import json
from contextlib import suppress
from datetime import timedelta
from functools import wraps
from inspect import signature


class RequestCache:
    DEFAULT_TTL = int(timedelta(days=7).total_seconds())

    def __init__(self, redis_client):
        self.redis_client = redis_client

    @staticmethod
    def _get_argument(argument_name, client_method, args, kwargs):
        with suppress(KeyError):
            return kwargs[argument_name]

        with suppress(ValueError, IndexError):
            argument_index = list(signature(client_method).parameters).index(
                argument_name
            )
            return args[argument_index]

        with suppress(KeyError):
            return signature(client_method).parameters[argument_name].default

        raise TypeError(
            "{}() takes no argument called '{}'".format(
                client_method.__name__, argument_name
            )
        )

    @staticmethod
    def _make_key(key_format, client_method, args, kwargs):
        return key_format.format(
            **{
                argument_name: RequestCache._get_argument(
                    argument_name, client_method, args, kwargs
                )
                for argument_name in list(signature(client_method).parameters)
            }
        )

    def set(self, key_format, *, ttl_in_seconds=DEFAULT_TTL):
        def _set(client_method):
            @wraps(client_method)
            def new_client_method(*args, **kwargs):
                redis_key = RequestCache._make_key(
                    key_format, client_method, args, kwargs
                )
                cached = self.redis_client.get(redis_key)
                if cached:
                    return json.loads(cached.decode("utf-8"))
                api_response = client_method(*args, **kwargs)
                self.redis_client.set(
                    redis_key,
                    json.dumps(api_response),
                    ex=int(ttl_in_seconds),
                )
                return api_response

            return new_client_method

        return _set

    def delete(self, key_format):
        def _delete(client_method):
            @wraps(client_method)
            def new_client_method(*args, **kwargs):
                try:
                    api_response = client_method(*args, **kwargs)
                finally:
                    redis_key = self._make_key(key_format, client_method, args, kwargs)
                    self.redis_client.delete(redis_key)
                return api_response

            return new_client_method

        return _delete

    def delete_by_pattern(self, key_format):
        def _delete(client_method):
            @wraps(client_method)
            def new_client_method(*args, **kwargs):
                try:
                    api_response = client_method(*args, **kwargs)
                finally:
                    redis_key = self._make_key(key_format, client_method, args, kwargs)
                    self.redis_client.delete_by_pattern(redis_key)
                return api_response

            return new_client_method

        return _delete