package storage

import (
	"bytes"
	"io"
	"os"
)

type MemoryStorage struct {
	cache map[string][]byte
}

func NewMemoryStorage(ids []string) (Storage, error) {
	s := &MemoryStorage{
		cache: make(map[string][]byte),
	}
	return s, nil
}

func (ms *MemoryStorage) Get(key string) (io.Reader, error) {
	content, ok := ms.cache[key]
	if !ok {
		return nil, os.ErrNotExist
	}
	return bytes.NewReader(content), nil
}

func (ms *MemoryStorage) Put(key string, data []byte) error {
	ms.cache[key] = data
	return nil
}

func (ms *MemoryStorage) Delete(key string) error {
	delete(ms.cache, key)
	return nil
}

func (ms *MemoryStorage) List(prefix string) ([]string, error) {
	res := make([]string, 0, len(ms.cache))
	for file, _ := range ms.cache {
		res = append(res, file)
	}
	return res, nil
}