import asyncio
from dataclasses import dataclass
from datetime import datetime, timezone
from typing import Any

from app.services.waybill_email_sender import WaybillEmailSenderService


@dataclass
class StoredOrder:
    order_uuid: str
    account_email: str
    provider_waybill_url: str | None = None
    waybill_email_sent_at: datetime | None = None


class StubSessionContext:
    def __init__(self, session: object) -> None:
        self._session = session

    async def __aenter__(self) -> object:
        return self._session

    async def __aexit__(self, exc_type, exc, traceback) -> None:
        return None


class StubRepository:
    def __init__(self, orders: list[StoredOrder]) -> None:
        self._orders = {order.order_uuid: order for order in orders}
        self.session_value = object()
        self.calls: list[tuple[str, dict[str, Any]]] = []

    def session(self) -> StubSessionContext:
        return StubSessionContext(self.session_value)

    async def list_orders_pending_waybill_email(
        self, session: object, *, limit: int
    ) -> list[StoredOrder]:
        self.calls.append(("list", {"limit": limit}))
        return [
            order
            for order in self._orders.values()
            if order.provider_waybill_url is not None
            and order.waybill_email_sent_at is None
        ]

    async def record_waybill_email_sent(
        self,
        session: object,
        *,
        order_uuid: str,
        sent_at: datetime,
    ) -> StoredOrder | None:
        self.calls.append(
            ("record", {"order_uuid": order_uuid, "sent_at": sent_at})
        )
        order = self._orders.get(order_uuid)
        if order is None:
            return None
        if order.waybill_email_sent_at is None:
            order.waybill_email_sent_at = sent_at
        return order


class StubDownloader:
    def __init__(self, results: dict[str, bytes | Exception]) -> None:
        self._results = results
        self.calls: list[str] = []

    async def download_waybill_pdf(self, url: str) -> bytes:
        self.calls.append(url)
        result = self._results[url]
        if isinstance(result, Exception):
            raise result
        return result


class StubEmailSender:
    def __init__(self, raise_for: set[str] | None = None) -> None:
        self.raise_for = raise_for or set()
        self.calls: list[dict[str, Any]] = []

    async def send_email(
        self,
        *,
        to: str,
        subject: str,
        body: str,
        attachment_bytes: bytes,
        attachment_filename: str,
    ) -> None:
        self.calls.append(
            {
                "to": to,
                "subject": subject,
                "body": body,
                "attachment_bytes": attachment_bytes,
                "attachment_filename": attachment_filename,
            }
        )
        if to in self.raise_for:
            raise RuntimeError(f"smtp blew up for {to}")


_SENT_AT = datetime(2026, 5, 24, 12, 0, tzinfo=timezone.utc)


def _make_service(
    *,
    repository: StubRepository,
    downloader: StubDownloader | None = None,
    email_sender: StubEmailSender | None = None,
) -> WaybillEmailSenderService:
    return WaybillEmailSenderService(
        order_repository=repository,
        waybill_downloader=downloader or StubDownloader({}),
        email_sender=email_sender or StubEmailSender(),
        batch_size=10,
        datetime_now=lambda: _SENT_AT,
    )


def test_poll_once_downloads_pdf_sends_email_and_marks_sent() -> None:
    order = StoredOrder(
        order_uuid="o-1",
        account_email="client@example.com",
        provider_waybill_url="https://cdek.test/1.pdf",
    )
    repo = StubRepository([order])
    downloader = StubDownloader({"https://cdek.test/1.pdf": b"%PDF"})
    email_sender = StubEmailSender()
    service = _make_service(
        repository=repo, downloader=downloader, email_sender=email_sender
    )

    summary = asyncio.run(service.poll_once())

    assert summary.processed == 1
    assert summary.succeeded == 1
    assert summary.failed == 0
    assert downloader.calls == ["https://cdek.test/1.pdf"]
    assert len(email_sender.calls) == 1
    call = email_sender.calls[0]
    assert call["to"] == "client@example.com"
    assert call["subject"] == "Накладная по заказу o-1"
    assert "o-1" in call["body"]
    assert "https://cdek.test/1.pdf" in call["body"]
    assert call["attachment_bytes"] == b"%PDF"
    assert call["attachment_filename"] == "waybill_o-1.pdf"
    assert order.waybill_email_sent_at == _SENT_AT


def test_poll_once_download_error_keeps_order_pending_and_skips_send() -> None:
    order = StoredOrder(
        order_uuid="o-1",
        account_email="client@example.com",
        provider_waybill_url="https://cdek.test/1.pdf",
    )
    repo = StubRepository([order])
    downloader = StubDownloader({"https://cdek.test/1.pdf": RuntimeError("cdek 500")})
    email_sender = StubEmailSender()
    service = _make_service(
        repository=repo, downloader=downloader, email_sender=email_sender
    )

    summary = asyncio.run(service.poll_once())

    assert summary.processed == 1
    assert summary.succeeded == 0
    assert summary.failed == 1
    assert email_sender.calls == []
    assert order.waybill_email_sent_at is None


def test_poll_once_smtp_error_keeps_order_pending() -> None:
    order = StoredOrder(
        order_uuid="o-1",
        account_email="bad@example.com",
        provider_waybill_url="https://cdek.test/1.pdf",
    )
    repo = StubRepository([order])
    downloader = StubDownloader({"https://cdek.test/1.pdf": b"%PDF"})
    email_sender = StubEmailSender(raise_for={"bad@example.com"})
    service = _make_service(
        repository=repo, downloader=downloader, email_sender=email_sender
    )

    summary = asyncio.run(service.poll_once())

    assert summary.failed == 1
    assert order.waybill_email_sent_at is None
    assert len(email_sender.calls) == 1


def test_poll_once_failure_on_one_order_does_not_break_batch() -> None:
    bad = StoredOrder(
        order_uuid="bad",
        account_email="bad@example.com",
        provider_waybill_url="https://cdek.test/bad.pdf",
    )
    good = StoredOrder(
        order_uuid="good",
        account_email="good@example.com",
        provider_waybill_url="https://cdek.test/good.pdf",
    )
    repo = StubRepository([bad, good])
    downloader = StubDownloader(
        {
            "https://cdek.test/bad.pdf": RuntimeError("cdek 500"),
            "https://cdek.test/good.pdf": b"%PDF",
        }
    )
    email_sender = StubEmailSender()
    service = _make_service(
        repository=repo, downloader=downloader, email_sender=email_sender
    )

    summary = asyncio.run(service.poll_once())

    assert summary.processed == 2
    assert summary.succeeded == 1
    assert summary.failed == 1
    assert good.waybill_email_sent_at == _SENT_AT
    assert bad.waybill_email_sent_at is None


def test_run_forever_exits_when_stop_event_is_set() -> None:
    repo = StubRepository([])
    service = _make_service(repository=repo)

    async def run() -> None:
        stop_event = asyncio.Event()
        stop_event.set()
        await asyncio.wait_for(
            service.run_forever(interval_seconds=0.01, stop_event=stop_event),
            timeout=1.0,
        )

    asyncio.run(run())