import copy
import functools
import re

from collections import OrderedDict
from random import Random
from typing import Any, Callable, Dict, List, Optional, Pattern, Sequence, Tuple, Union

from .config import DEFAULT_LOCALE
from .exceptions import UniquenessException
from .factory import Factory
from .generator import Generator, random
from .typing import SeedType
from .utils.distribution import choices_distribution

_UNIQUE_ATTEMPTS = 1000


class Faker:
    """Proxy class capable of supporting multiple locales"""

    cache_pattern: Pattern = re.compile(r"^_cached_\w*_mapping$")
    generator_attrs = [
        attr for attr in dir(Generator) if not attr.startswith("__") and attr not in ["seed", "seed_instance", "random"]
    ]

    def __init__(
        self,
        locale: Optional[Union[str, Sequence[str], Dict[str, Union[int, float]]]] = None,
        providers: Optional[List[str]] = None,
        generator: Optional[Generator] = None,
        includes: Optional[List[str]] = None,
        use_weighting: bool = True,
        **config: Any,
    ) -> None:
        self._factory_map = OrderedDict()
        self._weights = None
        self._unique_proxy = UniqueProxy(self)

        if isinstance(locale, str):
            locales = [locale.replace("-", "_")]

        # This guarantees a FIFO ordering of elements in `locales` based on the final
        # locale string while discarding duplicates after processing
        elif isinstance(locale, (list, tuple, set)):
            locales = []
            for code in locale:
                if not isinstance(code, str):
                    raise TypeError(f'The locale "{str(code)}" must be a string.')
                final_locale = code.replace("-", "_")
                if final_locale not in locales:
                    locales.append(final_locale)

        elif isinstance(locale, OrderedDict):
            assert all(isinstance(v, (int, float)) for v in locale.values())
            odict = OrderedDict()
            for k, v in locale.items():
                key = k.replace("-", "_")
                odict[key] = v
            locales = list(odict.keys())
            self._weights = list(odict.values())

        else:
            locales = [DEFAULT_LOCALE]

        for locale in locales:
            self._factory_map[locale] = Factory.create(
                locale,
                providers,
                generator,
                includes,
                use_weighting=use_weighting,
                **config,
            )

        self._locales = locales
        self._factories = list(self._factory_map.values())

    def __dir__(self):
        attributes = set(super(Faker, self).__dir__())
        for factory in self.factories:
            attributes |= {attr for attr in dir(factory) if not attr.startswith("_")}
        return sorted(attributes)

    def __getitem__(self, locale: str) -> Generator:
        return self._factory_map[locale.replace("-", "_")]

    def __getattribute__(self, attr: str) -> Any:
        """
        Handles the "attribute resolution" behavior for declared members of this proxy class

        The class method `seed` cannot be called from an instance.

        :param attr: attribute name
        :return: the appropriate attribute
        """
        if attr == "seed":
            msg = "Calling `.seed()` on instances is deprecated. " "Use the class method `Faker.seed()` instead."
            raise TypeError(msg)
        else:
            return super().__getattribute__(attr)

    def __getattr__(self, attr: str) -> Any:
        """
        Handles cache access and proxying behavior

        :param attr: attribute name
        :return: the appropriate attribute
        """
        if len(self._factories) == 1:
            return getattr(self._factories[0], attr)
        elif attr in self.generator_attrs:
            msg = "Proxying calls to `%s` is not implemented in multiple locale mode." % attr
            raise NotImplementedError(msg)
        elif self.cache_pattern.match(attr):
            msg = "Cached attribute `%s` does not exist" % attr
            raise AttributeError(msg)
        else:
            factory = self._select_factory(attr)
            return getattr(factory, attr)

    def __deepcopy__(self, memodict: Dict = {}) -> "Faker":
        cls = self.__class__
        result = cls.__new__(cls)
        result._locales = copy.deepcopy(self._locales)
        result._factories = copy.deepcopy(self._factories)
        result._factory_map = copy.deepcopy(self._factory_map)
        result._weights = copy.deepcopy(self._weights)
        result._unique_proxy = UniqueProxy(self)
        result._unique_proxy._seen = {k: {result._unique_proxy._sentinel} for k in self._unique_proxy._seen.keys()}
        return result

    def __setstate__(self, state: Any) -> None:
        self.__dict__.update(state)

    @property
    def unique(self) -> "UniqueProxy":
        return self._unique_proxy

    def _select_factory(self, method_name: str) -> Factory:
        """
        Returns a random factory that supports the provider method

        :param method_name: Name of provider method
        :return: A factory that supports the provider method
        """

        factories, weights = self._map_provider_method(method_name)

        if len(factories) == 0:
            msg = f"No generator object has attribute {method_name!r}"
            raise AttributeError(msg)
        elif len(factories) == 1:
            return factories[0]

        if weights:
            factory = self._select_factory_distribution(factories, weights)
        else:
            factory = self._select_factory_choice(factories)
        return factory

    def _select_factory_distribution(self, factories, weights):
        return choices_distribution(factories, weights, random, length=1)[0]

    def _select_factory_choice(self, factories):
        return random.choice(factories)

    def _map_provider_method(self, method_name: str) -> Tuple[List[Factory], Optional[List[float]]]:
        """
        Creates a 2-tuple of factories and weights for the given provider method name

        The first element of the tuple contains a list of compatible factories.
        The second element of the tuple contains a list of distribution weights.

        :param method_name: Name of provider method
        :return: 2-tuple (factories, weights)
        """

        # Return cached mapping if it exists for given method
        attr = f"_cached_{method_name}_mapping"
        if hasattr(self, attr):
            return getattr(self, attr)

        # Create mapping if it does not exist
        if self._weights:
            value = [
                (factory, weight)
                for factory, weight in zip(self.factories, self._weights)
                if hasattr(factory, method_name)
            ]
            factories, weights = zip(*value)
            mapping = list(factories), list(weights)
        else:
            value = [factory for factory in self.factories if hasattr(factory, method_name)]  # type: ignore
            mapping = value, None  # type: ignore

        # Then cache and return results
        setattr(self, attr, mapping)
        return mapping

    @classmethod
    def seed(cls, seed: Optional[SeedType] = None) -> None:
        """
        Hashables the shared `random.Random` object across all factories

        :param seed: seed value
        """
        Generator.seed(seed)

    def seed_instance(self, seed: Optional[SeedType] = None) -> None:
        """
        Creates and seeds a new `random.Random` object for each factory

        :param seed: seed value
        """
        for factory in self._factories:
            factory.seed_instance(seed)

    def seed_locale(self, locale: str, seed: Optional[SeedType] = None) -> None:
        """
        Creates and seeds a new `random.Random` object for the factory of the specified locale

        :param locale: locale string
        :param seed: seed value
        """
        self._factory_map[locale.replace("-", "_")].seed_instance(seed)

    @property
    def random(self) -> Random:
        """
        Proxies `random` getter calls

        In single locale mode, this will be proxied to the `random` getter
        of the only internal `Generator` object. Subclasses will have to
        implement desired behavior in multiple locale mode.
        """

        if len(self._factories) == 1:
            return self._factories[0].random
        else:
            msg = "Proxying `random` getter calls is not implemented in multiple locale mode."
            raise NotImplementedError(msg)

    @random.setter
    def random(self, value: Random) -> None:
        """
        Proxies `random` setter calls

        In single locale mode, this will be proxied to the `random` setter
        of the only internal `Generator` object. Subclasses will have to
        implement desired behavior in multiple locale mode.
        """

        if len(self._factories) == 1:
            self._factories[0].random = value
        else:
            msg = "Proxying `random` setter calls is not implemented in multiple locale mode."
            raise NotImplementedError(msg)

    @property
    def locales(self) -> List[str]:
        return list(self._locales)

    @property
    def weights(self) -> Optional[List[Union[int, float]]]:
        return self._weights

    @property
    def factories(self) -> List[Generator]:
        return self._factories

    def items(self) -> List[Tuple[str, Generator]]:
        return list(self._factory_map.items())


class UniqueProxy:
    def __init__(self, proxy: Faker):
        self._proxy = proxy
        self._seen: Dict = {}
        self._sentinel = object()

    def clear(self) -> None:
        self._seen = {}

    def __getattr__(self, name: str) -> Any:
        obj = getattr(self._proxy, name)
        if callable(obj):
            return self._wrap(name, obj)
        else:
            raise TypeError("Accessing non-functions through .unique is not supported.")

    def __getstate__(self):
        # Copy the object's state from self.__dict__ which contains
        # all our instance attributes. Always use the dict.copy()
        # method to avoid modifying the original state.
        state = self.__dict__.copy()
        return state

    def __setstate__(self, state):
        self.__dict__.update(state)

    def _wrap(self, name: str, function: Callable) -> Callable:
        @functools.wraps(function)
        def wrapper(*args, **kwargs):
            key = (name, args, tuple(sorted(kwargs.items())))

            generated = self._seen.setdefault(key, {self._sentinel})

            # With use of a sentinel value rather than None, we leave
            # None open as a valid return value.
            retval = self._sentinel

            for i in range(_UNIQUE_ATTEMPTS):
                if retval not in generated:
                    break
                retval = function(*args, **kwargs)
            else:
                raise UniquenessException(f"Got duplicated values after {_UNIQUE_ATTEMPTS:,} iterations.")

            generated.add(retval)

            return retval

        return wrapper
