class Eco::API::UseCases::Default::Utils::SplitCsv < Eco::API::Common::Loaders::UseCase
  require_relative 'cli/split_csv_cli'

  MAX_ROWS = 15_000

  name "split-csv"
  type :other

  def main(*_args)
    if simulate?
      count = Eco::CSV.count(input_file, start_at: start_at)
      log(:info) { "CSV '#{input_file}' has #{count} rows." }
    else
      Eco::CSV.split(
        input_file,
        max_rows: max_rows,
        start_at: start_at,
        &filter
      ).tap do |split|
        msg  = []
        msg << "Total rows copied: #{split.copy_count} (out of #{split.total_count})"
        msg << "Generated files:"
        split.out_files.each do |file|
          msg << "  * #{file}'"
        end

        log(:info) { msg.join("\n") }
      end
    end
  end

  private

  def filter
    nil
  end

  def input_file
    options.dig(:source, :file)
  end

  def max_rows
    max_rows_options || self.class::MAX_ROWS
  end

  def max_rows_options
    return nil unless (num = options.dig(:output, :file, :max_rows))

    num = num.to_i
    num = nil if num.zero?
    num
  end

  def start_at
    return nil unless (num = options.dig(:output, :file, :start_at))

    num = num.to_i
    num = nil if num.zero?
    num
  end
end