"""Utility Functions for Handlers."""

from functools import wraps

from flask import request
from oto.adaptors.flask import flaskify
from owsrequest import flask_request

from backend.constants import field
from backend.validation import json_schema


def get_headers(function):
    """Grab headers from request object.

    Args:
        Function (func): the function to be called after grabbing the headers.

    Returns:
        Function: The decorated function.
    """
    @wraps(function)
    def call_function_with_headers(*args, **kwargs):
        kwargs['correlation_id'] = \
            request.headers.get(field.CORRELATION_ID_FIELD)
        kwargs['account_type'], kwargs['account_id'] = \
            flask_request.get_grass_headers(request)

        function_return = function(*args, **kwargs)

        return function_return

    return call_function_with_headers


def validate_header(request, validator):
    """A decorator to call when validating HTTP request headers.

    Args:
        request (werkzeug.local.LocalProxy): the request object from the
        handler.
        validator (Draft3Validator): the JSON Draft3 Schema to validate
        against.

    Returns:
        callable: the wrapped function.
    """
    def decorator(f):
        @wraps(f)
        def _validate_header(*args, **kwargs):
            """Validate the request headers against a validator.

            Args:
                request (werkzeug.local.LocalProxy): the request object from
                the handler.
                validator (Draft3Validator): the JSON Draft3 Schema to validate
                against.

            Returns:
                Response: error HTTP response, or continue to the calling
                function if successful.
            """
            validation_response = json_schema.validate(
                dict(request.headers), validator)
            if validation_response.status != 200:
                return flaskify(validation_response)
            return f(*args, **kwargs)
        return _validate_header
    return decorator


def validate_body(request, validator):
    """A decorator to call when validating HTTP request body.

    Args:
        request (werkzeug.local.LocalProxy): the request object from the
        handler.
        validator (Draft3Validator): the JSON Draft3 Schema to validate
        against.
    Returns:
        callable: the wrapped function.
    """
    def decorator(f):
        """Decorator for validate_body method."""
        @wraps(f)
        def _validate_body(*args, **kwargs):
            """Validate the request body against a validator.

            Args:
                request (werkzeug.local.LocalProxy): the request object from
                the handler.
                validator (Draft3Validator): the JSON Draft3 Schema to validate
                against.
            Returns:
                Response: error HTTP response, or continue to the calling
                function if successful.
            """
            validation_response = json_schema.validate(
                request.get_json(), validator)
            if validation_response.status != 200:
                return flaskify(validation_response)
            return f(*args, **kwargs)
        return _validate_body
    return decorator