package mqe

import (
	"encoding/json"
	"io/ioutil"
	"net/http"

	null "gopkg.in/guregu/null.v3"

	"fmt"

	"github.com/grafana/grafana/pkg/log"
	"github.com/grafana/grafana/pkg/tsdb"
)

func NewResponseParser() *ResponseParser {
	return &ResponseParser{
		log: log.New("tsdb.mqe"),
	}
}

type MQEResponse struct {
	Success bool               `json:"success"`
	Name    string             `json:"name"`
	Body    []MQEResponseSerie `json:"body"`
}

type ResponseTimeRange struct {
	Start      int64 `json:"start"`
	End        int64 `json:"end"`
	Resolution int64 `json:"Resolution"`
}

type MQEResponseSerie struct {
	Query     string            `json:"query"`
	Name      string            `json:"name"`
	Type      string            `json:"type"`
	Series    []MQESerie        `json:"series"`
	TimeRange ResponseTimeRange `json:"timerange"`
}

type MQESerie struct {
	Values []null.Float      `json:"values"`
	Tagset map[string]string `json:"tagset"`
}

type ResponseParser struct {
	log log.Logger
}

func (parser *ResponseParser) Parse(res *http.Response, queryRef *Query) ([]*tsdb.TimeSeries, error) {
	body, err := ioutil.ReadAll(res.Body)
	defer res.Body.Close()
	if err != nil {
		return nil, err
	}

	if res.StatusCode/100 != 2 {
		parser.log.Error("Request failed", "status code", res.StatusCode, "body", string(body))
		return nil, fmt.Errorf("Returned invalid statuscode")
	}

	var data *MQEResponse = &MQEResponse{}
	err = json.Unmarshal(body, data)
	if err != nil {
		parser.log.Info("Failed to unmarshal response", "error", err, "status", res.Status, "body", string(body))
		return nil, err
	}

	if !data.Success {
		return nil, fmt.Errorf("Request failed.")
	}

	var series []*tsdb.TimeSeries
	for _, body := range data.Body {
		for _, mqeSerie := range body.Series {
			namePrefix := ""

			//append predefined tags to seriename
			for key, value := range mqeSerie.Tagset {
				if key == "cluster" && queryRef.AddClusterToAlias {
					namePrefix += value + " "
				}
			}
			for key, value := range mqeSerie.Tagset {
				if key == "host" && queryRef.AddHostToAlias {
					namePrefix += value + " "
				}
			}

			serie := &tsdb.TimeSeries{Name: namePrefix + body.Name}

			for i, value := range mqeSerie.Values {
				timestamp := body.TimeRange.Start + int64(i)*body.TimeRange.Resolution
				serie.Points = append(serie.Points, tsdb.NewTimePoint(value, float64(timestamp)))
			}

			series = append(series, serie)
		}
	}

	return series, nil
}