#!/usr/bin/env ruby

require "flex_station_data/services/load_plates"
require "flex_station_data/presenters/plates_hash"

module FlexStationData
  class LinearRegressionApp
    include Concerns::Service

    OPTION_RE = /\A--(\w+(?:-\w+)*)(?:=(.*))?\z/.freeze

    attr_reader :args, :options

    def initialize(*args)
      @options, @args = args.partition { |arg| arg =~ OPTION_RE }
      @options.map! do |option|
        option.scan(OPTION_RE).first
      end
    end

    def option(option_name)
      name, value = options.reverse.detect { |name, _| name == option_name.to_s }
      return if name.blank?

      value.nil? || value
    end

    def threshold
      Float(option(:threshold)) rescue nil
    end

    def min_r_squared
      Float(option("min-r-squared")) rescue 0.75
    end

    def files
      @files ||= args.map { |arg| Pathname(arg) }
    end

    def plates
      @plates ||= files.map do |file|
        [ file, LoadPlates.call(file) ]
      end
    end

    def plate_hashes
      plates.flat_map do |file, file_plates|
        Presenters::PlatesHash.present(
          file,
          file_plates,
          threshold:     threshold,
          min_r_squared: min_r_squared
        )
      end
    end

    def clean_values(values)
      values.each_with_object([]) do |value, memo|
        memo << ((value != memo.compact.last) ? value : nil)
      end
    end

    def hash
      @hash ||= begin
        result = plate_hashes.each_with_object({}) do |hash, memo|
          hash.each do |header, value|
            memo[header] ||= []
            memo[header] << value
          end
        end
        result["file"] = clean_values(result["file"])
        result["plate"] = clean_values(result["plate"])
        result
      end
    end

    def csv
      [ hash.keys, *hash.values.transpose ]
    end

    def call
      CSV do |out|
        csv.each do |row|
          out << row
        end
      end
    end
  end
end

FlexStationData::LinearRegressionApp.call(*ARGV)