package session

import (
	"bytes"
	"encoding/gob"
	"log/slog"

	"go.etcd.io/bbolt"
)

func NewBoltStore(db *bbolt.DB, bucketName []byte) Store {
	return &BoltStore{
		db:         db,
		bucketName: bucketName,
	}
}

type BoltStore struct {
	db         *bbolt.DB
	bucketName []byte
}

func (s *BoltStore) Load(sessionID string) Values {
	v := Values{}
	err := s.db.View(func(tx *bbolt.Tx) error {
		bucket := tx.Bucket(s.bucketName)
		if bucket == nil {
			// no bucket -- normal situation
			return nil
		}
		vb := bucket.Get([]byte(sessionID))
		if vb == nil {
			// no session -- no error
			return nil
		}
		rdr := bytes.NewBuffer(vb)

		return gob.NewDecoder(rdr).Decode(&v)
	})
	if err != nil {
		slog.Warn("failed load session", slog.Any("error", err))
	}
	return v
}

func (s *BoltStore) Save(sessionID string, value Values) error {
	return s.db.Update(func(tx *bbolt.Tx) error {
		bucket, err := tx.CreateBucketIfNotExists(s.bucketName)
		if err != nil {
			return err
		}
		wrt := bytes.NewBuffer([]byte{})
		if err := gob.NewEncoder(wrt).Encode(value); err != nil {
			return err
		}

		return bucket.Put([]byte(sessionID), wrt.Bytes())
	})
}

func (s *BoltStore) Remove(sessionID string) error {
	return s.db.Update(func(tx *bbolt.Tx) error {
		bucket, err := tx.CreateBucketIfNotExists(s.bucketName)
		if err != nil {
			return err
		}

		return bucket.Delete([]byte(sessionID))
	})
}