package children

import (
	"encoding/json"
	"errors"
	"os"
	"sync"

	"mcquay.me/fs"
)

var mut sync.Mutex

type DB map[string]int

func Load(filename string) (children DB, err error) {
	db := DB{}
	if !fs.Exists(filename) {
		return db, errors.New("db file doesn't exist")
	}
	f, err := os.Open(filename)
	if err != nil {
		return nil, err
	}
	if err := json.NewDecoder(f).Decode(&db); err != nil {
		return nil, err
	}
	return db, nil
}

func (db DB) Save(filename string) error {
	mut.Lock()
	defer mut.Unlock()
	f, err := os.Create(filename)
	if err != nil {
		return err
	}
	defer f.Close()
	if err := json.NewEncoder(f).Encode(db); err != nil {
		return err
	}
	return nil
}