from __future__ import absolute_import

import random
from copy import deepcopy
from typing import Any, Callable, Dict, List, Optional, Sequence, Tuple, Union, cast
from warnings import warn

import cv2
import numpy as np

from .serialization import Serializable, get_shortest_class_fullname
from .utils import format_args

__all__ = [
    "to_tuple",
    "BasicTransform",
    "DualTransform",
    "ImageOnlyTransform",
    "NoOp",
    "BoxType",
    "KeypointType",
    "ImageColorType",
    "ScaleFloatType",
    "ScaleIntType",
    "ImageColorType",
]

NumType = Union[int, float, np.ndarray]
BoxInternalType = Tuple[float, float, float, float]
BoxType = Union[BoxInternalType, Tuple[float, float, float, float, Any]]
KeypointInternalType = Tuple[float, float, float, float]
KeypointType = Union[KeypointInternalType, Tuple[float, float, float, float, Any]]
ImageColorType = Union[float, Sequence[float]]

ScaleFloatType = Union[float, Tuple[float, float]]
ScaleIntType = Union[int, Tuple[int, int]]

FillValueType = Optional[Union[int, float, Sequence[int], Sequence[float]]]


def to_tuple(param, low=None, bias=None):
    """Convert input argument to min-max tuple
    Args:
        param (scalar, tuple or list of 2+ elements): Input value.
            If value is scalar, return value would be (offset - value, offset + value).
            If value is tuple, return value would be value + offset (broadcasted).
        low:  Second element of tuple can be passed as optional argument
        bias: An offset factor added to each element
    """
    if low is not None and bias is not None:
        raise ValueError("Arguments low and bias are mutually exclusive")

    if param is None:
        return param

    if isinstance(param, (int, float)):
        if low is None:
            param = -param, +param
        else:
            param = (low, param) if low < param else (param, low)
    elif isinstance(param, Sequence):
        if len(param) != 2:
            raise ValueError("to_tuple expects 1 or 2 values")
        param = tuple(param)
    else:
        raise ValueError("Argument param must be either scalar (int, float) or tuple")

    if bias is not None:
        return tuple(bias + x for x in param)

    return tuple(param)


class BasicTransform(Serializable):
    call_backup = None
    interpolation: Any
    fill_value: Any
    mask_fill_value: Any

    def __init__(self, always_apply: bool = False, p: float = 0.5):
        self.p = p
        self.always_apply = always_apply
        self._additional_targets: Dict[str, str] = {}

        # replay mode params
        self.deterministic = False
        self.save_key = "replay"
        self.params: Dict[Any, Any] = {}
        self.replay_mode = False
        self.applied_in_replay = False

    def __call__(self, *args, force_apply: bool = False, **kwargs) -> Dict[str, Any]:
        if args:
            raise KeyError("You have to pass data to augmentations as named arguments, for example: aug(image=image)")
        if self.replay_mode:
            if self.applied_in_replay:
                return self.apply_with_params(self.params, **kwargs)

            return kwargs

        if (random.random() < self.p) or self.always_apply or force_apply:
            params = self.get_params()

            if self.targets_as_params:
                assert all(key in kwargs for key in self.targets_as_params), "{} requires {}".format(
                    self.__class__.__name__, self.targets_as_params
                )
                targets_as_params = {k: kwargs[k] for k in self.targets_as_params}
                params_dependent_on_targets = self.get_params_dependent_on_targets(targets_as_params)
                params.update(params_dependent_on_targets)
            if self.deterministic:
                if self.targets_as_params:
                    warn(
                        self.get_class_fullname() + " could work incorrectly in ReplayMode for other input data"
                        " because its' params depend on targets."
                    )
                kwargs[self.save_key][id(self)] = deepcopy(params)
            return self.apply_with_params(params, **kwargs)

        return kwargs

    def apply_with_params(self, params: Dict[str, Any], **kwargs) -> Dict[str, Any]:  # skipcq: PYL-W0613
        if params is None:
            return kwargs
        params = self.update_params(params, **kwargs)
        res = {}
        for key, arg in kwargs.items():
            if arg is not None:
                target_function = self._get_target_function(key)
                target_dependencies = {k: kwargs[k] for k in self.target_dependence.get(key, [])}
                res[key] = target_function(arg, **dict(params, **target_dependencies))
            else:
                res[key] = None
        return res

    def set_deterministic(self, flag: bool, save_key: str = "replay") -> "BasicTransform":
        assert save_key != "params", "params save_key is reserved"
        self.deterministic = flag
        self.save_key = save_key
        return self

    def __repr__(self) -> str:
        state = self.get_base_init_args()
        state.update(self.get_transform_init_args())
        return "{name}({args})".format(name=self.__class__.__name__, args=format_args(state))

    def _get_target_function(self, key: str) -> Callable:
        transform_key = key
        if key in self._additional_targets:
            transform_key = self._additional_targets.get(key, key)

        target_function = self.targets.get(transform_key, lambda x, **p: x)
        return target_function

    def apply(self, img: np.ndarray, **params) -> np.ndarray:
        raise NotImplementedError

    def get_params(self) -> Dict:
        return {}

    @property
    def targets(self) -> Dict[str, Callable]:
        # you must specify targets in subclass
        # for example: ('image', 'mask')
        #              ('image', 'boxes')
        raise NotImplementedError

    def update_params(self, params: Dict[str, Any], **kwargs) -> Dict[str, Any]:
        if hasattr(self, "interpolation"):
            params["interpolation"] = self.interpolation
        if hasattr(self, "fill_value"):
            params["fill_value"] = self.fill_value
        if hasattr(self, "mask_fill_value"):
            params["mask_fill_value"] = self.mask_fill_value
        params.update({"cols": kwargs["image"].shape[1], "rows": kwargs["image"].shape[0]})
        return params

    @property
    def target_dependence(self) -> Dict:
        return {}

    def add_targets(self, additional_targets: Dict[str, str]):
        """Add targets to transform them the same way as one of existing targets
        ex: {'target_image': 'image'}
        ex: {'obj1_mask': 'mask', 'obj2_mask': 'mask'}
        by the way you must have at least one object with key 'image'

        Args:
            additional_targets (dict): keys - new target name, values - old target name. ex: {'image2': 'image'}
        """
        self._additional_targets = additional_targets

    @property
    def targets_as_params(self) -> List[str]:
        return []

    def get_params_dependent_on_targets(self, params: Dict[str, Any]) -> Dict[str, Any]:
        raise NotImplementedError(
            "Method get_params_dependent_on_targets is not implemented in class " + self.__class__.__name__
        )

    @classmethod
    def get_class_fullname(cls) -> str:
        return get_shortest_class_fullname(cls)

    @classmethod
    def is_serializable(cls):
        return True

    def get_transform_init_args_names(self) -> Tuple[str, ...]:
        raise NotImplementedError(
            "Class {name} is not serializable because the `get_transform_init_args_names` method is not "
            "implemented".format(name=self.get_class_fullname())
        )

    def get_base_init_args(self) -> Dict[str, Any]:
        return {"always_apply": self.always_apply, "p": self.p}

    def get_transform_init_args(self) -> Dict[str, Any]:
        return {k: getattr(self, k) for k in self.get_transform_init_args_names()}

    def _to_dict(self) -> Dict[str, Any]:
        state = {"__class_fullname__": self.get_class_fullname()}
        state.update(self.get_base_init_args())
        state.update(self.get_transform_init_args())
        return state

    def get_dict_with_id(self) -> Dict[str, Any]:
        d = self._to_dict()
        d["id"] = id(self)
        return d


class DualTransform(BasicTransform):
    """Transform for segmentation task."""

    @property
    def targets(self) -> Dict[str, Callable]:
        return {
            "image": self.apply,
            "mask": self.apply_to_mask,
            "masks": self.apply_to_masks,
            "bboxes": self.apply_to_bboxes,
            "keypoints": self.apply_to_keypoints,
        }

    def apply_to_bbox(self, bbox: BoxInternalType, **params) -> BoxInternalType:
        raise NotImplementedError("Method apply_to_bbox is not implemented in class " + self.__class__.__name__)

    def apply_to_keypoint(self, keypoint: KeypointInternalType, **params) -> KeypointInternalType:
        raise NotImplementedError("Method apply_to_keypoint is not implemented in class " + self.__class__.__name__)

    def apply_to_bboxes(self, bboxes: Sequence[BoxType], **params) -> List[BoxType]:
        return [self.apply_to_bbox(tuple(bbox[:4]), **params) + tuple(bbox[4:]) for bbox in bboxes]  # type: ignore

    def apply_to_keypoints(self, keypoints: Sequence[KeypointType], **params) -> List[KeypointType]:
        return [  # type: ignore
            self.apply_to_keypoint(tuple(keypoint[:4]), **params) + tuple(keypoint[4:])  # type: ignore
            for keypoint in keypoints
        ]

    def apply_to_mask(self, img: np.ndarray, **params) -> np.ndarray:
        return self.apply(img, **{k: cv2.INTER_NEAREST if k == "interpolation" else v for k, v in params.items()})

    def apply_to_masks(self, masks: Sequence[np.ndarray], **params) -> List[np.ndarray]:
        return [self.apply_to_mask(mask, **params) for mask in masks]


class ImageOnlyTransform(BasicTransform):
    """Transform applied to image only."""

    @property
    def targets(self) -> Dict[str, Callable]:
        return {"image": self.apply}


class NoOp(DualTransform):
    """Does nothing"""

    def apply_to_keypoint(self, keypoint: KeypointInternalType, **params) -> KeypointInternalType:
        return keypoint

    def apply_to_bbox(self, bbox: BoxInternalType, **params) -> BoxInternalType:
        return bbox

    def apply(self, img: np.ndarray, **params) -> np.ndarray:
        return img

    def apply_to_mask(self, img: np.ndarray, **params) -> np.ndarray:
        return img

    def get_transform_init_args_names(self) -> Tuple:
        return ()