert handle not in stored and stored
    consume = json.dumps({"handle": handle}).encode()
    env = {
        "PATH_INFO": "/v1/registration-verifications/consume",
        "REQUEST_METHOD": "POST",
        "CONTENT_LENGTH": str(len(consume)),
        "wsgi.input": io.BytesIO(consume),
        "HTTP_AUTHORIZATION": "Bearer opaque",
    }
    evidence = json.loads(b"".join(app(env, lambda s, h: result.update(status=s))))
    assert evidence["purpose"] == "public-registration"
    assert evidence["email"] == "person@example.test"
    assert evidence["authorization"] is False
    assert evidence["evidence_ceiling"] == "mailbox_challenge_consumed"
    env["wsgi.input"] = io.BytesIO(consume)
    replay = json.loads(b"".join(app(env, lambda s, h: result.update(status=s))))
    assert replay["error"] == "verification_invalid"


def test_registration_cancellation_is_single_use_and_prevents_verification(tmp_path):
    provider = Provider()
    store = SQLiteDeliveryStore(str(tmp_path / "mail.db"))
    app = TransactionalApplication(store, provider, "opaque", "https://users.example")
    request = {
        "registration_id": "reg-cancel",
        "normalized_email": "person@example.test",
        "preferred_username": "person",
        "client_id": "coulomb-social",
        "tenant": "tenant:coulomb",
        "correlation_id": "corr-cancel",
    }
    raw = json.dumps(request).encode()
    result = {}
    app(
        {
            "PATH_INFO": "/v1/registration-verifications",
            "REQUEST_METHOD": "POST",
            "CONTENT_LENGTH": str(len(raw)),
            "wsgi.input": io.BytesIO(raw),
            "HTTP_AUTHORIZATION": "Bearer opaque",
        },
        lambda s, h: result.update(status=s),
    )
    text = provider.calls[0][2]
    handle = text.split("handle=", 1)[1].splitlines()[0]
    assert f"/registration/cancel?handle={handle}" in text
    payload = json.dumps({"handle": handle}).encode()
    cancel_env = {
        "PATH_INFO": "/v1/registration-verifications/cancel",
        "REQUEST_METHOD": "POST",
        "CONTENT_LENGTH": str(len(payload)),
        "wsgi.input": io.BytesIO(payload),
        "HTTP_AUTHORIZATION": "Bearer opaque",
    }
    canceled = json.loads(b"".join(app(cancel_env, lambda s, h: result.update(status=s))))
    assert canceled["purpose"] == "public-registration-cancel"
    assert canceled["authorization"] is False
    consume_env = {
        "PATH_INFO": "/v1/registration-verifications/consume",
        "REQUEST_METHOD": "POST",
        "CONTENT_LENGTH": str(len(payload)),
        "wsgi.input": io.BytesIO(payload),
        "HTTP_AUTHORIZATION": "Bearer opaque",
    }
    rejected = json.loads(b"".join(app(consume_env, lambda s, h: result.update(status=s))))
    assert rejected["error"] == "verification_invalid"
    cancel_env["wsgi.input"] = io.BytesIO(payload)
    replay = json.loads(b"".join(app(cancel_env, lambda s, h: result.update(status=s))))
    assert replay["error"] == "verification_invalid"


def test_mailbox_evidence_is_not_authorization(tmp_path):
    """Provider acceptance and mailbox challenge never grant user-engine authority."""
    provider = Provider()
    app = TransactionalApplication(
        SQLiteDeliveryStore(str(tmp_path / "mail.db")), provider, "opaque", "https://users.example"
    )
    _, accepted = invoke(app, event())
    assert accepted.get("authorization") is None or accepted.get("authorization") is False
    assert accepted["evidence_ceiling"] == "provider_accepted"
    # Ceiling is explicit; user-engine must not elevate this to authz.
    assert "authorized" not in accepted


class RecordingSMTP:
    """Minimal smtplib.SMTP stand-in that records the handshake it was given."""

    instances = []

    def __init__(self, host, port, timeout=None):
        self.host, self.port, self.timeout = host, port, timeout
        self.starttls_calls = 0
        self.logins = []
        self.sent = []
        RecordingSMTP.instances.append(self)

    def __enter__(self):
        return self

    def __exit__(self, *exc):
        return False

    def starttls(self):
        self.starttls_calls += 1

    def login(self, username, password):
        self.logins.append((username, password))

    def send_message(self, message):
        self.sent.append(message)


def test_smtp_provider_defaults_to_starttls(monkeypatch):
    monkeypatch.setattr(smtplib, "SMTP", RecordingSMTP)
    RecordingSMTP.instances = []
    provider = SMTPProvider("smtp.example.com", 587, "user", "pass", "noreply@example.com")

    assert provider.security == "starttls"
    provider.send("person@example.test", "Subject", "body")
    assert RecordingSMTP.instances[0].starttls_calls == 1


def test_plaintext_security_skips_starttls_on_loopback(monkeypatch):
    monkeypatch.setattr(smtplib, "SMTP", RecordingSMTP)
    RecordingSMTP.instances = []
    provider = SMTPProvider("127.0.0.1", 3025, "user", "pass", "noreply@example.com", security="plaintext")

    provider.send("person@example.test", "Subject", "body")
    smtp = RecordingSMTP.instances[0]
    assert smtp.starttls_calls == 0
    assert smtp.logins == [("user", "pass")]
    assert len(smtp.sent) == 1


@pytest.mark.parametrize("host", ["127.0.0.1", "127.0.1.1", "::1", "[::1]", "localhost", "LOCALHOST"])
def test_plaintext_security_is_allowed_for_loopback_hosts(host):
    assert SMTPProvider(host, 3025, "user", "pass", "noreply@example.com", security="plaintext")


@pytest.mark.parametrize("host", ["smtp.example.com", "10.0.0.5", "::ffff:10.0.0.5", "", "localhost.example.com"])
def test_plaintext_security_is_refused_for_non_loopback_hosts(host):
    with pytest.raises(ValueError, match="loopback"):
        SMTPProvider(host, 3025, "user", "pass", "noreply@example.com", security="plaintext")


def test_unsupported_security_mode_is_refused():
    with pytest.raises(ValueError, match="security mode"):
        SMTPProvider("127.0.0.1", 3025, "user", "pass", "noreply@example.com", security="none")