"""Decorator for view methods to help with data validation."""
from functools import wraps
import logging
from typing import Any, Awaitable, Callable

from aiohttp import web
import voluptuous as vol

from homeassistant.const import HTTP_BAD_REQUEST

from .view import HomeAssistantView

_LOGGER = logging.getLogger(__name__)


class RequestDataValidator:
    """Decorator that will validate the incoming data.

    Takes in a voluptuous schema and adds 'post_data' as
    keyword argument to the function call.

    Will return a 400 if no JSON provided or doesn't match schema.
    """

    def __init__(self, schema: vol.Schema, allow_empty: bool = False) -> None:
        """Initialize the decorator."""
        if isinstance(schema, dict):
            schema = vol.Schema(schema)

        self._schema = schema
        self._allow_empty = allow_empty

    def __call__(
        self, method: Callable[..., Awaitable[web.StreamResponse]]
    ) -> Callable:
        """Decorate a function."""

        @wraps(method)
        async def wrapper(
            view: HomeAssistantView, request: web.Request, *args: Any, **kwargs: Any
        ) -> web.StreamResponse:
            """Wrap a request handler with data validation."""
            data = None
            try:
                data = await request.json()
            except ValueError:
                if not self._allow_empty or (await request.content.read()) != b"":
                    _LOGGER.error("Invalid JSON received")
                    return view.json_message("Invalid JSON.", HTTP_BAD_REQUEST)
                data = {}

            try:
                kwargs["data"] = self._schema(data)
            except vol.Invalid as err:
                _LOGGER.error("Data does not match schema: %s", err)
                return view.json_message(
                    f"Message format incorrect: {err}", HTTP_BAD_REQUEST
                )

            result = await method(view, request, *args, **kwargs)
            return result

        return wrapper
