// Package gcp calls the GCP metrics api to return data
// about metric samples and logs ingested for edge clusters.
package gcp

import (
	"context"
	"fmt"

	monitoring "cloud.google.com/go/monitoring/apiv3/v2"
	monitoringpb "cloud.google.com/go/monitoring/apiv3/v2/monitoringpb"
	"google.golang.org/api/iterator"
)

// GetMetricSamples uses the write_sample_count metric from
// the MetricIngestionAttribution resource to determine the
// number of metric samples can be attributed to a given
// cluster id.
//
// ref: https://cloud.google.com/stackdriver/docs/managed-prometheus/cost-controls
func GetMetricSamples(scopingProject string, clusterID string, interval string) (int64, error) {
	ctx := context.Background()
	client, err := monitoring.NewQueryClient(ctx)
	if err != nil {
		return 0.0, fmt.Errorf("NewQueryClient for metrics: %v", err)
	}
	defer client.Close()

	query := "fetch monitoring.googleapis.com/MetricIngestionAttribution" +
		" | metric 'monitoring.googleapis.com/collection/attribution/write_sample_count'" +
		" | filter (resource.attribution_dimension == 'cluster' && resource.attribution_id == \"" + clusterID + "\")" +
		" | group_by " + interval + ", [samples_agg: aggregate(value.write_sample_count)]" +
		" | every 5m " +
		" | group_by [resource.attribution_id, resource.resource_container] "

	req := &monitoringpb.QueryTimeSeriesRequest{
		Name:  "projects/" + scopingProject,
		Query: query,
	}

	var bytes int64
	it := client.QueryTimeSeries(ctx, req)
	for {
		resp, err := it.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return 0, fmt.Errorf("could not read time series value: %v", err)
		}
		if len(resp.GetPointData()) > 0 {
			bytes = resp.GetPointData()[0].GetValues()[0].GetInt64Value()
		}
	}
	return bytes, nil
}

// GetLogBytes uses the byte_count to deterine the number of
// log bytes ingested can be attributed to a given cluster id.
func GetLogBytes(scopingProject string, clusterID string, interval string, logType string) (int64, error) {
	ctx := context.Background()
	client, err := monitoring.NewQueryClient(ctx)
	if err != nil {
		return 0.0, fmt.Errorf("NewQueryClient for logs: %v", err)
	}
	defer client.Close()

	query := "fetch " + logType +
		"| metric 'logging.googleapis.com/byte_count'" +
		"| filter (resource.project_id == \"" + scopingProject + "\" && resource.cluster_name == \"" + clusterID + "\")" +
		"| group_by " + interval + ", [byte_count_agg:aggregate(value.byte_count)]" +
		"| every 5m" +
		"| group_by [resource.cluster_name], [aggregate(byte_count_agg)]"

	req := &monitoringpb.QueryTimeSeriesRequest{
		Name:  "projects/" + scopingProject,
		Query: query,
	}

	var bytes int64
	it := client.QueryTimeSeries(ctx, req)
	for {
		resp, err := it.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return 0, fmt.Errorf("could not read time series value: %v", err)
		}
		if len(resp.GetPointData()) > 0 {
			bytes = resp.GetPointData()[0].GetValues()[0].GetInt64Value()
		}
	}
	return bytes, nil
}