# frozen_string_literal: true

require 'spec_helper'

describe Mongo::Operation::MapReduce do
  require_no_required_api_version

  let(:context) { Mongo::Operation::Context.new }

  let(:map) do
    %{
  function() {
    emit(this.name, { population: this.population });
  }}
  end

  let(:reduce) do
    %{
    function(key, values) {
      var result = { population: 0 };
      values.forEach(function(value) {
        result.population += value.population;
      });
      return result;
    }}
  end

  let(:options) do
    {}
  end

  let(:selector) do
    { mapreduce: TEST_COLL,
      map: map,
      reduce: reduce,
      query: {},
      out: { inline: 1 } }
  end

  let(:spec) do
    { selector: selector,
      options: options,
      db_name: SpecConfig.instance.test_db }
  end

  let(:op) do
    described_class.new(spec)
  end

  describe '#initialize' do
    context 'spec' do
      it 'sets the spec' do
        expect(op.spec).to be(spec)
      end
    end
  end

  describe '#==' do
    context 'when two ops have different specs' do
      let(:other_selector) do
        { mapreduce: 'other_test_coll',
          map: '',
          reduce: '', }
      end
      let(:other_spec) do
        { selector: other_selector,
          options: {},
          db_name: SpecConfig.instance.test_db, }
      end
      let(:other) { described_class.new(other_spec) }

      it 'returns false' do
        expect(op).not_to eq(other)
      end
    end
  end

  describe '#execute' do
    let(:documents) do
      [
        { name: 'Berlin', population: 3_000_000 },
        { name: 'London', population: 9_000_000 }
      ]
    end

    before do
      authorized_collection.insert_many(documents)
    end

    after do
      authorized_collection.delete_many
    end

    context 'when the map/reduce succeeds' do
      let(:response) do
        op.execute(authorized_primary, context: context)
      end

      it 'returns the response' do
        expect(response).to be_successful
      end
    end

    context 'when the map/reduce fails' do
      let(:selector) do
        { mapreduce: TEST_COLL,
          map: map,
          reduce: reduce,
          query: {} }
      end

      it 'raises an exception' do
        expect do
          op.execute(authorized_primary, context: context)
        end.to raise_error(Mongo::Error::OperationFailure)
      end
    end
  end
end
