canape/backend/events/torrent_eventer.go

package events

import (
	"fmt"
	"reflect"
	"time"

	"git.quimbo.fr/odwrtw/canape/backend/models"
	"github.com/odwrtw/papi"
	"github.com/sirupsen/logrus"
)

// TorrentEventer represents the Eventer for torrents
type TorrentEventer struct {
	*BaseEventer
	done     chan struct{}
	pClient  *papi.Client
	torrents []papi.Torrent
}

var torrentEventName = "torrents"

// NewTorrentEventers returns a new PolochonEventers for torrents
func NewTorrentEventers() *PolochonEventers {
	eventer := NewEventers()
	eventer.NewEventer = NewTorrentEventer
	eventer.Name = torrentEventName
	return eventer
}

// NewTorrentEventer returns a new Eventer for a specific Polochon
func NewTorrentEventer(polo *models.Polochon, log *logrus.Entry) (Eventer, error) {
	// Create a new papi client
	client, err := polo.NewPapiClient()
	if err != nil {
		return nil, fmt.Errorf("failed to instanciate polochon client %s", err)
	}

	// This is the first time this polochon is requested, create the TorrentEventer
	tn := &TorrentEventer{
		BaseEventer: &BaseEventer{
			users: []*Channel{},
			log:   log,
			name:  torrentEventName,
		},
		pClient:  client,
		done:     make(chan struct{}),
		torrents: []papi.Torrent{},
	}

	return tn, nil
}

// Append implements the Eventer interface
// It just appends a channel to the list of users
// When the user is appended, send him the torrents infos we have
func (t *TorrentEventer) Append(chanl *Channel) {
	event := ServerEvent{
		Event: Event{
			Type:   torrentEventName,
			Status: OK,
		},
		Data: t.torrents,
	}

	chanl.sendEvent(event)

	t.BaseEventer.Append(chanl)
}

// Launch implements the Eventer interface
// It starts a ticker to fetch torrents and notify the users
func (t *TorrentEventer) Launch() error {
	// Create the timer that will check for the torrents every X seconds
	timeTicker := time.NewTicker(10 * time.Second)
	defer timeTicker.Stop()

	err := t.torrentsUpdate()
	if err != nil {
		return err
	}

	for {
		select {
		case <-timeTicker.C:
			err := t.torrentsUpdate()
			if err != nil {
				return err
			}
		case <-t.done:
			t.log.Debug("quit torrent notifier")
			return nil
		}
	}
}

// torrentsUpdate sends to the eventStream if torrents change
func (t *TorrentEventer) torrentsUpdate() error {
	// Get torrents
	torrents, err := t.pClient.GetTorrents()
	if err != nil {
		return err
	}

	if reflect.DeepEqual(t.torrents, torrents) {
		return nil
	}

	t.log.Debugf("torrents have changed!")

	t.NotifyAll(torrents)

	t.torrents = torrents

	return nil
}

// Finish implements the Eventer interface
// It is called when there is no more users subscribed
func (t *TorrentEventer) Finish() {
	t.log.Debugf("sending the done channel")
	t.done <- struct{}{}
}