package deviceinfo

import (
	"os"
	"runtime"
	"strconv"
	"strings"
	"time"

	"networktool/internal/config"
	"networktool/internal/model"
)

type Service struct {
	cfg       config.Config
	startedAt time.Time
}

func New(cfg config.Config) *Service {
	return &Service{cfg: cfg, startedAt: time.Now()}
}

func (s *Service) Get() model.DeviceInfo {
	hostname, _ := os.Hostname()
	if hostname == "" {
		hostname = s.cfg.DeviceIDFallback
	}

	return model.DeviceInfo{
		DeviceID:      readMachineID(s.cfg.DeviceIDFallback),
		Hostname:      hostname,
		OSVersion:     readOSVersion(),
		ServerVersion: s.cfg.ServerVersion,
		UptimeSeconds: int64(time.Since(s.startedAt).Seconds()),
	}
}

func readMachineID(fallback string) string {
	for _, path := range []string{"/etc/machine-id", "/var/lib/dbus/machine-id"} {
		data, err := os.ReadFile(path)
		if err == nil {
			value := strings.TrimSpace(string(data))
			if value != "" {
				return value
			}
		}
	}
	return fallback
}

func readOSVersion() string {
	data, err := os.ReadFile("/etc/os-release")
	if err != nil {
		return runtime.GOOS
	}
	for _, line := range strings.Split(string(data), "\n") {
		if strings.HasPrefix(line, "PRETTY_NAME=") {
			return strings.Trim(strconv.Quote(strings.Trim(strings.TrimPrefix(line, "PRETTY_NAME="), `"`)), `"`)
		}
	}
	return runtime.GOOS
}