# frozen_string_literal: true

require 'spec_helper'

RSpec.describe Gitlab::Analytics::CycleAnalytics::Aggregated::RecordsFetcher do
  let_it_be(:project) { create(:project) }
  let_it_be(:issue_1) { create(:issue, project: project) }
  let_it_be(:issue_2) { create(:issue, project: project) }
  let_it_be(:issue_3) { create(:issue, project: project) }

  let_it_be(:stage_event_1) { create(:cycle_analytics_issue_stage_event, issue_id: issue_1.id, start_event_timestamp: 2.years.ago, end_event_timestamp: 1.year.ago) } # duration: 1 year
  let_it_be(:stage_event_2) { create(:cycle_analytics_issue_stage_event, issue_id: issue_2.id, start_event_timestamp: 5.years.ago, end_event_timestamp: 2.years.ago) } # duration: 3 years
  let_it_be(:stage_event_3) { create(:cycle_analytics_issue_stage_event, issue_id: issue_3.id, start_event_timestamp: 6.years.ago, end_event_timestamp: 3.months.ago) } # duration: 5+ years

  let_it_be(:stage) { create(:cycle_analytics_project_stage, start_event_identifier: :issue_created, end_event_identifier: :issue_deployed_to_production, project: project) }

  let(:params) { {} }

  subject(:records_fetcher) do
    described_class.new(stage: stage, query: Analytics::CycleAnalytics::IssueStageEvent.all, params: params)
  end

  shared_examples 'match returned records' do
    it 'returns issues in the correct order' do
      returned_iids = records_fetcher.serialized_records.pluck(:iid).map(&:to_i)

      expect(returned_iids).to eq(expected_issue_ids)
    end
  end

  describe '#serialized_records' do
    describe 'sorting' do
      context 'when sorting by end event DESC' do
        let(:expected_issue_ids) { [issue_3.iid, issue_1.iid, issue_2.iid] }

        before do
          params[:sort] = :end_event
          params[:direction] = :desc
        end

        it_behaves_like 'match returned records'
      end

      context 'when intervalstyle setting is configured to "postgres"' do
        it 'avoids nil durations' do
          # ActiveRecord cannot parse the 'postgres' intervalstyle, it returns nil
          # The setting is rolled back after the test case.
          Analytics::CycleAnalytics::IssueStageEvent.connection.execute("SET LOCAL intervalstyle='postgres'")

          records_fetcher.serialized_records do |relation|
            durations = relation.map(&:total_time)
            expect(durations).to all(be > 0)
          end
        end
      end

      context 'when sorting by end event ASC' do
        let(:expected_issue_ids) { [issue_2.iid, issue_1.iid, issue_3.iid] }

        before do
          params[:sort] = :end_event
          params[:direction] = :asc
        end

        it_behaves_like 'match returned records'
      end

      context 'when sorting by duration DESC' do
        let(:expected_issue_ids) { [issue_3.iid, issue_2.iid, issue_1.iid] }

        before do
          params[:sort] = :duration
          params[:direction] = :desc
        end

        it_behaves_like 'match returned records'
      end

      context 'when sorting by duration ASC' do
        let(:expected_issue_ids) { [issue_1.iid, issue_2.iid, issue_3.iid] }

        before do
          params[:sort] = :duration
          params[:direction] = :asc
        end

        it_behaves_like 'match returned records'
      end
    end

    describe 'pagination' do
      let(:expected_issue_ids) { [issue_3.iid] }

      before do
        params[:sort] = :duration
        params[:direction] = :asc
        params[:page] = 2

        stub_const('Gitlab::Analytics::CycleAnalytics::Aggregated::RecordsFetcher::MAX_RECORDS', 2)
      end

      it_behaves_like 'match returned records'
    end

    context 'when passing a block to serialized_records method' do
      before do
        params[:sort] = :duration
        params[:direction] = :asc
      end

      it 'yields the underlying stage event scope' do
        stage_event_records = []

        records_fetcher.serialized_records do |scope|
          stage_event_records.concat(scope.to_a)
        end

        expect(stage_event_records.map(&:issue_id)).to eq([issue_1.id, issue_2.id, issue_3.id])
      end
    end

    context 'when the issue record no longer exists' do
      it 'skips non-existing issue records' do
        create(:cycle_analytics_issue_stage_event, {
          issue_id: 0, # non-existing id
          start_event_timestamp: 5.months.ago,
          end_event_timestamp: 3.months.ago
        })

        stage_event_count = nil

        records_fetcher.serialized_records do |scope|
          stage_event_count = scope.to_a.size
        end

        issue_count = records_fetcher.serialized_records.to_a.size

        expect(stage_event_count).to eq(4)
        expect(issue_count).to eq(3)
      end
    end
  end
end
