require 'rails_helper'

RSpec.describe ActivityPub::SynchronizeFollowersService, type: :service do
  subject { described_class.new }

  let(:actor)          { Fabricate(:account, domain: 'example.com', uri: 'http://example.com/account', inbox_url: 'http://example.com/inbox') }
  let(:alice)          { Fabricate(:account, username: 'alice') }
  let(:bob)            { Fabricate(:account, username: 'bob') }
  let(:eve)            { Fabricate(:account, username: 'eve') }
  let(:mallory)        { Fabricate(:account, username: 'mallory') }
  let(:collection_uri) { 'http://example.com/partial-followers' }

  let(:items) do
    [
      ActivityPub::TagManager.instance.uri_for(alice),
      ActivityPub::TagManager.instance.uri_for(eve),
      ActivityPub::TagManager.instance.uri_for(mallory),
    ]
  end

  let(:payload) do
    {
      '@context': 'https://www.w3.org/ns/activitystreams',
      type: 'Collection',
      id: collection_uri,
      items: items,
    }.with_indifferent_access
  end

  shared_examples 'synchronizes followers' do
    before do
      alice.follow!(actor)
      bob.follow!(actor)
      mallory.request_follow!(actor)

      allow(ActivityPub::DeliveryWorker).to receive(:perform_async)

      subject.call(actor, collection_uri)
    end

    it 'keeps expected followers' do
      expect(alice.following?(actor)).to be true
    end

    it 'removes local followers not in the remote list' do
      expect(bob.following?(actor)).to be false
    end

    it 'converts follow requests to follow relationships when they have been accepted' do
      expect(mallory.following?(actor)).to be true
    end

    it 'sends an Undo Follow to the actor' do
      expect(ActivityPub::DeliveryWorker).to have_received(:perform_async).with(anything, eve.id, actor.inbox_url)
    end
  end

  describe '#call' do
    context 'when the endpoint is a Collection of actor URIs' do
      before do
        stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload))
      end

      it_behaves_like 'synchronizes followers'
    end

    context 'when the endpoint is an OrderedCollection of actor URIs' do
      let(:payload) do
        {
          '@context': 'https://www.w3.org/ns/activitystreams',
          type: 'OrderedCollection',
          id: collection_uri,
          orderedItems: items,
        }.with_indifferent_access
      end

      before do
        stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload))
      end

      it_behaves_like 'synchronizes followers'
    end

    context 'when the endpoint is a paginated Collection of actor URIs' do
      let(:payload) do
        {
          '@context': 'https://www.w3.org/ns/activitystreams',
          type: 'Collection',
          id: collection_uri,
          first: {
            type: 'CollectionPage',
            partOf: collection_uri,
            items: items,
          },
        }.with_indifferent_access
      end

      before do
        stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload))
      end

      it_behaves_like 'synchronizes followers'
    end
  end
end