package datasource

import (
	"time"

	"github.com/alexanderzobnin/grafana-zabbix/pkg/zabbix"
	"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.Item) ([]*data.Frame, error) {
	valueType := ds.getTrendValueType(query)
	consolidateBy := ds.getConsolidateBy(query)

	if consolidateBy == "" {
		consolidateBy = valueType
	}

	err := applyFunctionsPre(query, items)
	if err != nil {
		return nil, err
	}

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

	series := convertHistoryToTimeSeries(history, items)
	series, err = applyFunctions(series, query.Functions)
	if err != nil {
		return nil, err
	}

	frames := convertTimeSeriesToDataFrames(series)
	return frames, 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].(string)
		}
	}

	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].(string)
		}
	}
	return consolidateBy
}

func (ds *ZabbixDatasourceInstance) getHistotyOrTrend(ctx context.Context, query *QueryModel, items []*zabbix.Item, trendValueType string) (zabbix.History, error) {
	timeRange := query.TimeRange
	useTrend := ds.isUseTrend(timeRange)

	if useTrend {
		result, err := ds.zabbix.GetTrend(ctx, items, timeRange)
		if err != nil {
			return nil, err
		}
		return convertTrendToHistory(result, trendValueType)
	}

	return ds.zabbix.GetHistory(ctx, items, timeRange)
}

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
}