"""JSON Draft4 Schema Validator Wrapper.

A Wrapper for a JSON Draft4 schema validation library which allows us to
transform the results into an internal Response() format.
"""
from functools import wraps

from jsonschema import validate
from jsonschema import ValidationError
from oto import response
from oto.adaptors.flask import flaskify

from content_review.constants import error


def validate_headers(request, schema):
    """Validate HTTP request headers decorator.

    Args:
        request (werkzeug.local.LocalProxy): request object from the handler.
        schema (Draft4Validator): the JSON Draft4 Schema to validate against.

    Returns:
        callable: the wrapped function.
    """
    def wrap(fn):
        @wraps(fn)
        def wrapped_f(*args, **kwargs):
            try:
                validate(dict(request.headers), schema)
            except ValidationError as err:
                return flaskify(
                    response.create_error_response(
                        code=error.HEADER_VALIDATION_ERROR,
                        message=str(err)))
            return fn(*args, **kwargs)
        return wrapped_f
    return wrap


def validate_body(request, schema):
    """Validate HTTP request body decorator.

    Args:
        request (werkzeug.local.LocalProxy): request object from the handler.
        schema (Draft4Validator): the JSON Draft4 Schema to validate against.

    Returns:
        callable: the wrapped function.
    """
    def wrap(fn):
        @wraps(fn)
        def wrapped_f(*args, **kwargs):
            try:
                validate(request.get_json(silent=True, force=True), schema)
            except ValidationError as err:
                return flaskify(
                    response.create_error_response(
                        code=error.BODY_VALIDATION_ERROR,
                        message=str(err)))
            return fn(*args, **kwargs)
        return wrapped_f
    return wrap