package main

import (
	"time"

	badger "github.com/dgraph-io/badger/v3"
)

type Db struct {
	db *badger.DB
}

func NewDatabase() (*Db, error) {
	db, err := badger.Open(badger.DefaultOptions("./database"))
	if err != nil {
		return nil, err
	}
	return &Db{
		db: db,
	}, nil
}

type PrefixStore struct {
	db     *badger.DB
	prefix ItemType
}

type ItemType string

const (
	GenericItem ItemType = ""
	ImageItem   ItemType = "images:"
	FileIDItem  ItemType = "fileid:"
)

func (d *Db) Prefix(prefix ItemType) PrefixStore {
	return PrefixStore{
		db:     d.db,
		prefix: prefix,
	}
}

func (d *PrefixStore) StoreItem(key string, input []byte) error {
	fullKey := string(d.prefix) + key
	return d.db.Update(func(txn *badger.Txn) error {
		e := badger.NewEntry([]byte(fullKey), input).WithTTL(time.Hour * 60 * 24 * 10)
		return txn.SetEntry(e)
	})
}

func (d *PrefixStore) ItemExists(key string) bool {
	exists := false
	fullKey := string(d.prefix) + key
	d.db.View(func(txn *badger.Txn) error {
		_, err := txn.Get([]byte(fullKey))
		if err == nil {
			exists = true
		}
		return err
	})
	return exists
}

func (d *PrefixStore) GetItem(key string) ([]byte, error) {
	var image []byte
	fullKey := string(d.prefix) + key
	err := d.db.View(func(txn *badger.Txn) error {
		result, err := txn.Get([]byte(fullKey))
		if err != nil {
			return err
		}
		return result.Value(func(val []byte) error {
			image = append(image, val...)
			return nil
		})
	})
	if err != nil {
		return nil, err
	}
	return image, nil
}

func (d *Db) Close() {
	d.db.Close()
}