kf8a/alpkem

require "csv"

module Parsers

  class LachatLysimeterLineParser
    def self.parse(line)
      data = CSV.parse(line)[0]
      return nil unless data[1] == "Unknown"
      return nil if data[0] =~ /1\s.M\s+KCL/i
      return nil if data[0] =~ /H2O/i
      return nil if data[0] =~ /Blank/i

      plot, raw_date = data[0].split(/\s+/)
      first, second, third = plot[0..-2].split(/-/)

      manual_dilution_factor = data[5].to_f
      auto_dilution_factor = data[6].to_f
      dilution_factor = manual_dilution_factor * auto_dilution_factor

      nh4_id = nh4_id(data)
      nh4 = if nh4_id
              data[nh4_id].to_f * dilution_factor
            end
      no3_id = no3_id(data)
      no3 = if no3_id
              data[no3_id].to_f * dilution_factor
            end
      sample_date = parse_date(raw_date)
      [first, second, third, sample_date, nh4, no3]
    end

    def self.parse_date(raw_date)
      return unless raw_date

      Date.new(raw_date[0..3].to_i,
               raw_date[4..5].to_i,
               raw_date[6..7].to_i)
    end

    def self.nh4_id(data)
      if data[16] == "Ammonia"
        17
      elsif data[29] == "Ammonia"
        30
      end
    end

    def self.no3_id(data)
      if data[16] == "Nitrate-Nitrite"
        17
      elsif data[29] == "Nitrate-Nitrite"
        30
      end
    end
  end
end