status-im/status-go

package connection

import (
    "encoding/json"
    "sync"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/event"
    "github.com/status-im/status-go/services/wallet/walletevent"
)

// Client expects a single event with all states
type StatusNotification map[string]State // id -> State

type StatusNotifier struct {
    statuses  *sync.Map // id -> Status
    eventType walletevent.EventType
    feed      *event.Feed
}

func NewStatusNotifier(statuses *sync.Map, eventType walletevent.EventType, feed *event.Feed) *StatusNotifier {
    n := StatusNotifier{
        statuses:  statuses,
        eventType: eventType,
        feed:      feed,
    }

    statuses.Range(func(_, value interface{}) bool {
        value.(*Status).SetStateChangeCb(n.notify)
        return true
    })

    return &n
}

func (n *StatusNotifier) notify(state State) {
    // state is ignored, as client expects all valid states in
    // a single event, so we fetch them from the map
    if n.feed != nil {
        statusMap := make(StatusNotification)
        n.statuses.Range(func(id, value interface{}) bool {
            state := value.(*Status).GetState()
            if state.Value == StateValueUnknown {
                return true
            }
            statusMap[id.(string)] = state
            return true
        })

        encodedMessage, err := json.Marshal(statusMap)
        if err != nil {
            return
        }

        n.feed.Send(walletevent.Event{
            Type:     n.eventType,
            Accounts: []common.Address{},
            Message:  string(encodedMessage),
            At:       time.Now().Unix(),
        })
    }
}