require 'spec_helper'

describe MergeRequests::BuildService, services: true do
  include RepoHelpers

  let(:project) { create(:project) }
  let(:user) { create(:user) }
  let(:issue) { create(:issue, project: project, title: 'A bug') }
  let(:description) { nil }
  let(:source_branch) { 'feature-branch' }
  let(:target_branch) { 'master' }
  let(:merge_request) { service.execute }
  let(:compare) { double(:compare, commits: commits) }
  let(:commit_1) { double(:commit_1, safe_message: "Initial commit\n\nCreate the app") }
  let(:commit_2) { double(:commit_2, safe_message: 'This is a bad commit message!') }
  let(:commits) { nil }

  let(:service) do
    MergeRequests::BuildService.new(project, user,
                                    description: description,
                                    source_branch: source_branch,
                                    target_branch: target_branch)
  end

  before do
    allow(CompareService).to receive_message_chain(:new, :execute).and_return(compare)
  end

  describe 'execute' do
    context 'missing source branch' do
      let(:source_branch) { '' }

      it 'forbids the merge request from being created' do
        expect(merge_request.can_be_created).to eq(false)
      end

      it 'adds an error message to the merge request' do
        expect(merge_request.errors).to contain_exactly('You must select source and target branch')
      end
    end

    context 'missing target branch' do
      let(:target_branch) { '' }

      it 'forbids the merge request from being created' do
        expect(merge_request.can_be_created).to eq(false)
      end

      it 'adds an error message to the merge request' do
        expect(merge_request.errors).to contain_exactly('You must select source and target branch')
      end
    end

    context 'no commits in the diff' do
      let(:commits) { [] }

      it 'forbids the merge request from being created' do
        expect(merge_request.can_be_created).to eq(false)
      end
    end

    context 'one commit in the diff' do
      let(:commits) { [commit_1] }

      it 'allows the merge request to be created' do
        expect(merge_request.can_be_created).to eq(true)
      end

      it 'uses the title of the commit as the title of the merge request' do
        expect(merge_request.title).to eq(commit_1.safe_message.split("\n").first)
      end

      it 'uses the description of the commit as the description of the merge request' do
        expect(merge_request.description).to eq(commit_1.safe_message.split(/\n+/, 2).last)
      end

      context 'merge request already has a description set' do
        let(:description) { 'Merge request description' }

        it 'keeps the description from the initial params' do
          expect(merge_request.description).to eq(description)
        end
      end

      context 'commit has no description' do
        let(:commits) { [commit_2] }

        it 'uses the title of the commit as the title of the merge request' do
          expect(merge_request.title).to eq(commit_2.safe_message)
        end

        it 'sets the description to nil' do
          expect(merge_request.description).to be_nil
        end
      end

      context 'branch starts with issue IID followed by a hyphen' do
        let(:source_branch) { "#{issue.iid}-fix-issue" }

        it 'appends "Closes #$issue-iid" to the description' do
          expect(merge_request.description).to eq("#{commit_1.safe_message.split(/\n+/, 2).last}\nCloses ##{issue.iid}")
        end

        context 'merge request already has a description set' do
          let(:description) { 'Merge request description' }

          it 'appends "Closes #$issue-iid" to the description' do
            expect(merge_request.description).to eq("#{description}\nCloses ##{issue.iid}")
          end
        end

        context 'commit has no description' do
          let(:commits) { [commit_2] }

          it 'sets the description to "Closes #$issue-iid"' do
            expect(merge_request.description).to eq("Closes ##{issue.iid}")
          end
        end
      end
    end

    context 'more than one commit in the diff' do
      let(:commits) { [commit_1, commit_2] }

      it 'allows the merge request to be created' do
        expect(merge_request.can_be_created).to eq(true)
      end

      it 'uses the title of the branch as the merge request title' do
        expect(merge_request.title).to eq('Feature branch')
      end

      it 'does not add a description' do
        expect(merge_request.description).to be_nil
      end

      context 'merge request already has a description set' do
        let(:description) { 'Merge request description' }

        it 'keeps the description from the initial params' do
          expect(merge_request.description).to eq(description)
        end
      end

      context 'branch starts with GitLab issue IID followed by a hyphen' do
        let(:source_branch) { "#{issue.iid}-fix-issue" }

        it 'sets the title to: Resolves "$issue-title"' do
          expect(merge_request.title).to eq("Resolve \"#{issue.title}\"")
        end

        context 'issue does not exist' do
          let(:source_branch) { "#{issue.iid.succ}-fix-issue" }

          it 'uses the title of the branch as the merge request title' do
            expect(merge_request.title).to eq("#{issue.iid.succ} fix issue")
          end
        end
      end

      context 'branch starts with external issue IID followed by a hyphen' do
        let(:source_branch) { '12345-fix-issue' }

        before { allow(project).to receive(:default_issues_tracker?).and_return(false) }

        it 'sets the title to: Resolves External Issue $issue-iid' do
          expect(merge_request.title).to eq('Resolve External Issue 12345')
        end
      end
    end
  end
end