package internal

import (
	"fmt"

	"git.mills.io/prologic/bitcask"
	log "github.com/sirupsen/logrus"
)

const (
	urlsKeyPrefix = "/urls"
)

// BitcaskStore ...
type BitcaskStore struct {
	db *bitcask.Bitcask
}

func newBitcaskStore(path string) (*BitcaskStore, error) {
	db, err := bitcask.Open(
		path,
		bitcask.WithMaxKeySize(256),
	)
	if err != nil {
		return nil, err
	}

	return &BitcaskStore{db: db}, nil
}

// Sync ...
func (bs *BitcaskStore) Sync() error {
	return bs.db.Sync()
}

// Close ...
func (bs *BitcaskStore) Close() error {
	log.Info("syncing store ...")
	if err := bs.db.Sync(); err != nil {
		log.WithError(err).Error("error syncing store")
		return err
	}

	log.Info("closing store ...")
	if err := bs.db.Close(); err != nil {
		log.WithError(err).Error("error closing store")
		return err
	}

	return nil
}

// Merge ...
func (bs *BitcaskStore) Merge() error {
	log.Info("merging store ...")
	if err := bs.db.Merge(); err != nil {
		log.WithError(err).Error("error merging store")
		return err
	}

	return nil
}

func (bs *BitcaskStore) HasURL(hash string) bool {
	key := []byte(fmt.Sprintf("%s/%s", urlsKeyPrefix, hash))
	return bs.db.Has(key)
}

func (bs *BitcaskStore) DelURL(hash string) error {
	key := []byte(fmt.Sprintf("%s/%s", urlsKeyPrefix, hash))
	return bs.db.Delete(key)
}

func (bs *BitcaskStore) GetURL(hash string) (*URL, error) {
	key := []byte(fmt.Sprintf("%s/%s", urlsKeyPrefix, hash))
	data, err := bs.db.Get(key)
	if err == bitcask.ErrKeyNotFound {
		return nil, ErrURLNotFound
	}
	return LoadURL(data)
}

func (bs *BitcaskStore) SetURL(hash string, url *URL) error {
	data, err := url.Bytes()
	if err != nil {
		return err
	}

	key := []byte(fmt.Sprintf("%s/%s", urlsKeyPrefix, hash))
	if err := bs.db.Put(key, data); err != nil {
		return err
	}
	return nil
}

func (bs *BitcaskStore) URLCount() int64 {
	var count int64

	if err := bs.db.Scan([]byte(urlsKeyPrefix), func(_ []byte) error {
		count++
		return nil
	}); err != nil {
		log.WithError(err).Error("error scanning")
	}

	return count
}

func (bs *BitcaskStore) ForEachURL(f func(url *URL) error) error {
	err := bs.db.Scan([]byte(urlsKeyPrefix), func(key []byte) error {
		data, err := bs.db.Get(key)
		if err != nil {
			return err
		}

		url, err := LoadURL(data)
		if err != nil {
			return err
		}

		return f(url)
	})
	if err != nil {
		return err
	}

	return nil
}