import { readFile, readdir } from 'node:fs/promises';
import path from 'node:path';
import { randomBytes } from 'node:crypto';
import { Readable } from 'node:stream';
import { afterEach, beforeEach, describe, expect, it } from 'vitest';

import {
  createEmptyFile,
  finalizeFile,
  removeFile,
  saveFile,
  writeChunkAt,
} from '../src/lib/storage.js';
import { PayloadTooLargeError } from '../src/errors.js';
import { makeTempDir, removeDir, TINY_PNG } from './helpers.js';

let uploadDir: string;

beforeEach(async () => {
  uploadDir = await makeTempDir();
});

afterEach(async () => {
  await removeDir(uploadDir);
});

function params(maxFileSizeBytes = 1024 * 1024): { targetDir: string; maxFileSizeBytes: number } {
  return { targetDir: uploadDir, maxFileSizeBytes };
}

describe('saveFile', () => {
  it('écrit le fichier et renvoie ses métadonnées', async () => {
    const stored = await saveFile({
      source: Readable.from(TINY_PNG),
      originalName: 'photo.png',
      mimeType: 'image/png',
      ...params(),
    });

    expect(stored.size).toBe(TINY_PNG.length);
    expect(stored.storedName).toMatch(/^photo-\d+-[0-9a-f]{8}\.png$/);
    expect(await readFile(stored.path)).toEqual(TINY_PNG);
  });

  it('produit un nom sans séparateur de chemin même pour un nom hostile', async () => {
    const stored = await saveFile({
      source: Readable.from(TINY_PNG),
      originalName: '../../etc/passwd',
      mimeType: 'image/png',
      ...params(),
    });

    expect(stored.storedName).not.toMatch(/[/\\]/);
    expect(stored.storedName).not.toContain('..');
    expect(stored.storedName).toMatch(/^passwd-\d+-[0-9a-f]{8}\.png$/);
  });

  it('assainit les noms avec espaces et accents', async () => {
    const stored = await saveFile({
      source: Readable.from(TINY_PNG),
      originalName: 'mon joli cliché.PNG',
      mimeType: 'image/png',
      ...params(),
    });

    expect(stored.storedName).toMatch(/^[A-Za-z0-9_-]+-\d+-[0-9a-f]{8}\.png$/);
  });

  it('rejette au-delà de la taille maximale sans laisser de fichier partiel', async () => {
    await expect(
      saveFile({
        source: Readable.from(Buffer.alloc(5000, 1)),
        originalName: 'big.png',
        mimeType: 'image/png',
        ...params(1000),
      }),
    ).rejects.toBeInstanceOf(PayloadTooLargeError);

    expect(await readdir(uploadDir)).toHaveLength(0);
  });
});

describe('saveFile — mode dossier (placement)', () => {
  it('recrée les sous-dossiers et conserve le nom d’origine', async () => {
    const stored = await saveFile({
      source: Readable.from(TINY_PNG),
      originalName: 'ignoré.png',
      mimeType: 'image/png',
      ...params(),
      placement: { segments: ['vacances', 'plage'], fileName: 'DSC 001.jpg' },
    });

    expect(stored.storedName).toBe('vacances/plage/DSC 001.jpg');
    expect(stored.path).toBe(path.join(uploadDir, 'vacances', 'plage', 'DSC 001.jpg'));
    expect(await readFile(stored.path)).toEqual(TINY_PNG);
  });

  it('écrase un fichier déjà présent au même chemin', async () => {
    const common = { originalName: 'x', mimeType: 'image/png', ...params() };
    const placement = { segments: ['dir'], fileName: 'a.bin' };

    await saveFile({ ...common, source: Readable.from(Buffer.from('aaaa')), placement });
    const second = await saveFile({
      ...common,
      source: Readable.from(Buffer.from('bb')),
      placement,
    });

    expect(second.size).toBe(2);
    expect(await readFile(second.path)).toEqual(Buffer.from('bb'));
    expect(await readdir(path.join(uploadDir, 'dir'))).toEqual(['a.bin']);
  });
});

describe('writeChunkAt — réassemblage de morceaux', () => {
  it('écrit des morceaux à des offsets disjoints puis finalise, octets exacts', async () => {
    const chunkSize = 64 * 1024;
    const data = randomBytes(chunkSize * 2 + 777);
    const partPath = path.join(uploadDir, 'sub', 'video.bin.part');
    await createEmptyFile(partPath);

    // Dans le désordre pour vérifier l'indépendance des écritures positionnées.
    for (const index of [2, 0, 1]) {
      const slice = data.subarray(index * chunkSize, (index + 1) * chunkSize);
      const written = await writeChunkAt({
        data: slice,
        filePath: partPath,
        offset: index * chunkSize,
      });
      expect(written).toBe(slice.length);
    }

    const finalPath = path.join(uploadDir, 'sub', 'video.bin');
    await finalizeFile(partPath, finalPath);

    expect(await readFile(finalPath)).toEqual(data);
    expect(await readdir(path.join(uploadDir, 'sub'))).toEqual(['video.bin']);
  });

  it('removeFile ne lève pas si le fichier est absent', async () => {
    await expect(removeFile(path.join(uploadDir, 'absent'))).resolves.toBeUndefined();
  });
});