package metricdata

import (
	"bufio"
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"strconv"
	"time"

	"github.com/ClusterCockpit/cc-jobarchive/config"
	"github.com/ClusterCockpit/cc-jobarchive/schema"
)

type CCMetricStore struct {
	jwt    string
	url    string
	client http.Client
}

type ApiRequestBody struct {
	Metrics   []string   `json:"metrics"`
	Selectors [][]string `json:"selectors"`
}

type ApiMetricData struct {
	Error *string        `json:"error"`
	From  int64          `json:"from"`
	To    int64          `json:"to"`
	Data  []schema.Float `json:"data"`
	Avg   schema.Float   `json:"avg"`
	Min   schema.Float   `json:"min"`
	Max   schema.Float   `json:"max"`
}

type ApiStatsData struct {
	Error   *string      `json:"error"`
	From    int64        `json:"from"`
	To      int64        `json:"to"`
	Samples int          `json:"samples"`
	Avg     schema.Float `json:"avg"`
	Min     schema.Float `json:"min"`
	Max     schema.Float `json:"max"`
}

func (ccms *CCMetricStore) Init(url, token string) error {
	ccms.url = url
	ccms.jwt = token
	return nil
}

func (ccms *CCMetricStore) doRequest(job *schema.Job, suffix string, metrics []string, ctx context.Context) (*http.Response, error) {
	from, to := job.StartTime.Unix(), job.StartTime.Add(time.Duration(job.Duration)*time.Second).Unix()
	reqBody := ApiRequestBody{}
	reqBody.Metrics = metrics
	for _, node := range job.Resources {
		if node.Accelerators != nil || node.HWThreads != nil {
			// TODO/FIXME:
			return nil, errors.New("todo: cc-metric-store resources: Accelerator/HWThreads")
		}

		reqBody.Selectors = append(reqBody.Selectors, []string{job.Cluster, node.Hostname})
	}

	reqBodyBytes, err := json.Marshal(reqBody)
	if err != nil {
		return nil, err
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, fmt.Sprintf("%s/api/%d/%d/%s", ccms.url, from, to, suffix), bytes.NewReader(reqBodyBytes))
	if err != nil {
		return nil, err
	}
	if ccms.jwt != "" {
		req.Header.Add("Authorization", fmt.Sprintf("Bearer %s", ccms.jwt))
	}
	return ccms.client.Do(req)
}

func (ccms *CCMetricStore) LoadData(job *schema.Job, metrics []string, scopes []schema.MetricScope, ctx context.Context) (schema.JobData, error) {

	type ApiQuery struct {
		Metric     string   `json:"metric"`
		Hostname   string   `json:"hostname"`
		Type       *string  `json:"type,omitempty"`
		TypeIds    []string `json:"type-ids,omitempty"`
		SubType    *string  `json:"subtype,omitempty"`
		SubTypeIds []string `json:"subtype-ids,omitempty"`
	}

	type ApiQueryRequest struct {
		Cluster string     `json:"cluster"`
		From    int64      `json:"from"`
		To      int64      `json:"to"`
		Queries []ApiQuery `json:"queries"`
	}

	type ApiQueryResponse struct {
		ApiMetricData
		Query *ApiQuery `json:"query"`
	}

	reqBody := ApiQueryRequest{
		Cluster: job.Cluster,
		From:    job.StartTime.Unix(),
		To:      job.StartTime.Add(time.Duration(job.Duration)).Unix(),
		Queries: make([]ApiQuery, 0),
	}

	if len(scopes) != 1 {
		return nil, errors.New("todo: support more than one scope in a query")
	}

	topology := config.GetPartition(job.Cluster, job.Partition).Topology
	scopeForMetric := map[string]schema.MetricScope{}
	for _, metric := range metrics {
		mc := config.GetMetricConfig(job.Cluster, metric)
		nativeScope, requestedScope := mc.Scope, scopes[0]

		// case 1: A metric is requested at node scope with a native scope of node as well
		// case 2: A metric is requested at node scope and node is exclusive
		if (nativeScope == requestedScope && nativeScope == schema.MetricScopeNode) ||
			(job.Exclusive == 1 && requestedScope == schema.MetricScopeNode) {
			nodes := map[string]bool{}
			for _, resource := range job.Resources {
				nodes[resource.Hostname] = true
			}

			for node := range nodes {
				reqBody.Queries = append(reqBody.Queries, ApiQuery{
					Metric:   metric,
					Hostname: node,
				})
			}

			scopeForMetric[metric] = schema.MetricScopeNode
			continue
		}

		// case: Read a metric at hwthread scope with native scope hwthread
		if nativeScope == requestedScope && nativeScope == schema.MetricScopeHWThread && job.NumNodes == 1 {
			hwthreads := job.Resources[0].HWThreads
			if hwthreads == nil {
				hwthreads = topology.Node
			}

			t := "cpu" // TODO/FIXME: inconsistency between cc-metric-collector and ClusterCockpit
			for _, hwthread := range hwthreads {
				reqBody.Queries = append(reqBody.Queries, ApiQuery{
					Metric:   metric,
					Hostname: job.Resources[0].Hostname,
					Type:     &t,
					TypeIds:  []string{strconv.Itoa(hwthread)},
				})
			}

			scopeForMetric[metric] = schema.MetricScopeHWThread
			continue
		}

		// case: A metric is requested at node scope, has a hwthread scope and node is not exclusive and runs on a single node
		if requestedScope == schema.MetricScopeNode && nativeScope == schema.MetricScopeHWThread && job.Exclusive != 1 && job.NumNodes == 1 {
			hwthreads := job.Resources[0].HWThreads
			if hwthreads == nil {
				hwthreads = topology.Node
			}

			t := "cpu" // TODO/FIXME: inconsistency between cc-metric-collector and ClusterCockpit
			ids := make([]string, 0, len(hwthreads))
			for _, hwthread := range hwthreads {
				ids = append(ids, strconv.Itoa(hwthread))
			}

			reqBody.Queries = append(reqBody.Queries, ApiQuery{
				Metric:   metric,
				Hostname: job.Resources[0].Hostname,
				Type:     &t,
				TypeIds:  ids,
			})
			scopeForMetric[metric] = schema.MetricScopeNode
			continue
		}

		// TODO: Job teilt sich knoten und metric native scope ist kleiner als node
		panic("todo")
	}

	buf := &bytes.Buffer{}
	if err := json.NewEncoder(buf).Encode(reqBody); err != nil {
		return nil, err
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, ccms.url+"/api/query", buf)
	if err != nil {
		return nil, err
	}
	if ccms.jwt != "" {
		req.Header.Add("Authorization", fmt.Sprintf("Bearer %s", ccms.jwt))
	}
	res, err := ccms.client.Do(req)
	if err != nil {
		return nil, err
	}
	if res.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("cc-metric-store replied with: %s", res.Status)
	}

	var resBody []ApiQueryResponse
	if err := json.NewDecoder(bufio.NewReader(res.Body)).Decode(&resBody); err != nil {
		return nil, err
	}

	var jobData schema.JobData = make(schema.JobData)
	for _, res := range resBody {
		metric := res.Query.Metric
		if res.Error != nil {
			return nil, fmt.Errorf("cc-metric-store error while fetching %s: %s", metric, *res.Error)
		}

		mc := config.GetMetricConfig(job.Cluster, metric)
		scope := scopeForMetric[metric]
		jobMetric, ok := jobData[metric][scope]
		if !ok {
			jobMetric = &schema.JobMetric{
				Unit:     mc.Unit,
				Scope:    scope,
				Timestep: mc.Timestep,
				Series:   make([]schema.Series, 0),
			}
			jobData[metric][scope] = jobMetric
		}

		id := (*int)(nil)
		if res.Query.Type != nil {
			id = new(int)
			*id, _ = strconv.Atoi(res.Query.TypeIds[0])
		}

		jobMetric.Series = append(jobMetric.Series, schema.Series{
			Hostname: res.Query.Hostname,
			Id:       id,
			Statistics: &schema.MetricStatistics{
				Avg: float64(res.Avg),
				Min: float64(res.Min),
				Max: float64(res.Max),
			},
			Data: res.Data,
		})
	}

	return jobData, nil
}

func (ccms *CCMetricStore) LoadStats(job *schema.Job, metrics []string, ctx context.Context) (map[string]map[string]schema.MetricStatistics, error) {
	res, err := ccms.doRequest(job, "stats", metrics, ctx)
	if err != nil {
		return nil, err
	}

	resdata := make([]map[string]ApiStatsData, 0, len(job.Resources))
	if err := json.NewDecoder(res.Body).Decode(&resdata); err != nil {
		return nil, err
	}

	stats := map[string]map[string]schema.MetricStatistics{}
	for _, metric := range metrics {
		nodestats := map[string]schema.MetricStatistics{}
		for i, node := range job.Resources {
			if node.Accelerators != nil || node.HWThreads != nil {
				// TODO/FIXME:
				return nil, errors.New("todo: cc-metric-store resources: Accelerator/HWThreads")
			}

			data := resdata[i][metric]
			if data.Error != nil {
				return nil, errors.New(*data.Error)
			}

			if data.Samples == 0 {
				return nil, fmt.Errorf("no data for node '%s' and metric '%s'", node.Hostname, metric)
			}

			nodestats[node.Hostname] = schema.MetricStatistics{
				Avg: float64(data.Avg),
				Min: float64(data.Min),
				Max: float64(data.Max),
			}
		}

		stats[metric] = nodestats
	}

	return stats, nil
}

func (ccms *CCMetricStore) LoadNodeData(clusterId string, metrics, nodes []string, from, to int64, ctx context.Context) (map[string]map[string][]schema.Float, error) {
	reqBody := ApiRequestBody{}
	reqBody.Metrics = metrics
	for _, node := range nodes {
		reqBody.Selectors = append(reqBody.Selectors, []string{clusterId, node})
	}

	reqBodyBytes, err := json.Marshal(reqBody)
	if err != nil {
		return nil, err
	}

	var req *http.Request
	if nodes == nil {
		req, err = http.NewRequestWithContext(ctx, http.MethodPost, fmt.Sprintf("%s/api/%s/%d/%d/all-nodes", ccms.url, clusterId, from, to), bytes.NewReader(reqBodyBytes))
	} else {
		req, err = http.NewRequestWithContext(ctx, http.MethodPost, fmt.Sprintf("%s/api/%d/%d/timeseries", ccms.url, from, to), bytes.NewReader(reqBodyBytes))
	}
	if err != nil {
		return nil, err
	}
	if ccms.jwt != "" {
		req.Header.Add("Authorization", fmt.Sprintf("Bearer %s", ccms.jwt))
	}
	res, err := ccms.client.Do(req)
	if err != nil {
		return nil, err
	}

	data := map[string]map[string][]schema.Float{}
	if nodes == nil {
		resdata := map[string]map[string]ApiMetricData{}
		if err := json.NewDecoder(res.Body).Decode(&resdata); err != nil {
			return nil, err
		}

		for node, metrics := range resdata {
			nodedata := map[string][]schema.Float{}
			for metric, data := range metrics {
				if data.Error != nil {
					return nil, errors.New(*data.Error)
				}

				nodedata[metric] = data.Data
			}
			data[node] = nodedata
		}
	} else {
		resdata := make([]map[string]ApiMetricData, 0, len(nodes))
		if err := json.NewDecoder(res.Body).Decode(&resdata); err != nil {
			return nil, err
		}

		for i, node := range nodes {
			metricsData := map[string][]schema.Float{}
			for metric, data := range resdata[i] {
				if data.Error != nil {
					return nil, errors.New(*data.Error)
				}

				metricsData[metric] = data.Data
			}

			data[node] = metricsData
		}
	}

	return data, nil
}