package main

import (
	"context"
	"fmt"
	"github.com/ClickHouse/clickhouse-go/v2"
	"github.com/pkg/errors"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/sirupsen/logrus"
	"time"
)

type Aggregator struct {
	chCli                   clickhouse.Conn
	logger                  *logrus.Entry
	cfg                     AggregateConfig
	relation                *ServiceNameAppAliasCmdbIDRelation
	sqlQueryErrorCounter    prometheus.Counter
	endpointNotFoundCounter *prometheus.CounterVec
	endpointToLoadCounter   *prometheus.CounterVec
	apdexGoodMS             int64
	apdexBadMS              int64
}

func NewAggregator(chCli clickhouse.Conn, logger *logrus.Entry, cfg AggregateConfig, relation *ServiceNameAppAliasCmdbIDRelation, reg *prometheus.Registry) *Aggregator {
	endPointToLoadCounter := prometheus.NewCounterVec(prometheus.CounterOpts{
		Name: "i6000pusherAggregatorEndpointToLoadCounter",
		Help: "需要从clickhouse读取的endpoint数量",
	}, []string{"service", "endpoint"})
	endPointNotFoundCounter := prometheus.NewCounterVec(prometheus.CounterOpts{
		Name: "i6000pusherAggregatorEndpointNotFoundCounter",
		Help: "需要从clickhouse读取的endpoint但没有找到的数量",
	}, []string{"service", "endpoint"})
	reg.MustRegister(endPointToLoadCounter)
	reg.MustRegister(endPointNotFoundCounter)
	return &Aggregator{chCli: chCli, logger: logger, cfg: cfg, relation: relation,
		sqlQueryErrorCounter: prometheus.NewCounter(prometheus.CounterOpts{
			Name: "i6000pusherAggregatorSqlQueryErrorCounter",
			Help: "从clickhouse读取endpoint信息sql出现错误的counter",
		}),
		endpointToLoadCounter:   endPointToLoadCounter,
		endpointNotFoundCounter: endPointNotFoundCounter,
		apdexBadMS:              8000,
		apdexGoodMS:             2000,
	}
}

func (a *Aggregator) LoadMetricData(start time.Time, end time.Time, appAlias string) ([]ServiceMetricData, error) {
	cmdbID, findCmdbID := a.relation.GetCmdbIDFromAppAlias(appAlias)
	if !findCmdbID {
		return nil, errors.Errorf("cmdbID not found, appAlias: %s ", appAlias)
	}
	ctx, cancel := context.WithTimeout(context.Background(), a.cfg.LoadTimeout())
	defer cancel()
	/***
	1. 读这段时间内的 endpoint匹配的 sever span list
	2. 计算每个endpoint的metricMeters
	3. 聚合出所有的instance, 根据instance分组
	*/
	sql := `
WITH '\\b[a-fA-F0-9]{32,}\\b|\\b[a-fA-F0-9\\-]{36}\\b|\\b\\[1-9]\\d*\\b' AS varPattern, SpanAttributes['http.route'] AS route, multiIf(
        (SpanAttributes['url.path']) != '', SpanAttributes['url.path'], (SpanAttributes['http.target']) != '',
        path(SpanAttributes['http.target']), (SpanAttributes['http.url']) != '', path(SpanAttributes['http.url']),
        (SpanAttributes['u\nrl.full']) != '', path(SpanAttributes['url.full']),
        SpanAttributes['http.route']) AS path
	select 
	    ServiceName,
		concat(address, ':', port)   as instanceAddress,
		if(route != '', route, replaceRegexpOne(path, varPattern, '{:var}')) AS endpoint,
		countIf(StatusCodeNumber == 2)     as failedCount,
		count()                      as requestCount,
		sum(Duration)                as latencySum,
		sum(length(Exceptions.type)) as exceptionCount,
		countIf(Duration < ?) as apdexGood,
		countIf(Duration < ? and Duration > ?) as apdexFair
		from otel.otel_traces
		where 
		Timestamp >  ?
		and Timestamp < ?
		and SpanKindNumber = 2
		and AppAlias = ?
		group by ServiceName, SpanAttributes['net.host.name'] as address, SpanAttributes['net.host.port'] as port, endpoint
		`
	apdexGoodNS := a.apdexGoodMS * 1e6
	apdexFairNS := a.apdexBadMS * 1e6
	spanRows, errQuery := a.chCli.Query(ctx, sql, apdexGoodNS, apdexFairNS, apdexGoodNS, start.UTC(), end.UTC(), appAlias)
	if errQuery != nil {
		a.sqlQueryErrorCounter.Inc()
		return nil, errors.Wrapf(errQuery, "failed to query metrics: %s, sql:%s", appAlias, sql)
	}
	serviceName2MetricData := make(map[string]*ServiceMetricData, 100)
	for spanRows.Next() {
		var serviceName string
		var instance string
		var em ServiceInstanceEndpointMetrics
		em.Metrics.aggDuration = end.Sub(start)
		var failedCount uint64
		var requestCount uint64
		var exceptionCount uint64
		var apdexGoodRequestCount uint64
		var apdexFairRequestCount uint64
		if errScan := spanRows.Scan(&serviceName, &instance, &em.Endpoint, &failedCount, &requestCount,
			&em.Metrics.responseTimeSumNS, &exceptionCount, &apdexGoodRequestCount,
			&apdexFairRequestCount); errScan != nil {
			a.logger.WithError(errScan).Error("failed to scan metrics")
			a.sqlQueryErrorCounter.Inc()
			continue
		}
		em.Metrics.requestCount = int64(requestCount)
		em.Metrics.failedCount = int64(failedCount)
		em.Metrics.exceptionCount = int64(exceptionCount)
		em.Metrics.apdexFairRequestCount = int64(apdexFairRequestCount)
		em.Metrics.apdexGoodRequestCount = int64(apdexGoodRequestCount)
		a.logger.WithFields(logrus.Fields{
			"endpointMetric": em,
			"service":        serviceName,
			"instance":       instance,
			"startTime":      start,
			"endTime":        end,
		}).Debugf("Query metric from clickhouse")
		a.endpointToLoadCounter.With(
			prometheus.Labels{
				"service":  serviceName,
				"endpoint": em.Endpoint,
			}).Inc()
		serviceMetricData, find := serviceName2MetricData[serviceName]
		if !find {
			serviceName2MetricData[serviceName] = &ServiceMetricData{
				AppAlias:    appAlias,
				CmdbID:      cmdbID,
				ServiceName: serviceName,
				InstanceMetrics: []ServiceInstanceMetric{
					{
						InstanceID:      instance,
						InstanceIP:      instance,
						EndpointMetrics: []ServiceInstanceEndpointMetrics{em},
					},
				},
			}
			continue
		}
		serviceMetricData.AddMetric(instance, em)
	}
	sds := make([]ServiceMetricData, 0, len(serviceName2MetricData))
	for _, data := range serviceName2MetricData {
		sds = append(sds, *data)
	}
	return sds, nil
}

func (a *Aggregator) LoadTraceData(start, end time.Time, appAlias string) ([]TopoData, error) {
	cmdbID, findCmdbID := a.relation.GetCmdbIDFromAppAlias(appAlias)
	if !findCmdbID {
		return nil, errors.Errorf("cmdbID not found, appAlias: %s ", appAlias)
	}
	ctx, cancel := context.WithTimeout(context.Background(), a.cfg.LoadTimeout())
	defer cancel()
	/***
	1. 读这段时间内, appAlias的 拥有parent client span 的 server span
	2. 分段计算
	3. 通过traceID读出这段数据内某个整条链路
	4. serverName必须不一样
	5. 沿着parent向上找，一直找不到或appAlias是其他的, 找到的span就是顶点
	6. 顶点就是tx, client span是src, server span是dest
	*/
	traceIdSql := `
    select distinct TraceId from otel.otel_traces_url where 
		Timestamp > ? and Timestamp < ? and 
		AppAlias = ? and Route is not null and 
		Route != ''
		`
	traceRows, errQueryTraceId := a.chCli.Query(ctx, traceIdSql, start, end, appAlias,
		start, end, appAlias)
	if errQueryTraceId != nil {
		a.sqlQueryErrorCounter.Inc()
		return nil, errors.Wrapf(errQueryTraceId, "failed to query metrics: %s, sql:%s", appAlias, traceIdSql)
	}
	traceIds := make([]string, 0)
	for traceRows.Next() {
		var traceId string
		if errScan := traceRows.Scan(&traceId); errScan != nil {
			a.logger.WithError(errScan).Error("failed to scan traceId")
			continue
		}
		traceIds = append(traceIds, traceId)
	}
	a.logger.Infof("LoadTraceData from clickhouse, traceIds length %d, sql:%s, params:(%v, %v, %s)",
		len(traceIds), traceIdSql, start, end, appAlias)
	if len(traceIds) == 0 {
		return []TopoData{}, nil
	}
	topoData := make([]TopoData, 0, len(traceIds)*10)
	traceBatchSize := 50
	timePadding := 10 * time.Minute
	for i := 0; i < len(traceIds); i += traceBatchSize {
		upperBound := i + traceBatchSize
		if upperBound > len(traceIds) {
			upperBound = len(traceIds)
		}
		tidList := traceIds[i:upperBound]
		traceId2Spans, errLoadTraces := a.loadTraceList(start.Add(-timePadding), end.Add(timePadding), tidList)
		if errLoadTraces != nil {
			a.logger.WithError(errLoadTraces).Error("failed to load traces")
			continue
		}
		a.logger.Infof("LoadTrace from clickhouse by trace id, traceIds length %d, %d found", len(tidList),
			len(traceId2Spans))
		if len(traceId2Spans) == 0 {
			continue
		}
		for _, spans := range traceId2Spans {
			endpointTrees, errCalEndPointTree := a.calEndPointFromSpans(spans, appAlias)
			if errCalEndPointTree != nil {
				a.logger.WithError(errCalEndPointTree).Errorf("failed to cal end point, spans:%v", spans)
				continue
			}
			for _, endpointTree := range endpointTrees {
				topoDataInEndpointTree := serviceTopoDataWithEndpoint(cmdbID, endpointTree)
				topoData = append(topoData, topoDataInEndpointTree...)
			}
		}
	}
	return aggregateTopoData(topoData), nil
}

func aggregateTopoData(topoList []TopoData) []TopoData {
	topoID2TopoList := make(map[string][]TopoData, len(topoList))
	for _, t := range topoList {
		topoID := t.TopoID()
		if _, ok := topoID2TopoList[topoID]; !ok {
			topoID2TopoList[topoID] = make([]TopoData, 0, 200)
		}
		topoID2TopoList[topoID] = append(topoID2TopoList[topoID], t)
	}
	ret := make([]TopoData, 0, len(topoID2TopoList))
	for _, ds := range topoID2TopoList {
		if len(ds) == 0 {
			continue
		}
		topoData := fromTopoDataList2AggregatedTopo(ds)
		ret = append(ret, topoData)
	}
	return ret
}

func fromTopoDataList2AggregatedTopo(ds []TopoData) TopoData {
	ret := ds[0]
	ret.RequestCount = int64(len(ds))
	ret.FailedCount = 0
	su := int64(0)
	for _, d := range ds {
		su += d.AvgResponseTime
	}
	ret.AvgResponseTime = (su / int64(len(ds))) / 1e6 //ms
	return ret
}

type Span2Cal struct {
	TraceId      string
	ServiceName  string
	AppAlias     string
	SpanId       string
	ParentSpanId string
	Duration     int64
	Route        string
	StatusCode   int32 `ch:"StatusCodeNumber"`
	children     []*Span2Cal
}

func (s *Span2Cal) HasError() bool {
	return s.StatusCode < 200 || s.StatusCode > 299
}

type ServerEndpointNode struct {
	ServerName string
	Endpoint   string
	HasError   bool
	Duration   int64
	children   []*ServerEndpointNode
}

func (s ServerEndpointNode) String() string {
	str := fmt.Sprintf("%s:%s", s.ServerName, s.Endpoint)
	str += "children:\n"
	for _, child := range s.children {
		str += child.ServerName + ":" + child.Endpoint + "\n"
	}
	return str
}

func subTreesWithEndpointRoot(snn *ServerEndpointNode) []*ServerEndpointNode {
	if snn == nil {
		return nil
	}
	if snn.Endpoint != "" {
		return []*ServerEndpointNode{snn}
	}
	ret := make([]*ServerEndpointNode, 0)
	for _, child := range snn.children {
		ens := subTreesWithEndpointRoot(child)
		if ens != nil && len(ens) > 0 {
			ret = append(ret, ens...)
		}
	}
	return ret
}

func serviceTopoDataWithEndpoint(cmdbID string, snn *ServerEndpointNode) []TopoData {
	if snn == nil {
		return make([]TopoData, 0)
	}
	subTrees := subTreesWithEndpointRoot(snn)
	if subTrees == nil || len(subTrees) == 0 {
		return make([]TopoData, 0)
	}
	ret := make([]TopoData, 0)
	for _, tree := range subTrees {
		pairs := findTreeEndpointPair(tree)
		if pairs == nil || len(pairs) == 0 {
			continue
		}
		for _, pair := range pairs {
			failedCount := 0
			if pair.hasError {
				failedCount = 1
			}
			ret = append(ret, TopoData{
				TxServiceName:   tree.ServerName,
				TxEndpoint:      tree.Endpoint,
				TxCmdbID:        cmdbID,
				SrcServiceName:  pair.srcServiceName,
				SrcEndpoint:     pair.srcEndpoint,
				SrcCmdbID:       cmdbID,
				DestServiceName: pair.destService,
				DestEndpoint:    pair.destEndpoint,
				DestCmdbID:      cmdbID,
				RequestCount:    1,
				FailedCount:     int64(failedCount),
				AvgResponseTime: pair.duration,
			})
		}
	}
	return ret
}

type serviceEndpointPair struct {
	srcServiceName string
	srcEndpoint    string
	destService    string
	destEndpoint   string
	hasError       bool
	duration       int64
}

func findTreeEndpointPair(tree *ServerEndpointNode) []serviceEndpointPair {
	if tree == nil {
		return nil
	}
	ret := make([]serviceEndpointPair, 0)
	if tree.Endpoint != "" {
		for _, child := range tree.children {
			if child.Endpoint != "" {
				ret = append(ret, serviceEndpointPair{
					srcServiceName: tree.ServerName,
					srcEndpoint:    tree.Endpoint,
					destService:    child.ServerName,
					destEndpoint:   child.Endpoint,
					hasError:       child.HasError,
					duration:       child.Duration,
				})
			}
		}
	}
	for _, child := range tree.children {
		childPairs := findTreeEndpointPair(child)
		if len(childPairs) > 0 {
			ret = append(ret, childPairs...)
		}
	}
	return ret
}

func (a *Aggregator) loadTraceList(start, end time.Time, tidList []string) (map[string][]Span2Cal, error) {
	sql := ` 
WITH '\\b[a-fA-F0-9]{32,}\\b|\\b[a-fA-F0-9\\-]{36}\\b|\\b\\[1-9]\\d*\\b' AS varPattern, 
SpanAttributes['http.route'] AS route, 
multiIf( (SpanAttributes['url.path']) != '', SpanAttributes['url.path'], (SpanAttributes['http.target']) != '',
        path(SpanAttributes['http.target']), (SpanAttributes['http.url']) != '', path(SpanAttributes['http.url']),
        (SpanAttributes['u\nrl.full']) != '', path(SpanAttributes['url.full']),
        SpanAttributes['http.route']) AS path
SELECT TraceId,
       ServiceName,
       SpanId,
       ParentSpanId,
       Duration,
       StatusCodeNumber,
	if(route != '', route, replaceRegexpOne(path, varPattern, '{:var}')) AS Route,
       AppAlias
from otel.otel_traces
		where Timestamp > ? and Timestamp < ? and TraceId in ?
`
	ctx, cancel := context.WithTimeout(context.Background(), a.cfg.LoadTimeout())
	defer cancel()
	spanRows, errQueryTraceId := a.chCli.Query(ctx, sql, start, end,
		tidList)
	if errQueryTraceId != nil {
		a.sqlQueryErrorCounter.Inc()
		return nil, errors.Wrapf(errQueryTraceId, "failed to query Traces: %s, sql:%s", tidList, sql)
	}
	ret := make(map[string][]Span2Cal)
	for spanRows.Next() {
		var span2Cal Span2Cal
		if err := spanRows.ScanStruct(&span2Cal); err != nil {
			a.logger.WithError(err).Error("failed to scan span2")
			continue
		}
		_, ok := ret[span2Cal.TraceId]
		if !ok {
			ret[span2Cal.TraceId] = []Span2Cal{span2Cal}
			continue
		}
		ret[span2Cal.TraceId] = append(ret[span2Cal.TraceId], span2Cal)
	}
	return ret, nil
}

func (a *Aggregator) calEndPointFromSpans(spans []Span2Cal, targetAppAlias string) ([]*ServerEndpointNode, error) {
	nodeMap := make(map[string]*Span2Cal)
	for i := range spans {
		nodeMap[spans[i].SpanId] = &spans[i]
	}
	var tree []*Span2Cal
	for _, node := range spans {
		if node.ParentSpanId == "" {
			tree = append(tree, nodeMap[node.SpanId])
			continue
		}
		parent, findParent := nodeMap[node.ParentSpanId]
		if !findParent {
			// 丢数据了，让这个tree独立出来，最大限度去找
			tree = append(tree, nodeMap[node.SpanId])
			continue
		}
		parent.children = append(parent.children, nodeMap[node.SpanId])
	}
	if len(tree) == 0 {
		a.logger.Errorf("no tree found in :%+v", spans)
		return nil, fmt.Errorf("no tree found in :%+v", spans)
	}
	ret := make([]*ServerEndpointNode, 0)
	for _, rootSpan := range tree {
		sen := EndpointTreeFromSpanTree(rootSpan, nil, targetAppAlias)
		if sen != nil {
			ret = append(ret, sen...)
		}
	}
	return ret, nil
}

func EndpointTreeFromSpanTree(span *Span2Cal, parentEndpointNode *ServerEndpointNode, targetAppAlias string) []*ServerEndpointNode {
	if span == nil {
		return nil
	}
	currentService := span.ServiceName
	if (span.AppAlias != targetAppAlias) ||
		(parentEndpointNode != nil && parentEndpointNode.ServerName == currentService) {
		// 略过本节点，返回子节点结果
		ret := make([]*ServerEndpointNode, 0)
		for _, child := range span.children {
			childNodes := EndpointTreeFromSpanTree(child, parentEndpointNode, targetAppAlias)
			if childNodes != nil && len(childNodes) > 0 {
				ret = append(ret, childNodes...)
			}
		}
		return ret
	}
	serverEndpointNode := ServerEndpointNode{
		ServerName: currentService,
		Endpoint:   span.Route,
		HasError:   span.HasError(),
		Duration:   span.Duration,
		children:   nil,
	}
	for _, childSpan := range span.children {
		childNodes := EndpointTreeFromSpanTree(childSpan, &serverEndpointNode, targetAppAlias)
		if childNodes != nil && len(childNodes) > 0 {
			serverEndpointNode.children = append(serverEndpointNode.children, childNodes...)
		}
	}
	return []*ServerEndpointNode{&serverEndpointNode}
}