package datasource

import (
	"encoding/json"
	"fmt"
	"time"

	"github.com/alexanderzobnin/grafana-zabbix/pkg/zabbix"
	simplejson "github.com/bitly/go-simplejson"
	"github.com/grafana/grafana-plugin-sdk-go/backend"
	"github.com/grafana/grafana-plugin-sdk-go/data"
	"golang.org/x/net/context"
)

// ZabbixAPIQuery handles query requests to Zabbix API
func (ds *ZabbixDatasourceInstance) ZabbixAPIQuery(ctx context.Context, apiReq *zabbix.ZabbixAPIRequest) (*ZabbixAPIResourceResponse, error) {
	resultJson, err := ds.zabbix.Request(ctx, apiReq)
	if err != nil {
		return nil, err
	}
	result := resultJson.Interface()
	return BuildAPIResponse(&result)
}

func BuildAPIResponse(responseData *interface{}) (*ZabbixAPIResourceResponse, error) {
	return &ZabbixAPIResourceResponse{
		Result: *responseData,
	}, nil
}

// TestConnection checks authentication and version of the Zabbix API and returns that info
func (ds *ZabbixDatasourceInstance) TestConnection(ctx context.Context) (string, error) {
	_, err := ds.zabbix.GetAllGroups(ctx)
	if err != nil {
		return "", err
	}

	response, err := ds.zabbix.Request(ctx, &zabbix.ZabbixAPIRequest{Method: "apiinfo.version"})
	if err != nil {
		return "", err
	}

	resultByte, _ := response.MarshalJSON()
	return string(resultByte), nil
}

func (ds *ZabbixDatasourceInstance) queryNumericItems(ctx context.Context, query *QueryModel) (*data.Frame, error) {
	groupFilter := query.Group.Filter
	hostFilter := query.Host.Filter
	appFilter := query.Application.Filter
	itemFilter := query.Item.Filter

	items, err := ds.zabbix.GetItems(ctx, groupFilter, hostFilter, appFilter, itemFilter, "num")
	if err != nil {
		return nil, err
	}

	frames, err := ds.queryNumericDataForItems(ctx, query, items)
	if err != nil {
		return nil, err
	}

	return frames, nil
}

func (ds *ZabbixDatasourceInstance) queryNumericDataForItems(ctx context.Context, query *QueryModel, items zabbix.Items) (*data.Frame, error) {
	valueType := ds.getTrendValueType(query)
	consolidateBy := ds.getConsolidateBy(query)

	if consolidateBy == "" {
		consolidateBy = valueType
	}

	history, err := ds.getHistotyOrTrend(ctx, query, items)
	if err != nil {
		return nil, err
	}

	frame := convertHistoryToDataFrame(history, items)
	return frame, nil
}

func (ds *ZabbixDatasourceInstance) getTrendValueType(query *QueryModel) string {
	trendValue := "avg"

	for _, fn := range query.Functions {
		if fn.Def.Name == "trendValue" && len(fn.Params) > 0 {
			trendValue = fn.Params[0]
		}
	}

	return trendValue
}

func (ds *ZabbixDatasourceInstance) getConsolidateBy(query *QueryModel) string {
	consolidateBy := "avg"

	for _, fn := range query.Functions {
		if fn.Def.Name == "consolidateBy" && len(fn.Params) > 0 {
			consolidateBy = fn.Params[0]
		}
	}
	return consolidateBy
}

func (ds *ZabbixDatasourceInstance) getHistotyOrTrend(ctx context.Context, query *QueryModel, items zabbix.Items) (History, error) {
	timeRange := query.TimeRange
	useTrend := ds.isUseTrend(timeRange)
	allHistory := History{}

	groupedItems := map[int]zabbix.Items{}

	for _, j := range items {
		groupedItems[j.ValueType] = append(groupedItems[j.ValueType], j)
	}

	for k, l := range groupedItems {
		var itemids []string
		for _, m := range l {
			itemids = append(itemids, m.ID)
		}

		params := ZabbixAPIParams{
			"output":    "extend",
			"sortfield": "clock",
			"sortorder": "ASC",
			"itemids":   itemids,
			"time_from": timeRange.From.Unix(),
			"time_till": timeRange.To.Unix(),
		}

		var response *simplejson.Json
		var err error
		if useTrend {
			response, err = ds.zabbix.Request(ctx, &zabbix.ZabbixAPIRequest{Method: "trend.get", Params: params})
		} else {
			params["history"] = &k
			response, err = ds.zabbix.Request(ctx, &zabbix.ZabbixAPIRequest{Method: "history.get", Params: params})
		}

		if err != nil {
			return nil, err
		}

		pointJSON, err := response.MarshalJSON()
		if err != nil {
			return nil, fmt.Errorf("Internal error parsing response JSON: %w", err)
		}

		history := History{}
		err = json.Unmarshal(pointJSON, &history)
		if err != nil {
			ds.logger.Error("Error handling history response", "error", err.Error())
		} else {
			allHistory = append(allHistory, history...)
		}
	}
	return allHistory, nil
}

func (ds *ZabbixDatasourceInstance) isUseTrend(timeRange backend.TimeRange) bool {
	if !ds.Settings.Trends {
		return false
	}

	trendsFrom := ds.Settings.TrendsFrom
	trendsRange := ds.Settings.TrendsRange
	fromSec := timeRange.From.Unix()
	toSec := timeRange.To.Unix()
	rangeSec := float64(toSec - fromSec)

	if (fromSec < time.Now().Add(-trendsFrom).Unix()) || (rangeSec > trendsRange.Seconds()) {
		return true
	}
	return false
}