package main

import (
	"encoding/binary"
	"encoding/json"
	"errors"
	"fmt"

	"github.com/xujiajun/nutsdb"
)

func ReadUser(username string) (*UserData, error) {
	data, err := DbRead(bucketUsers, username)
	if err != nil {
		return nil, err
	}
	var user UserData
	err = json.Unmarshal(data, &user)
	return &user, err
}

func SaveUser(user *UserData) error {
	data, err := json.Marshal(user)
	if err != nil {
		return err
	}
	if user.Username == "" {
		return errors.New("user empty")
	}
	err = DbSave(bucketUsers, user.Username, data)
	return err
}

func ReadAnimes() ([]Anime, error) {
	var animes []Anime
	err := db.View(
		func(tx *nutsdb.Tx) error {
			entries, err := tx.GetAll(bucketAnime)
			if err != nil {
				return err
			}
			animes = make([]Anime, len(entries))
			// iterate entries
			for _, entry := range entries {
				// decode anime list
				malId, c := binary.Varint(entry.Key)
				if c <= 0 {
					return fmt.Errorf("int64 decode error: %s %s", entry.Key, entry.Value)
				}
				// parse user list
				var users []WatchUser
				err = json.Unmarshal(entry.Value, &users)
				if err != nil {
					return err
				}
				anime := Anime{
					Anime: malId,
					Users: users,
				}
				animes = append(animes, anime)
			}
			return nil
		})
	return animes, err
}

func DbClean() error {
	return db.Update(
		func(tx *nutsdb.Tx) error {
			return db.Merge()
		})
}

func DbSave(bucket, key string, val []byte) error {
	return db.Update(
		func(tx *nutsdb.Tx) error {
			keyBytes := []byte(key)
			return tx.Put(bucket, keyBytes, val, nutsdb.Persistent)
		})
}

func DbRead(bucket, key string) ([]byte, error) {
	var val []byte
	err := db.View(
		func(tx *nutsdb.Tx) error {
			keyBytes := []byte(key)
			e, err := tx.Get(bucket, keyBytes)
			if err != nil {
				return err
			}
			val = make([]byte, len(e.Value))
			copy(val, e.Value)
			return err
		})
	return val, err
}

func DbDelete(bucket, key string, val []byte) error {
	return db.Update(
		func(tx *nutsdb.Tx) error {
			keyBytes := []byte(key)
			return tx.Delete(bucket, keyBytes)
		})
}