from chalice import Response
from cerberus import Validator


def validate(schema, location="body"):
    def decorator(fn):
        def wrapped_f(*args, **kwargs):
            v = Validator(schema, allow_unknown=True)
            data = {}

            if location == "body":
                data = app.current_request.json_body or data
            if location == "query":
                data = app.current_request.query_params or data

            if v(data):
                return fn(*args, **kwargs)

            body = {"message": f"Invalid {location} parameters.", "data": v.errors}
            return Response(body=body, status_code=400)


"""
# Sample usage:

todo_list_params = {
    "keyword": {"type": "string", "required": False, "empty": False},
    "start_date": {"type": "datetime", "required": False, "empty": False,
                   "coerce": lambda date: datetime.datetime.strptime(date, "%Y-%m-%d")},
}

@app.route("/todos", methods=["GET"])
@validate(todo_list_params, location="query")
def get_todo_list():
    return {"todos": []}
"""