package metrics

import (
	"github.com/prometheus/client_golang/prometheus"
)

const (
	treePoolSubsystem = "tree_pool"

	methodGetNodes      = "get_nodes"
	methodGetSubTree    = "get_sub_tree"
	methodAddNode       = "add_node"
	methodAddNodeByPath = "add_node_by_path"
	methodMoveNode      = "move_node"
	methodRemoveNode    = "remove_node"
)

type treePoolMetricsCollector struct {
	statScraper     TreePoolStatistic
	requestDuration *prometheus.GaugeVec
}

func newTreePoolMetricsCollector(stat TreePoolStatistic) *treePoolMetricsCollector {
	return &treePoolMetricsCollector{
		statScraper:     stat,
		requestDuration: mustNewGaugeVec(appMetricsDesc[treePoolSubsystem][avgRequestDurationMetric]),
	}
}

func (m *treePoolMetricsCollector) Collect(ch chan<- prometheus.Metric) {
	m.updateStatistic()
	m.requestDuration.Collect(ch)
}

func (m *treePoolMetricsCollector) Describe(descs chan<- *prometheus.Desc) {
	m.requestDuration.Describe(descs)
}

func (m *treePoolMetricsCollector) updateStatistic() {
	stat := m.statScraper.Statistic()

	m.requestDuration.Reset()

	m.requestDuration.WithLabelValues(methodGetNodes).Set(float64(stat.AverageGetNodes().Milliseconds()))
	m.requestDuration.WithLabelValues(methodGetSubTree).Set(float64(stat.AverageGetSubTree().Milliseconds()))
	m.requestDuration.WithLabelValues(methodAddNode).Set(float64(stat.AverageAddNode().Milliseconds()))
	m.requestDuration.WithLabelValues(methodAddNodeByPath).Set(float64(stat.AverageAddNodeByPath().Milliseconds()))
	m.requestDuration.WithLabelValues(methodMoveNode).Set(float64(stat.AverageMoveNode().Milliseconds()))
	m.requestDuration.WithLabelValues(methodRemoveNode).Set(float64(stat.AverageRemoveNode().Milliseconds()))
}