package storage

import (
	"bytes"
	"context"
	"encoding/hex"
	"errors"
	"git.lumeweb.com/LumeWeb/libs5-go/encoding"
	"git.lumeweb.com/LumeWeb/libs5-go/types"
	"git.lumeweb.com/LumeWeb/portal/api/middleware"
	"git.lumeweb.com/LumeWeb/portal/db/models"
	"git.lumeweb.com/LumeWeb/portal/interfaces"
	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/config"
	"github.com/aws/aws-sdk-go-v2/credentials"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/go-co-op/gocron/v2"
	"github.com/google/uuid"
	"github.com/imroc/req/v3"
	tusd "github.com/tus/tusd/v2/pkg/handler"
	s3store "github.com/tus/tusd/v2/pkg/s3store"
	"go.uber.org/zap"
	"io"
	"lukechampine.com/blake3"
	"time"
)

var (
	_ interfaces.StorageService = (*StorageServiceImpl)(nil)
)

type StorageServiceImpl struct {
	portal   interfaces.Portal
	httpApi  *req.Client
	tus      *tusd.Handler
	tusStore tusd.DataStore
}

func (s *StorageServiceImpl) Tus() *tusd.Handler {
	return s.tus
}

func (s *StorageServiceImpl) Start() error {
	return nil
}

func (s *StorageServiceImpl) Portal() interfaces.Portal {
	return s.portal
}

func NewStorageService(portal interfaces.Portal) interfaces.StorageService {
	return &StorageServiceImpl{
		portal:  portal,
		httpApi: nil,
	}
}

func (s StorageServiceImpl) PutFileSmall(file io.ReadSeeker, bucket string, generateProof bool) ([]byte, error) {
	hash, err := s.GetHashSmall(file)
	hashStr, err := encoding.NewMultihash(s.getPrefixedHash(hash)).ToBase64Url()
	if err != nil {
		return nil, err
	}

	_, err = file.Seek(0, io.SeekStart)
	if err != nil {
		return nil, err
	}

	err = s.createBucketIfNotExists(bucket)
	if err != nil {
		return nil, err
	}

	resp, err := s.httpApi.R().
		SetPathParam("path", hashStr).
		SetQueryParam("bucket", bucket).
		SetBody(file).Put("/api/worker/objects/{path}")
	if err != nil {
		return nil, err
	}

	if resp.IsError() {
		if resp.Error() != nil {
			return nil, resp.Error().(error)
		}

		return nil, errors.New(resp.String())

	}

	return hash[:], nil
}
func (s StorageServiceImpl) PutFile(file io.Reader, bucket string, hash []byte) error {
	hashStr, err := encoding.NewMultihash(s.getPrefixedHash(hash)).ToBase64Url()
	err = s.createBucketIfNotExists(bucket)
	if err != nil {
		return err
	}

	resp, err := s.httpApi.R().
		SetPathParam("path", hashStr).
		SetQueryParam("bucket", bucket).
		SetBody(file).Put("/api/worker/objects/{path}")
	if err != nil {
		return err
	}

	if resp.IsError() {
		if resp.Error() != nil {
			return resp.Error().(error)
		}

		return errors.New(resp.String())

	}

	return nil
}

func (s *StorageServiceImpl) BuildUploadBufferTus(basePath string, preUploadCb interfaces.TusPreUploadCreateCallback, preFinishCb interfaces.TusPreFinishResponseCallback) (*tusd.Handler, tusd.DataStore, *s3.Client, error) {
	customResolver := aws.EndpointResolverWithOptionsFunc(func(service, region string, options ...interface{}) (aws.Endpoint, error) {
		if service == s3.ServiceID {
			return aws.Endpoint{
				URL:           s.portal.Config().GetString("core.storage.s3.endpoint"),
				SigningRegion: s.portal.Config().GetString("core.storage.s3.region"),
			}, nil
		}
		return aws.Endpoint{}, &aws.EndpointNotFoundError{}
	})

	cfg, err := config.LoadDefaultConfig(context.TODO(),
		config.WithRegion("us-east-1"),
		config.WithCredentialsProvider(credentials.NewStaticCredentialsProvider(
			s.portal.Config().GetString("core.storage.s3.accessKey"),
			s.portal.Config().GetString("core.storage.s3.secretKey"),
			"",
		)),
		config.WithEndpointResolverWithOptions(customResolver),
	)
	if err != nil {
		return nil, nil, nil, nil
	}

	s3Client := s3.NewFromConfig(cfg)

	store := s3store.New(s.portal.Config().GetString("core.storage.s3.bufferBucket"), s3Client)

	locker := NewMySQLLocker(s)

	composer := tusd.NewStoreComposer()
	store.UseIn(composer)
	composer.UseLocker(locker)

	handler, err := tusd.NewHandler(tusd.Config{
		BasePath:                basePath,
		StoreComposer:           composer,
		DisableDownload:         true,
		NotifyCompleteUploads:   true,
		NotifyTerminatedUploads: true,
		NotifyCreatedUploads:    true,
		PreUploadCreateCallback: preUploadCb,
	})

	return handler, store, s3Client, err
}

func (s *StorageServiceImpl) Init() error {
	client := req.NewClient()

	client.SetBaseURL(s.portal.Config().GetString("core.sia.url"))
	client.SetCommonBasicAuth("", s.portal.Config().GetString("core.sia.key"))
	client.SetTimeout(24 * time.Hour)

	s.httpApi = client

	preUpload := func(hook tusd.HookEvent) (tusd.HTTPResponse, tusd.FileInfoChanges, error) {
		blankResp := tusd.HTTPResponse{}
		blankChanges := tusd.FileInfoChanges{}

		hash, ok := hook.Upload.MetaData["hash"]
		if !ok {
			return blankResp, blankChanges, errors.New("missing hash")
		}

		decodedHash, err := encoding.MultihashFromBase64Url(hash)

		if err != nil {
			return blankResp, blankChanges, err
		}

		exists, _ := s.FileExists(decodedHash.HashBytes())

		if exists {
			return blankResp, blankChanges, errors.New("file already exists")
		}

		exists, _ = s.TusUploadExists(decodedHash.HashBytes())

		if exists {
			return blankResp, blankChanges, errors.New("file is already being uploaded")
		}

		return blankResp, blankChanges, nil
	}

	tus, store, err := s.BuildUploadBufferTus("/s5/upload/tus", preUpload, nil)

	if err != nil {
		return err
	}

	s.tus = tus
	s.tusStore = store

	s.portal.CronService().RegisterService(s)

	go s.tusWorker()

	return nil
}
func (s *StorageServiceImpl) LoadInitialTasks(cron interfaces.CronService) error {
	return nil
}

func (s *StorageServiceImpl) createBucketIfNotExists(bucket string) error {
	resp, err := s.httpApi.R().
		SetPathParam("bucket", bucket).
		Get("/api/bus/bucket/{bucket}")

	if err != nil {
		return err
	}

	if resp.StatusCode != 404 {
		if resp.IsError() && resp.Error() != nil {
			return resp.Error().(error)
		}
	} else {
		resp, err := s.httpApi.R().
			SetBody(map[string]string{
				"name": bucket,
			}).
			Post("/api/bus/buckets")
		if err != nil {
			return err
		}

		if resp.IsError() && resp.Error() != nil {
			return resp.Error().(error)
		}
	}

	return nil
}

func (s *StorageServiceImpl) FileExists(hash []byte) (bool, models.Upload) {
	hashStr := hex.EncodeToString(hash)

	var upload models.Upload
	result := s.portal.Database().Model(&models.Upload{}).Where(&models.Upload{Hash: hashStr}).First(&upload)

	return result.RowsAffected > 0, upload
}

func (s *StorageServiceImpl) GetHashSmall(file io.ReadSeeker) ([]byte, error) {
	buf := bytes.NewBuffer(nil)

	_, err := io.Copy(buf, file)
	if err != nil {
		return nil, err
	}

	hash := blake3.Sum256(buf.Bytes())

	return hash[:], nil
}
func (s *StorageServiceImpl) GetHash(file io.Reader) ([]byte, int64, error) {
	hasher := blake3.New(64, nil)

	totalBytes, err := io.Copy(hasher, file)

	if err != nil {
		return nil, 0, err
	}

	hash := hasher.Sum(nil)

	return hash[:32], totalBytes, nil
}

func (s *StorageServiceImpl) CreateUpload(hash []byte, uploaderID uint, uploaderIP string, size uint64, protocol string) (*models.Upload, error) {
	hashStr := hex.EncodeToString(hash)

	upload := &models.Upload{
		Hash:       hashStr,
		UserID:     uploaderID,
		UploaderIP: uploaderIP,
		Protocol:   protocol,
		Size:       size,
	}

	result := s.portal.Database().Create(upload)

	if result.Error != nil {
		return nil, result.Error
	}

	return upload, nil
}
func (s *StorageServiceImpl) tusWorker() {

	for {
		select {
		case info := <-s.tus.CreatedUploads:
			hash, ok := info.Upload.MetaData["hash"]
			errorResponse := tusd.HTTPResponse{StatusCode: 400, Header: nil}
			if !ok {
				s.portal.Logger().Error("Missing hash in metadata")
				continue
			}

			uploaderID, ok := info.Context.Value(middleware.S5AuthUserIDKey).(uint64)
			if !ok {
				errorResponse.Body = "Missing user id in context"
				info.Upload.StopUpload(errorResponse)
				s.portal.Logger().Error("Missing user id in context")
				continue
			}

			uploaderIP := info.HTTPRequest.RemoteAddr

			decodedHash, err := encoding.MultihashFromBase64Url(hash)

			if err != nil {
				errorResponse.Body = "Could not decode hash"
				info.Upload.StopUpload(errorResponse)
				s.portal.Logger().Error("Could not decode hash", zap.Error(err))
				continue
			}

			_, err = s.CreateTusUpload(decodedHash.HashBytes(), info.Upload.ID, uint(uploaderID), uploaderIP, info.Context.Value("protocol").(string))
			if err != nil {
				errorResponse.Body = "Could not create tus upload"
				info.Upload.StopUpload(errorResponse)
				s.portal.Logger().Error("Could not create tus upload", zap.Error(err))
				continue
			}
		case info := <-s.tus.UploadProgress:
			err := s.TusUploadProgress(info.Upload.ID)
			if err != nil {
				s.portal.Logger().Error("Could not update tus upload", zap.Error(err))
				continue
			}
		case info := <-s.tus.TerminatedUploads:
			err := s.DeleteTusUpload(info.Upload.ID)
			if err != nil {
				s.portal.Logger().Error("Could not delete tus upload", zap.Error(err))
				continue
			}

		case info := <-s.tus.CompleteUploads:
			if !(!info.Upload.SizeIsDeferred && info.Upload.Offset == info.Upload.Size) {
				continue
			}
			err := s.TusUploadCompleted(info.Upload.ID)
			if err != nil {
				s.portal.Logger().Error("Could not complete tus upload", zap.Error(err))
				continue
			}
			err = s.ScheduleTusUpload(info.Upload.ID, 0)
			if err != nil {
				s.portal.Logger().Error("Could not schedule tus upload", zap.Error(err))
				continue
			}

		}
	}
}

func (s *StorageServiceImpl) TusUploadExists(hash []byte) (bool, models.TusUpload) {
	hashStr := hex.EncodeToString(hash)

	var upload models.TusUpload
	result := s.portal.Database().Model(&models.TusUpload{}).Where(&models.TusUpload{Hash: hashStr}).First(&upload)

	return result.RowsAffected > 0, upload
}

func (s *StorageServiceImpl) CreateTusUpload(hash []byte, uploadID string, uploaderID uint, uploaderIP string, protocol string) (*models.TusUpload, error) {
	hashStr := hex.EncodeToString(hash)

	upload := &models.TusUpload{
		Hash:       hashStr,
		UploadID:   uploadID,
		UploaderID: uploaderID,
		UploaderIP: uploaderIP,
		Uploader:   models.User{},
		Protocol:   protocol,
	}

	result := s.portal.Database().Create(upload)

	if result.Error != nil {
		return nil, result.Error
	}

	return upload, nil
}
func (s *StorageServiceImpl) TusUploadProgress(uploadID string) error {

	find := &models.TusUpload{UploadID: uploadID}

	var upload models.TusUpload
	result := s.portal.Database().Model(&models.TusUpload{}).Where(find).First(&upload)

	if result.RowsAffected == 0 {
		return errors.New("upload not found")
	}

	result = s.portal.Database().Model(&models.TusUpload{}).Where(find).Update("updated_at", time.Now())

	if result.Error != nil {
		return result.Error
	}

	return nil
}
func (s *StorageServiceImpl) TusUploadCompleted(uploadID string) error {

	find := &models.TusUpload{UploadID: uploadID}

	var upload models.TusUpload
	result := s.portal.Database().Model(&models.TusUpload{}).Where(find).First(&upload)

	if result.RowsAffected == 0 {
		return errors.New("upload not found")
	}

	result = s.portal.Database().Model(&models.TusUpload{}).Where(find).Update("completed", true)

	return nil
}
func (s *StorageServiceImpl) DeleteTusUpload(uploadID string) error {
	result := s.portal.Database().Where(&models.TusUpload{UploadID: uploadID}).Delete(&models.TusUpload{})

	if result.Error != nil {
		return result.Error
	}

	return nil
}

func (s *StorageServiceImpl) ScheduleTusUpload(uploadID string, attempt int) error {
	find := &models.TusUpload{UploadID: uploadID}

	var upload models.TusUpload
	result := s.portal.Database().Model(&models.TusUpload{}).Where(find).First(&upload)

	if result.RowsAffected == 0 {
		return errors.New("upload not found")
	}

	job, task := s.buildNewTusUploadTask(&upload)

	if attempt > 0 {
		job = gocron.OneTimeJob(gocron.OneTimeJobStartDateTime(time.Now().Add(time.Duration(attempt) * time.Minute)))
	}

	_, err := s.portal.Cron().NewJob(job, task, gocron.WithEventListeners(gocron.AfterJobRunsWithError(func(jobID uuid.UUID, jobName string, err error) {
		s.portal.Logger().Error("Error running job", zap.Error(err))
		err = s.ScheduleTusUpload(uploadID, attempt+1)
		if err != nil {
			s.portal.Logger().Error("Error rescheduling job", zap.Error(err))
		}
	}),
		gocron.AfterJobRuns(func(jobID uuid.UUID, jobName string) {
			s.portal.Logger().Info("Job finished", zap.String("jobName", jobName), zap.String("uploadID", uploadID))
			err := s.DeleteTusUpload(uploadID)
			if err != nil {
				s.portal.Logger().Error("Error deleting tus upload", zap.Error(err))
			}
		})))

	if err != nil {
		return err
	}
	return nil
}

func (s *StorageServiceImpl) buildNewTusUploadTask(upload *models.TusUpload) (job gocron.JobDefinition, task gocron.Task) {
	job = gocron.OneTimeJob(gocron.OneTimeJobStartImmediately())

	task = gocron.NewTask(
		func(upload *models.TusUpload) error {
			ctx := context.Background()
			tusUpload, err := s.tusStore.GetUpload(ctx, upload.UploadID)
			if err != nil {
				s.portal.Logger().Error("Could not get upload", zap.Error(err))
				return err
			}

			reader, err := tusUpload.GetReader(ctx)
			if err != nil {
				s.portal.Logger().Error("Could not get tus file", zap.Error(err))
				return err
			}

			hash, byteCount, err := s.GetHash(reader)

			if err != nil {
				s.portal.Logger().Error("Could not compute hash", zap.Error(err))
				return err
			}

			dbHash, err := hex.DecodeString(upload.Hash)

			if err != nil {
				s.portal.Logger().Error("Could not decode hash", zap.Error(err))
				return err
			}

			if !bytes.Equal(hash, dbHash) {
				s.portal.Logger().Error("Hashes do not match", zap.Any("upload", upload), zap.Any("hash", hash), zap.Any("dbHash", dbHash))
				return err
			}

			reader, err = tusUpload.GetReader(ctx)
			if err != nil {
				s.portal.Logger().Error("Could not get tus file", zap.Error(err))
				return err
			}

			err = s.PutFile(reader, upload.Protocol, dbHash)

			if err != nil {
				s.portal.Logger().Error("Could not upload file", zap.Error(err))
				return err
			}

			info, err := tusUpload.GetInfo(ctx)
			if err != nil {
				s.portal.Logger().Error("Could not get upload info", zap.Error(err))
				return err
			}

			_, err = s.CreateUpload(dbHash, upload.UploaderID, upload.UploaderIP, uint64(byteCount), upload.Protocol)
			if err != nil {
				s.portal.Logger().Error("Could not create upload", zap.Error(err))
				return err
			}

			return nil
		}, upload)

	return job, task
}

func (s *StorageServiceImpl) getPrefixedHash(hash []byte) []byte {
	return append([]byte{byte(types.HashTypeBlake3)}, hash...)
}