from dataclasses import dataclass, field
from typing import Any

from common.global_symbols import NotFound, NotInit


class ConceptDefaultProps:
    """
    Lists metadata that can contains some code
    """
    WHERE = "#where#"
    PRE = "#pre#"
    POST = "#post#"
    BODY = "#body#"
    RET = "#ret#"


ConceptDefaultPropsAttrs = [v for k, v in ConceptDefaultProps.__dict__.items() if not k.startswith("_")]


class DefinitionType:
    DEFAULT = "Default"
    BNF = "Bnf"


@dataclass
class ConceptMetadata:
    """
    Static information of the Concept

    """
    id: str  # unique identifier for a concept. The id will never be modified (but the key can)
    name: str
    key: str
    is_builtin: bool
    is_unique: bool
    body: str  # main method, can also be the value of the concept
    where: str  # condition to recognize variables in name
    pre: str  # list of preconditions before calling the main function
    post: str  # list of post conditions after calling the main function
    ret: str  # variable to return when a concept is recognized
    definition: str  # regex used to define the concept
    definition_type: DefinitionType  # definition can be done with something else than regex
    desc: str  # possible description for the concept
    autouse: bool  # indicates if eval must be automatically called on the concept once validated
    bound_body: str  # which property must be considered have default value for the concept
    props: dict  # hashmap of properties, values
    variables: tuple  # list of concept variables(tuple), with their default values
    parameters: tuple  # list of variables that are part of the name of the concept
    digest: str = None
    all_attrs: tuple = None

    def get_metadata(self):
        return self


@dataclass
class ConceptRuntimeInfo:
    """
    Dynamic information of the Concept
    They are related to the instance of the concept
    """
    is_evaluated: bool = False  # True is the concept is evaluated by sheerka.eval_concept()
    error: Any = None  # when failed to evaluate the concept
    info: dict = field(default_factory=dict)  # give context of why 'where' or 'pre' constraints fail

    def copy(self):
        return ConceptRuntimeInfo(self.is_evaluated,
                                  self.error,
                                  self.info)


class Concept:
    """
    Default concept object
    A concept is the base object of our universe
    Everything is a concept
    """

    def __init__(self, metadata: ConceptMetadata):

        self._metadata: ConceptMetadata = metadata
        self._runtime_info = ConceptRuntimeInfo()  # runtime settings for the concept
        self._all_attrs = None

    def __repr__(self):
        text = f"(Concept {self._metadata.name}#{self._metadata.id}"
        if self._metadata.pre:
            text += f", #pre={self._metadata.pre}"

        for attr in [attr for attr in self.all_attrs() if not attr.startswith("#")]:
            text += f", {attr}={self.get_value(attr)}"

        return text + ")"

    def __eq__(self, other):
        # I don't want this test to be part of the recursion
        # So let's just get rif ogf it
        if not isinstance(other, Concept):
            return False

        # I chose to use an iterative algorithm in order to be able to spot circular reference
        # without inner functions.
        # I also think that it's a better approach for a function that can be massively called

        stack = [self, other]
        id_self = id(self)

        while stack:
            right = stack.pop()
            left = stack.pop()

            if id(left) == id(right):
                return True

            # 1. in order for two concepts to be equal, they must have the same definition
            # 2. They must have the same variables
            if left.get_definition_digest() != right.get_definition_digest():
                return False

            if left.all_attrs() != right.all_attrs():
                return False

            for attr in left.all_attrs():
                value = left.get_value(attr)
                other_value = right.get_value(attr)

                if isinstance(value, Concept) and isinstance(other_value, Concept):
                    if id(value) == id_self or id(other_value) == id_self:
                        # infinite recursion detected
                        pass
                    else:
                        stack.extend([value, other_value])
                else:
                    if value != other_value:
                        return False

        return True

    def __hash__(self):
        return self._metadata.digest

    @property
    def id(self):
        return self._metadata.id

    @property
    def name(self):
        return self._metadata.name

    @property
    def key(self):
        return self._metadata.key

    @property
    def body(self):
        return self.get_value(ConceptDefaultProps.BODY)

    @property
    def str_id(self):
        return f"c:#{self.id}:" if self.id else f"c:{self.name}:"

    def get_definition_digest(self):
        return self._metadata.digest

    def all_attrs(self):
        if self._all_attrs is None:
            return self._metadata.all_attrs

        return self._all_attrs

    def get_metadata(self) -> ConceptMetadata:
        return self._metadata

    def set_value(self, name: str, value: object):
        """
        Set the resolved value of a metadata or a variable (not the metadata itself)
        :param name:
        :param value:
        :return:
        """
        setattr(self, name, value)
        if name == self._metadata.bound_body:
            setattr(self, ConceptDefaultProps.BODY, value)
        elif self._metadata.bound_body and name == ConceptDefaultProps.BODY:
            setattr(self, self._metadata.bound_body, value)

        return self

    def get_value(self, name: str):
        """
        Gets the resolved value of a metadata
        :param name:
        :return:
        """
        try:
            return getattr(self, name)
        except AttributeError:
            return NotInit if name in self.all_attrs() else NotFound

    def get_runtime_info(self):
        return self._runtime_info