Refactor stations discovery and add hostapd discovery

internal/station/backend/types.go

@@ -0,0 +1,99 @@
+package backend
+
+import (
+	"strings"
+	"time"
+)
+
+// StationBackend defines the interface for station/device discovery backends.
+// Implementations include ARP-based, DHCP-based, and Hostapd DBus-based discovery.
+type StationBackend interface {
+	// Initialize initializes the backend with the given configuration
+	Initialize(config BackendConfig) error
+
+	// Close cleans up backend resources
+	Close() error
+
+	// GetStations returns all currently connected stations
+	GetStations() ([]Station, error)
+
+	// StartEventMonitoring starts monitoring for station events
+	// Backends that don't support real-time events will poll and simulate events
+	StartEventMonitoring(callbacks EventCallbacks) error
+
+	// StopEventMonitoring stops event monitoring
+	StopEventMonitoring()
+
+	// SupportsRealTimeEvents returns true if backend supports real-time events (e.g., DBus)
+	// Returns false for polling-based backends (ARP, DHCP)
+	SupportsRealTimeEvents() bool
+}
+
+// Station represents a connected device in a backend-agnostic format
+type Station struct {
+	MAC         string    // Hardware MAC address (required, primary identifier)
+	IP          string    // IP address (may be empty for some backends initially)
+	Hostname    string    // Device hostname (may be empty)
+	Type        string    // Device type: "mobile", "laptop", "tablet", "unknown"
+	Signal      int32     // Signal strength in dBm (0 if not available)
+	RxBytes     uint64    // Received bytes (0 if not available)
+	TxBytes     uint64    // Transmitted bytes (0 if not available)
+	ConnectedAt time.Time // When station connected (best effort)
+}
+
+// EventCallbacks defines callback functions for station events.
+// Backends call these when stations connect, disconnect, or update.
+type EventCallbacks struct {
+	// OnStationConnected is called when a new station connects
+	OnStationConnected func(station Station)
+
+	// OnStationDisconnected is called when a station disconnects
+	OnStationDisconnected func(mac string)
+
+	// OnStationUpdated is called when station information changes
+	// (e.g., IP discovered, signal strength changed)
+	OnStationUpdated func(station Station)
+}
+
+// BackendConfig provides configuration for backend initialization
+type BackendConfig struct {
+	// Common
+	InterfaceName string // Network interface (e.g., "wlan1")
+
+	// ARP-specific
+	ARPTablePath string // Path to /proc/net/arp (default: "/proc/net/arp")
+
+	// DHCP-specific
+	DHCPLeasesPath string // Path to DHCP leases file
+
+	// Hostapd-specific
+	HostapdInterface string // Hostapd interface name for DBus
+}
+
+// GuessDeviceType attempts to guess device type from hostname and MAC address
+func GuessDeviceType(hostname, mac string) string {
+	hostname = strings.ToLower(hostname)
+
+	if strings.Contains(hostname, "iphone") || strings.Contains(hostname, "android") {
+		return "mobile"
+	} else if strings.Contains(hostname, "ipad") || strings.Contains(hostname, "tablet") {
+		return "tablet"
+	} else if strings.Contains(hostname, "macbook") || strings.Contains(hostname, "laptop") {
+		return "laptop"
+	}
+
+	// Guess by MAC prefix (OUI)
+	if len(mac) >= 8 {
+		macPrefix := strings.ToUpper(mac[:8])
+		switch macPrefix {
+		case "00:50:56", "00:0C:29", "00:05:69": // VMware
+			return "laptop"
+		case "08:00:27": // VirtualBox
+			return "laptop"
+		default:
+			return "mobile"
+		}
+	}
+
+	return "unknown"
+}