"""Utilities for filtering or searching :class:`list` of objects / list data.

Note
----
This is an internal API not covered by versioning policy.
"""
import re
import traceback
from collections.abc import Mapping, Sequence
from re import Pattern
from typing import TYPE_CHECKING, Any, Callable, List, Optional, TypeVar, Union

if TYPE_CHECKING:
    from typing_extensions import Protocol

    class LookupProtocol(Protocol):
        """Protocol for :class:`QueryList` filtering operators."""

        def __call__(
            self,
            data: Union[str, List[str], "Mapping[str, str]"],
            rhs: Union[str, List[str], "Mapping[str, str]", "Pattern[str]"],
        ) -> bool:
            """Callback for :class:`QueryList` filtering operators."""
            ...


T = TypeVar("T", Any, Any)

no_arg = object()


class MultipleObjectsReturned(Exception):
    """The requested object does not exist"""


class ObjectDoesNotExist(Exception):
    """The query returned multiple objects when only one was expected."""


def keygetter(
    obj: "Mapping[str, Any]",
    path: str,
) -> Union[None, Any, str, List[str], "Mapping[str, str]"]:
    """obj, "foods__breakfast", obj['foods']['breakfast']

    >>> keygetter({ "foods": { "breakfast": "cereal" } }, "foods__breakfast")
    'cereal'
    >>> keygetter({ "foods": { "breakfast": "cereal" } }, "foods")
    {'breakfast': 'cereal'}

    """
    try:
        sub_fields = path.split("__")
        dct = obj
        for sub_field in sub_fields:
            if isinstance(dct, dict):
                dct = dct[sub_field]
            elif hasattr(dct, sub_field):
                dct = getattr(dct, sub_field)

        return dct
    except Exception as e:
        traceback.print_stack()
        print(f"Above error was {e}")
    return None


def parse_lookup(obj: "Mapping[str, Any]", path: str, lookup: str) -> Optional[Any]:
    """Check if field lookup key, e.g. "my__path__contains" has comparator, return val.

    If comparator not used or value not found, return None.

    mykey__endswith("mykey") -> "mykey" else None

    >>> parse_lookup({ "food": "red apple" }, "food__istartswith", "__istartswith")
    'red apple'
    """
    try:
        if isinstance(path, str) and isinstance(lookup, str) and path.endswith(lookup):
            field_name = path.rsplit(lookup)[0]
            if field_name is not None:
                return keygetter(obj, field_name)
    except Exception:
        traceback.print_stack()
    return None


def lookup_exact(
    data: Union[str, List[str], "Mapping[str, str]"],
    rhs: Union[str, List[str], "Mapping[str, str]", "Pattern[str]"],
) -> bool:
    return rhs == data


def lookup_iexact(
    data: Union[str, List[str], "Mapping[str, str]"],
    rhs: Union[str, List[str], "Mapping[str, str]", "Pattern[str]"],
) -> bool:
    if not isinstance(rhs, str) or not isinstance(data, str):
        return False

    return rhs.lower() == data.lower()


def lookup_contains(
    data: Union[str, List[str], "Mapping[str, str]"],
    rhs: Union[str, List[str], "Mapping[str, str]", "Pattern[str]"],
) -> bool:
    if not isinstance(rhs, str) or not isinstance(data, (str, Mapping, list)):
        return False

    return rhs in data


def lookup_icontains(
    data: Union[str, List[str], "Mapping[str, str]"],
    rhs: Union[str, List[str], "Mapping[str, str]", "Pattern[str]"],
) -> bool:
    if not isinstance(rhs, str) or not isinstance(data, (str, Mapping, list)):
        return False

    if isinstance(data, str):
        return rhs.lower() in data.lower()
    if isinstance(data, Mapping):
        return rhs.lower() in [k.lower() for k in data.keys()]

    return False


def lookup_startswith(
    data: Union[str, List[str], "Mapping[str, str]"],
    rhs: Union[str, List[str], "Mapping[str, str]", "Pattern[str]"],
) -> bool:
    if not isinstance(rhs, str) or not isinstance(data, str):
        return False

    return data.startswith(rhs)


def lookup_istartswith(
    data: Union[str, List[str], "Mapping[str, str]"],
    rhs: Union[str, List[str], "Mapping[str, str]", "Pattern[str]"],
) -> bool:
    if not isinstance(rhs, str) or not isinstance(data, str):
        return False

    return data.lower().startswith(rhs.lower())


def lookup_endswith(
    data: Union[str, List[str], "Mapping[str, str]"],
    rhs: Union[str, List[str], "Mapping[str, str]", "Pattern[str]"],
) -> bool:
    if not isinstance(rhs, str) or not isinstance(data, str):
        return False

    return data.endswith(rhs)


def lookup_iendswith(
    data: Union[str, List[str], "Mapping[str, str]"],
    rhs: Union[str, List[str], "Mapping[str, str]", "Pattern[str]"],
) -> bool:
    if not isinstance(rhs, str) or not isinstance(data, str):
        return False
    return data.lower().endswith(rhs.lower())


def lookup_in(
    data: Union[str, List[str], "Mapping[str, str]"],
    rhs: Union[str, List[str], "Mapping[str, str]", "Pattern[str]"],
) -> bool:
    if isinstance(rhs, list):
        return data in rhs

    try:
        if isinstance(rhs, str) and isinstance(data, Mapping):
            return rhs in data
        if isinstance(rhs, str) and isinstance(data, (str, list)):
            return rhs in data
        if isinstance(rhs, str) and isinstance(data, Mapping):
            return rhs in data
        # TODO: Add a deep Mappingionary matcher
        # if isinstance(rhs, Mapping) and isinstance(data, Mapping):
        #     return rhs.items() not in data.items()
    except Exception:
        return False
    return False


def lookup_nin(
    data: Union[str, List[str], "Mapping[str, str]"],
    rhs: Union[str, List[str], "Mapping[str, str]", "Pattern[str]"],
) -> bool:
    if isinstance(rhs, list):
        return data not in rhs

    try:
        if isinstance(rhs, str) and isinstance(data, Mapping):
            return rhs not in data
        if isinstance(rhs, str) and isinstance(data, (str, list)):
            return rhs not in data
        if isinstance(rhs, str) and isinstance(data, Mapping):
            return rhs not in data
        # TODO: Add a deep Mappingionary matcher
        # if isinstance(rhs, Mapping) and isinstance(data, Mapping):
        #     return rhs.items() not in data.items()
    except Exception:
        return False
    return False


def lookup_regex(
    data: Union[str, List[str], "Mapping[str, str]"],
    rhs: Union[str, List[str], "Mapping[str, str]", "Pattern[str]"],
) -> bool:
    if isinstance(data, (str, bytes, re.Pattern)) and isinstance(rhs, (str, bytes)):
        return bool(re.search(rhs, data))
    return False


def lookup_iregex(
    data: Union[str, List[str], "Mapping[str, str]"],
    rhs: Union[str, List[str], "Mapping[str, str]", "Pattern[str]"],
) -> bool:
    if isinstance(data, (str, bytes, re.Pattern)) and isinstance(rhs, (str, bytes)):
        return bool(re.search(rhs, data, re.IGNORECASE))
    return False


LOOKUP_NAME_MAP: 'Mapping[str, "LookupProtocol"]' = {
    "eq": lookup_exact,
    "exact": lookup_exact,
    "iexact": lookup_iexact,
    "contains": lookup_contains,
    "icontains": lookup_icontains,
    "startswith": lookup_startswith,
    "istartswith": lookup_istartswith,
    "endswith": lookup_endswith,
    "iendswith": lookup_iendswith,
    "in": lookup_in,
    "nin": lookup_nin,
    "regex": lookup_regex,
    "iregex": lookup_iregex,
}


class QueryList(List[T]):
    """Filter list of object/dictionaries. For small, local datasets.

    *Experimental, unstable*.

    >>> query = QueryList(
    ...     [
    ...         {
    ...             "place": "Largo",
    ...             "city": "Tampa",
    ...             "state": "Florida",
    ...             "foods": {"fruit": ["banana", "orange"], "breakfast": "cereal"},
    ...         },
    ...         {
    ...             "place": "Chicago suburbs",
    ...             "city": "Elmhurst",
    ...             "state": "Illinois",
    ...             "foods": {"fruit": ["apple", "cantelope"], "breakfast": "waffles"},
    ...         },
    ...     ]
    ... )
    >>> query.filter(place="Chicago suburbs")[0]['city']
    'Elmhurst'
    >>> query.filter(place__icontains="chicago")[0]['city']
    'Elmhurst'
    >>> query.filter(foods__breakfast="waffles")[0]['city']
    'Elmhurst'
    >>> query.filter(foods__fruit__in="cantelope")[0]['city']
    'Elmhurst'
    >>> query.filter(foods__fruit__in="orange")[0]['city']
    'Tampa'
    >>> query.get(foods__fruit__in="orange")['city']
    'Tampa'
    """

    data: "Sequence[T]"
    pk_key: Optional[str]

    def items(self) -> List[T]:
        data: "Sequence[T]"

        if self.pk_key is None:
            raise Exception("items() require a pk_key exists")
        return [(getattr(item, self.pk_key), item) for item in self]

    def __eq__(
        self,
        other: object,
        # other: Union[
        #     "QueryList[T]",
        #     List[Mapping[str, str]],
        #     List[Mapping[str, int]],
        #     List[Mapping[str, Union[str, Mapping[str, Union[List[str], str]]]]],
        # ],
    ) -> bool:
        data = other

        if not isinstance(self, list) or not isinstance(data, list):
            return False

        if len(self) == len(data):
            for (a, b) in zip(self, data):
                if isinstance(a, Mapping):
                    a_keys = a.keys()
                    if a.keys == b.keys():
                        for key in a_keys:
                            if abs(a[key] - b[key]) > 1:
                                return False
                else:
                    if a != b:
                        return False

            return True
        return False

    def filter(
        self, matcher: Optional[Union[Callable[[T], bool], T]] = None, **kwargs: Any
    ) -> "QueryList[T]":
        """Filter list of objects."""

        def filter_lookup(obj: Any) -> bool:
            for path, v in kwargs.items():
                try:
                    lhs, op = path.rsplit("__", 1)

                    if op not in LOOKUP_NAME_MAP:
                        raise ValueError(f"{op} not in LOOKUP_NAME_MAP")
                except ValueError:
                    lhs = path
                    op = "exact"

                assert op in LOOKUP_NAME_MAP
                path = lhs
                data = keygetter(obj, path)

                if data is None or not LOOKUP_NAME_MAP[op](data, v):
                    return False

            return True

        if callable(matcher):
            _filter = matcher
        elif matcher is not None:

            def val_match(obj: Union[str, List[Any]]) -> bool:
                if isinstance(matcher, list):
                    return obj in matcher
                else:
                    return obj == matcher

            _filter = val_match
        else:
            _filter = filter_lookup

        return self.__class__(k for k in self if _filter(k))

    def get(
        self,
        matcher: Optional[Union[Callable[[T], bool], T]] = None,
        default: Optional[Any] = no_arg,
        **kwargs: Any,
    ) -> Optional[T]:
        """Retrieve one object.

        Raises :exc:`MultipleObjectsReturned` if multiple objects found.

        Raises :exc:`ObjectDoesNotExist` if no object found, unless ``default`` stated.
        """
        objs = self.filter(matcher=matcher, **kwargs)
        if len(objs) > 1:
            raise MultipleObjectsReturned()
        elif len(objs) == 0:
            if default == no_arg:
                raise ObjectDoesNotExist()
            return default
        return objs[0]