//! Health check endpoint for the imks server.
//!
//! Returns JSON with server status, version, uptime, and connection counts
//! sourced from live runtime state (session store + atomic counter).

use actix_web::{HttpResponse, web};
use serde::Serialize;

use crate::engine::session::SessionStore;
use crate::telemetry;

#[derive(Serialize)]
struct HealthResponse {
    status: String,
    version: String,
    timestamp: String,
    uptime_secs: u64,
    connections_active: u64,
    sessions_count: usize,
}

/// GET /health — returns server health status with live connection metrics.
pub async fn health_check(store: web::Data<SessionStore>) -> HttpResponse {
    HttpResponse::Ok().json(HealthResponse {
        status: "healthy".into(),
        version: env!("CARGO_PKG_VERSION").into(),
        timestamp: chrono::Utc::now().to_rfc3339(),
        uptime_secs: telemetry::health::uptime_secs(),
        connections_active: telemetry::health::connections_active_count(),
        sessions_count: store.len(),
    })
}