# frozen_string_literal: true

RSpec.describe CsvBuilder do
  let(:csv_data) { subject.render }
  let(:header_to_value_hash) do
    { 'Q & A' => :question, 'Reversed' => ->(o) { o.question.to_s.reverse } }
  end

  let(:subject) do
    described_class.new(enumerable, header_to_value_hash)
  end

  shared_examples 'csv builder examples' do
    let(:items) { [object] }

    it 'has a version number' do
      expect(CsvBuilder::Version::VERSION).not_to be nil
    end

    it 'generates a csv' do
      expect(csv_data.scan(/(,|\n)/).join).to include ",\n,"
    end

    it 'uses a temporary file to reduce memory allocation' do
      expect(CSV).to receive(:new).with(instance_of(Tempfile)).and_call_original

      subject.render
    end

    it 'counts the number of rows' do
      subject.render

      expect(subject.rows_written).to eq 1
    end

    describe 'rows_expected' do
      it 'uses rows_written if CSV rendered successfully' do
        subject.render

        expect(enumerable).not_to receive(:count)
        expect(subject.rows_expected).to eq 1
      end

      it 'falls back to calling .count before rendering begins' do
        expect(subject.rows_expected).to eq 1
      end
    end

    it 'avoids loading all data in a single query' do
      expect(enumerable).to receive(:find_each)

      subject.render
    end

    it 'uses hash keys as headers' do
      expect(csv_data).to start_with 'Q & A'
    end

    it 'gets data by calling method provided as hash value' do
      expect(csv_data).to include 'answer'
    end

    it 'allows lambdas to look up more complicated data' do
      expect(csv_data).to include 'rewsna'
    end
  end

  shared_examples 'csv builder with truncation ability' do
    let(:items) { [big_object, big_object, big_object] }
    let(:row_size) { question_value.length * 2 }

    it 'occurs after given number of bytes' do
      expect(subject.render(row_size * 2).length).to be_between(row_size * 2, row_size * 3)
      expect(subject).to be_truncated
      expect(subject.rows_written).to eq 2
    end

    it 'is ignored by default' do
      expect(subject.render.length).to be > row_size * 3
      expect(subject.rows_written).to eq 3
    end

    it 'causes rows_expected to fall back to .count' do
      subject.render(0)

      expect(enumerable).to receive(:count).and_call_original
      expect(subject.rows_expected).to eq 3
    end
  end

  shared_examples 'excel sanitization' do
    let(:dangerous_title) { double(title: "=cmd|' /C calc'!A0 title", description: "*safe_desc") }
    let(:dangerous_desc) { double(title: "*safe_title", description: "=cmd|' /C calc'!A0 desc") }
    let(:header_to_value_hash) { { 'Title' => 'title', 'Description' => 'description' } }
    let(:items) { [dangerous_title, dangerous_desc] }

    it 'sanitizes dangerous characters at the beginning of a column' do
      expect(csv_data).to include "'=cmd|' /C calc'!A0 title"
      expect(csv_data).to include "'=cmd|' /C calc'!A0 desc"
    end

    it 'does not sanitize safe symbols at the beginning of a column' do
      expect(csv_data).not_to include "'*safe_desc"
      expect(csv_data).not_to include "'*safe_title"
    end

    context 'when dangerous characters are after a line break' do
      let(:items) { [double(title: "Safe title", description: "With task list\n-[x] todo 1")] }

      it 'does not append single quote to description' do
        expect(csv_data).to eq("Title,Description\nSafe title,\"With task list\n-[x] todo 1\"\n")
      end
    end
  end

  shared_examples 'builder that replaces newlines' do
    let(:object) { double(title: "title", description: "Line 1\n\nLine 2") }
    let(:header_to_value_hash) { { 'Title' => 'title', 'Description' => 'description' } }
    let(:items) { [object] }

    it 'does not replace newlines by default' do
      expect(csv_data).to eq("Title,Description\ntitle,\"Line 1\n\nLine 2\"\n")
    end

    context 'when replace_newlines is set to true' do
      let(:subject) { described_class.new(enumerable, header_to_value_hash, replace_newlines: true) }

      it 'replaces newlines with a literal "\n"' do
        expect(csv_data).to eq("Title,Description\ntitle,Line 1\\n\\nLine 2\n")
      end
    end

    context 'when line is nil' do
      let(:object) { double(title: "title", description: nil) }

      it 'gracefully generates CSV' do
        expect(csv_data).to eq("Title,Description\ntitle,\n")
      end
    end

    context 'when data is not a string' do
      let(:object) { double(title: "title", created_at: Date.new(2001, 2, 3)) }
      let(:header_to_value_hash) { { 'Title' => 'title', 'Created At' => 'created_at' } }

      it 'gracefully generates CSV' do
        expect(csv_data).to eq("Title,Created At\ntitle,2001-02-03\n")
      end
    end
  end

  context 'when ActiveRecord::Relation like object is given' do
    let(:object) { double(question: :answer) }
    let(:enumerable) { described_class::FakeRelation.new(items) }

    before do
      stub_const("#{described_class}::FakeRelation", Array)

      described_class::FakeRelation.class_eval do
        def find_each(&block)
          each(&block)
        end
      end
    end

    it_behaves_like 'csv builder examples'
    it_behaves_like 'excel sanitization'
    it_behaves_like 'builder that replaces newlines'
    it_behaves_like 'csv builder with truncation ability' do
      let(:big_object) { double(question: 'Long' * 1024) }
      let(:question_value) { big_object.question }
    end
  end

  context 'when Enumerable like object is given' do
    let(:object) { double(question: :answer) }
    let(:enumerable) { items }

    it_behaves_like 'csv builder examples'
    it_behaves_like 'excel sanitization'
    it_behaves_like 'builder that replaces newlines'
    it_behaves_like 'csv builder with truncation ability' do
      let(:big_object) { double(question: 'Long' * 1024) }
      let(:question_value) { big_object.question }
    end
  end

  context 'when Hash object is given' do
    let(:object) { { question: :answer } }
    let(:enumerable) { items }
    let(:header_to_value_hash) do
      { 'Q & A' => :question, 'Reversed' => ->(o) { o[:question].to_s.reverse } }
    end

    it_behaves_like 'csv builder examples'
    it_behaves_like 'builder that replaces newlines'

    it_behaves_like 'excel sanitization' do
      let(:dangerous_title) { { title: "=cmd|' /C calc'!A0 title", description: "*safe_desc" } }
      let(:dangerous_desc) { { title: "*safe_title", description: "=cmd|' /C calc'!A0 desc" } }
      let(:header_to_value_hash) { { 'Title' => :title, 'Description' => :description } }
    end

    it_behaves_like 'csv builder with truncation ability' do
      let(:big_object) { { question: 'Long' * 1024 } }
      let(:question_value) { big_object[:question] }
    end
  end
end