// Sample logging-quickstart writes a log entry to Stackdriver Logging.
package main

import (
	"log"
	"cloud.google.com/go/logging"
	"golang.org/x/net/context"
	"cloud.google.com/go/logging/logadmin"
	"google.golang.org/api/iterator"
	"fmt"
	"time"
	"cloud.google.com/go/bigquery"
)

type StackDriverQuery struct {
	projectID string
	appName string
	filter string
}

func (q StackDriverQuery) getQuery() string {
	//return fmt.Sprintf(`logName:%s %s`, q.appName, q.filter)
	return fmt.Sprintf(`logName = "projects/%s/logs/%s" %s`, q.projectID, q.appName, q.filter)
}

func main() {

	tryCount := 20

	query := StackDriverQuery{
		projectID: "tsdn091",
		appName: "event-exporter",
		filter: `textPayload: watch`,
	}

	fmt.Println("=== Call stackdriver API directly ===")
	for i:=1; i< tryCount+ 1; i++ {
		testProcessingTime(query, i*10)
	}
	fmt.Println("")

	query = StackDriverQuery{
		projectID: "tsdn091",
		appName: "event-exporter",
		filter: `resource.labels.project_id = "tsdn091"`,
	}

	fmt.Println("=== Call BigQuery API ===")
	for i:=1; i< tryCount+1; i++ {
		testProcessingTimeWithBigQuery(query, i*10)
	}
	fmt.Println("")


}

func testProcessingTime(query StackDriverQuery, count int) {

	startTime := time.Now()
	entries, err := getLogEntries(query.projectID, query.getQuery(), count)
	if err != nil {
		log.Fatalf("Failed to get log entries: %v", err)
	}
	endTime := time.Now()
	fmt.Printf("count: %d(%d), time: %s \n", count, len(entries), endTime.Sub(startTime))
}

func testProcessingTimeWithBigQuery(query StackDriverQuery, count int) {

	startTime := time.Now()
	entries, err := getLogEntriesWithBigQuery(
		query.projectID,
		query.appName,
		"20180720",
		query.filter,
		count)
	if err != nil {
		log.Fatalf("Failed to get log entries: %v", err)
	}
	endTime := time.Now()
	fmt.Printf("count: %d(%d), time: %s \n", count, len(entries), endTime.Sub(startTime))
}

func getLogEntries(projectID, filter string, maxRecord int) ([]*logging.Entry, error) {
	ctx := context.Background()

	// Sets your Google Cloud Platform project ID.

	// Creates a client.
	client, err := logadmin.NewClient(ctx, projectID)
	if err != nil {
		log.Fatalf("Failed to create client: %v", err)
	}

	// Get Iterable.
	iter := client.Entries(ctx,
		// Only get entries from the log-example log.
		logadmin.Filter(filter),
		//logadmin.Filter(""),
		// Get most recent entries first.
		logadmin.NewestFirst(),
	)

	// Fetch entries.
	var entries []*logging.Entry
	for len(entries) < maxRecord {
		entry, err := iter.Next()
		if err == iterator.Done {
			return entries, nil
		}

		//log.Print(entry)
		if err != nil {
			return nil, err
		}
		entries = append(entries, entry)
	}
	return entries, nil

}

func getLogEntriesWithBigQuery(projectID, appName, date, filter string, maxRecord int) ([]*bigquery.Value, error) {
	ctx := context.Background()

	// Sets your Google Cloud Platform project ID.

	// Creates a client.
	client, err := bigquery.NewClient(ctx, projectID)
	if err != nil {
		log.Fatalf("Failed to create client: %v", err)
	}

	// Get Iterable.
	queryFmt := `
       SELECT textPayload
       FROM %s.event_exporter.%s_%s
       WHERE %s
       LIMIT %d`
	queryStr := fmt.Sprintf(queryFmt, projectID, appName, date, filter, maxRecord)
	q := client.Query(queryStr)
	it, err := q.Read(ctx)
	if err != nil {
		log.Fatalf("Failed to read records: %v", err)
	}

	// Fetch entries.
	var values []*bigquery.Value
	var value []bigquery.Value
	for {
		err := it.Next(&value)
		if err == iterator.Done {
			return values, nil
		}
		if err != nil {
			log.Fatalf("Failed to get next iteration: %v", err)
		}
		values = append(values, &value[0])
	}
	return values, nil
}