require "rails_helper"

RSpec.describe BulkUpload::Lettings::Year2022::CsvParser do
  subject(:service) { described_class.new(path:) }

  let(:file) { Tempfile.new }
  let(:path) { file.path }
  let(:log) { build(:lettings_log, :completed) }

  context "when parsing csv with headers" do
    before do
      file.write(BulkUpload::LogToCsv.new(log:).default_2022_field_numbers_row)
      file.write(BulkUpload::LogToCsv.new(log:).to_2022_csv_row)
      file.rewind
    end

    it "returns correct offsets" do
      expect(service.row_offset).to eq(1)
      expect(service.col_offset).to eq(1)
    end

    it "parses csv correctly" do
      expect(service.row_parsers[0].field_12.to_i).to eq(35)
    end
  end

  context "when parsing csv with headers with extra rows" do
    before do
      file.write("Extra row\n")
      file.write(BulkUpload::LogToCsv.new(log:).default_2022_field_numbers_row)
      file.write(BulkUpload::LogToCsv.new(log:).to_2022_csv_row)
      file.rewind
    end

    it "returns correct offsets" do
      expect(service.row_offset).to eq(2)
      expect(service.col_offset).to eq(1)
    end

    it "parses csv correctly" do
      expect(service.row_parsers[0].field_12.to_i).to eq(35)
    end
  end

  context "when parsing csv with headers in arbitrary order" do
    let(:seed) { rand }

    before do
      file.write(BulkUpload::LogToCsv.new(log:).default_2022_field_numbers_row(seed:))
      file.write(BulkUpload::LogToCsv.new(log:).to_2022_csv_row(seed:))
      file.rewind
    end

    it "returns correct offsets" do
      expect(service.row_offset).to eq(1)
      expect(service.col_offset).to eq(1)
    end

    it "parses csv correctly" do
      expect(service.row_parsers[0].field_12.to_i).to eq(35)
    end
  end

  context "when parsing csv with extra invalid headers" do
    let(:seed) { rand }
    let(:log_to_csv) { BulkUpload::LogToCsv.new(log:) }
    let(:field_numbers) { log_to_csv.default_2022_field_numbers + %w[invalid_field_number] }
    let(:field_values) { log_to_csv.to_2022_row + %w[value_for_invalid_field_number] }

    before do
      file.write(log_to_csv.custom_field_numbers_row(seed:, field_numbers:))
      file.write(log_to_csv.to_custom_csv_row(seed:, field_values:))
      file.rewind
    end

    it "parses csv correctly" do
      expect(service.row_parsers[0].field_12.to_i).to eq(35)
    end

    it "counts the number of valid field numbers correctly" do
      expect(service.incorrect_field_count?).to be false
    end
  end

  context "when parsing csv without headers" do
    before do
      file.write(BulkUpload::LogToCsv.new(log:, col_offset: 0).to_2022_csv_row)
      file.rewind
    end

    it "returns correct offsets" do
      expect(service.row_offset).to eq(0)
      expect(service.col_offset).to eq(0)
    end

    it "parses csv correctly" do
      expect(service.row_parsers[0].field_12.to_i).to be(35)
    end
  end

  context "when parsing with BOM aka byte order mark" do
    let(:bom) { "\uFEFF" }

    before do
      file.write(bom)
      file.write(BulkUpload::LogToCsv.new(log:, col_offset: 0).to_2022_csv_row)
      file.rewind
    end

    it "parses csv correctly" do
      expect(service.row_parsers[0].field_12.to_i).to be(35)
    end
  end

  context "when an invalid byte sequence" do
    let(:invalid_sequence) { "\x81" }

    before do
      file.write(invalid_sequence)
      file.write(BulkUpload::LogToCsv.new(log:, col_offset: 0).to_2022_csv_row)
      file.rewind
    end

    it "parses csv correctly" do
      expect(service.row_parsers[0].field_12.to_i).to be(35)
    end
  end

  describe "#column_for_field", aggregate_failures: true do
    context "when with headers using default ordering" do
      before do
        file.write(BulkUpload::LogToCsv.new(log:).default_2022_field_numbers_row)
        file.write(BulkUpload::LogToCsv.new(log:).to_2022_csv_row)
        file.rewind
      end

      it "returns correct column" do
        expect(service.column_for_field("field_1")).to eql("B")
        expect(service.column_for_field("field_134")).to eql("EE")
      end
    end

    context "when without headers using default ordering" do
      before do
        file.write(BulkUpload::LogToCsv.new(log:).to_2022_csv_row)
        file.rewind
      end

      it "returns correct column" do
        expect(service.column_for_field("field_1")).to eql("A")
        expect(service.column_for_field("field_134")).to eql("ED")
      end
    end

    context "when with headers using custom ordering" do
      let(:seed) { 123 }

      before do
        file.write(BulkUpload::LogToCsv.new(log:).default_2022_field_numbers_row(seed:))
        file.write(BulkUpload::LogToCsv.new(log:).to_2022_csv_row(seed:))
        file.rewind
      end

      it "returns correct column" do
        expect(service.column_for_field("field_1")).to eql("I")
        expect(service.column_for_field("field_45")).to eql("BE")
        expect(service.column_for_field("field_90")).to eql("AN")
        expect(service.column_for_field("field_134")).to eql("BA")
      end
    end
  end
end