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use async_trait::async_trait;
use crate::error::TaskResult;
use crate::message::TaskMessage;
use crate::task_id::TaskId;
/// Message broker responsible for enqueuing and dequeuing task messages.
#[async_trait]
pub trait Broker: Send + Sync + 'static {
/// Push a message onto a queue.
async fn enqueue(&self, message: TaskMessage) -> TaskResult<()>;
/// Blocking dequeue from one of the given queues.
/// Returns `None` if shutdown is signaled or timeout occurs.
async fn dequeue(
&self,
queues: &[String],
timeout: std::time::Duration,
) -> TaskResult<Option<TaskMessage>>;
/// Acknowledge successful processing — remove from processing queue.
async fn ack(&self, id: &TaskId) -> TaskResult<()>;
/// Negative acknowledge — message will be re-enqueued or dead-lettered.
async fn nack(&self, message: TaskMessage) -> TaskResult<()>;
/// Move a message to the dead-letter queue.
async fn dead_letter(&self, message: TaskMessage) -> TaskResult<()>;
/// Schedule a message for future delivery.
async fn schedule(
&self,
message: TaskMessage,
eta: chrono::DateTime<chrono::Utc>,
) -> TaskResult<()>;
/// Get the length of a queue.
async fn queue_len(&self, queue: &str) -> TaskResult<usize>;
/// Get the number of messages in the dead-letter queue for a given queue.
async fn dlq_len(&self, queue: &str) -> TaskResult<usize> {
let _ = queue;
Ok(0)
}
/// List all known queue names.
async fn list_queues(&self) -> TaskResult<Vec<String>> {
Ok(Vec::new())
}
/// Retrieve messages from the dead-letter queue with pagination.
async fn dlq_messages(
&self,
queue: &str,
offset: usize,
limit: usize,
) -> TaskResult<Vec<TaskMessage>> {
let _ = (queue, offset, limit);
Ok(Vec::new())
}
}