package manager

import (
	"fmt"
	"strings"
	"sync"
	"syscall"
	"time"

	"github.com/lbryio/ytsync/v5/blobs_reflector"
	"github.com/lbryio/ytsync/v5/configs"
	"github.com/lbryio/ytsync/v5/ip_manager"
	"github.com/lbryio/ytsync/v5/namer"
	"github.com/lbryio/ytsync/v5/sdk"
	"github.com/lbryio/ytsync/v5/shared"
	logUtils "github.com/lbryio/ytsync/v5/util"

	"github.com/lbryio/lbry.go/v2/extras/errors"
	"github.com/lbryio/lbry.go/v2/extras/util"

	log "github.com/sirupsen/logrus"
)

type SyncManager struct {
	CliFlags   shared.SyncFlags
	ApiConfig  *sdk.APIConfig
	LbrycrdDsn string

	blobsDir       string
	channelsToSync []Sync
}

func NewSyncManager(cliFlags shared.SyncFlags, blobsDir string) *SyncManager {
	return &SyncManager{
		CliFlags:   cliFlags,
		blobsDir:   blobsDir,
		LbrycrdDsn: configs.Configuration.LbrycrdString,
		ApiConfig:  sdk.GetAPIsConfigs(),
	}
}
func (s *SyncManager) enqueueChannel(channel *shared.YoutubeChannel) {
	s.channelsToSync = append(s.channelsToSync, Sync{
		DbChannelData: channel,
		Manager:       s,
		namer:         namer.NewNamer(),
		hardVideoFailure: hardVideoFailure{
			lock: &sync.Mutex{},
		},
	})
}

func (s *SyncManager) Start() error {
	if logUtils.ShouldCleanOnStartup() {
		err := logUtils.CleanForStartup()
		if err != nil {
			return err
		}
	}

	var lastChannelProcessed string
	var secondLastChannelProcessed string
	syncCount := 0
	for {
		s.channelsToSync = make([]Sync, 0, 10) // reset sync queue
		err := s.checkUsedSpace()
		if err != nil {
			return errors.Err(err)
		}
		shouldInterruptLoop := false

		if s.CliFlags.IsSingleChannelSync() {
			channels, err := s.ApiConfig.FetchChannels("", &s.CliFlags)
			if err != nil {
				return errors.Err(err)
			}
			if len(channels) != 1 {
				return errors.Err("Expected 1 channel, %d returned", len(channels))
			}
			s.enqueueChannel(&channels[0])
			shouldInterruptLoop = true
		} else {
			var queuesToSync []string
			if s.CliFlags.Status != "" {
				queuesToSync = append(queuesToSync, shared.StatusSyncing, s.CliFlags.Status)
			} else if s.CliFlags.SyncUpdate {
				queuesToSync = append(queuesToSync, shared.StatusSyncing, shared.StatusSynced)
			} else {
				queuesToSync = append(queuesToSync, shared.StatusSyncing, shared.StatusQueued)
			}
			if s.CliFlags.SecondaryStatus != "" {
				queuesToSync = append(queuesToSync, s.CliFlags.SecondaryStatus)
			}
		queues:
			for _, q := range queuesToSync {
				channels, err := s.ApiConfig.FetchChannels(q, &s.CliFlags)
				if err != nil {
					return err
				}
				log.Infof("Currently processing the \"%s\" queue with %d channels", q, len(channels))
				for _, c := range channels {
					s.enqueueChannel(&c)
					queueAll := q == shared.StatusFailed || q == shared.StatusSyncing
					if !queueAll {
						break queues
					}
				}
				log.Infof("Drained the \"%s\" queue", q)
			}
		}
		if len(s.channelsToSync) == 0 {
			log.Infoln("No channels to sync. Pausing 5 minutes!")
			time.Sleep(5 * time.Minute)
		}
		for _, sync := range s.channelsToSync {
			if lastChannelProcessed == sync.DbChannelData.ChannelId && secondLastChannelProcessed == lastChannelProcessed {
				util.SendToSlack("We just killed a sync for %s to stop looping! (%s)", sync.DbChannelData.DesiredChannelName, sync.DbChannelData.ChannelId)
				stopTheLoops := errors.Err("Found channel %s running 3 times, set it to failed, and reprocess later", sync.DbChannelData.DesiredChannelName)
				sync.setChannelTerminationStatus(&stopTheLoops)
				continue
			}
			secondLastChannelProcessed = lastChannelProcessed
			lastChannelProcessed = sync.DbChannelData.ChannelId
			shouldNotCount := false
			logUtils.SendInfoToSlack("Syncing %s (%s) to LBRY! total processed channels since startup: %d", sync.DbChannelData.DesiredChannelName, sync.DbChannelData.ChannelId, syncCount+1)
			err := sync.FullCycle()
			//TODO: THIS IS A TEMPORARY WORK AROUND FOR THE STUPID IP LOCKUP BUG
			ipPool, _ := ip_manager.GetIPPool(sync.grp)
			if ipPool != nil {
				ipPool.ReleaseAll()
			}

			if err != nil {
				if strings.Contains(err.Error(), "quotaExceeded") {
					logUtils.SleepUntilQuotaReset()
				}
				fatalErrors := []string{
					"default_wallet already exists",
					"WALLET HAS NOT BEEN MOVED TO THE WALLET BACKUP DIR",
					"NotEnoughFunds",
					"no space left on device",
					"there was a problem uploading the wallet",
					"the channel in the wallet is different than the channel in the database",
					"this channel does not belong to this wallet!",
					"You already have a stream claim published under the name",
				}

				if util.SubstringInSlice(err.Error(), fatalErrors) {
					return errors.Prefix("@Nikooo777 this requires manual intervention! Exiting...", err)
				}
				shouldNotCount = strings.Contains(err.Error(), "this youtube channel is being managed by another server")
				if !shouldNotCount {
					logUtils.SendInfoToSlack("A non fatal error was reported by the sync process.\n%s", errors.FullTrace(err))
				}
			}
			err = logUtils.CleanupMetadata()
			if err != nil {
				log.Errorf("something went wrong while trying to clear out the video metadata directory: %s", errors.FullTrace(err))
			}
			err = blobs_reflector.ReflectAndClean()
			if err != nil {
				return errors.Prefix("@Nikooo777 something went wrong while reflecting blobs", err)
			}
			logUtils.SendInfoToSlack("%s (%s) reached an end. Total processed channels since startup: %d", sync.DbChannelData.DesiredChannelName, sync.DbChannelData.ChannelId, syncCount+1)
			if !shouldNotCount {
				syncCount++
			}
			if sync.IsInterrupted() || (s.CliFlags.Limit != 0 && syncCount >= s.CliFlags.Limit) {
				shouldInterruptLoop = true
				break
			}
		}
		if shouldInterruptLoop || s.CliFlags.SingleRun {
			break
		}
	}
	return nil
}

func (s *SyncManager) checkUsedSpace() error {
	usedPctile, err := GetUsedSpace(logUtils.GetBlobsDir())
	if err != nil {
		return errors.Err(err)
	}
	if usedPctile >= 0.90 && !s.CliFlags.SkipSpaceCheck {
		return errors.Err(fmt.Sprintf("more than 90%% of the space has been used. use --skip-space-check to ignore. Used: %.1f%%", usedPctile*100))
	}
	log.Infof("disk usage: %.1f%%", usedPctile*100)
	return nil
}

// GetUsedSpace returns a value between 0 and 1, with 0 being completely empty and 1 being full, for the disk that holds the provided path
func GetUsedSpace(path string) (float32, error) {
	var stat syscall.Statfs_t
	err := syscall.Statfs(path, &stat)
	if err != nil {
		return 0, err
	}
	// Available blocks * size per block = available space in bytes
	all := stat.Blocks * uint64(stat.Bsize)
	free := stat.Bfree * uint64(stat.Bsize)
	used := all - free

	return float32(used) / float32(all), nil
}