import inspect
import logging
import os
import time
from datetime import datetime, timedelta

from peewee import (
    BlobField,
    CharField,
    DateField,
    ForeignKeyField,
    IntegerField,
    PeeweeException,
)

from defence360agent.model import instance, Model

#: seconds in a POSIX day
POSIX_DAY = 24 * 60 * 60

logger = logging.getLogger(__name__)


class FilenameField(BlobField):
    """
    Class to store file names in database
    """

    def db_value(self, value):
        return os.fsencode(value)

    def python_value(self, value):
        return os.fsdecode(value)


class ScanPathField(CharField):
    REALTIME_SCAN_PATH_STUB = "list_of_files"

    def db_value(self, value):
        if isinstance(value, list):
            return self.REALTIME_SCAN_PATH_STUB
        return value


class ModelError(PeeweeException):
    """
    Model exception. Please use this one from other modules instead
    PeeweeException directly
    """

    pass


async def run_in_executor(loop, cb, *args):
    """
    Fake run_in_executor() test (DEF-4541)
    """
    return cb(*args)


def remove_old_and_truncate(
    table: Model, num_days: int, max_count: int
) -> int:
    """
    Removes records that is older that *num_days* days and
    all others that are out of range *max_count* from *table*.
    Returns count of rows deleted.
    """
    has_timestamp = getattr(table, "timestamp", False)
    if not has_timestamp:
        raise ValueError("No 'timestamp' column in table {!r}".format(table))

    # keep no more than *max_count* rows that are newer than *num_days*
    end_save_time = time.time() - num_days * POSIX_DAY
    to_keep = (
        table.select(table.timestamp)
        .order_by(table.timestamp.desc())
        .limit(max_count)
        .where(table.timestamp > end_save_time)
    )
    deleted_count = (
        table.delete().where(table.timestamp.not_in(to_keep)).execute()
    )

    return deleted_count


class Eula(Model):
    """Keeps track of updates and acceptions of end user license agreement.

    Admins will be asked to accept EULA if the latest version is not accepted
    yet.
    """

    class Meta:
        database = instance.db
        db_table = "eula"

    #: Date when EULA was updated.
    updated = DateField(primary_key=True)
    #: Timestamp when EULA was accepted.
    accepted = IntegerField(null=True, default=None)

    @classmethod
    def is_accepted(cls) -> bool:
        unaccepted = next(
            iter(
                cls.select()
                .where(cls.accepted.is_null())
                .order_by(cls.updated)
                .limit(1)
            ),
            None,
        )
        return unaccepted is None

    @classmethod
    def accept(cls) -> None:
        cls.update(accepted=time.time()).where(
            cls.accepted.is_null()
        ).execute()


def get_models(module):
    return [
        obj
        for _, obj in inspect.getmembers(
            module,
            lambda obj: inspect.isclass(obj)
            and issubclass(obj, Model)
            and obj != Model,
        )
    ]


def create_tables(module):
    instance.db.connect()
    instance.db.create_tables(get_models(module), safe=True)


class ApplyOrderBy:
    @staticmethod
    def resolve_nodes(_model, column_name: str) -> tuple:
        """
        :param _model: peewee.Model or peewee.ForeignKeyField
        :param column_name: str
        :return: tuple<peewee.Node>
        """
        model = (
            _model.rel_model if isinstance(_model, ForeignKeyField) else _model
        )
        nodes = ()
        custom_order_by = getattr(model, "OrderBy", None)
        if custom_order_by is not None:
            nodes = getattr(custom_order_by, column_name, lambda: nodes)()
        if not nodes:
            node = getattr(model, column_name, None)
            if node is not None:
                nodes = (node,)  # type: ignore
        return nodes

    @staticmethod
    def get_nodes(model, column_names: list) -> list:
        """
        :param model: peewee.Model or peewee.ForeignKeyField
        :param column_names: list<str>
        :return: list<peewee.Node>
        """
        column_name, rest = column_names[0], column_names[1:]
        nodes = ApplyOrderBy.resolve_nodes(model, column_name)
        result = []
        for node_or_model in nodes:
            if rest:  # model
                for node in ApplyOrderBy.get_nodes(node_or_model, rest):
                    result.append(node)
            else:  # node
                result.append(node_or_model)

        return result

    def __call__(self, order_by, model, query_builder):
        """
        :param order_by: list<OrderBy>
        :param model: peewee.Model or peewee.ForeignKeyField
        :param query_builder: peewee.Query
        :return: peewee.Query with applied order_by
        """
        orders = []
        for order in order_by:
            nodes = ApplyOrderBy.get_nodes(model, order.column_name.split("."))
            for node in nodes:
                orders.append(node.desc() if order.desc else node)

        return query_builder.order_by(*orders)


apply_order_by = ApplyOrderBy()