package commands

import (
	"errors"
	"path/filepath"
	"sync"

	"github.com/spf13/cobra"
	"github.com/syndtr/goleveldb/leveldb"
	"github.com/syndtr/goleveldb/leveldb/opt"
	"github.com/syndtr/goleveldb/leveldb/util"

	"github.com/cometbft/cometbft/libs/log"
)

var CompactGoLevelDBCmd = &cobra.Command{
	Use:     "experimental-compact-goleveldb",
	Aliases: []string{"experimental_compact_goleveldb"},
	Short:   "force compacts the CometBFT storage engine (only GoLevelDB supported)",
	Long: `
This is a temporary utility command that performs a force compaction on the state 
and blockstores to reduce disk space for a pruning node. This should only be run 
once the node has stopped. This command will likely be omitted in the future after
the planned refactor to the storage engine.

Currently, only GoLevelDB is supported.
	`,
	RunE: func(cmd *cobra.Command, args []string) error {
		if config.DBBackend != "goleveldb" {
			return errors.New("compaction is currently only supported with goleveldb")
		}

		compactGoLevelDBs(config.RootDir, logger)
		return nil
	},
}

func compactGoLevelDBs(rootDir string, logger log.Logger) {
	dbNames := []string{"state", "blockstore"}
	o := &opt.Options{
		DisableSeeksCompaction: true,
	}
	wg := sync.WaitGroup{}

	for _, dbName := range dbNames {
		dbName := dbName
		wg.Add(1)
		go func() {
			defer wg.Done()
			dbPath := filepath.Join(rootDir, "data", dbName+".db")
			store, err := leveldb.OpenFile(dbPath, o)
			if err != nil {
				logger.Error("failed to initialize cometbft db", "path", dbPath, "err", err)
				return
			}
			defer store.Close()

			logger.Info("starting compaction...", "db", dbPath)

			err = store.CompactRange(util.Range{Start: nil, Limit: nil})
			if err != nil {
				logger.Error("failed to compact cometbft db", "path", dbPath, "err", err)
			}
		}()
	}
	wg.Wait()
}