use std::fmt::Debug;

use serde::{Deserialize, Serialize};

use crate::schema::ApiName;

/// An API request type.

pub trait Api: Serialize + for<'de> Deserialize<'de> + Send + Sync + Debug + 'static {

    /// The type that represents an API response. This type will be sent to clients from the server.

    type Response: Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync + Debug;

    /// The error type that this  can return.

    type Error: ApiError;

    /// Returns the unique name of this api.

    fn name() -> ApiName;

}

/// An Error type that can be used in within an [`Api`] definition.

///

/// The reason `std::convert::Infallible` can't be used is because `Api`

/// errors must be able to be serialized across a network connection. While a

/// value will never be present when this is Infallible, the associated type

/// still must be declared as Serializable.

#[error("an unreachable error")]

pub enum Infallible {}

/// An error that can be used within a [`Api`] definition.

pub trait ApiError:

    std::fmt::Display + Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync + Debug

{

}

impl<T> ApiError for T where

    T: std::fmt::Display + Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync + Debug

{

}

/// The result of executing a custom API call.

pub type ApiResult<Api> = Result<<Api as self::Api>::Response, <Api as self::Api>::Error>;