package nsqd

import (

    "fmt"

    "math"

    "runtime"

    "sort"

    "time"

    "github.com/nsqio/nsq/internal/statsd"

)

type Uint64Slice []uint64

func (s Uint64Slice) Len() int {

    return len(s)

}

func (s Uint64Slice) Swap(i, j int) {

    s[i], s[j] = s[j], s[i]

}

func (s Uint64Slice) Less(i, j int) bool {

    return s[i] < s[j]

}

func (n *NSQD) statsdLoop() {

    var lastMemStats runtime.MemStats

    var lastStats []TopicStats

    ticker := time.NewTicker(n.getOpts().StatsdInterval)

    for {

        select {

        case <-n.exitChan:

            goto exit

        case <-ticker.C:

            client := statsd.NewClient(n.getOpts().StatsdAddress, n.getOpts().StatsdPrefix)

            err := client.CreateSocket()

            if err != nil {

                n.logf("ERROR: failed to create UDP socket to statsd(%s)", client)

                continue

            }

            n.logf("STATSD: pushing stats to %s", client)

            stats := n.GetStats()

            for _, topic := range stats {

                // try to find the topic in the last collection

                lastTopic := TopicStats{}

                for _, checkTopic := range lastStats {

                    if topic.TopicName == checkTopic.TopicName {

                        lastTopic = checkTopic

                        break

                    }

                }

                diff := topic.MessageCount - lastTopic.MessageCount

                stat := fmt.Sprintf("topic.%s.message_count", topic.TopicName)

                client.Incr(stat, int64(diff))

                stat = fmt.Sprintf("topic.%s.depth", topic.TopicName)

                client.Gauge(stat, topic.Depth)

                stat = fmt.Sprintf("topic.%s.backend_depth", topic.TopicName)

                client.Gauge(stat, topic.BackendDepth)

                for _, item := range topic.E2eProcessingLatency.Percentiles {

                    stat = fmt.Sprintf("topic.%s.e2e_processing_latency_%.0f", topic.TopicName, item["quantile"]*100.0)

                    // We can cast the value to int64 since a value of 1 is the

                    // minimum resolution we will have, so there is no loss of

                    // accuracy

                    client.Gauge(stat, int64(item["value"]))

                }

                for _, channel := range topic.Channels {

                    // try to find the channel in the last collection

                    lastChannel := ChannelStats{}

                    for _, checkChannel := range lastTopic.Channels {

                        if channel.ChannelName == checkChannel.ChannelName {

                            lastChannel = checkChannel

                            break

                        }

                    }

                    diff := channel.MessageCount - lastChannel.MessageCount

                    stat := fmt.Sprintf("topic.%s.channel.%s.message_count", topic.TopicName, channel.ChannelName)

                    client.Incr(stat, int64(diff))

                    stat = fmt.Sprintf("topic.%s.channel.%s.depth", topic.TopicName, channel.ChannelName)

                    client.Gauge(stat, channel.Depth)

                    stat = fmt.Sprintf("topic.%s.channel.%s.backend_depth", topic.TopicName, channel.ChannelName)

                    client.Gauge(stat, channel.BackendDepth)

                    stat = fmt.Sprintf("topic.%s.channel.%s.in_flight_count", topic.TopicName, channel.ChannelName)

                    client.Gauge(stat, int64(channel.InFlightCount))

                    stat = fmt.Sprintf("topic.%s.channel.%s.deferred_count", topic.TopicName, channel.ChannelName)

                    client.Gauge(stat, int64(channel.DeferredCount))

                    diff = channel.RequeueCount - lastChannel.RequeueCount

                    stat = fmt.Sprintf("topic.%s.channel.%s.requeue_count", topic.TopicName, channel.ChannelName)

                    client.Incr(stat, int64(diff))

                    diff = channel.TimeoutCount - lastChannel.TimeoutCount

                    stat = fmt.Sprintf("topic.%s.channel.%s.timeout_count", topic.TopicName, channel.ChannelName)

                    client.Incr(stat, int64(diff))

                    stat = fmt.Sprintf("topic.%s.channel.%s.clients", topic.TopicName, channel.ChannelName)

                    client.Gauge(stat, int64(len(channel.Clients)))

                    for _, item := range channel.E2eProcessingLatency.Percentiles {

                        stat = fmt.Sprintf("topic.%s.channel.%s.e2e_processing_latency_%.0f", topic.TopicName, channel.ChannelName, item["quantile"]*100.0)

                        client.Gauge(stat, int64(item["value"]))

                    }

                }

            }

            lastStats = stats

            if n.getOpts().StatsdMemStats {

                var memStats runtime.MemStats

                runtime.ReadMemStats(&memStats)

                // sort the GC pause array

                length := len(memStats.PauseNs)

                if int(memStats.NumGC) < length {

                    length = int(memStats.NumGC)

                }

                gcPauses := make(Uint64Slice, length)

                copy(gcPauses, memStats.PauseNs[:length])

                sort.Sort(gcPauses)

                client.Gauge("mem.heap_objects", int64(memStats.HeapObjects))

                client.Gauge("mem.heap_idle_bytes", int64(memStats.HeapIdle))

                client.Gauge("mem.heap_in_use_bytes", int64(memStats.HeapInuse))

                client.Gauge("mem.heap_released_bytes", int64(memStats.HeapReleased))

                client.Gauge("mem.gc_pause_usec_100", int64(percentile(100.0, gcPauses, len(gcPauses))/1000))

                client.Gauge("mem.gc_pause_usec_99", int64(percentile(99.0, gcPauses, len(gcPauses))/1000))

                client.Gauge("mem.gc_pause_usec_95", int64(percentile(95.0, gcPauses, len(gcPauses))/1000))

                client.Gauge("mem.next_gc_bytes", int64(memStats.NextGC))

                client.Incr("mem.gc_runs", int64(memStats.NumGC-lastMemStats.NumGC))

                lastMemStats = memStats

            }

            client.Close()

        }

    }

exit