package s3api

import (
	"context"
	"errors"
	"fmt"
	"strings"

	"github.com/seaweedfs/seaweedfs/weed/filer"
	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
	"github.com/seaweedfs/seaweedfs/weed/s3api/s3_constants"
	"github.com/seaweedfs/seaweedfs/weed/util"
)

func (s3a *S3ApiServer) mkdir(parentDirectoryPath string, dirName string, fn func(entry *filer_pb.Entry)) error {

	return filer_pb.Mkdir(context.Background(), s3a, parentDirectoryPath, dirName, fn)

}

func (s3a *S3ApiServer) mkFile(parentDirectoryPath string, fileName string, chunks []*filer_pb.FileChunk, fn func(entry *filer_pb.Entry)) error {

	return filer_pb.MkFile(context.Background(), s3a, parentDirectoryPath, fileName, chunks, fn)

}

func (s3a *S3ApiServer) list(parentDirectoryPath, prefix, startFrom string, inclusive bool, limit uint32) (entries []*filer_pb.Entry, isLast bool, err error) {

	err = filer_pb.List(context.Background(), s3a, parentDirectoryPath, prefix, func(entry *filer_pb.Entry, isLastEntry bool) error {
		entries = append(entries, entry)
		if isLastEntry {
			isLast = true
		}
		return nil
	}, startFrom, inclusive, limit)

	if len(entries) == 0 {
		isLast = true
	}

	return

}

func (s3a *S3ApiServer) rm(parentDirectoryPath, entryName string, isDeleteData, isRecursive bool) error {

	return s3a.WithFilerClient(false, func(client filer_pb.SeaweedFilerClient) error {

		err := doDeleteEntry(client, parentDirectoryPath, entryName, isDeleteData, isRecursive)
		if err != nil {
			return err
		}

		return nil
	})

}

func doDeleteEntry(client filer_pb.SeaweedFilerClient, parentDirectoryPath string, entryName string, isDeleteData bool, isRecursive bool) error {
	request := &filer_pb.DeleteEntryRequest{
		Directory:            parentDirectoryPath,
		Name:                 entryName,
		IsDeleteData:         isDeleteData,
		IsRecursive:          isRecursive,
		IgnoreRecursiveError: true,
	}

	glog.V(1).Infof("delete entry %v/%v: %v", parentDirectoryPath, entryName, request)
	if resp, err := client.DeleteEntry(context.Background(), request); err != nil {
		glog.V(0).Infof("delete entry %v: %v", request, err)
		return fmt.Errorf("delete entry %s/%s: %v", parentDirectoryPath, entryName, err)
	} else {
		if resp.Error != "" {
			return fmt.Errorf("delete entry %s/%s: %v", parentDirectoryPath, entryName, resp.Error)
		}
	}
	return nil
}

func (s3a *S3ApiServer) exists(parentDirectoryPath string, entryName string, isDirectory bool) (exists bool, err error) {

	return filer_pb.Exists(context.Background(), s3a, parentDirectoryPath, entryName, isDirectory)

}

func (s3a *S3ApiServer) touch(parentDirectoryPath string, entryName string, entry *filer_pb.Entry) (err error) {

	return filer_pb.Touch(context.Background(), s3a, parentDirectoryPath, entryName, entry)

}

func (s3a *S3ApiServer) getEntry(parentDirectoryPath, entryName string) (entry *filer_pb.Entry, err error) {
	fullPath := util.NewFullPath(parentDirectoryPath, entryName)
	return filer_pb.GetEntry(context.Background(), s3a, fullPath)
}

func (s3a *S3ApiServer) updateEntry(parentDirectoryPath string, newEntry *filer_pb.Entry) error {
	updateEntryRequest := &filer_pb.UpdateEntryRequest{
		Directory: parentDirectoryPath,
		Entry:     newEntry,
	}

	err := s3a.WithFilerClient(false, func(client filer_pb.SeaweedFilerClient) error {
		err := filer_pb.UpdateEntry(context.Background(), client, updateEntryRequest)
		if err != nil {
			return err
		}
		return nil
	})
	return err
}

func (s3a *S3ApiServer) updateEntriesTTL(parentDirectoryPath string, ttlSec int32) error {
	// Use iterative approach with a queue to avoid recursive WithFilerClient calls
	// which would create a new connection for each subdirectory
	return s3a.WithFilerClient(false, func(client filer_pb.SeaweedFilerClient) error {
		ctx := context.Background()
		var updateErrors []error
		dirsToProcess := []string{parentDirectoryPath}

		for len(dirsToProcess) > 0 {
			dir := dirsToProcess[0]
			dirsToProcess = dirsToProcess[1:]

			// Process directory in paginated batches
			if err := s3a.processDirectoryTTL(ctx, client, dir, ttlSec, &dirsToProcess, &updateErrors); err != nil {
				updateErrors = append(updateErrors, err)
			}
		}

		if len(updateErrors) > 0 {
			return errors.Join(updateErrors...)
		}
		return nil
	})
}

// processDirectoryTTL processes a single directory in paginated batches
func (s3a *S3ApiServer) processDirectoryTTL(ctx context.Context, client filer_pb.SeaweedFilerClient, 
	dir string, ttlSec int32, dirsToProcess *[]string, updateErrors *[]error) error {
	
	const batchSize = filer.PaginationSize
	startFrom := ""

	for {
		lastEntryName, entryCount, err := s3a.processTTLBatch(ctx, client, dir, ttlSec, startFrom, batchSize, dirsToProcess, updateErrors)
		if err != nil {
			return fmt.Errorf("list entries in %s: %w", dir, err)
		}

		// If we got fewer entries than batch size, we've reached the end
		if entryCount < batchSize {
			break
		}
		startFrom = lastEntryName
	}
	return nil
}

// processTTLBatch processes a single batch of entries
func (s3a *S3ApiServer) processTTLBatch(ctx context.Context, client filer_pb.SeaweedFilerClient,
	dir string, ttlSec int32, startFrom string, batchSize uint32,
	dirsToProcess *[]string, updateErrors *[]error) (lastEntry string, count int, err error) {

	err = filer_pb.SeaweedList(ctx, client, dir, "", func(entry *filer_pb.Entry, isLast bool) error {
		lastEntry = entry.Name
		count++

		if entry.IsDirectory {
			*dirsToProcess = append(*dirsToProcess, string(util.NewFullPath(dir, entry.Name)))
			return nil
		}

		// Update entry TTL and S3 expiry flag
		if updateErr := s3a.updateEntryTTL(ctx, client, dir, entry, ttlSec); updateErr != nil {
			*updateErrors = append(*updateErrors, updateErr)
		}
		return nil
	}, startFrom, false, batchSize)

	return lastEntry, count, err
}

// updateEntryTTL updates a single entry's TTL and S3 expiry flag
func (s3a *S3ApiServer) updateEntryTTL(ctx context.Context, client filer_pb.SeaweedFilerClient,
	dir string, entry *filer_pb.Entry, ttlSec int32) error {

	if entry.Attributes == nil {
		entry.Attributes = &filer_pb.FuseAttributes{}
	}
	if entry.Extended == nil {
		entry.Extended = make(map[string][]byte)
	}

	// Check if both TTL and S3 expiry flag are already set correctly
	flagAlreadySet := string(entry.Extended[s3_constants.SeaweedFSExpiresS3]) == "true"
	if entry.Attributes.TtlSec == ttlSec && flagAlreadySet {
		return nil // Already up to date
	}

	// Set the S3 expiry flag
	entry.Extended[s3_constants.SeaweedFSExpiresS3] = []byte("true")
	// Update TTL if needed
	if entry.Attributes.TtlSec != ttlSec {
		entry.Attributes.TtlSec = ttlSec
	}

	if err := filer_pb.UpdateEntry(ctx, client, &filer_pb.UpdateEntryRequest{
		Directory: dir,
		Entry:     entry,
	}); err != nil {
		return fmt.Errorf("file %s/%s: %w", dir, entry.Name, err)
	}
	return nil
}

func (s3a *S3ApiServer) getCollectionName(bucket string) string {
	if s3a.option.FilerGroup != "" {
		return fmt.Sprintf("%s_%s", s3a.option.FilerGroup, bucket)
	}
	return bucket
}

func objectKey(key *string) *string {
	if strings.HasPrefix(*key, "/") {
		t := (*key)[1:]
		return &t
	}
	return key
}