# Copyright (c) 2022 Kyle Schouviller (https://github.com/kyle0654)

from abc import ABC, abstractmethod
from inspect import signature
from typing import get_args, get_type_hints

from pydantic import BaseModel, Field

from ..services.invocation_services import InvocationServices


class InvocationContext:
    services: InvocationServices
    graph_execution_state_id: str

    def __init__(self, services: InvocationServices, graph_execution_state_id: str):
        self.services = services
        self.graph_execution_state_id = graph_execution_state_id


class BaseInvocationOutput(BaseModel):
    """Base class for all invocation outputs"""

    # All outputs must include a type name like this:
    # type: Literal['your_output_name']

    @classmethod
    def get_all_subclasses_tuple(cls):
        subclasses = []
        toprocess = [cls]
        while len(toprocess) > 0:
            next = toprocess.pop(0)
            next_subclasses = next.__subclasses__()
            subclasses.extend(next_subclasses)
            toprocess.extend(next_subclasses)
        return tuple(subclasses)


class BaseInvocation(ABC, BaseModel):
    """A node to process inputs and produce outputs.
    May use dependency injection in __init__ to receive providers.
    """

    # All invocations must include a type name like this:
    # type: Literal['your_output_name']

    @classmethod
    def get_all_subclasses(cls):
        subclasses = []
        toprocess = [cls]
        while len(toprocess) > 0:
            next = toprocess.pop(0)
            next_subclasses = next.__subclasses__()
            subclasses.extend(next_subclasses)
            toprocess.extend(next_subclasses)
        return subclasses

    @classmethod
    def get_invocations(cls):
        return tuple(BaseInvocation.get_all_subclasses())

    @classmethod
    def get_invocations_map(cls):
        # Get the type strings out of the literals and into a dictionary
        return dict(map(lambda t: (get_args(get_type_hints(t)['type'])[0], t),BaseInvocation.get_all_subclasses()))
    
    @classmethod
    def get_output_type(cls):
        return signature(cls.invoke).return_annotation

    @abstractmethod
    def invoke(self, context: InvocationContext) -> BaseInvocationOutput:
        """Invoke with provided context and return outputs."""
        pass
    
    #fmt: off
    id: str = Field(description="The id of this node. Must be unique among all nodes.")
    #fmt: on