require 'spec_helper'

describe Gitlab::BackgroundMigration::CreateForkNetworkMembershipsRange, :migration, schema: 20170929131201 do
  let(:migration) { described_class.new }

  let(:base1) { create(:project) }
  let(:base1_fork1) { create(:project) }
  let(:base1_fork2) { create(:project) }

  let(:base2) { create(:project) }
  let(:base2_fork1) { create(:project) }
  let(:base2_fork2) { create(:project) }

  let(:fork_of_fork) { create(:project) }
  let(:fork_of_fork2) { create(:project) }
  let(:second_level_fork) { create(:project) }
  let(:third_level_fork) { create(:project) }

  let(:fork_network1) { fork_networks.find_by(root_project_id: base1.id) }
  let(:fork_network2) { fork_networks.find_by(root_project_id: base2.id) }

  let!(:forked_project_links) { table(:forked_project_links) }
  let!(:fork_networks) { table(:fork_networks) }
  let!(:fork_network_members) { table(:fork_network_members) }

  before do
    # The fork-network relation created for the forked project
    fork_networks.create(id: 1, root_project_id: base1.id)
    fork_network_members.create(project_id: base1.id, fork_network_id: 1)
    fork_networks.create(id: 2, root_project_id: base2.id)
    fork_network_members.create(project_id: base2.id, fork_network_id: 2)

    # Normal fork links
    forked_project_links.create(id: 1, forked_from_project_id: base1.id, forked_to_project_id: base1_fork1.id)
    forked_project_links.create(id: 2, forked_from_project_id: base1.id, forked_to_project_id: base1_fork2.id)
    forked_project_links.create(id: 3, forked_from_project_id: base2.id, forked_to_project_id: base2_fork1.id)
    forked_project_links.create(id: 4, forked_from_project_id: base2.id, forked_to_project_id: base2_fork2.id)

    # Fork links
    forked_project_links.create(id: 5, forked_from_project_id: base1_fork1.id, forked_to_project_id: fork_of_fork.id)
    forked_project_links.create(id: 6, forked_from_project_id: base1_fork1.id, forked_to_project_id: fork_of_fork2.id)

    # Forks 3 levels down
    forked_project_links.create(id: 7, forked_from_project_id: fork_of_fork.id, forked_to_project_id: second_level_fork.id)
    forked_project_links.create(id: 8, forked_from_project_id: second_level_fork.id, forked_to_project_id: third_level_fork.id)

    migration.perform(1, 8)
  end

  it 'creates a memberships for the direct forks' do
    base1_fork1_membership = fork_network_members.find_by(fork_network_id: fork_network1.id,
                                                          project_id: base1_fork1.id)
    base1_fork2_membership = fork_network_members.find_by(fork_network_id: fork_network1.id,
                                                          project_id: base1_fork2.id)
    base2_fork1_membership = fork_network_members.find_by(fork_network_id: fork_network2.id,
                                                          project_id: base2_fork1.id)
    base2_fork2_membership = fork_network_members.find_by(fork_network_id: fork_network2.id,
                                                          project_id: base2_fork2.id)

    expect(base1_fork1_membership.forked_from_project_id).to eq(base1.id)
    expect(base1_fork2_membership.forked_from_project_id).to eq(base1.id)
    expect(base2_fork1_membership.forked_from_project_id).to eq(base2.id)
    expect(base2_fork2_membership.forked_from_project_id).to eq(base2.id)
  end

  it 'adds the fork network members for forks of forks' do
    fork_of_fork_membership = fork_network_members.find_by(project_id: fork_of_fork.id,
                                                           fork_network_id: fork_network1.id)
    fork_of_fork2_membership = fork_network_members.find_by(project_id: fork_of_fork2.id,
                                                            fork_network_id: fork_network1.id)
    second_level_fork_membership = fork_network_members.find_by(project_id: second_level_fork.id,
                                                                fork_network_id: fork_network1.id)
    third_level_fork_membership = fork_network_members.find_by(project_id: third_level_fork.id,
                                                               fork_network_id: fork_network1.id)

    expect(fork_of_fork_membership.forked_from_project_id).to eq(base1_fork1.id)
    expect(fork_of_fork2_membership.forked_from_project_id).to eq(base1_fork1.id)
    expect(second_level_fork_membership.forked_from_project_id).to eq(fork_of_fork.id)
    expect(third_level_fork_membership.forked_from_project_id).to eq(second_level_fork.id)
  end

  it 'reschedules itself when there are missing members' do
    allow(migration).to receive(:missing_members?).and_return(true)

    expect(BackgroundMigrationWorker)
      .to receive(:perform_in).with(described_class::RESCHEDULE_DELAY, "CreateForkNetworkMembershipsRange", [1, 3])

    migration.perform(1, 3)
  end

  it 'can be repeated without effect' do
    expect { fork_network_members.count }.not_to change { migration.perform(1, 7) }
  end

  it 'knows it is finished for this range' do
    expect(migration.missing_members?(1, 8)).to be_falsy
  end

  it 'does not miss members for forks of forks for which the root was deleted' do
    forked_project_links.create(id: 9, forked_from_project_id: base1_fork1.id, forked_to_project_id: create(:project).id)
    base1.destroy

    expect(migration.missing_members?(7, 10)).to be_falsy
  end

  context 'with more forks' do
    before do
      forked_project_links.create(id: 9, forked_from_project_id: fork_of_fork.id, forked_to_project_id: create(:project).id)
      forked_project_links.create(id: 10, forked_from_project_id: fork_of_fork.id, forked_to_project_id: create(:project).id)
    end

    it 'only processes a single batch of links at a time' do
      expect(fork_network_members.count).to eq(10)

      migration.perform(8, 10)

      expect(fork_network_members.count).to eq(12)
    end

    it 'knows when not all memberships withing a batch have been created' do
      expect(migration.missing_members?(8, 10)).to be_truthy
    end
  end
end
