import flask.views

from common_apispec.annotations import activate


def inherit(child, parents):
    child.__apispec__ = child.__dict__.get("__apispec__", {})
    for key in ["args", "schemas", "docs"]:
        child.__apispec__.setdefault(key, []).extend(
            annotation
            for parent in parents
            for annotation in getattr(parent, "__apispec__", {}).get(key, [])
            if annotation not in child.__apispec__[key]
        )


class ResourceMeta(type):
    def __new__(mcs, name, bases, attrs):
        klass = super().__new__(mcs, name, bases, attrs)
        mro = klass.mro()
        inherit(klass, mro[1:])
        methods = [
            each.lower()
            for each in getattr(klass, "methods", None) or flask.views.http_method_funcs
        ]
        for key, value in attrs.items():
            if key.lower() in methods:
                parents = [
                    getattr(parent, key) for parent in mro if hasattr(parent, key)
                ]
                inherit(value, parents)
                setattr(klass, key, activate(value))
                if not isinstance(value, staticmethod):
                    value.__dict__.setdefault("__apispec__", {})
                    value.__apispec__["ismethod"] = True
        return klass


class MethodResourceMeta(ResourceMeta, type(flask.views.MethodView)):  # type: ignore
    pass


class MethodResource(flask.views.MethodView, metaclass=MethodResourceMeta):
    """Subclass of `MethodView` that uses the `ResourceMeta` metaclass. Behaves
    exactly like `MethodView` but inherits **flask-apispec** annotations.
    """

    methods = None