import logbook
import logbook.queues
from jsonrpc.exceptions import JSONRPCError
from dbt.dataclass_schema import StrEnum

from dataclasses import dataclass, field
from datetime import datetime, timedelta
from queue import Empty
from typing import Optional, Any

from dbt.contracts.rpc import (
    RemoteResult,
)
from dbt.exceptions import InternalException
from dbt.utils import restrict_to


class QueueMessageType(StrEnum):
    Error = 'error'
    Result = 'result'
    Timeout = 'timeout'
    Log = 'log'

    terminating = frozenset((Error, Result, Timeout))


# This class was subclassed from JsonSchemaMixin, but it
# doesn't appear to be necessary, and Mashumaro does not
# handle logbook.LogRecord
@dataclass
class QueueMessage:
    message_type: QueueMessageType


@dataclass
class QueueLogMessage(QueueMessage):
    message_type: QueueMessageType = field(
        metadata=restrict_to(QueueMessageType.Log)
    )
    record: logbook.LogRecord

    @classmethod
    def from_record(cls, record: logbook.LogRecord):
        return QueueLogMessage(
            message_type=QueueMessageType.Log,
            record=record,
        )


@dataclass
class QueueErrorMessage(QueueMessage):
    message_type: QueueMessageType = field(
        metadata=restrict_to(QueueMessageType.Error)
    )
    error: JSONRPCError

    @classmethod
    def from_error(cls, error: JSONRPCError):
        return QueueErrorMessage(
            message_type=QueueMessageType.Error,
            error=error,

        )


@dataclass
class QueueResultMessage(QueueMessage):
    message_type: QueueMessageType = field(
        metadata=restrict_to(QueueMessageType.Result)
    )
    result: RemoteResult

    @classmethod
    def from_result(cls, result: RemoteResult):
        return cls(
            message_type=QueueMessageType.Result,
            result=result,
        )


@dataclass
class QueueTimeoutMessage(QueueMessage):
    message_type: QueueMessageType = field(
        metadata=restrict_to(QueueMessageType.Timeout),
    )

    @classmethod
    def create(cls):
        return cls(message_type=QueueMessageType.Timeout)


class QueueLogHandler(logbook.queues.MultiProcessingHandler):
    def emit(self, record: logbook.LogRecord):
        # trigger the cached proeprties here
        record.pull_information()
        self.queue.put_nowait(QueueLogMessage.from_record(record))

    def emit_error(self, error: JSONRPCError):
        self.queue.put_nowait(QueueErrorMessage.from_error(error))

    def emit_result(self, result: RemoteResult):
        self.queue.put_nowait(QueueResultMessage.from_result(result))


def _next_timeout(
    started: datetime,
    timeout: Optional[float],
) -> Optional[float]:
    if timeout is None:
        return None

    end = started + timedelta(seconds=timeout)
    message_timeout = end - datetime.utcnow()
    return message_timeout.total_seconds()


class QueueSubscriber(logbook.queues.MultiProcessingSubscriber):
    def _recv_raw(self, timeout: Optional[float]) -> Any:
        if timeout is None:
            return self.queue.get()

        if timeout < 0:
            return QueueTimeoutMessage.create()

        try:
            return self.queue.get(block=True, timeout=timeout)
        except Empty:
            return QueueTimeoutMessage.create()

    def recv(
        self,
        timeout: Optional[float] = None
    ) -> QueueMessage:
        """Receives one record from the socket, loads it and dispatches it.
        Returns the message type if something was dispatched or `None` if it
        timed out.
        """
        rv = self._recv_raw(timeout)
        if not isinstance(rv, QueueMessage):
            raise InternalException(
                'Got invalid queue message: {}'.format(rv)
            )
        return rv

    def handle_message(
        self,
        timeout: Optional[float]
    ) -> QueueMessage:
        msg = self.recv(timeout)
        if isinstance(msg, QueueLogMessage):
            logbook.dispatch_record(msg.record)
            return msg
        elif msg.message_type in QueueMessageType.terminating:
            return msg
        else:
            raise InternalException(
                'Got invalid queue message type {}'.format(msg.message_type)
            )

    def dispatch_until_exit(
        self,
        started: datetime,
        timeout: Optional[float] = None
    ) -> QueueMessage:
        while True:
            message_timeout = _next_timeout(started, timeout)
            msg = self.handle_message(message_timeout)
            if msg.message_type in QueueMessageType.terminating:
                return msg


# a bunch of processors to push/pop that set various rpc-related extras
class ServerContext(logbook.Processor):
    def process(self, record):
        # the server context is the last processor in the stack, so it should
        # not overwrite a context if it's already been set.
        if not record.extra['context']:
            record.extra['context'] = 'server'


class HTTPRequest(logbook.Processor):
    def __init__(self, request):
        self.request = request

    def process(self, record):
        record.extra['addr'] = self.request.remote_addr
        record.extra['http_method'] = self.request.method


class RPCRequest(logbook.Processor):
    def __init__(self, request):
        self.request = request
        super().__init__()

    def process(self, record):
        record.extra['request_id'] = self.request._id
        record.extra['method'] = self.request.method


class RPCResponse(logbook.Processor):
    def __init__(self, response):
        self.response = response
        super().__init__()

    def process(self, record):
        record.extra['response_code'] = 200
        # the request_id could be None if the request was bad
        record.extra['request_id'] = getattr(
            self.response.request, '_id', None
        )


class RequestContext(RPCRequest):
    def process(self, record):
        super().process(record)
        record.extra['context'] = 'request'