"""Module for requests validation."""

from functools import wraps
import json
import os

import jsonschema
from oto import response
from oto.adaptors.flask import flaskify as oto_flaskify

from availability import config
from availability.constants import error


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

    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(function):
        @wraps(function)
        def wrapped_f(*args, **kwargs):
            try:
                jsonschema.validate(dict(request.headers), schema)
            except jsonschema.ValidationError as err:
                return oto_flaskify(
                    response.create_error_response(
                        code=error.HEADER_VALIDATION_ERROR,
                        message=str(err)))
            return function(*args, **kwargs)
        return wrapped_f
    return wrap


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

    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(function):
        @wraps(function)
        def wrapped_f(*args, **kwargs):
            try:
                jsonschema.validate(
                    request.get_json(), schema,
                    format_checker=jsonschema.draft4_format_checker)
            except jsonschema.ValidationError as err:
                return oto_flaskify(
                    response.create_error_response(
                        code=error.BODY_VALIDATION_ERROR,
                        message=str(err)))
            return function(*args, **kwargs)
        return wrapped_f
    return wrap


def load_schema(name):
    """Load schema from json file.

    Args:
        name (str): name of file with schema.

    Returns:
        dict: JSON schema from given file
    """
    schema_path = os.path.join(
        config.BASE_DIR, '..', 'spec', name)
    with open(schema_path) as schema_file:
        return json.load(schema_file)