emoji-diary/emoji-diary/storages/fileio.ts

import { DiaryEntry, EntryIndex } from '@/types/entry';
import { File, Directory, Paths } from 'expo-file-system';

const JSON_MIMETYPE = 'application/json';
const JPG_MIMETYPE = 'image/jpeg';
const ROOT = new Directory(Paths.document, 'diary');
const ENTRIES_DIR = ROOT.createDirectory('entries');
const IMAGE_DIR = ROOT.createDirectory('images');
export const INDEX_FILE = ROOT.createFile('entries.json', JSON_MIMETYPE);
export const INDEX_BAK = ROOT.createFile('entries.json.bak', JSON_MIMETYPE);

export function ensureDirs() {
  if (!ROOT.exists) ROOT.create();
  if (!ENTRIES_DIR.exists) ENTRIES_DIR.create();
  if (!IMAGE_DIR.exists) IMAGE_DIR.create();
}

export function writeTextAtomic(file: File, text: string) {
  const tmp = new File(file.parentDirectory, `${file.name}.tmp`, file.type);
  if (tmp.exists) tmp.delete();
  tmp.create();
  tmp.write(text);

  if (file.exists) file.delete();
  tmp.move(file);
}

export function readJsonSafe<T>(file: File, fallback?: T): T | undefined {
  try {
    if (!file.exists) return fallback;
    const raw = file.textSync();
    return JSON.parse(raw) as T;
  } catch (e) {
    console.warn(`[FILEIO_READ] ${e}`);

    return fallback;
  }
}

export function writeIndexAtomic(index: EntryIndex) {
  ensureDirs();
  if (INDEX_FILE.exists) {
    if (INDEX_BAK.exists) INDEX_BAK.delete();

    INDEX_FILE.copy(INDEX_BAK);
  }

  try {
    writeTextAtomic(INDEX_FILE, JSON.stringify(index));
  } catch (e) {
    console.warn(`[FILEIO_WRITE] ${e}`);

    if (INDEX_BAK.exists) {
      if (INDEX_FILE.exists) INDEX_FILE.delete();

      INDEX_BAK.copy(INDEX_FILE);
    }
    throw e;
  }
}

export function entryFile(id: string) {
  return ENTRIES_DIR.createFile(`${id}.json`, JSON_MIMETYPE);
}

export function imageFile(id: string) {
  return IMAGE_DIR.createFile(`${id}.jpg`, JPG_MIMETYPE);
}

export function readEntry(id: string) {
  return readJsonSafe<DiaryEntry>(entryFile(id));
}

export function writeEntryAtomic(entry: DiaryEntry) {
  writeTextAtomic(entryFile(entry.id), JSON.stringify(entry));
}

export function deleteEntryFile(id: string) {
  const e = entryFile(id);
  if (e.exists) e.delete();

  const img = imageFile(id);
  if (img.exists) img.delete();
}