has way too many things

In short: added the ability to detect when a device has disconnected.
From this we have to achieve a way of:
- reconnecting the device
- re-subscribing to the fields it needs (it should already be subscribed
since the ESDI didn't stop tho - but for the sake of it, or in case a
device joins later)
- start sending data to it (which should be automatic given how we are
handling the devices)

services/devices_lookup.go

@@ -0,0 +1,222 @@
+package services
+
+import (
+	"errors"
+	"log/slog"
+	"maps"
+	"sync"
+	"time"
+
+	"esdi/devices"
+	"esdi/peripheral"
+)
+
+var (
+	ErrPeripheralAlreadyRegistered = errors.New("peripheral is already registered")
+	ErrNoSuchDevice                = errors.New("device doesn't exist")
+	ErrDeviceIsNotConnected        = errors.New("device isn't connected")
+)
+
+type DeviceState = uint8
+
+const (
+	DeviceTimedOut uint8 = iota
+	DeviceIsConnected
+	DeviceIsDisconnected
+	DeviceReconnected
+)
+
+type PeripheralState struct {
+	device     *devices.Device
+	Peripheral peripheral.Peripheral
+	State      DeviceState
+}
+
+func NewPeripheralState(
+	dev *devices.Device,
+	peripheral peripheral.Peripheral,
+	state DeviceState,
+) *PeripheralState {
+	perState := PeripheralState{
+		device:     dev,
+		Peripheral: peripheral,
+		State:      state,
+	}
+
+	return &perState
+}
+
+type PeripheralStateStore struct {
+	Logger *slog.Logger
+	mu     sync.RWMutex
+	store  map[string]*PeripheralState
+}
+
+func NewPeripheralStateStore(
+	nLogger *slog.Logger,
+	devList map[string]*devices.Device,
+) *PeripheralStateStore {
+	store := PeripheralStateStore{
+		Logger: nLogger,
+		store:  make(map[string]*PeripheralState),
+	}
+
+	for _, dev := range devList {
+		store.AddDevice(dev)
+	}
+
+	return &store
+}
+
+func (pss *PeripheralStateStore) GetStates() map[string]*PeripheralState {
+	pss.mu.RLock()
+	defer pss.mu.RUnlock()
+
+	return maps.Clone(pss.store)
+}
+
+func (pss *PeripheralStateStore) GetState(pname string) (*PeripheralState, error) {
+	if !pss.DeviceExists(pname) {
+		return nil, ErrNoSuchDevice
+	}
+
+	pss.mu.RLock()
+	defer pss.mu.RUnlock()
+	return pss.store[pname], nil
+}
+
+func (pss *PeripheralStateStore) GetPeripheral(pname string) (peripheral.Peripheral, error) {
+	state, err := pss.GetState(pname)
+	if err != nil {
+		return nil, err
+	}
+
+	if state.State != DeviceIsConnected {
+		return nil, ErrDeviceIsNotConnected
+	}
+
+	return state.Peripheral, nil
+}
+
+// AddDevice adds a new device for tracking
+func (pss *PeripheralStateStore) AddDevice(dev *devices.Device) error {
+	if pss.DeviceExists(dev.Name) {
+		return ErrPeripheralAlreadyRegistered
+	}
+
+	pss.mu.Lock()
+	defer pss.mu.Unlock()
+	pss.store[dev.Name] = NewPeripheralState(dev, nil, DeviceIsDisconnected)
+
+	return nil
+}
+
+// DeviceExists returns whether the store is already tracking `pname`
+func (pss *PeripheralStateStore) DeviceExists(pname string) bool {
+	pss.mu.RLock()
+	defer pss.mu.RUnlock()
+
+	if _, ok := pss.store[pname]; ok {
+		return true
+	}
+
+	return false
+}
+
+// DeleteDevice deletes `pname` from tracking
+func (pss *PeripheralStateStore) DeleteDevice(pname string) error {
+	if !pss.DeviceExists(pname) {
+		return ErrNoSuchDevice
+	}
+
+	pss.mu.Lock()
+	defer pss.mu.Unlock()
+
+	delete(pss.store, pname)
+
+	return nil
+}
+
+// "Events" [START] ------------------------------------------------------------
+func (ds *DeviceService) onDeviceTimedOut(pname string) {
+	// We need to deregister the device
+	ds.PSS.setDeviceTimedOut(pname)
+}
+
+// "Events" [END] --------------------------------------------------------------
+
+// Device State Handling [START] -----------------------------------------------
+func (pss *PeripheralStateStore) setDeviceConnected(pname string, per peripheral.Peripheral) {
+	pss.Logger.Info("found device", "device", pname)
+
+	pss.mu.Lock()
+	defer pss.mu.Unlock()
+	pss.store[pname].Peripheral = per
+	pss.store[pname].State = DeviceIsConnected
+}
+
+func (pss *PeripheralStateStore) setDeviceTimedOut(pname string) {
+	pss.Logger.Info("device timed out", "device", pname)
+
+	pss.mu.Lock()
+	defer pss.mu.Unlock()
+	pss.store[pname].Peripheral = nil
+	pss.store[pname].State = DeviceTimedOut
+}
+
+func (pss *PeripheralStateStore) setDeviceReconnected(pname string, per peripheral.Peripheral) {
+	pss.Logger.Info("device reconnecting", "device", pname)
+
+	pss.mu.Lock()
+	defer pss.mu.Unlock()
+	pss.store[pname].Peripheral = per
+	pss.store[pname].State = DeviceReconnected
+}
+
+// Device State Handling [END] -------------------------------------------------
+
+// Device Handling [START] -----------------------------------------------------
+func (pss *PeripheralStateStore) HandleDeviceState() {
+	peripherals := pss.GetStates()
+
+	for pName, pState := range peripherals {
+		switch pState.State {
+		case DeviceIsDisconnected:
+			pss.Logger.Debug("looking for device", "name", pName)
+			dev, err := pState.device.Discover()
+			if err != nil {
+				continue
+			}
+
+			// Register the device we just found
+			pss.setDeviceConnected(pName, dev)
+		case DeviceIsConnected:
+			// Need to check if its streaming, if its not streaming than we have to do a healthcheck
+			pss.Logger.Debug("Device is connected. Normal", "device", pName)
+		case DeviceReconnected:
+			// If the device has reconnected we need to reset the device and then set it as connected
+			pss.Logger.Debug("Device has reconnected. Clearing up state", "device", pName)
+		case DeviceTimedOut:
+			// If the device has timed out we need to re-discover it or something
+			pss.Logger.Debug("Device is timed out. Attempting to recconect", "device", pName)
+		}
+	}
+}
+
+// Device Handling [END] -------------------------------------------------------
+
+// FindDevices is a routine that goes over the devices in the PeripheralStateStore
+// and handles their state accordingly
+func (ds *DeviceService) FindDevices() {
+	ticker := time.NewTicker(2 * time.Second)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ds.ctxDiscovery.Done():
+			return
+		case <-ticker.C:
+			ds.PSS.HandleDeviceState()
+		}
+	}
+}