# frozen_string_literal: true

require 'spec_helper'

describe MergeRequests::FfMergeService do
  let(:user) { create(:user) }
  let(:user2) { create(:user) }
  let(:merge_request) do
    create(:merge_request,
           source_branch: 'flatten-dir',
           target_branch: 'improve/awesome',
           assignees: [user2],
           author: create(:user))
  end
  let(:project) { merge_request.project }
  let(:valid_merge_params) { { sha: merge_request.diff_head_sha } }

  before do
    project.add_maintainer(user)
    project.add_developer(user2)
  end

  describe '#execute' do
    [true, false].each do |state_tracking_enabled|
      context "valid params with state_tracking #{state_tracking_enabled ? 'enabled' : 'disabled'}" do
        let(:service) { described_class.new(project, user, valid_merge_params) }

        def execute_ff_merge
          perform_enqueued_jobs do
            service.execute(merge_request)
          end
        end

        before do
          stub_feature_flags(track_resource_state_change_events: state_tracking_enabled)

          allow(service).to receive(:execute_hooks)
        end

        it "does not create merge commit" do
          execute_ff_merge

          source_branch_sha = merge_request.source_project.repository.commit(merge_request.source_branch).sha
          target_branch_sha = merge_request.target_project.repository.commit(merge_request.target_branch).sha

          expect(source_branch_sha).to eq(target_branch_sha)
        end

        it 'keeps the merge request valid' do
          expect { execute_ff_merge }
            .not_to change { merge_request.valid? }
        end

        it 'updates the merge request to merged' do
          expect { execute_ff_merge }
            .to change { merge_request.merged? }
            .from(false)
            .to(true)
        end

        it 'sends email to user2 about merge of new merge_request' do
          execute_ff_merge

          email = ActionMailer::Base.deliveries.last
          expect(email.to.first).to eq(user2.email)
          expect(email.subject).to include(merge_request.title)
        end

        it 'creates system note about merge_request merge' do
          execute_ff_merge

          if state_tracking_enabled
            event = merge_request.resource_state_events.last
            expect(event.state).to eq('merged')
          else
            note = merge_request.notes.last
            expect(note.note).to include 'merged'
          end
        end

        it 'does not update squash_commit_sha if it is not a squash' do
          expect { execute_ff_merge }.not_to change { merge_request.squash_commit_sha }
        end

        it 'updates squash_commit_sha if it is a squash' do
          merge_request.update!(squash: true)

          expect { execute_ff_merge }
            .to change { merge_request.squash_commit_sha }
            .from(nil)
        end
      end
    end

    context 'error handling' do
      let(:service) { described_class.new(project, user, valid_merge_params.merge(commit_message: 'Awesome message')) }

      before do
        allow(Gitlab::AppLogger).to receive(:error)
      end

      it 'logs and saves error if there is an exception' do
        error_message = 'error message'

        allow(service).to receive(:repository).and_raise("error message")
        allow(service).to receive(:execute_hooks)

        service.execute(merge_request)

        expect(merge_request.merge_error).to include(error_message)
        expect(Gitlab::AppLogger).to have_received(:error).with(a_string_matching(error_message))
      end

      it 'logs and saves error if there is an PreReceiveError exception' do
        error_message = 'error message'

        allow(service).to receive(:repository).and_raise(Gitlab::Git::PreReceiveError, "GitLab: #{error_message}")
        allow(service).to receive(:execute_hooks)

        service.execute(merge_request)

        expect(merge_request.merge_error).to include(error_message)
        expect(Gitlab::AppLogger).to have_received(:error).with(a_string_matching(error_message))
      end

      it 'does not update squash_commit_sha if squash merge is not successful' do
        merge_request.update!(squash: true)

        expect(project.repository.raw).to receive(:ff_merge) do
          raise 'Merge error'
        end

        expect { service.execute(merge_request) }.not_to change { merge_request.squash_commit_sha }
      end
    end
  end
end
