package main

import (
	"fmt"
	"log"
	"os"
	"path"
	"strconv"
	"sync"
	"time"

	"github.com/anacrolix/torrent"
	"github.com/anacrolix/torrent/metainfo"
)

const TxExt = ".tx"

var (
	TxStats  = map[metainfo.Hash]int64{}
	TxStatsM sync.Mutex
	TxsDir   string
)

func txStatsLoad(h metainfo.Hash) {
	pth := path.Join(TxsDir, h.HexString()+TxExt)
	data, err := os.ReadFile(pth)
	if err != nil {
		return
	}
	if len(data) == 0 {
		return
	}
	v, err := strconv.ParseInt(string(data[:len(data)-1]), 10, 64)
	if err != nil {
		log.Println("ParseInt:", pth, err)
		return
	}
	TxStatsM.Lock()
	TxStats[h] = v
	TxStatsM.Unlock()
}

func txStatsDel(h metainfo.Hash) {
	TxStatsM.Lock()
	delete(TxStats, h)
	TxStatsM.Unlock()
}

func txStatsDump(t *torrent.Torrent) {
	stats := t.Stats()
	TxStatsM.Lock()
	s := stats.BytesWrittenData.Int64() + TxStats[t.InfoHash()]
	pth := path.Join(TxsDir, t.InfoHash().HexString()+TxExt)
	if err := os.WriteFile(pth, []byte(fmt.Sprintf("%d\n", s)), 0666); err != nil {
		log.Println("WriteFile:", pth, err)
	}
	TxStatsM.Unlock()
}

func txStatsDumpAll(c *torrent.Client) {
	for _, t := range c.Torrents() {
		if t.Info() != nil {
			txStatsDump(t)
		}
	}
}

func txStatsDumper(c *torrent.Client) {
	tick := time.Tick(10 * time.Second)
	for {
		txStatsDumpAll(c)
		select {
		case <-Cancel:
			Jobs.Done()
			return
		case <-tick:
		}
	}
}