edge/pkg/module/cast/cast.go

package cast

import (
	"context"
	"sync"
	"time"

	"github.com/pkg/errors"
	"gitlab.com/wpetit/goweb/logger"
)

type CachedDevice struct {
	Device
	UpdatedAt time.Time
}

func (d CachedDevice) Expired() bool {
	return d.UpdatedAt.Add(30 * time.Minute).Before(time.Now())
}

var cache sync.Map

func getCachedDevice(uuid string) (Device, bool) {
	value, exists := cache.Load(uuid)
	if !exists {
		return nil, false
	}

	cachedDevice, ok := value.(CachedDevice)
	if !ok {
		return nil, false
	}

	if cachedDevice.Expired() {
		return nil, false
	}

	return cachedDevice.Device, true
}

func cacheDevice(dev Device) {
	cache.Store(dev.DeviceID(), CachedDevice{
		Device:    dev,
		UpdatedAt: time.Now(),
	})
}

func getDeviceClientByID(ctx context.Context, deviceID string) (Client, error) {
	device, err := findCachedDeviceByID(ctx, deviceID)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	client, err := NewClient(ctx, device)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return client, nil
}

func findCachedDeviceByID(ctx context.Context, deviceID string) (Device, error) {
	device, exists := getCachedDevice(deviceID)
	if exists {
		return device, nil
	}

	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	device, err := Find(ctx, deviceID)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	cacheDevice(device)

	return device, nil
}

func ListDevices(ctx context.Context, refresh bool) ([]Device, error) {
	devices := make([]Device, 0)

	if !refresh {
		cache.Range(func(key, value any) bool {
			cached, ok := value.(CachedDevice)
			if !ok || cached.Expired() {
				return true
			}

			devices = append(devices, cached.Device)
			return true
		})

		return devices, nil
	}

	devices, err := SearchDevices(ctx)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return devices, nil
}

var searchDevicesMutex sync.Mutex

func SearchDevices(ctx context.Context) ([]Device, error) {
	searchDevicesMutex.Lock()
	defer searchDevicesMutex.Unlock()

	devices, err := Scan(ctx)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	for _, device := range devices {
		cacheDevice(device)
	}

	return devices, nil
}

var loadURLMutex sync.Mutex

func LoadURL(ctx context.Context, deviceID string, url string) error {
	loadURLMutex.Lock()
	defer loadURLMutex.Unlock()

	client, err := getDeviceClientByID(ctx, deviceID)
	if err != nil {
		return errors.WithStack(err)
	}

	defer func() {
		if err := client.Close(); err != nil {
			logger.Error(ctx, "could not close client", logger.CapturedE(errors.WithStack(err)))
		}
	}()

	if err := client.Load(ctx, url); err != nil {
		return errors.WithStack(err)
	}

	return nil
}

var stopCastMutex sync.Mutex

func StopCast(ctx context.Context, deviceID string) error {
	stopCastMutex.Lock()
	defer stopCastMutex.Unlock()

	client, err := getDeviceClientByID(ctx, deviceID)
	if err != nil {
		return errors.WithStack(err)
	}

	defer func() {
		if err := client.Close(); err != nil {
			logger.Error(ctx, "could not close client", logger.CapturedE(errors.WithStack(err)))
		}
	}()

	if err := client.Unload(ctx); err != nil {
		return errors.WithStack(err)
	}

	return nil
}

var getStatusMutex sync.Mutex

func GetStatus(ctx context.Context, deviceID string) (DeviceStatus, error) {
	getStatusMutex.Lock()
	defer getStatusMutex.Unlock()

	client, err := getDeviceClientByID(ctx, deviceID)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	defer func() {
		if err := client.Close(); err != nil {
			logger.Error(ctx, "could not close client", logger.CapturedE(errors.WithStack(err)))
		}
	}()

	status, err := client.Status(ctx)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return status, nil
}