import { createReadStream, createWriteStream } from 'node:fs';
import { mkdir, rm, stat } from 'node:fs/promises';
import { dirname, resolve, sep } from 'node:path';
import type { Readable } from 'node:stream';
import { pipeline } from 'node:stream/promises';
import type { IFileStorage } from '../../domain/ports/file-storage.port.js';

/** Хранилище на локальном диске — для разработки и тестов */
export class LocalFileStorage implements IFileStorage {
  private readonly root: string;

  constructor(root: string) {
    this.root = resolve(root);
  }

  async put(key: string, body: Readable): Promise<void> {
    const path = this.resolveKey(key);
    await mkdir(dirname(path), { recursive: true });
    await pipeline(body, createWriteStream(path));
  }

  async get(key: string): Promise<Readable> {
    const path = this.resolveKey(key);
    await stat(path);
    return createReadStream(path);
  }

  async delete(key: string): Promise<void> {
    await rm(this.resolveKey(key), { force: true });
  }

  /** Ключи генерирует приложение, но выход за пределы root всё равно запрещаем */
  private resolveKey(key: string): string {
    const path = resolve(this.root, key);
    if (!path.startsWith(this.root + sep)) {
      throw new Error(`Недопустимый ключ хранилища: ${key}`);
    }
    return path;
  }
}