defmodule ConfigCat.ConfigCache do

@moduledoc """

Defines a configuration cache.

A calling application can optionally supply its own cache implementation to use

in place of the default in-memory cache by providing the implementation's module name

as the `:cache` option in `ConfigCat.child_spec/1`.

The provided implementation must explicitly or implicitly implement this behaviour.

If the cache implementation is a GenServer or similar, it is the calling

application's responsibility to add it to its own supervision tree.

"""

@typedoc "The cache key under which the configuration is stored"

@type key :: String.t()

@typedoc "The result of a cache fetch."

@type result :: {:ok, String.t()} | {:error, :not_found}

@doc """

Fetches the serialized configuration stored under the given cache key.

Returns `{:ok, serialized_config}` if there is a cached configuration or

`{:error, :not_found}` if not.

"""

@callback get(key) :: result()

@doc """

Stores an updated serialized configuration under the given cache key.

Returns :ok.

"""

@callback set(key, config :: String.t()) :: :ok | {:error, term()}

end