"""Implements classes for generating data by schema."""

from types import LambdaType
from typing import Any, Callable, List, Optional

from mimesis.exceptions import (UndefinedField, UndefinedSchema,
                                UnsupportedField)
from mimesis.providers.base import StrMixin
from mimesis.providers.generic import Generic
from mimesis.typing import JSON, Seed

__all__ = ['AbstractField', 'Field', 'Schema']


class AbstractField(StrMixin):
    """
    AbstractField is a class for generating data by the name of the method.

    Instance of this object takes any string which represents name
    of any method of any supported data provider (class ``Generic()``)
    and the ``**kwargs`` of the method:

    >>> _ = AbstractField('en', 0xf)
    >>> _('full_name')
    'Jack Allison'
    """

    def __init__(self, locale: str = 'en',
                 seed: Optional[Seed] = None) -> None:
        """Initialize field.

        :param locale: Locale
        :param seed: Seed for random.
        """
        self.locale = locale
        self.seed = seed
        self.gen = Generic(self.locale, self.seed)
        self._table = {}    # type: ignore

    def __call__(self, name: Optional[str] = None,
                 key: Optional[Callable] = None, **kwargs) -> Any:
        """Override standard call.

        This magic method override standard call so it's take any string which
        represents name of the any method of any supported data provider
        and the ``**kwargs`` of this method.

        ..note:: Some data providers have methods with the same name and
        in such cases, you can explicitly define that the method belongs to
        data-provider ``name='provider.name'``.

        You can apply a *key function* to result returned by the method,
        to do it, just pass parameter ``key`` with a callable object which
        returns final result.

        :param name: Name of the method.
        :param key: A key function (or other callable object)
            which will be applied to result.
        :param kwargs: Kwargs of method.
        :return: Value which represented by method.
        :raises ValueError: if provider is not
            supported or if field is not defined.
        """
        if name is None:
            raise UndefinedField()

        def tail_parser(tails: str, obj: Any) -> Any:
            """Return method from end of tail.

            :param tails: Tail string
            :param obj: Search tail from this object
            :return last tailed method
            """
            first, second = tails.split('.', 1)
            if hasattr(obj, first):
                attr = getattr(obj, first)
                if '.' in second:
                    return tail_parser(attr, second)
                else:
                    return getattr(attr, second)

        try:
            if name not in self._table:
                if '.' not in name:
                    for provider in dir(self.gen):
                        provider = getattr(self.gen, provider)
                        if name in dir(provider):
                            self._table[name] = getattr(provider, name)
                else:
                    self._table[name] = tail_parser(name, self.gen)

            result = self._table[name](**kwargs)
            if key and callable(key):
                return key(result)
            return result
        except Exception:
            raise UnsupportedField(name)


class Schema(object):
    """Class which return list of filled schemas."""

    def __init__(self, schema: LambdaType) -> None:
        """Initialize schema.

        :param schema: A schema.
        """
        if isinstance(schema, LambdaType):
            self.schema = schema
        else:
            raise UndefinedSchema()

    def create(self, iterations: int = 1) -> List[JSON]:
        """Return filled schema.

        Create a list of a filled schemas with elements in
        an amount of ``iterations``.

        :param iterations: Amount of iterations.
        :return: List of willed schemas.
        """
        return [self.schema() for _ in range(iterations)]


# Alias for AbstractField
Field = AbstractField

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