package writecache

import (
	"context"
	"errors"
	"fmt"
	"math"
	"os"
	"path/filepath"

	"git.frostfs.info/TrueCloudLab/frostfs-node/internal/logs"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/common"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/fstree"
	storagelog "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/internal/log"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/shard/mode"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client"
	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
	"github.com/cockroachdb/pebble"
	"go.uber.org/zap"
)

const dbName = "pebble"

func (c *cache) openStore(mod mode.ComponentMode) error {
	err := util.MkdirAllX(filepath.Join(c.path, dbName), os.ModePerm)
	if err != nil {
		return err
	}

	c.db, err = OpenDB(filepath.Join(c.path, dbName), mod.ReadOnly())
	if err != nil {
		return fmt.Errorf("could not open database: %w", err)
	}

	c.fsTree = fstree.New(
		fstree.WithPath(filepath.Join(c.path, "fstree")),
		fstree.WithPerm(os.ModePerm),
		fstree.WithDepth(1),
		fstree.WithDirNameLen(1),
		fstree.WithNoSync(c.noSync),
		fstree.WithFileCounter(&c.objCounters),
	)
	if err := c.fsTree.Open(mod); err != nil {
		return fmt.Errorf("could not open FSTree: %w", err)
	}
	if err := c.fsTree.Init(); err != nil {
		return fmt.Errorf("could not init FSTree: %w", err)
	}

	return nil
}

func (c *cache) deleteFromDB(key string) {
	c.dbEditLocker.Lock(key)
	defer func() {
		c.dbEditLocker.Unlock(key)
	}()
	var dataSize uint32
	dbKey := []byte(key)
	data, closer, err := c.db.Get(dbKey)
	if err == nil {
		dataSize = uint32(len(data))
		err = closer.Close()
	}
	if err != nil && !errors.Is(err, pebble.ErrNotFound) {
		c.log.Error(logs.WritecacheCantRemoveObjectsFromTheDatabase, zap.Error(err))
		return
	}
	if err := c.db.DeleteSized(dbKey, dataSize, pebble.Sync); err != nil {
		c.log.Error(logs.WritecacheCantRemoveObjectsFromTheDatabase, zap.Error(err))
		return
	}

	c.metrics.Evict(StorageTypeDB)
	storagelog.Write(c.log,
		storagelog.AddressField(key),
		storagelog.StorageTypeField(wcStorageType),
		storagelog.OpField("db DELETE"),
	)
	if dataSize > 0 {
		c.objCounters.cDB.Add(math.MaxUint64)
		c.estimateCacheSize()
	}
}

func (c *cache) deleteFromDisk(ctx context.Context, addr oid.Address) {
	_, err := c.fsTree.Delete(ctx, common.DeletePrm{Address: addr})
	if err != nil && !client.IsErrObjectNotFound(err) {
		c.log.Error(logs.WritecacheCantRemoveObjectFromWritecache, zap.Error(err))
	} else if err == nil {
		storagelog.Write(c.log,
			storagelog.AddressField(addr.EncodeToString()),
			storagelog.StorageTypeField(wcStorageType),
			storagelog.OpField("fstree DELETE"),
		)
		c.metrics.Evict(StorageTypeFSTree)
		// counter changed by fstree
		c.estimateCacheSize()
	}
}