package consensusstatestore

import (
	"github.com/kaspanet/kaspad/domain/consensus/database"
	"github.com/kaspanet/kaspad/domain/consensus/model"
	"github.com/pkg/errors"
)

var importingPruningPointUTXOSetKey = database.MakeBucket(nil).Key([]byte("importing-pruning-point-utxo-set"))

func (css *consensusStateStore) StartImportingPruningPointUTXOSet(dbContext model.DBWriter) error {
	return dbContext.Put(importingPruningPointUTXOSetKey, []byte{0})
}

func (css *consensusStateStore) HadStartedImportingPruningPointUTXOSet(dbContext model.DBWriter) (bool, error) {
	return dbContext.Has(importingPruningPointUTXOSetKey)
}

func (css *consensusStateStore) FinishImportingPruningPointUTXOSet(dbContext model.DBWriter) error {
	return dbContext.Delete(importingPruningPointUTXOSetKey)
}

func (css *consensusStateStore) ImportPruningPointUTXOSetIntoVirtualUTXOSet(dbContext model.DBWriter,
	pruningPointUTXOSetIterator model.ReadOnlyUTXOSetIterator) error {

	if css.virtualUTXODiffStaging != nil {
		return errors.New("cannot import virtual UTXO set while virtual UTXO diff is staged")
	}

	hadStartedImportingPruningPointUTXOSet, err := css.HadStartedImportingPruningPointUTXOSet(dbContext)
	if err != nil {
		return err
	}
	if !hadStartedImportingPruningPointUTXOSet {
		return errors.New("cannot import pruning point UTXO set " +
			"without calling StartImportingPruningPointUTXOSet first")
	}

	// Clear the cache
	css.virtualUTXOSetCache.Clear()

	// Delete all the old UTXOs from the database
	deleteCursor, err := dbContext.Cursor(utxoSetBucket)
	if err != nil {
		return err
	}
	for ok := deleteCursor.First(); ok; ok = deleteCursor.Next() {
		key, err := deleteCursor.Key()
		if err != nil {
			return err
		}
		err = dbContext.Delete(key)
		if err != nil {
			return err
		}
	}

	// Insert all the new UTXOs into the database
	for ok := pruningPointUTXOSetIterator.First(); ok; ok = pruningPointUTXOSetIterator.Next() {
		outpoint, entry, err := pruningPointUTXOSetIterator.Get()
		if err != nil {
			return err
		}

		key, err := utxoKey(outpoint)
		if err != nil {
			return err
		}
		serializedUTXOEntry, err := serializeUTXOEntry(entry)
		if err != nil {
			return err
		}

		err = dbContext.Put(key, serializedUTXOEntry)
		if err != nil {
			return err
		}
	}

	return nil
}