demarches-normaliennes/spec/lib/download_manager/parallel_download_queue_spec.rb

# frozen_string_literal: true

describe DownloadManager::ParallelDownloadQueue do
  let(:test_dir) { Dir.mktmpdir(nil, Dir.tmpdir) }
  let(:download_to_dir) { test_dir }
  before do
    downloadable_manager.on_error = proc { |_, _, _| }
  end

  after { FileUtils.remove_entry_secure(test_dir) if Dir.exist?(test_dir) }

  let(:downloadable_manager) { DownloadManager::ParallelDownloadQueue.new([attachment], download_to_dir) }
  let(:http_client) { instance_double(Typhoeus::Hydra) }

  describe '#download_one' do
    subject { downloadable_manager.download_one(attachment: attachment, path_in_download_dir: destination, http_client:) }

    let(:destination) { 'lol.png' }
    let(:attachment) do
      ActiveStorage::FakeAttachment.new(
        file: StringIO.new('coucou'),
        filename: "export-dossier.pdf",
        name: 'pdf_export_for_instructeur',
        id: 1,
        created_at: Time.zone.now
      )
    end

    context 'with a ActiveStorage::FakeAttachment and it works' do
      it 'write attachment.file to disk' do
        target = File.join(download_to_dir, destination)
        expect { subject }.to change { File.exist?(target) }
        attachment.file.rewind
        expect(attachment.file.read).to eq(File.read(target))
      end
    end

    context 'with a ActiveStorage::FakeAttachment and it fails' do
      it 'write attachment.file to disk' do
        expect(attachment.file).to receive(:read).and_raise("boom")
        target = File.join(download_to_dir, destination)
        expect { subject }.to raise_error(StandardError)
        expect(File.exist?(target)).to be_falsey
        # expect(downloadable_manager.errors).to have_key(destination)
      end
    end

    context 'with a destination filename too long' do
      let(:destination) { 'a' * 252 + '.txt' }

      it 'limit the file path to 255 bytes' do
        target = File.join(download_to_dir, 'a' * 251 + '.txt')
        expect { subject }.to change { File.exist?(target) }
        attachment.file.rewind
        expect(attachment.file.read).to eq(File.read(target))
      end
    end

    context 'with filename containing unsafe characters for storage' do
      let(:destination) { "file:éà\u{202e} K.txt" }

      it 'sanitize the problematic chars' do
        target = File.join(download_to_dir, 'file-éà- K.txt')
        expect { subject }.to change { File.exist?(target) }
        attachment.file.rewind
        expect(attachment.file.read).to eq(File.read(target))
      end

      context 'with a destination tree' do
        let(:destination) { 'subdir/file.txt' }

        it 'preserves the destination tree' do
          target = File.join(download_to_dir, 'subdir/file.txt')
          expect { subject }.to change { File.exist?(target) }
          attachment.file.rewind
          expect(attachment.file.read).to eq(File.read(target))
        end
      end
    end

    context "download strategies" do
      subject { super(); http_client.run }
      let(:byte_size) { 1.kilobyte }
      let(:file_url) { 'http://example.com/test_file' }
      let(:destination) { 'test_file.txt' }
      let(:http_client) { Typhoeus::Hydra.new }
      let(:blob) { instance_double('ActiveStorage::Blob', byte_size:, url: file_url) }
      let(:attachment) { double('ActiveStorage::Attachment', blob: blob) }

      before do
        allow(attachment).to receive(:url).and_return(file_url)
        stub_request(:get, file_url).to_return(body: file_content, status: 200)
      end

      context 'for small files using request_in_whole method' do
        let(:file_content) { 'downloaded content' }
        it 'downloads the file in whole' do
          target = Pathname.new(download_to_dir).join(destination)
          expect { subject }.to change { target.exist? }.from(false).to(true)

          expect(File.read(target)).to eq(file_content)
        end
      end

      context 'for large files using request_in_chunks method' do
        let(:byte_size) { 20.megabytes } # Adjust byte size for large file scenario
        let(:file_content) { 'downloaded content' * 1000 }

        before do
          allow(downloadable_manager).to receive(:request_in_chunks).and_call_original
        end

        it 'downloads the file in chunks' do
          target = Pathname.new(download_to_dir).join(destination)
          expect { subject }.to change { target.exist? }.from(false).to(true)

          expect(File.read(target)).to eq(file_content)
          expect(downloadable_manager).to have_received(:request_in_chunks) # ensure we're taking the chunks code path
        end
      end
    end
  end
end