"""LiveCheck - Faust Application."""
import asyncio
from datetime import timedelta
from typing import (
    Any,
    Callable,
    ClassVar,
    Dict,
    Iterable,
    List,
    Optional,
    Tuple,
    Type,
    cast,
)

from mode.signals import BaseSignalT
from mode.utils.compat import want_bytes
from mode.utils.objects import annotations, cached_property, qualname
from mode.utils.times import Seconds

import faust
from faust.app.base import SCAN_CATEGORIES
from faust.sensors.base import Sensor
from faust.types import TP, AgentT, AppT, EventT, StreamT, TopicT
from faust.utils import venusian

from . import patches
from .case import Case
from .exceptions import LiveCheckError
from .locals import current_test, current_test_stack
from .models import SignalEvent, TestExecution, TestReport
from .signals import BaseSignal, Signal

__all__ = ["LiveCheck"]

SCAN_CASE = "livecheck.case"
WARN_STALLED_AFTER_DEFAULT = timedelta(minutes=30)

#: alias for mypy bug
_Case = Case

patches.patch_all()  # XXX


class LiveCheckSensor(Sensor):
    def on_stream_event_in(
        self, tp: TP, offset: int, stream: StreamT, event: EventT
    ) -> Optional[Dict]:
        """Call when stream starts processing event."""
        test = TestExecution.from_headers(event.headers)
        if test is not None:
            stream.current_test = test  # type: ignore
            current_test_stack.push_without_automatic_cleanup(test)
        return None

    def on_stream_event_out(
        self, tp: TP, offset: int, stream: StreamT, event: EventT, state: Dict = None
    ) -> None:
        """Call when stream is finished handling event."""
        has_active_test = getattr(stream, "current_test", None)
        if has_active_test:
            stream.current_test = None  # type: ignore
            current_test_stack.pop()


class LiveCheck(faust.App):
    """LiveCheck application."""

    SCAN_CATEGORIES = list(SCAN_CATEGORIES) + [SCAN_CASE]

    Signal: ClassVar[Type[BaseSignal]]
    Signal = Signal

    Case: ClassVar[Type[_Case]]
    Case = _Case

    #: Number of concurrent actors processing signal events.
    bus_concurrency: int = 30

    #: Number of concurrent actors executing test cases.
    test_concurrency: int = 100

    #: Unset this if you don't want reports to be sent to
    #: the :attr:`report_topic_name` topic.
    send_reports: bool = True

    test_topic_name: str = "livecheck"
    bus_topic_name: str = "livecheck-bus"
    report_topic_name: str = "livecheck-report"

    cases: Dict[str, _Case]

    _resolved_signals: Dict[Tuple[str, str, Any], SignalEvent]

    @classmethod
    def for_app(
        cls,
        app: AppT,
        *,
        prefix: str = "livecheck-",
        web_port: int = 9999,
        test_topic_name: str = None,
        bus_topic_name: str = None,
        report_topic_name: str = None,
        bus_concurrency: int = None,
        test_concurrency: int = None,
        send_reports: bool = None,
        **kwargs: Any,
    ) -> "LiveCheck":
        """Create LiveCheck application targeting specific app.

        The target app will be used to configure the LiveCheck app.
        """
        app_id, passed_kwargs = app._default_options
        livecheck_id = f"{prefix}{app_id}"
        override = {
            "web_port": web_port,
            "test_topic_name": test_topic_name,
            "bus_topic_name": bus_topic_name,
            "report_topic_name": report_topic_name,
            "bus_concurrency": bus_concurrency,
            "test_concurrency": test_concurrency,
            "send_reports": send_reports,
            **kwargs,
        }
        options = {**passed_kwargs, **override}

        livecheck_app = cls(livecheck_id, **options)
        livecheck_app._contribute_to_app(app)

        return livecheck_app

    def _contribute_to_app(self, app: AppT) -> None:
        from .patches.aiohttp import LiveCheckMiddleware

        web_app = app.web.web_app  # type: ignore
        web_app.middlewares.append(LiveCheckMiddleware())
        app.sensors.add(LiveCheckSensor())
        app.livecheck = self  # type: ignore

    def __init__(
        self,
        id: str,
        *,
        test_topic_name: str = None,
        bus_topic_name: str = None,
        report_topic_name: str = None,
        bus_concurrency: int = None,
        test_concurrency: int = None,
        send_reports: bool = None,
        **kwargs: Any,
    ) -> None:
        super().__init__(id, **kwargs)

        if test_topic_name is not None:
            self.test_topic_name = test_topic_name
        if bus_topic_name is not None:
            self.bus_topic_name = bus_topic_name
        if report_topic_name is not None:
            self.report_topic_name = report_topic_name
        if bus_concurrency is not None:
            self.bus_concurrency = bus_concurrency
        if test_concurrency is not None:
            self.test_concurrency = test_concurrency
        if send_reports is not None:
            self.send_reports = send_reports

        self.cases = {}
        self._resolved_signals = {}
        patches.patch_all()
        self._apply_monkeypatches()
        self._connect_signals()

    @property
    def current_test(self) -> Optional[TestExecution]:
        """Return the current test context (if any)."""
        return current_test()

    @cached_property
    def _can_resolve(self) -> asyncio.Event:
        return asyncio.Event()

    def _apply_monkeypatches(self) -> None:
        patches.patch_all()

    def _connect_signals(self) -> None:
        AppT.on_produce_message.connect(
            self.on_produce_attach_test_headers
        )  # type: ignore

    def on_produce_attach_test_headers(
        self,
        sender: AppT,
        key: bytes = None,
        value: bytes = None,
        partition: int = None,
        timestamp: float = None,
        headers: List[Tuple[str, bytes]] = None,
        signal: BaseSignalT = None,
        **kwargs: Any,
    ) -> None:
        """Attach test headers to Kafka produce requests."""
        test = current_test()
        if test is not None:
            if headers is None:
                raise TypeError("Produce request missing headers list")
            headers.extend([(k, want_bytes(v)) for k, v in test.as_headers().items()])

    def case(
        self,
        *,
        name: str = None,
        probability: float = None,
        warn_stalled_after: Seconds = WARN_STALLED_AFTER_DEFAULT,
        active: bool = None,
        test_expires: Seconds = None,
        frequency: Seconds = None,
        max_history: int = None,
        max_consecutive_failures: int = None,
        url_timeout_total: float = None,
        url_timeout_connect: float = None,
        url_error_retries: float = None,
        url_error_delay_min: float = None,
        url_error_delay_backoff: float = None,
        url_error_delay_max: float = None,
        base: Type[_Case] = Case,
    ) -> Callable[[Type], _Case]:
        """Decorate class to be used as a test case.

        Returns:
            :class:`faust.livecheck.Case`.
        """
        base_case = base

        def _inner(cls: Type) -> _Case:
            case_cls = type(
                cls.__name__,
                (cls, base_case),
                {
                    "__module__": cls.__module__,
                    "app": self,
                },
            )

            signal_types = dict(self._extract_signals(case_cls, base_case))
            signals = []

            for i, (attr_name, attr_type) in enumerate(signal_types.items()):
                signal = getattr(case_cls, attr_name, None)
                if signal is None:
                    signal = attr_type(name=attr_name, index=i + 1)
                    setattr(case_cls, attr_name, signal)
                    signals.append(signal)
                else:
                    signal.index = i + 1

            case = self.add_case(
                case_cls(
                    app=self,
                    name=self._prepare_case_name(name or qualname(cls)),
                    active=active,
                    probability=probability,
                    warn_stalled_after=warn_stalled_after,
                    signals=signals,
                    test_expires=test_expires,
                    frequency=frequency,
                    max_history=max_history,
                    max_consecutive_failures=max_consecutive_failures,
                    url_timeout_total=url_timeout_total,
                    url_timeout_connect=url_timeout_connect,
                    url_error_retries=url_error_retries,
                    url_error_delay_min=url_error_delay_min,
                    url_error_delay_backoff=url_error_delay_backoff,
                    url_error_delay_max=url_error_delay_max,
                )
            )
            venusian.attach(cast(Callable, case), category=SCAN_CASE)
            return case

        return _inner

    def _extract_signals(
        self, case_cls: Type[_Case], base_case: Type[_Case]
    ) -> Iterable[Tuple[str, Type[BaseSignal]]]:
        fields, defaults = annotations(
            case_cls,
            stop=base_case,
            skip_classvar=True,
            localns={case_cls.__name__: case_cls},
        )

        for attr_name, attr_type in fields.items():
            actual_type = getattr(attr_type, "__origin__", attr_type)
            if actual_type is None:  # Python <3.7
                actual_type = attr_type
            try:
                if issubclass(actual_type, BaseSignal):
                    yield attr_name, attr_type
            except TypeError:  # pragma: no cover
                pass  # pragma: no cover

    def add_case(self, case: _Case) -> _Case:
        """Add and register new test case."""
        self.cases[case.name] = case
        return case

    async def post_report(self, report: TestReport) -> None:
        """Publish test report to reporting topic."""
        key = None
        if report.test is not None:
            key = report.test.id
        await self.reports.send(key=key, value=report)

    async def on_start(self) -> None:
        """Call when LiveCheck application starts."""
        await super().on_start()
        self._install_bus_agent()
        self._install_test_execution_agent()

    async def on_started(self) -> None:
        """Call when LiveCheck application is fully started."""
        await super().on_started()
        for case in self.cases.values():
            await self.add_runtime_dependency(case)

    def _install_bus_agent(self) -> AgentT:
        return self.agent(
            channel=self.bus,
            concurrency=self.bus_concurrency,
        )(self._populate_signals)

    def _install_test_execution_agent(self) -> AgentT:
        return self.agent(
            channel=self.pending_tests,
            concurrency=self.test_concurrency,
        )(self._execute_tests)

    async def _populate_signals(self, events: StreamT[SignalEvent]) -> None:
        async for test_id, event in events.items():
            event.case_name = self._prepare_case_name(event.case_name)
            try:
                case = self.cases[event.case_name]
            except KeyError:
                self.log.error(
                    "Received signal %r for unregistered case %r",
                    event,
                    (test_id, event.case_name),
                )
            else:
                await case.resolve_signal(test_id, event)

    async def _execute_tests(self, tests: StreamT[TestExecution]) -> None:
        async for test_id, test in tests.items():
            test.case_name = self._prepare_case_name(test.case_name)
            try:
                case = self.cases[test.case_name]
            except KeyError:
                self.log.error(
                    "Unregistered test case %r with id %r: %r",
                    test.case_name,
                    test_id,
                    test,
                )
            else:
                try:
                    await case.execute(test)
                except LiveCheckError:
                    pass

    def _prepare_case_name(self, name: str) -> str:
        if name.startswith("__main__."):
            if not self.conf.origin:
                raise RuntimeError("LiveCheck app missing origin argument")
            return self.conf.origin + name[8:]
        return name

    @cached_property
    def bus(self) -> TopicT:
        """Topic used for signal communication."""
        return self.topic(
            self.bus_topic_name,
            key_type=str,
            value_type=SignalEvent,
        )

    @cached_property
    def pending_tests(self) -> TopicT:
        """Topic used to keep pending test executions."""
        return self.topic(
            self.test_topic_name,
            key_type=str,
            value_type=TestExecution,
        )

    @cached_property
    def reports(self) -> TopicT:
        """Topic used to log test reports."""
        return self.topic(
            self.report_topic_name,
            key_type=str,
            value_type=TestReport,
        )