#pragma once
#include "diagnostics.hpp"
#include <functional>
#include <string>
#include <string_view>

namespace kpn {

// Called when a node's function throws. Return true to skip the failed
// invocation and keep running, false to stop the node.
using NodeErrorHandler = std::function<bool(std::string_view node_name, std::exception_ptr)>;

// ── INode — type-erased interface for Network / watchdog ─────────────────────

struct INode {
    virtual ~INode()       = default;
    virtual void start()   = 0;
    virtual void stop()    = 0;
    virtual bool running() const = 0;
    virtual const NodeStats& stats() const = 0;
    virtual NodeSnapshot node_snapshot(const std::string& name, double elapsed_s) const = 0;
    virtual void set_name(std::string name) = 0;

    // halt(): alias for stop() — immediate, discards in-flight work.
    virtual void halt() { stop(); }

    // shutdown(): graceful drain before stopping. Base implementation falls
    // back to stop(). Network and StaticNetwork override with topo-ordered drain.
    virtual void shutdown() { stop(); }
};

} // namespace kpn