//! Traits and enumerations for connections.

use std::{error::Error as StdError, sync::Arc};

use async_trait::async_trait;

/// Connection status.

#[derive(Debug, PartialEq)]

pub enum Status {

    /// The connection is closing.

    Closing,

    /// The connection is closed by the program.

    Closed,

    /// Connecting to the message broker.

    Connecting,

    /// Connected to the message broker.

    Connected,

    /// The connection is not connected. It will retry connecting to the broker automatically.

    Disconnected,

}

/// The operations for connections.

#[async_trait]

pub trait GmqConnection: Send + Sync {

    /// To get the connection status.

    fn status(&self) -> Status;

    /// To add a connection event handler. This will return an identifier for applications to manage

    /// handlers.

    fn add_handler(&mut self, handler: Arc<dyn EventHandler>) -> String;

    /// To remove a handler with an idenfier from [`GmqConnection::add_handler`].

    fn remove_handler(&mut self, id: &str);

    /// To connect to the message broker. The [`GmqConnection`] will connect to the broker using

    /// another runtime task and report status with [`Status`]s.

    fn connect(&mut self) -> Result<(), Box<dyn StdError>>;

    /// To close the connection.

    async fn close(&mut self) -> Result<(), Box<dyn StdError + Send + Sync>>;

}

/// The event handler for connections.

#[async_trait]

pub trait EventHandler: Send + Sync {

    /// Triggered when there are errors.

    async fn on_error(

        &self,

        handler_id: String,

        conn: Arc<dyn GmqConnection>,

        err: Box<dyn StdError + Send + Sync>,

    );

    /// Triggered by [`Status`].

    async fn on_status(&self, handler_id: String, conn: Arc<dyn GmqConnection>, status: Status);

}

impl Copy for Status {}

impl Clone for Status {

}