type Backend interface {
	AddLocal([]byte) ([]byte, error)
	Etherbase() (common.Address, error)
	NetVersion() (uint64, error)
	Subscribe(func(*remote.SubscribeReply)) error
}

type BucketConfigsFunc func(defaultBuckets dbutils.BucketsCfg) dbutils.BucketsCfg

type BucketMigrator interface {
	DropBucket(string) error
	CreateBucket(string) error
	ExistsBucket(string) bool
	ClearBucket(string) error
	ExistingBuckets() ([]string, error)
}

type BucketsMigrator interface {
	BucketExists(bucket string) (bool, error) // makes them empty
	ClearBuckets(buckets ...string) error     // makes them empty
	DropBuckets(buckets ...string) error      // drops them, use of them after drop will panic
}

type Closer interface {
	Close()
}

type Cursor interface {
	First() ([]byte, []byte, error)               // First - position at first key/data item
	Seek(seek []byte) ([]byte, []byte, error)     // Seek - position at first key greater than or equal to specified key
	SeekExact(key []byte) ([]byte, []byte, error) // SeekExact - position at first key greater than or equal to specified key
	Next() ([]byte, []byte, error)                // Next - position at next key/value (can iterate over DupSort key/values automatically)
	Prev() ([]byte, []byte, error)                // Prev - position at previous key
	Last() ([]byte, []byte, error)                // Last - position at last key and last possible value
	Current() ([]byte, []byte, error)             // Current - return key/data at current cursor position

	Put(k, v []byte) error           // Put - based on order
	Append(k []byte, v []byte) error // Append - append the given key/data pair to the end of the database. This option allows fast bulk loading when keys are already known to be in the correct order.
	Delete(k, v []byte) error        // Delete - short version of SeekExact+DeleteCurrent or SeekBothExact+DeleteCurrent

	// DeleteCurrent This function deletes the key/data pair to which the cursor refers.
	// This does not invalidate the cursor, so operations such as MDB_NEXT
	// can still be used on it.
	// Both MDB_NEXT and MDB_GET_CURRENT will return the same record after
	// this operation.
	DeleteCurrent() error

	// PutNoOverwrite(key, value []byte) error
	Reserve(k []byte, n int) ([]byte, error)

	// PutCurrent - replace the item at the current cursor position.
	PutCurrent(key, value []byte) error

	Count() (uint64, error) // Count - fast way to calculate amount of keys in bucket. It counts all keys even if Prefix was set.

	Close()
}

type CursorDupSort interface {
	Cursor

	// SeekBothExact -
	// second parameter can be nil only if searched key has no duplicates, or return error
	SeekBothExact(key, value []byte) ([]byte, []byte, error)
	SeekBothRange(key, value []byte) ([]byte, []byte, error)
	FirstDup() ([]byte, error)          // FirstDup - position at first data item of current key
	NextDup() ([]byte, []byte, error)   // NextDup - position at next data item of current key
	NextNoDup() ([]byte, []byte, error) // NextNoDup - position at first data item of next key
	LastDup(k []byte) ([]byte, error)   // LastDup - position at last data item of current key

	CountDuplicates() (uint64, error)  // CountDuplicates - number of duplicates for the current key
	DeleteCurrentDuplicates() error    // DeleteCurrentDuplicates - deletes all of the data items for the current key
	AppendDup(key, value []byte) error // AppendDup - same as Append, but for sorted dup data

}

type DBCounterStats struct {
	Put           uint64
	Get           uint64
	GetS          uint64
	GetAsOf       uint64
	Has           uint64
	Walk          uint64
	WalkAsOf      uint64
	MultiWalkAsOf uint64
	Delete        uint64
	MultiPut      uint64
}

type Database interface {
	Getter
	Putter
	Deleter
	Closer

	// MultiPut inserts or updates multiple entries.
	// Entries are passed as an array:
	// bucket0, key0, val0, bucket1, key1, val1, ...
	MultiPut(tuples ...[]byte) (uint64, error)

	// NewBatch - starts in-mem batch
	//
	// Common pattern:
	//
	// batch := db.NewBatch()
	// defer batch.Rollback()
	// ... some calculations on `batch`
	// batch.Commit()
	//
	NewBatch() DbWithPendingMutations                                         //
	Begin(ctx context.Context, flags TxFlags) (DbWithPendingMutations, error) // starts db transaction
	Last(bucket string) ([]byte, []byte, error)

	// IdealBatchSize defines the size of the data batches should ideally add in one write.
	IdealBatchSize() int

	Keys() ([][]byte, error)

	Append(bucket string, key, value []byte) error
	AppendDup(bucket string, key, value []byte) error
	Sequence(bucket string, amount uint64) (uint64, error)
}

type DbCopier interface {
	NewDbWithTheSameParameters() *ObjectDatabase
}

type DbProvider uint8

type DbWithPendingMutations interface {
	Database

	// Commit - commits transaction (or flush data into underlying db object in case of `mutation`)
	//
	// Common pattern:
	//
	// tx := db.Begin()
	// defer tx.Rollback()
	// ... some calculations on `tx`
	// tx.Commit()
	//
	Commit() (uint64, error)

	// CommitAndBegin - commits and starts new transaction inside same db object.
	// useful for periodical commits implementation.
	//
	// Common pattern:
	//
	// tx := db.Begin()
	// defer tx.Rollback()
	// for {
	// 		... some calculations on `tx`
	//       tx.CommitAndBegin()
	//       // defer here - is not useful, because 'tx' object is reused and first `defer` will work perfectly
	// }
	// tx.Commit()
	//
	CommitAndBegin(ctx context.Context) error
	Rollback()
	BatchSize() int

	Reserve(bucket string, key []byte, i int) ([]byte, error)
}

type Deleter interface {
	// Delete removes a single entry.
	Delete(bucket string, k, v []byte) error
}

type Getter interface {
	// Get returns the value for a given key if it's present.
	Get(bucket string, key []byte) ([]byte, error)

	// Has indicates whether a key exists in the database.
	Has(bucket string, key []byte) (bool, error)

	// Walk iterates over entries with keys greater or equal to startkey.
	// Only the keys whose first fixedbits match those of startkey are iterated over.
	// walker is called for each eligible entry.
	// If walker returns false or an error, the walk stops.
	Walk(bucket string, startkey []byte, fixedbits int, walker func(k, v []byte) (bool, error)) error
}

type GetterPutter interface {
	Getter
	Putter
}

type HasKV interface {
	KV() KV
	SetKV(kv KV)
}

type HasNetInterface interface {
	DB() Database
}

type HasStats interface {
	DiskSize(context.Context) (uint64, error) // db size
}

type HasTx interface {
	Tx() Tx
}

type KV interface {
	View(ctx context.Context, f func(tx Tx) error) error
	Update(ctx context.Context, f func(tx Tx) error) error
	Close()

	// Begin - creates transaction
	// 	tx may be discarded by .Rollback() method
	//
	// A transaction and its cursors must only be used by a single
	// 	thread (not goroutine), and a thread may only have a single transaction at a time.
	//  It happen automatically by - because this method calls runtime.LockOSThread() inside (Rollback/Commit releases it)
	//  By this reason application code can't call runtime.UnlockOSThread() - it leads to undefined behavior.
	//
	// If this `parent` is non-NULL, the new transaction
	//	will be a nested transaction, with the transaction indicated by parent
	//	as its parent. Transactions may be nested to any level. A parent
	//	transaction and its cursors may not issue any other operations than
	//	Commit and Rollback while it has active child transactions.
	Begin(ctx context.Context, flags TxFlags) (Tx, error)
	AllBuckets() dbutils.BucketsCfg

	CollectMetrics()
}

type KvData struct {
	K []byte
	V []byte
}

type LmdbCursor struct {
	// contains filtered or unexported fields
}

type LmdbDupSortCursor struct {
	*LmdbCursor
}

type LmdbKV struct {
	// contains filtered or unexported fields
}

type LmdbOpts struct {
	// contains filtered or unexported fields
}

type MinDatabase interface {
	Get(bucket string, key []byte) ([]byte, error)
	Put(bucket string, key, value []byte) error
	Delete(bucket string, k, v []byte) error
}

type MultiPutTuples [][]byte

type MutationItem struct {
	// contains filtered or unexported fields
}

type ObjectDatabase struct {
	// contains filtered or unexported fields
}

type Putter interface {
	// Put inserts or updates a single entry.
	Put(bucket string, key, value []byte) error
}

type RWCounterDecorator struct {
	Database
	DBCounterStats
}

type RemoteBackend struct {
	// contains filtered or unexported fields
}

type RemoteKV struct {
	// contains filtered or unexported fields
}

type SnapshotKV2 struct {
	// contains filtered or unexported fields
}

type StorageMode struct {
	History    bool
	Receipts   bool
	TxIndex    bool
	CallTraces bool
}

type Tx interface {
	// Cursor - creates cursor object on top of given bucket. Type of cursor - depends on bucket configuration.
	// If bucket was created with lmdb.DupSort flag, then cursor with interface CursorDupSort created
	// Otherwise - object of interface Cursor created
	//
	// Cursor, also provides a grain of magic - it can use a declarative configuration - and automatically break
	// long keys into DupSort key/values. See docs for `bucket.go:BucketConfigItem`
	Cursor(bucket string) Cursor
	CursorDupSort(bucket string) CursorDupSort // CursorDupSort - can be used if bucket has lmdb.DupSort flag
	GetOne(bucket string, key []byte) (val []byte, err error)
	HasOne(bucket string, key []byte) (bool, error)

	Commit(ctx context.Context) error // Commit all the operations of a transaction into the database.
	Rollback()                        // Rollback - abandon all the operations of the transaction instead of saving them.

	BucketSize(name string) (uint64, error)

	Comparator(bucket string) dbutils.CmpFunc
	Cmp(bucket string, a, b []byte) int
	DCmp(bucket string, a, b []byte) int

	// Allows to create a linear sequence of unique positive integers for each table.
	// Can be called for a read transaction to retrieve the current sequence value, and the increment must be zero.
	// Sequence changes become visible outside the current write transaction after it is committed, and discarded on abort.
	// Starts from 0.
	Sequence(bucket string, amount uint64) (uint64, error)

	CHandle() unsafe.Pointer // Pointer to the underlying C transaction handle (e.g. *C.MDB_txn)
}

type TxDb struct {
	// contains filtered or unexported fields
}

type TxFlags uint