package database import (	"time" 	_ "github.com/mattn/go-sqlite3") type ServerMetric struct {	Timestamp        string  `json:"timestamp"`	CPU              float64 `json:"cpu"`	CPUModel         string  `json:"cpuModel"`	CPUCores         int32   `json:"cpuCores"`	CPUPhysicalCores int32   `json:"cpuPhysicalCores"`	CPUSpeed         float64 `json:"cpuSpeed"`	OS               string  `json:"os"`	Distro           string  `json:"distro"`	Kernel           string  `json:"kernel"`	Arch             string  `json:"arch"`	MemUsed          float64 `json:"memUsed"`	MemUsedGB        float64 `json:"memUsedGB"`	MemTotal         float64 `json:"memTotal"`	Uptime           uint64  `json:"uptime"`	DiskUsed         float64 `json:"diskUsed"`	TotalDisk        float64 `json:"totalDisk"`	NetworkIn        float64 `json:"networkIn"`	NetworkOut       float64 `json:"networkOut"`} func (db *DB) SaveMetric(metric ServerMetric) error {	if metric.Timestamp == "" {		metric.Timestamp = time.Now().UTC().Format(time.RFC3339Nano)	} 	_, err := db.Exec(`		INSERT INTO server_metrics (timestamp, cpu, cpu_model, cpu_cores, cpu_physical_cores, cpu_speed, os, distro, kernel, arch, mem_used, mem_used_gb, mem_total, uptime, disk_used, total_disk, network_in, network_out)		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)	`, metric.Timestamp, metric.CPU, metric.CPUModel, metric.CPUCores, metric.CPUPhysicalCores, metric.CPUSpeed, metric.OS, metric.Distro, metric.Kernel, metric.Arch, metric.MemUsed, metric.MemUsedGB, metric.MemTotal, metric.Uptime, metric.DiskUsed, metric.TotalDisk, metric.NetworkIn, metric.NetworkOut)	return err} func (db *DB) GetMetricsInRange(start, end time.Time) ([]ServerMetric, error) {	rows, err := db.Query(`		SELECT timestamp, cpu, cpu_model, cpu_cores, cpu_physical_cores, cpu_speed, os, distro, kernel, arch, mem_used, mem_used_gb, mem_total, uptime, disk_used, total_disk, network_in, network_out		FROM server_metrics		WHERE timestamp BETWEEN ? AND ?		ORDER BY timestamp ASC	`, start.UTC().Format(time.RFC3339Nano), end.UTC().Format(time.RFC3339Nano))	if err != nil {		return nil, err	}	defer rows.Close() 	var metrics []ServerMetric	for rows.Next() {		var m ServerMetric		err := rows.Scan(&m.Timestamp, &m.CPU, &m.CPUModel, &m.CPUCores, &m.CPUPhysicalCores, &m.CPUSpeed, &m.OS, &m.Distro, &m.Kernel, &m.Arch, &m.MemUsed, &m.MemUsedGB, &m.MemTotal, &m.Uptime, &m.DiskUsed, &m.TotalDisk, &m.NetworkIn, &m.NetworkOut)		if err != nil {			return nil, err		}		metrics = append(metrics, m)	}	return metrics, nil} func (db *DB) GetLastNMetrics(n int) ([]ServerMetric, error) {	rows, err := db.Query(`		WITH recent_metrics AS (			SELECT timestamp, cpu, cpu_model, cpu_cores, cpu_physical_cores, cpu_speed, os, distro, kernel, arch, mem_used, mem_used_gb, mem_total, uptime, disk_used, total_disk, network_in, network_out			FROM server_metrics			ORDER BY timestamp DESC			LIMIT ?		)		SELECT * FROM recent_metrics		ORDER BY timestamp ASC	`, n)	if err != nil {		return nil, err	}	defer rows.Close() 	var metrics []ServerMetric	for rows.Next() {		var m ServerMetric		err := rows.Scan(&m.Timestamp, &m.CPU, &m.CPUModel, &m.CPUCores, &m.CPUPhysicalCores, &m.CPUSpeed, &m.OS, &m.Distro, &m.Kernel, &m.Arch, &m.MemUsed, &m.MemUsedGB, &m.MemTotal, &m.Uptime, &m.DiskUsed, &m.TotalDisk, &m.NetworkIn, &m.NetworkOut)		if err != nil {			return nil, err		}		metrics = append(metrics, m)	}	return metrics, nil} func (db *DB) GetAllMetrics() ([]ServerMetric, error) {	rows, err := db.Query(`		SELECT timestamp, cpu, cpu_model, cpu_cores, cpu_physical_cores, cpu_speed, os, distro, kernel, arch, mem_used, mem_used_gb, mem_total, uptime, disk_used, total_disk, network_in, network_out		FROM server_metrics		ORDER BY timestamp ASC	`)	if err != nil {		return nil, err	}	defer rows.Close() 	var metrics []ServerMetric	for rows.Next() {		var m ServerMetric		err := rows.Scan(&m.Timestamp, &m.CPU, &m.CPUModel, &m.CPUCores, &m.CPUPhysicalCores, &m.CPUSpeed, &m.OS, &m.Distro, &m.Kernel, &m.Arch, &m.MemUsed, &m.MemUsedGB, &m.MemTotal, &m.Uptime, &m.DiskUsed, &m.TotalDisk, &m.NetworkIn, &m.NetworkOut)		if err != nil {			return nil, err		}		metrics = append(metrics, m)	}	return metrics, nil}