package engine

import (
	"fmt"
	"io"
	"os"
	"time"

	"github.com/anacrolix/torrent"
	"github.com/asdine/storm"
	Settings "github.com/deranjer/goTorrent/settings"
	"github.com/deranjer/goTorrent/storage"
	Storage "github.com/deranjer/goTorrent/storage"
	"github.com/sirupsen/logrus"
)

func secondsToMinutes(inSeconds int64) string {
	minutes := inSeconds / 60
	seconds := inSeconds % 60
	minutesString := fmt.Sprintf("%d", minutes)
	secondsString := fmt.Sprintf("%d", seconds)
	str := minutesString + " Min/ " + secondsString + " Sec"
	return str
}

//VerifyData just verifies the data of a torrent by hash
func VerifyData(singleTorrent *torrent.Torrent) {
	singleTorrent.VerifyData()
}

//MakeRange creates a range of pieces to set their priority based on a file
func MakeRange(min, max int) []int {
	a := make([]int, max-min+1)
	for i := range a {
		a[i] = min + i
	}
	return a
}

//HumanizeBytes returns a nice humanized version of bytes in either GB or MB
func HumanizeBytes(bytes float32) string {
	if bytes < 1000000 { //if we have less than 1MB in bytes convert to KB
		pBytes := fmt.Sprintf("%.2f", bytes/1024)
		pBytes = pBytes + " KB"
		return pBytes
	}
	bytes = bytes / 1024 / 1024 //Converting bytes to a useful measure
	if bytes > 1024 {
		pBytes := fmt.Sprintf("%.2f", bytes/1024)
		pBytes = pBytes + " GB"
		return pBytes
	}
	pBytes := fmt.Sprintf("%.2f", bytes) //If not too big or too small leave it as MB
	pBytes = pBytes + " MB"
	return pBytes
}

//CopyFile takes a source file string and a destination file string and copies the file
func CopyFile(srcFile string, destFile string) { //TODO move this to our imported copy repo
	fileContents, err := os.Open(srcFile)
	defer fileContents.Close()
	if err != nil {
		Logger.WithFields(logrus.Fields{"File": srcFile, "Error": err}).Error("Cannot open source file")
	}
	outfileContents, err := os.Create(destFile)
	defer outfileContents.Close()
	if err != nil {
		Logger.WithFields(logrus.Fields{"File": destFile, "Error": err}).Error("Cannot open destination file")
	}
	_, err = io.Copy(outfileContents, fileContents)
	if err != nil {
		Logger.WithFields(logrus.Fields{"Source File": srcFile, "Destination File": destFile, "Error": err}).Error("Cannot write contents to destination file")
	}

}

//SetFilePriority sets the priorities for all of the files in all of the torrents
func SetFilePriority(t *torrent.Client, db *storm.DB) {
	storedTorrents := Storage.FetchAllStoredTorrents(db)
	for _, singleTorrent := range t.Torrents() {
		for _, storedTorrent := range storedTorrents {
			if storedTorrent.Hash == singleTorrent.InfoHash().String() {
				for _, file := range singleTorrent.Files() {
					for _, storedFile := range storedTorrent.TorrentFilePriority {
						if storedFile.TorrentFilePath == file.DisplayPath() {
							switch storedFile.TorrentFilePriority {
							case "High":
								file.SetPriority(torrent.PiecePriorityHigh)
							case "Normal":
								file.SetPriority(torrent.PiecePriorityNormal)
							case "Cancel":
								file.SetPriority(torrent.PiecePriorityNone)
							default:
								file.SetPriority(torrent.PiecePriorityNormal)
							}
						}
					}
				}
			}
		}
	}
}

//CalculateTorrentSpeed is used to calculate the torrent upload and download speed over time c is current clientdb, oc is last client db to calculate speed over time
func CalculateTorrentSpeed(t *torrent.Torrent, c *ClientDB, oc ClientDB, completedSize int64) {
	now := time.Now()
	bytes := completedSize
	bytesUpload := t.Stats().BytesWrittenData
	dt := float32(now.Sub(oc.UpdatedAt))     // get the delta time length between now and last updated
	db := float32(bytes - oc.BytesCompleted) //getting the delta bytes
	rate := db * (float32(time.Second) / dt) // converting into seconds
	dbU := float32(bytesUpload - oc.DataBytesWritten)
	rateUpload := dbU * (float32(time.Second) / dt)
	if rate >= 0 {
		rateMB := rate / 1024 / 1024 //creating MB to calculate ETA
		c.DownloadSpeed = fmt.Sprintf("%.2f", rateMB)
		c.DownloadSpeed = c.DownloadSpeed + " MB/s"
		c.downloadSpeedInt = int64(rate)
	}
	if rateUpload >= 0 {
		rateUpload = rateUpload / 1024 / 1024
		c.UploadSpeed = fmt.Sprintf("%.2f", rateUpload)
		c.UploadSpeed = c.UploadSpeed + " MB/s"

	}
	c.UpdatedAt = now
}

//CalculateDownloadSize will calculate the download size once file priorities are sorted out
func CalculateDownloadSize(tFromStorage *Storage.TorrentLocal, activeTorrent *torrent.Torrent) int64 {
	var totalLength int64
	for _, file := range tFromStorage.TorrentFilePriority {
		if file.TorrentFilePriority != "Cancel" {
			totalLength = totalLength + file.TorrentFileSize
		}
	}
	return totalLength
}

//CalculateCompletedSize will be used to calculate how much of the actual torrent we have completed minus the canceled files (even if they have been partially downloaded)
func CalculateCompletedSize(tFromStorage *Storage.TorrentLocal, activeTorrent *torrent.Torrent) int64 {
	var discardByteLength int64
	for _, storageFile := range tFromStorage.TorrentFilePriority {
		if storageFile.TorrentFilePriority == "Cancel" { //If the file is canceled don't count it as downloaded
			for _, activeFile := range activeTorrent.Files() {
				if activeFile.DisplayPath() == storageFile.TorrentFilePath { //match the file from storage to active
					for _, piece := range activeFile.State() {
						if piece.Partial || piece.Complete {
							discardByteLength = discardByteLength + piece.Bytes
						}
					}
				}
			}
		}
	}
	downloadedLength := activeTorrent.BytesCompleted() - discardByteLength
	if downloadedLength < 0 {
		downloadedLength = 0
	}
	return downloadedLength
}

//CalculateTorrentETA is used to estimate the remaining dl time of the torrent based on the speed that the MB are being downloaded
func CalculateTorrentETA(tSize int64, tBytesCompleted int64, c *ClientDB) {
	missingBytes := tSize - tBytesCompleted
	if missingBytes == 0 {
		c.ETA = "Done"
	} else if c.downloadSpeedInt == 0 {
		c.ETA = "N/A"
	} else {
		ETASeconds := missingBytes / c.downloadSpeedInt
		str := secondsToMinutes(ETASeconds) //converting seconds to minutes + seconds
		c.ETA = str
	}
}

//CalculateUploadRatio calculates the download to upload ratio so you can see if you are being a good seeder
func CalculateUploadRatio(t *torrent.Torrent, c *ClientDB) string {
	if c.TotalUploadedBytes > 0 && t.BytesCompleted() > 0 { //If we have actually started uploading and downloading stuff start calculating our ratio
		uploadRatio := fmt.Sprintf("%.2f", float64(c.TotalUploadedBytes)/float64(t.BytesCompleted()))
		return uploadRatio
	}
	uploadRatio := "0.00" //we haven't uploaded anything so no upload ratio just pass a string directly
	return uploadRatio
}

//CalculateTorrentStatus is used to determine what the STATUS column of the frontend will display ll2
func CalculateTorrentStatus(t *torrent.Torrent, c *ClientDB, config Settings.FullClientSettings, tFromStorage *storage.TorrentLocal, bytesCompleted int64, totalSize int64) {
	if (tFromStorage.TorrentStatus == "Stopped") || (float64(c.TotalUploadedBytes)/float64(bytesCompleted) >= config.SeedRatioStop && tFromStorage.TorrentUploadLimit == true) { //If storage shows torrent stopped or if it is over the seeding ratio AND is under the global limit
		c.Status = "Stopped"
		c.MaxConnections = 0
		t.SetMaxEstablishedConns(0)

	} else { //Only has 2 states in storage, stopped or running, so we know it should be running, and the websocket request handled updating the database with connections and status
		bytesMissing := totalSize - bytesCompleted
		c.MaxConnections = 80
		t.SetMaxEstablishedConns(80)
		//t.DownloadAll() //ensure that we are setting the torrent to download
		if t.Seeding() && t.Stats().ActivePeers > 0 && bytesMissing == 0 {
			c.Status = "Seeding"
		} else if t.Stats().ActivePeers > 0 && bytesMissing > 0 {
			c.Status = "Downloading"
		} else if t.Stats().ActivePeers == 0 && bytesMissing == 0 {
			c.Status = "Completed"
		} else if t.Stats().ActivePeers == 0 && bytesMissing > 0 {
			c.Status = "Awaiting Peers"
		} else {
			c.Status = "Unknown"
		}
	}
}