longpolling

type ClientSubPair struct {
	ClientUUID           uuid.UUID
	SubscriptionCategory string
}

type ClientSubscription struct {
	ClientSubPair
	// used to ensure no events skipped between long polls
	LastEventTime time.Time
	// we channel arrays of events since we need to send everything a client
	// cares about in a single channel send.  This makes channel receives a
	// one shot deal.
	Events chan []Event
}

type Event struct {
	Timestamp int64  `json:"timestamp"` // milliseconds since epoch to match javascrits Date.getTime()
	Category  string `json:"category"`
	Data      string `json:"data"` // TODO: eventually make byte[] instead?
}

type EventBuffer struct {
	// Doubly linked list of events where new events are added to the back/tail
	// and old events are removed from the front/root
	// NOTE: this is efficient for front/back operations since it is
	// implemented as a ring with root.prev being the tail
	// SEE: https://golang.org/src/container/list/list.go
	*list.List
	MaxBufferSize int
}

type EventResponse struct {
	Events *[]Event `json:"events"`
}

type SubscriptionManager struct {
	ClientSubscriptions chan ClientSubscription
	ClientTimeouts      <-chan ClientSubPair
	Events              <-chan Event
	// Contains all client sub channels grouped first by sub id then by
	// client uuid
	ClientSubChannels map[string]map[uuid.UUID]chan<- []Event
	SubEventBuffer    map[string]EventBuffer // TODO: ptr to EventBuffer instead of actual value?
	// channel to inform manager to stop running
	Quit <-chan bool
	// How big the buffers are (1-n) before events are discareded FIFO
	// TODO: enforce sane range 1-n where n isn't batshit crazy
	MaxEventBufferSize int
}