package main

import "log"
import "io/ioutil"
import "github.com/dgraph-io/badger"

// SteemDataStore is the object with which the rest of this tool interacts
type SteemDataStore struct {
	kv KeyValueStorer
}

func NewSteemDataStore(dir string) *SteemDataStore {
	self := new(SteemDataStore)
	self.kv = NewBadgerKeyValueStore(dir)
	return self
}

func (self *SteemDataStore) StoreBlockOps(blockNum int, blockOps []byte) {
	panic("not implemented")
}

// KeyValueStorer is an interface for the backend kv store used by
// SteemDataStore
// it could be fs, badgerdb, whatever

type KeyValueStorer interface {
	Open(string)
	Get(*string) (*string, error)
	Put(*string, *string) error
	Close()
}

// BadgerKeyValueStore is an object that conforms to KeyValueStorer for use
// by SteemDataStore to persist Steem data

type BadgerKeyValueStore struct {
	db *badger.DB
}

func NewBadgerKeyValueStore(dir string) *BadgerKeyValueStore {
	kv := new(BadgerKeyValueStore)
	kv.Open(dir)
	return kv
}

func (kv *BadgerKeyValueStore) Open(dir string) {
	dir, err := ioutil.TempDir("", "badger")
	if err != nil {
		log.Fatal(err)
	}

	opts := badger.DefaultOptions
	opts.Dir = dir
	opts.ValueDir = dir
	kv.db, err = badger.Open(opts)
	if err != nil {
		log.Fatal(err)
	}
}

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

func (kv *BadgerKeyValueStore) Put(key *string, value *string) error {
	txn := kv.db.NewTransaction(true) // Read-write txn
	err := txn.Set([]byte(*key), []byte(*value))
	if err != nil {
		log.Fatal(err)
	}
	err = txn.Commit(nil)
	if err != nil {
		log.Fatal(err)
	}
	return nil
}

func (kv *BadgerKeyValueStore) Get(key *string) (*string, error) {
	txn := kv.db.NewTransaction(true) // Read-write txn
	item, err := txn.Get([]byte(*key))
	if err != nil {
		return nil, err
	}

	val, err := item.ValueCopy(nil)
	if err != nil {
		return nil, err
	}
	s := string(val)
	return &s, nil
}