package main

import (
	"bytes"
	"compress/flate"
	"encoding/gob"
	"log"
	"math/rand"
	"os"

	"github.com/tecbot/gorocksdb"
)

// CheckErrorPanic 查错误 存在就panic操作
func CheckErrorPanic(err error) {
	if err != nil {
		log.Panic(err)
	}
}

// OpenDB 打开rocksdb
func OpenDB() *gorocksdb.DB {
	bbto := gorocksdb.NewDefaultBlockBasedTableOptions()

	bbto.SetBlockCache(gorocksdb.NewLRUCache(2 << 30))
	bbto.SetCacheIndexAndFilterBlocksWithHighPriority(true)

	opts := gorocksdb.NewDefaultOptions()

	bbto.SetFilterPolicy(gorocksdb.NewBloomFilter(16))

	opts.SetBlockBasedTableFactory(bbto)
	opts.SetCreateIfMissing(true)
	opts.SetCreateIfMissingColumnFamilies(true)
	opts.SetCompression(gorocksdb.LZ4Compression)

	db, err := gorocksdb.OpenDb(opts, ".rocksdb")
	CheckErrorPanic(err)
	return db
}

var db = OpenDB()
var wopts = gorocksdb.NewDefaultWriteOptions()
var ropts = gorocksdb.NewDefaultReadOptions()

// IKeyList key list interface
type IKeyList interface {
	AppendKey(key []byte)
	GetKeyList() [][]byte
	GetLength() int
}

// SaveGobFromRocksdb save data from rocksdb keyseek
func SaveGobFromRocksdb(fname string, seekKey string, v IKeyList) {
	i := 0
	iter := db.NewIterator(ropts)
	iter.Seek([]byte(seekKey))
	for ; iter.Valid(); iter.Next() {
		i++
		// if i%1000 == 0 {
		// 	t.Error(string(iter.Key().Data()))
		// 	t.Error(string(iter.Value().Data()))

		// }
		v.AppendKey(iter.Value().Data())
	}
	log.Println(i)

	var keybuf = &bytes.Buffer{}

	enc := gob.NewEncoder(keybuf)
	enc.Encode(v)
	log.Println((len(keybuf.Bytes())))

	f, err := os.OpenFile(fname, os.O_CREATE|os.O_CREATE|os.O_RDWR|os.O_TRUNC, os.ModePerm)
	CheckErrorPanic(err)

	gw, err := flate.NewWriter(f, 5)
	CheckErrorPanic(err)
	defer gw.Close()

	gw.Write(keybuf.Bytes())
}

// LoadGob load gob from file
func LoadGob(fname string, v IKeyList) {
	f, err := os.Open(fname)
	CheckErrorPanic(err)
	reader := flate.NewReader(f)
	dec := gob.NewDecoder(reader)
	dec.Decode(v)
}

// GetRandomKey get ikeylist key by random
func GetRandomKey(v IKeyList) []byte {
	return v.GetKeyList()[rand.Intn(v.GetLength())]
}