feat: métriques serveur dans footer dashboard + notification offline WS

server/main.go

@@ -1,8 +1,13 @@
 package main
 
 import (
+	"bufio"
+	"fmt"
 	"log"
 	"net/http"
+	"os"
+	"strconv"
+	"strings"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -59,13 +64,35 @@ func main() {
 		}
 	}
 
+	// Maintenance : nettoyage + détection offline avec notification WS
 	go func() {
 		ticker := time.NewTicker(time.Minute)
 		defer ticker.Stop()
 		for range ticker.C {
 			srvCfg, _ := database.GetServerConfig()
 			_ = database.PruneOldMetrics(srvCfg.RetentionDays)
-			_ = database.MarkOffline(30)
+			ids, _ := database.MarkOfflineAndGetIDs(30)
+			for _, id := range ids {
+				hub.Broadcast(models.WSMessage{
+					Type:    "status_update",
+					AgentID: id,
+					Data:    map[string]string{"status": "offline"},
+				})
+			}
+		}
+	}()
+
+	// Métriques du serveur lui-même → footer du dashboard
+	go func() {
+		ticker := time.NewTicker(5 * time.Second)
+		defer ticker.Stop()
+		var prevIdle, prevTotal uint64
+		for range ticker.C {
+			stats, err := collectServerStats(&prevIdle, &prevTotal)
+			if err != nil {
+				continue
+			}
+			hub.Broadcast(models.WSMessage{Type: "server_stats", Data: stats})
 		}
 	}()
 
@@ -96,3 +123,92 @@ func main() {
 func endsWith(path, suffix string) bool {
 	return len(path) >= len(suffix) && path[len(path)-len(suffix):] == suffix
 }
+
+func collectServerStats(prevIdle, prevTotal *uint64) (*models.ServerStats, error) {
+	idle, total, err := readCPUStat()
+	if err != nil {
+		return nil, err
+	}
+	var cpuPct float64
+	if *prevTotal > 0 && total > *prevTotal {
+		deltaIdle := float64(idle - *prevIdle)
+		deltaTotal := float64(total - *prevTotal)
+		cpuPct = 100.0 * (1.0 - deltaIdle/deltaTotal)
+		if cpuPct < 0 {
+			cpuPct = 0
+		}
+	}
+	*prevIdle = idle
+	*prevTotal = total
+
+	memTotal, memAvail, err := readMemInfo()
+	if err != nil {
+		return nil, err
+	}
+	return &models.ServerStats{
+		CPUPercent: cpuPct,
+		MemUsed:    memTotal - memAvail,
+		MemTotal:   memTotal,
+	}, nil
+}
+
+func readCPUStat() (idle, total uint64, err error) {
+	f, err := os.Open("/proc/stat")
+	if err != nil {
+		return 0, 0, err
+	}
+	defer f.Close()
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !strings.HasPrefix(line, "cpu ") {
+			continue
+		}
+		fields := strings.Fields(line)[1:]
+		var vals [10]uint64
+		for i, v := range fields {
+			if i >= 10 {
+				break
+			}
+			vals[i], _ = strconv.ParseUint(v, 10, 64)
+		}
+		// idle = idle + iowait
+		idle = vals[3] + vals[4]
+		for _, v := range vals {
+			total += v
+		}
+		return idle, total, nil
+	}
+	return 0, 0, fmt.Errorf("cpu line not found in /proc/stat")
+}
+
+func readMemInfo() (totalBytes, availBytes int64, err error) {
+	f, err := os.Open("/proc/meminfo")
+	if err != nil {
+		return 0, 0, err
+	}
+	defer f.Close()
+	scanner := bufio.NewScanner(f)
+	var total, avail int64
+	for scanner.Scan() {
+		line := scanner.Text()
+		fields := strings.Fields(line)
+		if len(fields) < 2 {
+			continue
+		}
+		val, _ := strconv.ParseInt(fields[1], 10, 64)
+		switch fields[0] {
+		case "MemTotal:":
+			total = val * 1024
+		case "MemAvailable:":
+			avail = val * 1024
+		}
+		if total > 0 && avail > 0 {
+			break
+		}
+	}
+	if total == 0 {
+		return 0, 0, fmt.Errorf("MemTotal not found in /proc/meminfo")
+	}
+	return total, avail, nil
+}