package caches

import (
	"github.com/TeaOSLab/EdgeNode/internal/remotelogs"
	"os"
)

func MigrateSQLiteFileListDir(sqliteDir string, kvDir string) error {
	if len(sqliteDir) == 0 || len(kvDir) == 0 {
		return nil
	}

	_, err := os.Stat(sqliteDir)
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return err
	}

	remotelogs.Println("CACHE", "migrating sqlite indexes from '"+sqliteDir+"' to '"+kvDir+"' ...")

	src := NewSQLiteFileList(sqliteDir).(*SQLiteFileList)
	err = src.Init()
	if err != nil {
		return err
	}
	defer func() {
		_ = src.Close()
	}()

	dst := NewKVFileList(kvDir)
	err = dst.Init()
	if err != nil {
		return err
	}
	defer func() {
		_ = dst.Close()
	}()

	err = dst.CleanAll()
	if err != nil {
		return err
	}

	for _, db := range src.dbList {
		if db == nil {
			continue
		}

		var lastId int64
		for {
			hashes, maxId, listErr := db.ListHashes(lastId)
			if listErr != nil {
				return listErr
			}
			if len(hashes) == 0 {
				break
			}

			for _, hash := range hashes {
				item, readErr := db.ReadItem(hash)
				if readErr != nil {
					return readErr
				}
				if item == nil {
					continue
				}

				addErr := dst.Add(hash, item)
				if addErr != nil {
					return addErr
				}
			}

			lastId = maxId
		}
	}

	for _, store := range dst.stores {
		if store != nil && store.rawStore != nil {
			err = store.rawStore.Flush()
			if err != nil {
				return err
			}
		}
	}

	err = os.RemoveAll(sqliteDir)
	if err != nil {
		return err
	}

	remotelogs.Println("CACHE", "migrated sqlite indexes to pebble")
	return nil
}