import inspect
import json
import os
import pkgutil
from abc import ABC, abstractmethod
from copy import deepcopy
from typing import Any, Dict, List, Union, final

from .dataclass import Dataclass, Field, asdict, fields
from .text_utils import camel_to_snake_case, is_camel_case
from .type_utils import issubtype


class Artifactories(object):
    def __new__(cls):
        if not hasattr(cls, "instance"):
            cls.instance = super(Artifactories, cls).__new__(cls)
            cls.instance.artifactories = []

        return cls.instance

    def __iter__(self):
        return iter(self.artifactories)

    def __next__(self):
        return next(self.artifactories)

    def register_atrifactory(self, artifactory):
        assert isinstance(artifactory, Artifactory), "Artifactory must be an instance of Artifactory"
        assert hasattr(artifactory, "__contains__"), "Artifactory must have __contains__ method"
        assert hasattr(artifactory, "__getitem__"), "Artifactory must have __getitem__ method"
        self.artifactories = [artifactory] + self.artifactories


def map_values_in_place(object, mapper):
    if isinstance(object, dict):
        for key, value in object.items():
            object[key] = mapper(value)
        return object
    if isinstance(object, list):
        for i in range(len(object)):
            object[i] = mapper(object[i])
        return object
    return mapper(object)


class Artifact(Dataclass):
    type: str = Field(default=None, final=True, init=False)

    _class_register = {}

    @classmethod
    def is_artifact_dict(cls, d):
        return isinstance(d, dict) and "type" in d and d["type"] in cls._class_register

    @classmethod
    def get_artifact_type(cls):
        return camel_to_snake_case(cls.__name__)

    @classmethod
    def register_class(cls, artifact_class):
        assert issubclass(
            artifact_class, Artifact
        ), f"Artifact class must be a subclass of Artifact, got {artifact_class}"
        assert is_camel_case(
            artifact_class.__name__
        ), f"Artifact class name must be legal camel case, got {artifact_class.__name__}"

        snake_case_key = camel_to_snake_case(artifact_class.__name__)

        if snake_case_key in cls._class_register:
            assert (
                cls._class_register[snake_case_key] == artifact_class
            ), f"Artifact class name must be unique, {snake_case_key} already exists for {cls._class_register[snake_case_key]}"

            return snake_case_key

        cls._class_register[snake_case_key] = artifact_class

        return snake_case_key

    @classmethod
    def is_artifact_file(cls, path):
        if not os.path.exists(path) or not os.path.isfile(path):
            return False
        with open(path, "r") as f:
            d = json.load(f)
        return cls.is_artifact_dict(d)

    @classmethod
    def _recursive_load(cls, d):
        if isinstance(d, dict):
            new_d = {}
            for key, value in d.items():
                new_d[key] = cls._recursive_load(value)
            d = new_d
        elif isinstance(d, list):
            d = [cls._recursive_load(value) for value in d]
        else:
            pass
        if cls.is_artifact_dict(d):
            instance = cls._class_register[d.pop("type")](**d)
            return instance
        else:
            return d

    @classmethod
    def from_dict(cls, d):
        assert cls.is_artifact_dict(d), "Input must be a dict with type field"
        return cls._recursive_load(d)

    @classmethod
    def load(cls, path):
        try:
            with open(path, "r") as f:
                d = json.load(f)
            assert "type" in d, "Saved artifact must have a type field"
            return cls._recursive_load(d)
        except Exception as e:
            raise Exception(f"{e}\n\nFailed to load artifact from {path} see above for more details.")

    def prepare(self):
        pass

    def verify(self):
        pass

    @final
    def __pre_init__(self, **kwargs):
        self._init_dict = kwargs

    @final
    def __post_init__(self):
        self.type = self.register_class(self.__class__)

        for field in fields(self):
            if issubtype(field.type, Union[Artifact, List[Artifact], Dict[str, Artifact]]):
                value = getattr(self, field.name)
                value = map_values_in_place(value, maybe_recover_artifact)
                setattr(self, field.name, value)

        self.prepare()
        self.verify()

    def _to_raw_dict(self):
        return {"type": self.type, **self._init_dict}

    def save(self, path):
        with open(path, "w") as f:
            init_dict = self.to_dict()
            json.dump(init_dict, f, indent=4)


class ArtifactList(list, Artifact):
    def prepare(self):
        for artifact in self:
            artifact.prepare()


class Artifactory(Artifact):
    @abstractmethod
    def __contains__(self, name: str) -> bool:
        pass

    @abstractmethod
    def __getitem__(self, name) -> Artifact:
        pass


class UnitxtArtifactNotFoundError(Exception):
    def __init__(self, name, artifactories):
        self.name = name
        self.artifactories = artifactories

    def __str__(self):
        return f"Artifact {self.name} does not exist, in artifactories:{self.artifactories}"


def fetch_artifact(name):
    if Artifact.is_artifact_file(name):
        return Artifact.load(name), None
    else:
        for artifactory in Artifactories():
            if name in artifactory:
                return artifactory[name], artifactory

    raise UnitxtArtifactNotFoundError(name, Artifactories().artifactories)


def verbosed_fetch_artifact(identifer):
    artifact, artifactory = fetch_artifact(identifer)
    print(f"Artifact {identifer} is fetched from {artifactory}")
    return artifact


def maybe_recover_artifact(artifact):
    if isinstance(artifact, str):
        return verbosed_fetch_artifact(artifact)
    else:
        return artifact


def register_all_artifacts(path):
    for loader, module_name, is_pkg in pkgutil.walk_packages(path):
        print(__name__)
        if module_name == __name__:
            continue
        print(f"Loading {module_name}")
        # Import the module
        module = loader.find_module(module_name).load_module(module_name)

        # Iterate over every object in the module
        for name, obj in inspect.getmembers(module):
            # Make sure the object is a class
            if inspect.isclass(obj):
                # Make sure the class is a subclass of Artifact (but not Artifact itself)
                if issubclass(obj, Artifact) and obj is not Artifact:
                    print(obj)