//! Streaming-output consumer hook.

use serde_json::Value;

/// Consumer callbacks for a claude run's output streams. Every method has a
/// no-op default, so an implementor overrides only what it needs.
///
/// Methods are called synchronously from the stdout/stderr readers as lines
/// arrive, so keep them cheap — the idiomatic body forwards to a channel or an
/// event bus rather than blocking. The driver handles sentinel classification
/// (rate-limit, prompt-too-long, …) itself; a sink only *observes* the stream.
pub trait Sink {
    /// A parsed `stream-json` object from stdout (assistant/result/system/…
    /// event). The driver has already classified it for sentinels.
    fn on_event(&self, _event: &Value) {}

    /// A stdout line that was not valid JSON — occasional Claude Code CLI
    /// chatter rather than conversation content.
    fn on_stdout_line(&self, _line: &str) {}

    /// A stderr line, delivered verbatim. The last several are also retained
    /// by the driver for [`crate::Error::Exit`].
    fn on_stderr_line(&self, _line: &str) {}
}

/// A [`Sink`] that discards everything. Useful for fire-and-forget runs where
/// only the [`crate::Outcome`] matters.
pub struct NoopSink;

impl Sink for NoopSink {}