memberlist-core 0.2.0-alpha.2

use std::{borrow::Cow, collections::HashMap};

use nodecraft::{resolver::AddressResolver, Node};
use smol_str::SmolStr;

use crate::{
  delegate::{Delegate, DelegateError},
  transport::{MaybeResolvedAddress, Transport},
  types::{ErrorResponse, SmallVec},
};

pub use crate::{
  transport::TransportError,
  types::{UnknownDelegateVersion, UnknownProtocolVersion},
};

/// Error returned by `Memberlist::join_many`.
pub struct JoinError<T: Transport, D>
where
  D: Delegate<Id = T::Id, Address = <T::Resolver as AddressResolver>::ResolvedAddress>,
{
  pub(crate) joined: SmallVec<Node<T::Id, <T::Resolver as AddressResolver>::ResolvedAddress>>,
  pub(crate) errors: HashMap<Node<T::Id, MaybeResolvedAddress<T>>, Error<T, D>>,
}

impl<D, T: Transport> From<JoinError<T, D>>
  for (
    SmallVec<Node<T::Id, <T::Resolver as AddressResolver>::ResolvedAddress>>,
    HashMap<Node<T::Id, MaybeResolvedAddress<T>>, Error<T, D>>,
  )
where
  D: Delegate<Id = T::Id, Address = <T::Resolver as AddressResolver>::ResolvedAddress>,
{
  fn from(e: JoinError<T, D>) -> Self {
    (e.joined, e.errors)
  }
}

impl<D, T: Transport> core::fmt::Debug for JoinError<T, D>
where
  D: Delegate<Id = T::Id, Address = <T::Resolver as AddressResolver>::ResolvedAddress>,
{
  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
    if !self.joined.is_empty() {
      writeln!(f, "Successes: {:?}", self.joined)?;
    }

    if !self.errors.is_empty() {
      writeln!(f, "Failures:")?;
      for (addr, err) in self.errors.iter() {
        writeln!(f, "\t{}: {}", addr, err)?;
      }
    }

    Ok(())
  }
}

impl<D, T: Transport> core::fmt::Display for JoinError<T, D>
where
  D: Delegate<Id = T::Id, Address = <T::Resolver as AddressResolver>::ResolvedAddress>,
{
  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
    if !self.joined.is_empty() {
      writeln!(f, "Successes: {:?}", self.joined)?;
    }

    if !self.errors.is_empty() {
      writeln!(f, "Failures:")?;
      for (addr, err) in self.errors.iter() {
        writeln!(f, "\t{addr}: {err}")?;
      }
    }

    Ok(())
  }
}

impl<T: Transport, D> std::error::Error for JoinError<T, D> where
  D: Delegate<Id = T::Id, Address = <T::Resolver as AddressResolver>::ResolvedAddress>
{
}

impl<T: Transport, D> JoinError<T, D>
where
  D: Delegate<Id = T::Id, Address = <T::Resolver as AddressResolver>::ResolvedAddress>,
{
  /// Return the number of successful joined nodes
  pub fn num_joined(&self) -> usize {
    self.joined.len()
  }

  /// Return the joined nodes
  pub const fn joined(
    &self,
  ) -> &SmallVec<Node<T::Id, <T::Resolver as AddressResolver>::ResolvedAddress>> {
    &self.joined
  }
}

impl<T: Transport, D> JoinError<T, D>
where
  D: Delegate<Id = T::Id, Address = <T::Resolver as AddressResolver>::ResolvedAddress>,
{
  /// Return the errors
  pub const fn errors(&self) -> &HashMap<Node<T::Id, MaybeResolvedAddress<T>>, Error<T, D>> {
    &self.errors
  }
}

/// Error type for the [`Memberlist`](crate::Memberlist)
#[derive(thiserror::Error)]
pub enum Error<T: Transport, D: Delegate> {
  /// Returns when the node is not running.
  #[error("memberlist: node is not running, please bootstrap first")]
  NotRunning,
  /// Returns when timeout waiting for update broadcast.
  #[error("memberlist: timeout waiting for update broadcast")]
  UpdateTimeout,
  /// Returns when timeout waiting for leave broadcast.
  #[error("memberlist: timeout waiting for leave broadcast")]
  LeaveTimeout,
  /// Returns when lost connection with a peer.
  #[error("memberlist: no response from node {0}")]
  Lost(Node<T::Id, <T::Resolver as AddressResolver>::ResolvedAddress>),
  /// Delegate error
  #[error("memberlist: {0}")]
  Delegate(#[from] DelegateError<D>),
  /// Transport error
  #[error("memberlist: {0}")]
  Transport(T::Error),
  /// Returned when a message is received with an unexpected type.
  #[error("memberlist: unexpected message: expected {expected}, got {got}")]
  UnexpectedMessage {
    /// The expected message type.
    expected: &'static str,
    /// The actual message type.
    got: &'static str,
  },
  /// Returned when the sequence number of [`Ack`](crate::types::Ack) is not
  /// match the sequence number of [`Ping`](crate::types::Ping).
  #[error("memberlist: sequence number mismatch: ping({ping}), ack({ack})")]
  SequenceNumberMismatch {
    /// The sequence number of [`Ping`](crate::types::Ping).
    ping: u32,
    /// The sequence number of [`Ack`](crate::types::Ack).
    ack: u32,
  },
  /// Returned when a remote error is received.
  #[error("memberlist: remote error: {0}")]
  Remote(SmolStr),
  /// Returned when a custom error is created by users.
  #[error("memberlist: {0}")]
  Other(Cow<'static, str>),
}

impl<T: Transport, D: Delegate> core::fmt::Debug for Error<T, D> {
  fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
    write!(f, "{self}")
  }
}

impl<T: Transport, D: Delegate> Error<T, D> {
  /// Creates a new error with the given delegate error.
  #[inline]
  pub fn delegate(e: DelegateError<D>) -> Self {
    Self::Delegate(e)
  }

  /// Creates a [`Error::SequenceNumberMismatch`] error.
  #[inline]
  pub fn sequence_number_mismatch(ping: u32, ack: u32) -> Self {
    Self::SequenceNumberMismatch { ping, ack }
  }

  /// Creates a [`Error::UnexpectedMessage`] error.
  #[inline]
  pub fn unexpected_message(expected: &'static str, got: &'static str) -> Self {
    Self::UnexpectedMessage { expected, got }
  }

  /// Creates a new error with the given transport error.
  #[inline]
  pub fn transport(e: T::Error) -> Self {
    Self::Transport(e)
  }

  /// Creates a new error with the given remote error.
  #[inline]
  pub fn remote(e: ErrorResponse) -> Self {
    Self::Remote(e.into())
  }

  /// Creates a new error with the given message.
  #[inline]
  pub fn custom(e: std::borrow::Cow<'static, str>) -> Self {
    Self::Other(e)
  }

  #[inline]
  pub(crate) fn is_remote_failure(&self) -> bool {
    match self {
      Self::Transport(e) => e.is_remote_failure(),
      _ => false,
    }
  }
}