diff --git a/agent/src/main.rs b/agent/src/main.rs
index 833a47d..8e97b03 100644
--- a/agent/src/main.rs
+++ b/agent/src/main.rs
@@ -1,9 +1,133 @@
-use nanometrics_agent::config;
+use nanometrics_agent::{config, metrics, payload, transport};
+use sysinfo::{Components, Disks, Networks, System};
+use std::time::{Duration, Instant};
+use std::sync::mpsc;
+
+fn get_local_ip() -> String {
+    use std::net::UdpSocket;
+    if let Ok(s) = UdpSocket::bind("0.0.0.0:0") {
+        if s.connect("8.8.8.8:80").is_ok() {
+            if let Ok(addr) = s.local_addr() {
+                return addr.ip().to_string();
+            }
+        }
+    }
+    "0.0.0.0".to_string()
+}
+
+fn apply_config_update(cfg: &mut config::Config, data: &[u8]) {
+    if let Ok(new_cfg) = serde_json::from_slice::<config::Config>(data) {
+        cfg.metrics = new_cfg.metrics;
+        eprintln!("[config] mis à jour depuis le serveur");
+    }
+}
 
 fn main() {
     let cfg_path = std::env::args()
         .nth(1)
         .unwrap_or_else(|| "config.toml".to_string());
-    let _cfg = config::load(std::path::Path::new(&cfg_path));
-    println!("nanometrics-agent starting");
+    let mut cfg = config::load(std::path::Path::new(&cfg_path))
+        .expect("Impossible de charger config.toml");
+
+    let hostname = System::host_name().unwrap_or_else(|| "unknown".to_string());
+    let ip = get_local_ip();
+
+    let mut sys = System::new();
+    let mut networks = Networks::new_with_refreshed_list();
+    let mut disks = Disks::new_with_refreshed_list();
+    let mut components = Components::new_with_refreshed_list();
+
+    let udp_sender = if cfg.protocols.udp.enabled {
+        Some(transport::udp::UdpSender::new(&cfg.server.ip, cfg.server.port))
+    } else {
+        None
+    };
+
+    let (incoming_tx, incoming_rx) = mpsc::channel::<transport::mqtt::MqttIncoming>();
+    let mqtt_client = if cfg.protocols.mqtt.enabled {
+        Some(transport::mqtt::start(&hostname, &cfg.protocols.mqtt, incoming_tx))
+    } else {
+        None
+    };
+
+    let mut last_slow = Instant::now();
+    let mut last_medium = Instant::now();
+    let mut first_medium = true;
+    let mut first_slow = true;
+
+    loop {
+        let now = Instant::now();
+
+        while let Ok(transport::mqtt::MqttIncoming::ConfigUpdate(data)) = incoming_rx.try_recv() {
+            apply_config_update(&mut cfg, &data);
+        }
+
+        sys.refresh_cpu_usage();
+        sys.refresh_memory();
+
+        let mut m = payload::AgentMetrics {
+            hostname: hostname.clone(),
+            ip: ip.clone(),
+            status: "online".to_string(),
+            cpu_percent: Some(metrics::cpu::get(&sys)),
+            ..Default::default()
+        };
+
+        let (mem_used, mem_free, mem_total) = metrics::memory::get(&sys);
+        m.memory_used = Some(mem_used);
+        m.memory_free = Some(mem_free);
+        m.memory_total = Some(mem_total);
+
+        if first_medium || now.duration_since(last_medium).as_secs() >= 10 {
+            networks.refresh();
+            components.refresh();
+            let (rx, tx) = metrics::network::get(&networks);
+            if cfg.metrics.network.udp || cfg.metrics.network.mqtt {
+                m.network_rx = Some(rx);
+                m.network_tx = Some(tx);
+            }
+            if cfg.metrics.uptime.udp || cfg.metrics.uptime.mqtt {
+                m.uptime = Some(metrics::uptime::get());
+            }
+            if cfg.metrics.temperature.udp || cfg.metrics.temperature.mqtt {
+                m.temperature = metrics::temperature::get(&components);
+            }
+            last_medium = now;
+            first_medium = false;
+        }
+
+        if first_slow || now.duration_since(last_slow).as_secs() >= 60 {
+            disks.refresh();
+            if cfg.metrics.disk.udp || cfg.metrics.disk.mqtt {
+                let (used, free, total) = metrics::disk::get(&disks);
+                m.hdd_used = Some(used);
+                m.hdd_free = Some(free);
+                m.hdd_total = Some(total);
+            }
+            if cfg.metrics.smart.udp || cfg.metrics.smart.mqtt {
+                m.smart = metrics::smart::collect();
+            }
+            last_slow = now;
+            first_slow = false;
+        }
+
+        let json = serde_json::to_string(&m).expect("sérialisation JSON impossible");
+
+        if let Some(ref udp) = udp_sender {
+            udp.send(&json);
+        }
+
+        if let Some(ref client) = mqtt_client {
+            if cfg.protocols.mqtt.enabled {
+                transport::mqtt::publish_metrics(
+                    client,
+                    &cfg.protocols.mqtt.topic_base,
+                    &hostname,
+                    &json,
+                );
+            }
+        }
+
+        std::thread::sleep(Duration::from_secs(2));
+    }
 }