package blobtree

import (
	"os"
	"path/filepath"
	"strconv"
	"strings"

	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/compression"
	"golang.org/x/sync/errgroup"
)

var Type = "blobtree"

func (b *BlobTree) Open(readOnly bool) error {
	b.cfg.readOnly = readOnly
	b.cfg.metrics.SetMode(readOnly)
	return nil
}

func (b *BlobTree) Init() error {
	if err := b.createDir(b.cfg.rootPath); err != nil {
		return err
	}

	var eg errgroup.Group
	eg.SetLimit(b.cfg.initWorkersCount)
	eg.Go(func() error {
		return b.initDir(&eg, b.cfg.rootPath, 0)
	})
	return eg.Wait()
}

func (b *BlobTree) initDir(eg *errgroup.Group, dir string, depth uint64) error {
	entities, err := os.ReadDir(dir)
	if err != nil {
		return err
	}
	for _, entity := range entities {
		if depth < b.cfg.depth && entity.IsDir() {
			eg.Go(func() error {
				return b.initDir(eg, filepath.Join(dir, entity.Name()), depth+1)
			})
			continue
		}

		if depth != b.cfg.depth {
			continue
		}

		if b.isTempFile(entity.Name()) {
			if err = os.Remove(filepath.Join(dir, entity.Name())); err != nil {
				return err
			}
			continue
		}

		idx, err := b.parseIdx(entity.Name())
		if err != nil {
			continue
		}
		b.dispatcher.Init(dir, idx)
		b.cfg.metrics.IncFilesCount()

		stat, err := os.Stat(filepath.Join(dir, entity.Name()))
		if err != nil {
			return err
		}
		if stat.Size() < int64(b.cfg.targetFileSizeBytes) {
			b.dispatcher.ReturnIdx(dir, idx)
		}
	}
	return nil
}

func (b *BlobTree) isTempFile(name string) bool {
	return strings.Contains(name, tempFileSymbols)
}

func (b *BlobTree) parseIdx(name string) (uint64, error) {
	return strconv.ParseUint(name, 16, 64)
}

func (b *BlobTree) Close() error {
	b.cfg.metrics.Close()
	return nil
}

func (b *BlobTree) Type() string { return Type }
func (b *BlobTree) Path() string { return b.cfg.rootPath }

func (b *BlobTree) SetCompressor(cc *compression.Config) {
	b.compressor = cc
}

func (b *BlobTree) Compressor() *compression.Config {
	return b.compressor
}

func (b *BlobTree) SetReportErrorFunc(_ func(string, error)) {}

func (b *BlobTree) SetParentID(parentID string) {
	b.cfg.metrics.SetParentID(parentID)
}