# frozen_string_literal: true

require 'spec_helper'

describe Gitlab::PaginatedResponse do
  before do
    array = [1, 2, 3, 4]
    @paginated_response = described_class.new array
  end

  it 'responds to *_page and has_*_page methods' do
    expect(@paginated_response).to respond_to :first_page
    expect(@paginated_response).to respond_to :last_page
    expect(@paginated_response).to respond_to :next_page
    expect(@paginated_response).to respond_to :prev_page
    expect(@paginated_response).to respond_to :has_first_page?
    expect(@paginated_response).to respond_to :has_last_page?
    expect(@paginated_response).to respond_to :has_next_page?
    expect(@paginated_response).to respond_to :has_prev_page?
  end

  describe '.parse_headers!' do
    it 'parses headers' do
      @paginated_response.parse_headers!('Link' => '<http://example.com/api/v3/projects?page=1&per_page=5>; rel="first", <http://example.com/api/v3/projects?page=20&per_page=5>; rel="last"')
      client = @paginated_response.client = double('client')
      first_page_response = double('first_page_response')
      last_page_response = double('last_page_response')
      allow(client).to receive(:endpoint).and_return('http://example.com/api/v3')
      allow(client).to receive(:get).with('/projects?page=1&per_page=5').and_return(first_page_response)
      allow(client).to receive(:get).with('/projects?page=20&per_page=5').and_return(last_page_response)
      expect(@paginated_response.has_first_page?).to be true
      expect(@paginated_response.has_last_page?).to be true
      expect(@paginated_response.has_next_page?).to be false
      expect(@paginated_response.has_prev_page?).to be false
      expect(@paginated_response.first_page).to be first_page_response
      expect(@paginated_response.last_page).to be last_page_response
      expect(@paginated_response.next_page).to be_nil
      expect(@paginated_response.prev_page).to be_nil
    end

    context 'when the Link header endpoint does not match the configured endpoint' do
      it 'removes the apprpriate prefix from the pagination link' do
        @paginated_response.parse_headers!('Link' => '<http://example.com/api/v3/projects?page=1&per_page=5>; rel="first", <http://example.com/api/v3/projects?page=20&per_page=5>; rel="last"')
        client = @paginated_response.client = double('client')
        first_page_response = double('first_page_response')
        last_page_response = double('last_page_response')
        allow(client).to receive(:endpoint).and_return('http://internal.example.com/api/v3')
        allow(client).to receive(:get).with('/projects?page=1&per_page=5').and_return(first_page_response)
        allow(client).to receive(:get).with('/projects?page=20&per_page=5').and_return(last_page_response)
        expect(@paginated_response.first_page).to be first_page_response
        expect(@paginated_response.last_page).to be last_page_response
      end
    end
  end

  describe '.each_page' do
    it 'iterates pages' do
      next_page = double('next_page')
      allow(@paginated_response).to receive(:has_next_page?).and_return(true)
      allow(@paginated_response).to receive(:next_page).and_return(next_page)
      allow(next_page).to receive(:has_next_page?).and_return(false)
      expect { |b| @paginated_response.each_page(&b) }.to yield_successive_args(@paginated_response, next_page)
    end
  end

  describe '.lazy_paginate' do
    it 'returns a lazy enumerator' do
      expect(@paginated_response.lazy_paginate).to be_an(Enumerator::Lazy)
    end

    it 'only requests needed pages' do
      next_page = double('next_page')
      allow(@paginated_response).to receive(:has_next_page?).and_return(true)
      allow(@paginated_response).to receive(:next_page).and_return(next_page)
      allow(next_page).to receive(:has_next_page?).and_return(true)
      # NOTE: Do not define :next_page on the next_page double
      # to prove that it is NOT called even though :has_next_page?
      # has been defined to claim another page is available.
      allow(next_page).to receive(:to_ary).and_return([5, 6, 7, 8])
      expect(@paginated_response.lazy_paginate.take(8)).to contain_exactly(1, 2, 3, 4, 5, 6, 7, 8)
    end
  end

  describe '.auto_paginate' do
    it 'returns an array if block is not given' do
      next_page = double('next_page')
      allow(@paginated_response).to receive(:has_next_page?).and_return(true)
      allow(@paginated_response).to receive(:next_page).and_return(next_page)
      allow(next_page).to receive(:has_next_page?).and_return(false)
      allow(next_page).to receive(:to_ary).and_return([5, 6, 7, 8])
      expect(@paginated_response.auto_paginate).to contain_exactly(1, 2, 3, 4, 5, 6, 7, 8)
    end
  end

  shared_context 'when performing limited pagination returning an array' do
    before do
      next_page = double('next_page')
      allow(@paginated_response).to receive(:has_next_page?).and_return(true)
      allow(@paginated_response).to receive(:next_page).and_return(next_page)
      allow(next_page).to receive(:has_next_page?).and_return(false)
      allow(next_page).to receive(:to_ary).and_return([5, 6, 7, 8])
    end
  end

  describe '.paginate_with_limit' do
    include_context 'when performing limited pagination returning an array'
    it 'returns a limited array' do
      expect(@paginated_response.paginate_with_limit(3)).to contain_exactly(1, 2, 3)
    end
  end

  describe '.paginate_with_limit' do
    include_context 'when performing limited pagination returning an array'
    it 'returns exactly the first page' do
      expect(@paginated_response.paginate_with_limit(4)).to contain_exactly(1, 2, 3, 4)
    end
  end

  describe '.paginate_with_limit' do
    it 'returns a page plus one' do
      next_page = double('next_page')
      allow(@paginated_response).to receive(:has_next_page?).and_return(true)
      allow(@paginated_response).to receive(:next_page).and_return(next_page)
      allow(next_page).to receive(:has_next_page?).and_return(false)
      allow(next_page).to receive(:to_ary).and_return([5])
      expect(@paginated_response.paginate_with_limit(5)).to contain_exactly(1, 2, 3, 4, 5)
    end
  end

  shared_context 'when performing limited pagination with a block' do
    before do
      next_page = double('next_page')
      allow(@paginated_response).to receive(:has_next_page?).and_return(true)
      allow(@paginated_response).to receive(:next_page).and_return(next_page)
      allow(next_page).to receive(:has_next_page?).and_return(false)
      allow(next_page).to receive(:to_ary).and_return([5, 6, 7, 8])
    end
  end

  describe '.paginate_with_limit' do
    include_context 'when performing limited pagination with a block'
    it 'iterates items with limit' do
      expect { |b| @paginated_response.paginate_with_limit(3, &b) }.to yield_successive_args(1, 2, 3)
    end
  end

  describe '.paginate_with_limit' do
    include_context 'when performing limited pagination with a block'
    it 'iterates exactly the first page' do
      expect { |b| @paginated_response.paginate_with_limit(4, &b) }.to yield_successive_args(1, 2, 3, 4)
    end
  end

  describe '.paginate_with_limit' do
    include_context 'when performing limited pagination with a block'
    it 'iterates the first page plus one' do
      expect { |b| @paginated_response.paginate_with_limit(5, &b) }.to yield_successive_args(1, 2, 3, 4, 5)
    end
  end

  describe '.client_relative_path' do
    subject(:client_relative_path) do
      @paginated_response.client_relative_path('https://127.0.0.1/api/v4/projects/1/merge_requests/2/notes')
    end

    it 'removes the prefix and api version from the link' do
      client = @paginated_response.client = double('client')
      allow(client).to receive(:endpoint).and_return('https://example.com/api/v4')

      expect(client_relative_path).to eq '/projects/1/merge_requests/2/notes'
    end
  end
end