//! Helper macros for the circuit reactors.

derive_deftly::define_derive_deftly! {

    /// Helper for deriving the boilerplate `run()` function of a circuit reactor.

    ///

    ///

    /// ### Custom attributes

    ///

    ///  * **`#[deftly(reactor_name = "...")]`** (toplevel):

    ///    The name of the reactor, for logging purposes.

    ///    Must be a literal string.

    ///

    ///  * **`#[deftly(run_inner_fn = "FUNCTION")]`** (toplevel):

    ///    The function to run from `run()`, possibly in a loop.

    ///    `FUNCTION` is a function with the signature

    ///    `async fn run_once(&mut Self) -> Result<(), ReactorError>`

    ///

    ///  * **`#[deftly(only_run_once)]`** (toplevel):

    ///    Whether the `run()` function should only run `run_inner_fn` once

    export CircuitReactor expect items:

    impl<$tgens> $ttype where

        $twheres

    {

        /// Launch the reactor, and run until the circuit closes or we

        /// encounter an error.

        ///

        /// Once this method returns, the circuit is dead and cannot be

        /// used again.

            let unique_id = self.unique_id;

            tracing::debug!(

                circ_uniq_id = %unique_id,

                backward_circ_id = %self.circ_id,

                "Running {}", ${tmeta(reactor_name) as str}

            );

            let result: $crate::Result<()> = loop {

                match ${tmeta(run_inner_fn) as expr}(&mut self).await {

                    Ok(()) => {

                        ${if tmeta(only_run_once) {

                            break Ok(());

                        }}

                    },

                    Err(ReactorError::Shutdown) => break Ok(()),

                    Err(ReactorError::Err(e)) => break Err(e),

                }

            };

            // Log that the reactor stopped, possibly with the associated error as a report.

            // May log at a higher level depending on the error kind.

            let msg = format!("{} shut down", ${tmeta(reactor_name) as str});

            match &result {

                Ok(()) => tracing::trace!(

                    circ_uniq_id = %unique_id,

                    backward_circ_id = %self.circ_id,

                    "{msg}"

                ),

                Err(e) => tor_error::debug_report!(

                    e,

                    circ_uniq_id = %unique_id,

                    backward_circ_id = %self.circ_id,

                    "{msg}"

                ),

            }

            result

        }

    }

}

pub(crate) use derive_deftly_template_CircuitReactor;