// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

// Package ethdb defines the interfaces for an Ethereum data store.
package olddb

import (
	"context"
	"fmt"

	"github.com/ledgerwatch/erigon-lib/kv"
	"github.com/ledgerwatch/erigon/common"
	"github.com/ledgerwatch/erigon/ethdb"
	"github.com/ledgerwatch/log/v3"
)

// ObjectDatabase - is an object-style interface of DB accessing
type ObjectDatabase struct {
	kv kv.RwDB
}

// NewObjectDatabase returns a AbstractDB wrapper.
// Deprecated
func NewObjectDatabase(kv kv.RwDB) *ObjectDatabase {
	return &ObjectDatabase{
		kv: kv,
	}
}

// Put inserts or updates a single entry.
func (db *ObjectDatabase) Put(table string, k, v []byte) error {
	err := db.kv.Update(context.Background(), func(tx kv.RwTx) error {
		return tx.Put(table, k, v)
	})
	return err
}

// Append appends a single entry to the end of the bucket.
func (db *ObjectDatabase) Append(bucket string, key []byte, value []byte) error {
	err := db.kv.Update(context.Background(), func(tx kv.RwTx) error {
		c, err := tx.RwCursor(bucket)
		if err != nil {
			return err
		}
		return c.Append(key, value)
	})
	return err
}

// AppendDup appends a single entry to the end of the bucket.
func (db *ObjectDatabase) AppendDup(bucket string, key []byte, value []byte) error {
	err := db.kv.Update(context.Background(), func(tx kv.RwTx) error {
		c, err := tx.RwCursorDupSort(bucket)
		if err != nil {
			return err
		}
		return c.AppendDup(key, value)
	})
	return err
}

func (db *ObjectDatabase) Has(bucket string, key []byte) (bool, error) {
	var has bool
	err := db.kv.View(context.Background(), func(tx kv.Tx) error {
		v, err := tx.GetOne(bucket, key)
		if err != nil {
			return err
		}
		has = v != nil
		return nil
	})
	return has, err
}

func (db *ObjectDatabase) IncrementSequence(bucket string, amount uint64) (res uint64, err error) {
	err = db.kv.Update(context.Background(), func(tx kv.RwTx) error {
		res, err = tx.IncrementSequence(bucket, amount)
		return err
	})
	return res, err
}
func (db *ObjectDatabase) ReadSequence(bucket string) (res uint64, err error) {
	err = db.kv.View(context.Background(), func(tx kv.Tx) error {
		res, err = tx.ReadSequence(bucket)
		return err
	})
	return res, err
}

// Get returns the value for a given key if it's present.
func (db *ObjectDatabase) GetOne(bucket string, key []byte) ([]byte, error) {
	var dat []byte
	err := db.kv.View(context.Background(), func(tx kv.Tx) error {
		v, err := tx.GetOne(bucket, key)
		if err != nil {
			return err
		}
		if v != nil {
			dat = make([]byte, len(v))
			copy(dat, v)
		}
		return nil
	})
	return dat, err
}

func (db *ObjectDatabase) Get(bucket string, key []byte) ([]byte, error) {
	dat, err := db.GetOne(bucket, key)
	return ethdb.GetOneWrapper(dat, err)
}

func (db *ObjectDatabase) Last(bucket string) ([]byte, []byte, error) {
	var key, value []byte
	if err := db.kv.View(context.Background(), func(tx kv.Tx) error {
		c, err := tx.Cursor(bucket)
		if err != nil {
			return err
		}
		k, v, err := c.Last()
		if err != nil {
			return err
		}
		if k != nil {
			key, value = common.CopyBytes(k), common.CopyBytes(v)
		}
		return nil
	}); err != nil {
		return nil, nil, err
	}
	return key, value, nil
}

func (db *ObjectDatabase) ForEach(bucket string, fromPrefix []byte, walker func(k, v []byte) error) error {
	return db.kv.View(context.Background(), func(tx kv.Tx) error {
		return tx.ForEach(bucket, fromPrefix, walker)
	})
}
func (db *ObjectDatabase) ForAmount(bucket string, fromPrefix []byte, amount uint32, walker func(k, v []byte) error) error {
	return db.kv.View(context.Background(), func(tx kv.Tx) error {
		return tx.ForAmount(bucket, fromPrefix, amount, walker)
	})
}

func (db *ObjectDatabase) ForPrefix(bucket string, prefix []byte, walker func(k, v []byte) error) error {
	return db.kv.View(context.Background(), func(tx kv.Tx) error {
		return tx.ForPrefix(bucket, prefix, walker)
	})
}

// Delete deletes the key from the queue and database
func (db *ObjectDatabase) Delete(table string, k []byte) error {
	// Execute the actual operation
	err := db.kv.Update(context.Background(), func(tx kv.RwTx) error {
		return tx.Delete(table, k)
	})
	return err
}

func (db *ObjectDatabase) BucketExists(name string) (bool, error) {
	exists := false
	if err := db.kv.View(context.Background(), func(tx kv.Tx) (err error) {
		migrator, ok := tx.(kv.BucketMigrator)
		if !ok {
			return fmt.Errorf("%T doesn't implement ethdb.TxMigrator interface", db.kv)
		}
		exists, err = migrator.ExistsBucket(name)
		if err != nil {
			return err
		}
		return nil
	}); err != nil {
		return false, err
	}
	return exists, nil
}

func (db *ObjectDatabase) ClearBuckets(buckets ...string) error {
	for i := range buckets {
		name := buckets[i]
		if err := db.kv.Update(context.Background(), func(tx kv.RwTx) error {
			migrator, ok := tx.(kv.BucketMigrator)
			if !ok {
				return fmt.Errorf("%T doesn't implement ethdb.TxMigrator interface", db.kv)
			}
			if err := migrator.ClearBucket(name); err != nil {
				return err
			}
			return nil
		}); err != nil {
			return err
		}
	}

	return nil
}

func (db *ObjectDatabase) DropBuckets(buckets ...string) error {
	for i := range buckets {
		name := buckets[i]
		log.Info("Dropping bucket", "name", name)
		if err := db.kv.Update(context.Background(), func(tx kv.RwTx) error {
			migrator, ok := tx.(kv.BucketMigrator)
			if !ok {
				return fmt.Errorf("%T doesn't implement ethdb.TxMigrator interface", db.kv)
			}
			if err := migrator.DropBucket(name); err != nil {
				return err
			}
			return nil
		}); err != nil {
			return err
		}
	}
	return nil
}

func (db *ObjectDatabase) Close() {
	db.kv.Close()
}

func (db *ObjectDatabase) RwKV() kv.RwDB {
	return db.kv
}

func (db *ObjectDatabase) SetRwKV(kv kv.RwDB) {
	db.kv = kv
}

func (db *ObjectDatabase) Begin(ctx context.Context, flags ethdb.TxFlags) (ethdb.DbWithPendingMutations, error) {
	batch := &TxDb{db: db}
	if err := batch.begin(ctx, flags); err != nil {
		return batch, err
	}
	return batch, nil
}