use axum::extract::State;
use axum::response::Json;
use axum::routing::get;
use axum::Router;
use serde_json::{json, Value};
use std::sync::Arc;
use std::time::Instant;
use tokio::sync::watch;

pub struct HealthState {
    pub started_at: Instant,
    pub cycle_count: watch::Receiver<u64>,
    pub last_cycle_ok: watch::Receiver<bool>,
    pub db_path: String,
}

pub async fn start_health_server(port: u16, state: Arc<HealthState>) -> anyhow::Result<()> {
    let app = Router::new()
        .route("/health", get(health_handler))
        .route("/api/mirror-health", get(health_handler))
        .with_state(state);

    let listener = tokio::net::TcpListener::bind(format!("127.0.0.1:{}", port)).await?;
    tracing::info!(port, "health server listening");
    axum::serve(listener, app).await?;
    Ok(())
}

async fn health_handler(State(state): State<Arc<HealthState>>) -> Json<Value> {
    let uptime = state.started_at.elapsed();
    let cycle_count = *state.cycle_count.borrow();
    let last_ok = *state.last_cycle_ok.borrow();

    Json(json!({
        "status": if last_ok || cycle_count == 0 { "ok" } else { "degraded" },
        "uptime_secs": uptime.as_secs(),
        "cycle_count": cycle_count,
        "last_cycle_ok": last_ok,
    }))
}