package main

import (
	"context"
	"fmt"
	"html/template"
	"log"
	"os"
	"sort"
	"time"

	"github.com/hekmon/cunits/v2"
	"github.com/hekmon/transmissionrpc"
)

func byteCountIEC(b int64) string {
	const unit = 1024
	if b < unit {
		return fmt.Sprintf("%d B", b)
	}

	div, exp := int64(unit), 0
	for n := b / unit; n >= unit; n /= unit {
		div *= unit
		exp++
	}

	return fmt.Sprintf("%.1f %ciB", float64(b)/float64(div), "KMGTPE"[exp])
}

func convertTime(seconds int64) string {
	switch {
	case seconds > 86400:
		day := seconds / 86400
		remainder := seconds % 86400
		hour := remainder / 3600
		remainder = remainder % 3600
		minutes := remainder / 60
		remainder = remainder % 60

		return fmt.Sprintf("%d days, %d hours, %d minutes, %d seconds", day, hour, minutes, remainder)

	case seconds < 86400 && seconds > 3600:
		hour := seconds / 3600
		remainder := seconds % 3600
		minutes := remainder / 60
		remainder = remainder % 60

		return fmt.Sprintf("%d hours, %d minutes, %d seconds", hour, minutes, remainder)

	case seconds < 3600 && seconds > 60:
		minutes := seconds / 60
		remainder := seconds % 60

		return fmt.Sprintf("%d minutes, %d seconds", minutes, remainder)

	default:
		return fmt.Sprintf("%d seconds", seconds)
	}

}

type SessionStat struct {
	Label string
	Value string
}

type TorrentInfo struct {
	Name         string
	ActivityDate time.Time
	TotalSize    cunits.Bits
	Leechers     int64
	Seeders      int64
}

type TorrentStatsPageData struct {
	Date            string
	SessionStats    []SessionStat
	CurrentStats    []SessionStat
	CumulativeStats []SessionStat
	TorrentInfo     []TorrentInfo
}

func main() {
	transmissionbt, err := transmissionrpc.New("127.0.0.1", "", "", nil)
	if err != nil {
		log.Fatalln(err)
	}

	stats, err := transmissionbt.SessionStats(context.TODO())
	if err != nil {
		log.Fatalln(err)
	}

	sessionStats := []SessionStat{
		{Label: "Active torrent count", Value: fmt.Sprintf("%d", stats.ActiveTorrentCount)},
		{Label: "Download speed", Value: fmt.Sprintf("%s/sec", byteCountIEC(stats.DownloadSpeed))},
		{Label: "Upload speed", Value: fmt.Sprintf("%s/sec", byteCountIEC(stats.UploadSpeed))},
		{Label: "Paused torrent count", Value: fmt.Sprintf("%d", stats.PausedTorrentCount)},
		{Label: "Torrent count", Value: fmt.Sprintf("%d", stats.TorrentCount)},
	}

	currentStats := []SessionStat{
		{Label: "Uploaded bytes", Value: fmt.Sprintf("%s", byteCountIEC(stats.CurrentStats.UploadedBytes))},
		{Label: "Downloaded bytes", Value: fmt.Sprintf("%s", byteCountIEC(stats.CurrentStats.DownloadedBytes))},
		{Label: "Files added", Value: fmt.Sprintf("%d", stats.CurrentStats.FilesAdded)},
		{Label: "Session count", Value: fmt.Sprintf("%d", stats.CurrentStats.SessionCount)},
		{Label: "Time active", Value: convertTime(stats.CurrentStats.SecondsActive)},
	}

	cumulativeStats := []SessionStat{
		{Label: "Uploaded bytes", Value: fmt.Sprintf("%s", byteCountIEC(stats.CumulativeStats.UploadedBytes))},
		{Label: "Downloaded bytes", Value: fmt.Sprintf("%s", byteCountIEC(stats.CumulativeStats.DownloadedBytes))},
		{Label: "Files added", Value: fmt.Sprintf("%d", stats.CumulativeStats.FilesAdded)},
		{Label: "Session count", Value: fmt.Sprintf("%d", stats.CumulativeStats.SessionCount)},
		{Label: "Time active", Value: convertTime(stats.CumulativeStats.SecondsActive)},
	}

	var torrentInfo = []TorrentInfo{}
	var (
		leecherCount int64
		seederCount  int64
	)

	torrents, err := transmissionbt.TorrentGet(context.TODO(), []string{"name", "activityDate", "totalSize", "trackerStats"}, nil)
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
	} else {
		for _, torrent := range torrents {
			for _, stat := range torrent.TrackerStats {
				leecherCount = stat.LeecherCount
				seederCount = stat.SeederCount
			}
			torrentInfo = append(torrentInfo, TorrentInfo{
				Name:         *torrent.Name,
				ActivityDate: *torrent.ActivityDate,
				TotalSize:    *torrent.TotalSize,
				Leechers:     leecherCount,
				Seeders:      seederCount,
			})
		}
	}

	sort.Slice(torrentInfo, func(i, j int) bool {
		return torrentInfo[i].Name < torrentInfo[j].Name
	})

	data := TorrentStatsPageData{
		Date:            time.Now().Format(time.UnixDate),
		SessionStats:    sessionStats,
		CurrentStats:    currentStats,
		CumulativeStats: cumulativeStats,
		TorrentInfo:     torrentInfo,
	}

	htmlTemplate, err := template.ParseFiles("template.html")
	if err != nil {
		log.Fatalln(err)
	}

	htmlFile, err := os.Create(os.Getenv("HTML_FILE"))
	if err != nil {
		log.Fatalln(err)
	}
	defer htmlFile.Close()

	if err = htmlTemplate.Execute(htmlFile, data); err != nil {
		log.Fatalln(err)
	}
}