package main

import "sync"

type SyncFilter interface {
	Then(what SyncFilter) SyncFilter
	Call(msg GenericMessage)
}

type CollectFromChannel struct {
	next SyncFilter
}

func (self *CollectFromChannel) Then(what SyncFilter) SyncFilter {
	self.next = what
	return what
}

func (self *CollectFromChannel) Call(msg GenericMessage) {
	if self.next != nil {
		self.next.Call(msg)
	}
}

func (self CollectFromChannel) Collect(events <-chan GenericMessage, wg *sync.WaitGroup) {
	wg.Add(1)
	go func() {
		defer wg.Done()

		for e := range events {
			self.Call(e)
		}
	}()
}