# frozen_string_literal: true

require 'spec_helper'

RSpec.describe Projects::MergeRequests::DiffsController, feature_category: :code_review_workflow do
  include ProjectForksHelper
  include TrackingHelpers

  shared_examples '404 for unexistent diffable' do
    context 'when diffable does not exists' do
      it 'returns 404' do
        go(diff_id: non_existing_record_id)

        expect(MergeRequestDiff.find_by(id: non_existing_record_id)).to be_nil
        expect(response).to have_gitlab_http_status(:not_found)
      end
    end

    context 'when the merge_request_diff.id is blank' do
      it 'returns 404' do
        allow_next_instance_of(MergeRequest) do |instance|
          allow(instance).to receive(:merge_request_diff).and_return(MergeRequestDiff.new(merge_request_id: instance.id))

          go

          expect(response).to have_gitlab_http_status(:not_found)
        end
      end
    end
  end

  shared_examples 'diff tracking' do
    it 'tracks mr_diffs event' do
      expect(Gitlab::UsageDataCounters::MergeRequestActivityUniqueCounter)
        .to receive(:track_mr_diffs_action)
        .with(merge_request: merge_request)

      method_call
    end

    context 'when DNT is enabled' do
      before do
        stub_do_not_track('1')
      end

      it 'does not track any mr_diffs event' do
        expect(Gitlab::UsageDataCounters::MergeRequestActivityUniqueCounter)
          .not_to receive(:track_mr_diffs_action)

        expect(Gitlab::UsageDataCounters::MergeRequestActivityUniqueCounter)
          .not_to receive(:track_mr_diffs_single_file_action)

        method_call
      end
    end

    context 'when user has view_diffs_file_by_file set to false' do
      before do
        user.update!(view_diffs_file_by_file: false)
      end

      it 'does not track single_file_diffs events' do
        expect(Gitlab::UsageDataCounters::MergeRequestActivityUniqueCounter)
          .not_to receive(:track_mr_diffs_single_file_action)

        method_call
      end
    end

    context 'when user has view_diffs_file_by_file set to true' do
      before do
        user.update!(view_diffs_file_by_file: true)
      end

      it 'tracks single_file_diffs events' do
        expect(Gitlab::UsageDataCounters::MergeRequestActivityUniqueCounter)
          .to receive(:track_mr_diffs_single_file_action)
          .with(merge_request: merge_request, user: user)

        method_call
      end
    end
  end

  shared_examples 'forked project with submodules' do
    render_views

    let(:project) { create(:project, :repository) }
    let(:forked_project) { fork_project_with_submodules(project) }
    let(:merge_request) { create(:merge_request_with_diffs, source_project: forked_project, source_branch: 'add-submodule-version-bump', target_branch: 'master', target_project: project) }

    before do
      project.add_developer(user)

      merge_request.reload
      go
    end

    it 'renders' do
      expect(response).to be_successful
      expect(response.body).to have_content('Subproject commit')
    end
  end

  shared_examples 'cached diff collection' do
    it 'ensures diff highlighting cache writing' do
      expect_next_instance_of(Gitlab::Diff::HighlightCache) do |cache|
        expect(cache).to receive(:write_if_empty).once
      end

      go
    end
  end

  shared_examples "diff note on-demand position creation" do
    it "updates diff discussion positions" do
      service = double("service")

      expect(Discussions::CaptureDiffNotePositionsService).to receive(:new).with(merge_request).and_return(service)
      expect(service).to receive(:execute)

      go
    end
  end

  shared_examples 'show the right diff files with previous diff_id' do
    context 'with previous diff_id' do
      let!(:merge_request_diff_1) { merge_request.merge_request_diffs.create!(head_commit_sha: '6f6d7e7ed97bb5f0054f2b1df789b39ca89b6ff9') }
      let!(:merge_request_diff_2) { merge_request.merge_request_diffs.create!(head_commit_sha: '5937ac0a7beb003549fc5fd26fc247adbce4a52e', diff_type: :merge_head) }

      subject { go(diff_id: merge_request_diff_1.id, diff_head: true) }

      it 'shows the right diff files' do
        subject
        expect(json_response["diff_files"].size).to eq(merge_request_diff_1.files_count)
      end
    end
  end

  let(:project) { create(:project, :repository) }
  let(:maintainer) { true }
  let(:merge_request) { create(:merge_request_with_diffs, target_project: project, source_project: project) }

  let_it_be_with_reload(:user) { create(:user) }
  let_it_be(:other_project) { create(:project, maintainers: user) }

  before do
    project.add_maintainer(user) if maintainer
    sign_in(user)
  end

  describe 'GET show' do
    def go(extra_params = {})
      params = {
        namespace_id: project.namespace.to_param,
        project_id: project,
        id: merge_request.iid,
        format: 'json'
      }

      get :show, params: params.merge(extra_params)
    end

    context 'with default params' do
      context 'for the same project' do
        before do
          allow(controller).to receive(:rendered_for_merge_request?).and_return(true)
        end

        it 'serializes merge request diff collection' do
          expect_next_instance_of(DiffsSerializer) do |instance|
            expect(instance).to receive(:represent).with(an_instance_of(Gitlab::Diff::FileCollection::MergeRequestDiff), an_instance_of(Hash))
          end

          go
        end
      end

      context 'when note is a legacy diff note' do
        before do
          create(:legacy_diff_note_on_merge_request, project: project, noteable: merge_request)
        end

        it 'serializes merge request diff collection' do
          expect_next_instance_of(DiffsSerializer) do |instance|
            expect(instance).to receive(:represent).with(an_instance_of(Gitlab::Diff::FileCollection::MergeRequestDiff), an_instance_of(Hash))
          end

          go
        end
      end

      it_behaves_like 'forked project with submodules'
    end

    it_behaves_like 'cached diff collection'
    it_behaves_like 'diff note on-demand position creation'
  end

  describe 'GET diffs_metadata' do
    shared_examples_for 'serializes diffs metadata with expected arguments' do
      it 'returns success' do
        subject

        expect(response).to have_gitlab_http_status(:ok)
      end

      it 'serializes paginated merge request diff collection' do
        expect_next_instance_of(DiffsMetadataSerializer) do |instance|
          expect(instance).to receive(:represent)
            .with(an_instance_of(collection), expected_options)
            .and_call_original
        end

        subject
      end
    end

    def go(extra_params = {})
      params = {
        namespace_id: project.namespace.to_param,
        project_id: project,
        id: merge_request.iid,
        format: 'json'
      }

      get :diffs_metadata, params: params.merge(extra_params)
    end

    it_behaves_like '404 for unexistent diffable'

    it_behaves_like 'show the right diff files with previous diff_id'

    context 'when not authorized' do
      let(:another_user) { create(:user) }

      before do
        sign_in(another_user)
      end

      it 'returns 404 when not a member' do
        go

        expect(response).to have_gitlab_http_status(:not_found)
      end

      it 'returns 404 when visibility level is not enough' do
        project.add_guest(another_user)

        go

        expect(response).to have_gitlab_http_status(:not_found)
      end
    end

    context 'with valid diff_id' do
      subject { go(diff_id: merge_request.merge_request_diff.id) }

      it_behaves_like 'serializes diffs metadata with expected arguments' do
        let(:collection) { Gitlab::Diff::FileCollection::MergeRequestDiff }
        let(:expected_options) do
          {
            merge_request: merge_request,
            merge_request_diff: merge_request.merge_request_diff,
            merge_request_diffs: merge_request.merge_request_diffs,
            start_version: nil,
            start_sha: nil,
            commit: nil,
            latest_diff: true,
            only_context_commits: false,
            merge_ref_head_diff: false
          }
        end
      end
    end

    context 'with diff_head param passed' do
      before do
        allow(merge_request).to receive(:diffable_merge_ref?)
          .and_return(diffable_merge_ref)
      end

      context 'the merge request can be compared with head' do
        let(:diffable_merge_ref) { true }

        it 'compares diffs with the head' do
          create(:merge_request_diff, :merge_head, merge_request: merge_request)

          go(diff_head: true)

          expect(response).to have_gitlab_http_status(:ok)
        end

        context 'when diff_id and start_sha are set' do
          it 'correctly generates the right diff between versions' do
            MergeRequests::MergeToRefService.new(project: project, current_user: merge_request.author).execute(merge_request)

            expect_next_instance_of(CompareService) do |service|
              expect(service).to receive(:execute).with(
                project,
                merge_request.merge_request_diff.head_commit_sha,
                straight: true)
            end

            go(
              diff_head: true,
              diff_id: merge_request.merge_request_diff.id,
              start_sha: merge_request.merge_request_diff.start_commit_sha
            )
          end
        end
      end

      context 'the merge request cannot be compared with head' do
        let(:diffable_merge_ref) { false }

        it 'compares diffs with the base' do
          go(diff_head: true)

          expect(response).to have_gitlab_http_status(:ok)
        end
      end
    end

    context 'with MR regular diff params' do
      subject { go }

      it_behaves_like 'serializes diffs metadata with expected arguments' do
        let(:collection) { Gitlab::Diff::FileCollection::MergeRequestDiff }
        let(:expected_options) do
          {
            merge_request: merge_request,
            merge_request_diff: merge_request.merge_request_diff,
            merge_request_diffs: merge_request.merge_request_diffs,
            start_version: nil,
            start_sha: nil,
            commit: nil,
            latest_diff: true,
            only_context_commits: false,
            merge_ref_head_diff: nil
          }
        end
      end
    end

    context 'with commit param' do
      subject { go(commit_id: merge_request.diff_head_sha) }

      it_behaves_like 'serializes diffs metadata with expected arguments' do
        let(:collection) { Gitlab::Diff::FileCollection::Commit }
        let(:expected_options) do
          {
            merge_request: merge_request,
            merge_request_diff: nil,
            merge_request_diffs: merge_request.merge_request_diffs,
            start_version: nil,
            start_sha: nil,
            commit: merge_request.diff_head_commit,
            latest_diff: nil,
            only_context_commits: false,
            merge_ref_head_diff: nil
          }
        end
      end
    end
  end

  describe 'GET diff_for_path' do
    def diff_for_path(extra_params = {})
      params = {
        namespace_id: project.namespace.to_param,
        project_id: project,
        id: merge_request.iid,
        format: 'json'
      }

      get :diff_for_path, params: params.merge(extra_params)
    end

    let(:existing_path) { 'files/ruby/popen.rb' }

    context 'when the merge request exists' do
      context 'when the user can view the merge request' do
        context 'when the path exists in the diff' do
          include_examples 'diff tracking' do
            let(:method_call) { diff_for_path(old_path: existing_path, new_path: existing_path) }
          end

          it 'enables diff notes' do
            diff_for_path(old_path: existing_path, new_path: existing_path)

            expect(assigns(:diff_notes_disabled)).to be_falsey
            expect(assigns(:new_diff_note_attrs)).to eq(
              noteable_type: 'MergeRequest',
              noteable_id: merge_request.id,
              commit_id: nil
            )
          end

          it 'only renders the diffs for the path given' do
            diff_for_path(old_path: existing_path, new_path: existing_path)

            paths = json_response['diff_files'].pluck('new_path')

            expect(paths).to include(existing_path)
          end
        end
      end

      context 'when the user cannot view the merge request' do
        let(:maintainer) { false }

        before do
          diff_for_path(old_path: existing_path, new_path: existing_path)
        end

        it 'returns a 404' do
          expect(response).to have_gitlab_http_status(:not_found)
        end
      end
    end

    context 'when the merge request does not exist' do
      before do
        diff_for_path(id: merge_request.iid.succ, old_path: existing_path, new_path: existing_path)
      end

      it 'returns a 404' do
        expect(response).to have_gitlab_http_status(:not_found)
      end
    end

    context 'when the merge request belongs to a different project' do
      before do
        diff_for_path(old_path: existing_path, new_path: existing_path, project_id: other_project)
      end

      it 'returns a 404' do
        expect(response).to have_gitlab_http_status(:not_found)
      end
    end
  end

  describe 'GET diff_by_file_hash' do
    def diff_by_file_hash(extra_params = {})
      params = {
        namespace_id: project.namespace.to_param,
        project_id: project,
        id: merge_request.iid,
        format: 'json'
      }

      get :diff_by_file_hash, params: params.merge(extra_params)
    end

    let(:file) { merge_request.merge_request_diff.diffs.diff_files.first }
    let(:file_hash) { file.file_hash }

    context 'when the merge request exists' do
      context 'when the user can view the merge request' do
        context 'when the path exists in the diff' do
          include_examples 'diff tracking' do
            let(:method_call) { diff_by_file_hash(file_hash: file_hash) }
          end

          it 'enables diff notes' do
            diff_by_file_hash(file_hash: file_hash)

            expect(assigns(:diff_notes_disabled)).to be_falsey
            expect(assigns(:new_diff_note_attrs)).to eq(
              noteable_type: 'MergeRequest',
              noteable_id: merge_request.id,
              commit_id: nil
            )
          end

          it 'only renders diff for the hash given' do
            diff_by_file_hash(file_hash: file_hash)

            diffs = json_response['diff_files']

            expect(diffs.count).to eq(1)
            expect(diffs.first['file_hash']).to eq(file_hash)
          end
        end
      end

      context 'when the user cannot view the merge request' do
        let(:maintainer) { false }

        before do
          diff_by_file_hash(file_hash: file_hash)
        end

        it 'returns a 404' do
          expect(response).to have_gitlab_http_status(:not_found)
        end
      end
    end

    context 'when the merge request does not exist' do
      before do
        diff_by_file_hash(id: merge_request.iid.succ, file_hash: file_hash)
      end

      it 'returns a 404' do
        expect(response).to have_gitlab_http_status(:not_found)
      end
    end

    context 'when the merge request belongs to a different project' do
      before do
        diff_by_file_hash(project_id: other_project, file_hash: file_hash)
      end

      it 'returns a 404' do
        expect(response).to have_gitlab_http_status(:not_found)
      end
    end
  end

  describe 'GET diffs_batch' do
    shared_examples_for 'serializes diffs with expected arguments' do
      it 'serializes paginated merge request diff collection' do
        expect_next_instance_of(PaginatedDiffSerializer) do |instance|
          expect(instance).to receive(:represent)
            .with(an_instance_of(collection), expected_options)
            .and_call_original
        end

        subject
      end
    end

    shared_examples_for 'successful request' do
      include_examples 'diff tracking' do
        let(:method_call) { subject }
      end

      it 'returns success' do
        subject

        expect(response).to have_gitlab_http_status(:ok)
      end

      it 'measures certain parts of the request' do
        allow(Gitlab::Metrics).to receive(:measure).and_call_original
        expect(Gitlab::Metrics).to receive(:measure).with(:diffs_unfoldable_positions).and_call_original
        expect(Gitlab::Metrics).to receive(:measure).with(:diffs_unfold).and_call_original
        expect(Gitlab::Metrics).to receive(:measure).with(:diffs_write_cache).and_call_original
        expect(Gitlab::Metrics).to receive(:measure).with(:diffs_render).and_call_original

        subject
      end
    end

    def collection_arguments(pagination_data = {})
      {
        merge_request: merge_request,
        commit: nil,
        diff_view: :inline,
        merge_ref_head_diff: nil,
        pagination_data: {
          total_pages: nil
        }.merge(pagination_data)
      }
    end

    def go(extra_params = {})
      params = {
        namespace_id: project.namespace.to_param,
        project_id: project,
        id: merge_request.iid,
        page: 0,
        per_page: 20,
        format: 'json'
      }

      get :diffs_batch, params: params.merge(extra_params)
    end

    it_behaves_like '404 for unexistent diffable'

    it_behaves_like 'show the right diff files with previous diff_id'

    context 'when not authorized' do
      let(:other_user) { create(:user) }

      before do
        sign_in(other_user)
      end

      it 'returns 404' do
        go

        expect(response).to have_gitlab_http_status(:not_found)
      end
    end

    context 'with valid diff_id' do
      subject { go(diff_id: merge_request.merge_request_diff.id) }

      it_behaves_like 'serializes diffs with expected arguments' do
        let(:collection) { Gitlab::Diff::FileCollection::MergeRequestDiffBatch }
        let(:expected_options) { collection_arguments(total_pages: 20).merge(merge_ref_head_diff: false) }
      end

      it_behaves_like 'successful request'
    end

    context 'with commit_id param' do
      subject { go(commit_id: merge_request.diff_head_sha) }

      it_behaves_like 'serializes diffs with expected arguments' do
        let(:collection) { Gitlab::Diff::FileCollection::Commit }
        let(:expected_options) { collection_arguments.merge(commit: merge_request.commits(limit: 1).first) }
      end
    end

    context 'with diff_id and start_sha params' do
      subject do
        go(diff_id: merge_request.merge_request_diff.id, start_sha: merge_request.merge_request_diff.start_commit_sha)
      end

      it_behaves_like 'serializes diffs with expected arguments' do
        let(:collection) { Gitlab::Diff::FileCollection::Compare }
        let(:expected_options) { collection_arguments.merge(merge_ref_head_diff: false) }
      end

      it_behaves_like 'successful request'
    end

    context 'with paths param' do
      let(:example_file_path) { "README" }
      let(:file_path_option) { { paths: [example_file_path] } }

      subject do
        go(file_path_option)
      end

      it_behaves_like 'serializes diffs with expected arguments' do
        let(:collection) { Gitlab::Diff::FileCollection::MergeRequestDiffBatch }
        let(:expected_options) do
          collection_arguments(total_pages: 20)
        end
      end

      it_behaves_like 'successful request'

      it 'filters down the response to the expected file path' do
        subject

        expect(json_response["diff_files"].size).to eq(1)
        expect(json_response["diff_files"].first["file_path"]).to eq(example_file_path)
      end
    end

    context 'with default params' do
      subject { go }

      it_behaves_like 'serializes diffs with expected arguments' do
        let(:collection) { Gitlab::Diff::FileCollection::MergeRequestDiffBatch }
        let(:expected_options) { collection_arguments(total_pages: 20) }
      end

      it_behaves_like 'successful request'
    end

    context 'with smaller diff batch params' do
      subject { go(page: 5, per_page: 5) }

      it_behaves_like 'serializes diffs with expected arguments' do
        let(:collection) { Gitlab::Diff::FileCollection::MergeRequestDiffBatch }
        let(:expected_options) { collection_arguments(total_pages: 20) }
      end

      it_behaves_like 'successful request'
    end

    it_behaves_like 'forked project with submodules'
    it_behaves_like 'cached diff collection'

    context 'diff unfolding' do
      let!(:unfoldable_diff_note) do
        create(:diff_note_on_merge_request, :folded_position, project: project, noteable: merge_request)
      end

      let!(:diff_note) do
        create(:diff_note_on_merge_request, project: project, noteable: merge_request)
      end

      it 'unfolds correct diff file positions' do
        expect_next_instance_of(Gitlab::Diff::FileCollection::MergeRequestDiffBatch) do |instance|
          expect(instance)
            .to receive(:unfold_diff_files)
            .with([unfoldable_diff_note.position])
            .and_call_original
        end

        go
      end
    end

    context 'when ck param is present' do
      let(:cache_key) { 'abc123' }

      before do
        create(:merge_request_diff, :merge_head, merge_request: merge_request)
      end

      it 'sets Cache-Control with max-age' do
        go(ck: cache_key, diff_head: true)

        expect(response.headers['Cache-Control']).to eq('max-age=86400, private')
      end

      context 'when diffs_batch_cache_with_max_age feature flag is disabled' do
        before do
          stub_feature_flags(diffs_batch_cache_with_max_age: false)
        end

        it 'does not set Cache-Control with max-age' do
          go(ck: cache_key, diff_head: true)

          expect(response.headers['Cache-Control']).not_to eq('max-age=86400, private')
        end
      end

      context 'when not rendering merge head diff' do
        it 'does not set Cache-Control with max-age' do
          go(ck: cache_key, diff_head: false)

          expect(response.headers['Cache-Control']).not_to eq('max-age=86400, private')
        end
      end
    end

    it 'sets generated' do
      go
      expect(json_response["diff_files"][0]["viewer"]["generated"]).to eq(false)
    end
  end
end