package database

import (
	"errors"
	"os"
	"strconv"

	"go.etcd.io/bbolt"
)

var (
	stonelandBucket = []byte("stoneland")
	stonesKey       = []byte("stones")
)

type Database struct {
	db *bbolt.DB
}

func New(dbPath string) (*Database, error) {
	db, err := bbolt.Open(dbPath, os.ModePerm, bbolt.DefaultOptions)
	if err != nil {
		return nil, err
	}
	return &Database{
			db: db,
		}, db.Update(func(tx *bbolt.Tx) error {
			_, err := tx.CreateBucketIfNotExists(stonelandBucket)
			return err
		})
}

func (db *Database) Close() error {
	return db.db.Close()
}

func (db *Database) Rock(num int) error {
	return db.db.Update(func(tx *bbolt.Tx) error {
		bucket := tx.Bucket(stonelandBucket)
		if bucket == nil {
			return errors.New("bucket for stones was not created")
		}
		stones, err := db.rocks(tx)
		if err != nil {
			return err
		}
		stones += num
		return bucket.Put(stonesKey, []byte(strconv.Itoa(stones)))
	})
}

func (db *Database) Rocks() (count int, err error) {
	return count, db.db.View(func(tx *bbolt.Tx) error {
		count, err = db.rocks(tx)
		return err
	})
}

func (db *Database) rocks(tx *bbolt.Tx) (int, error) {
	bucket := tx.Bucket(stonelandBucket)
	if bucket == nil {
		return -1, errors.New("bucket for stones was not created")
	}
	stones := bucket.Get(stonesKey)
	if stones == nil {
		return 0, nil
	}
	return strconv.Atoi(string(stones))
}