class RailsDataExplorer
  class DataType
    class Quantitative < DataType

      # This is an abstract class. Use sub_classes

      def all_available_chart_types
        [
          {
            chart_class: Chart::BoxPlot,
            chart_roles: [:y],
            dimensions_count_min: 1,
            dimensions_count_max: 1
          },
          {
            chart_class: Chart::HistogramQuantitative,
            chart_roles: [:x],
            dimensions_count_min: 1,
            dimensions_count_max: 1
          },
          {
            chart_class: Chart::BoxPlotGroup,
            chart_roles: [:x],
            dimensions_count_min: 2,
            dimensions_count_max: 2,
          },
          {
            chart_class: Chart::Scatterplot,
            chart_roles: [:x, :y, :size],
            dimensions_count_min: 2
          },
          {
            chart_class: Chart::DescriptiveStatisticsTable,
            chart_roles: [:any],
            dimensions_count_min: 1,
            dimensions_count_max: 1
          },
          {
            chart_class: Chart::ParallelCoordinates,
            chart_roles: [:dimension],
            dimensions_count_min: 3,
          },
        ].freeze
      end

      def descriptive_statistics(values)
        stats = ::DescriptiveStatistics::Stats.new(values)
        ruby_formatters = {
          :integer => Proc.new { |v| number_with_delimiter(v.round) },
          :decimal => Proc.new { |v| number_with_precision(v, :precision => 3, :significant => true, :strip_insignificant_zeros => true, :delimiter => ',') },
          :pass_through => Proc.new { |v| v },
        }
        [
          { :label => 'Min', :value => stats.min, :ruby_formatter => ruby_formatters[:decimal], :table_row => 1 },
          { :label => '1%ile', :value => stats.value_from_percentile(1), :ruby_formatter => ruby_formatters[:decimal], :table_row => 1 },
          { :label => '10%ile', :value => stats.value_from_percentile(10), :ruby_formatter => ruby_formatters[:decimal], :table_row => 1 },
          { :label => '25%ile', :value => stats.value_from_percentile(25), :ruby_formatter => ruby_formatters[:decimal], :table_row => 1 },
          { :label => 'Median', :value => stats.median, :ruby_formatter => ruby_formatters[:decimal], :table_row => 1 },
          { :label => '75%ile', :value => stats.value_from_percentile(75), :ruby_formatter => ruby_formatters[:decimal], :table_row => 1 },
          { :label => '90%ile', :value => stats.value_from_percentile(90), :ruby_formatter => ruby_formatters[:decimal], :table_row => 1 },
          { :label => '99%ile', :value => stats.value_from_percentile(99), :ruby_formatter => ruby_formatters[:decimal], :table_row => 1 },
          { :label => 'Max', :value => stats.max, :ruby_formatter => ruby_formatters[:decimal], :table_row => 1 },
          { :label => '', :value => '', :ruby_formatter => ruby_formatters[:pass_through], :table_row => 1 },

          { :label => 'Range', :value => stats.range, :ruby_formatter => ruby_formatters[:decimal], :table_row => 2 },
          { :label => 'Mean', :value => stats.mean, :ruby_formatter => ruby_formatters[:decimal], :table_row => 2 },
          { :label => 'Mode', :value => stats.mode, :ruby_formatter => ruby_formatters[:decimal], :table_row => 2 },
          { :label => 'Count', :value => values.length, :ruby_formatter => ruby_formatters[:integer], :table_row => 2 },
          { :label => 'Sum', :value => values.inject(0) { |m,e| m += e }, :ruby_formatter => ruby_formatters[:decimal], :table_row => 2 },
          { :label => 'Variance', :value => stats.variance, :ruby_formatter => ruby_formatters[:decimal], :table_row => 2 },
          { :label => 'Std. dev.', :value => stats.standard_deviation, :ruby_formatter => ruby_formatters[:decimal], :table_row => 2 },
          { :label => 'Rel. std. dev.', :value => stats.relative_standard_deviation, :ruby_formatter => ruby_formatters[:decimal], :table_row => 2 },
          { :label => 'Skewness', :value => stats.skewness, :ruby_formatter => ruby_formatters[:decimal], :table_row => 2 },
          { :label => 'Kurtosis', :value => stats.kurtosis, :ruby_formatter => ruby_formatters[:decimal], :table_row => 2 },
        ]
      end

      # Returns an OpenStruct that describes a statistics table.
      def descriptive_statistics_table(values)
        desc_stats = descriptive_statistics(values)
        table = OpenStruct.new(
          :rows => []
        )
        [1,2].each do |table_row|
          table.rows << OpenStruct.new(
            :css_class => 'rde-column_header',
            :tag => :tr,
            :cells => desc_stats.find_all { |e| table_row == e[:table_row] }.map { |stat|
              OpenStruct.new(:value => stat[:label], :ruby_formatter => Proc.new { |e| e }, :tag => :th, :css_class => 'rde-cell-label')
            }
          )
          table.rows << OpenStruct.new(
            :css_class => 'rde-data_row',
            :tag => :tr,
            :cells => desc_stats.find_all { |e| table_row == e[:table_row] }.map { |stat|
              OpenStruct.new(:value => stat[:value], :ruby_formatter => stat[:ruby_formatter], :tag => :td, :css_class => 'rde-cell-value')
            }
          )
        end
        table
      end

      def axis_tick_format(values)
        raise "Implement me in sub_class"
      end

    end
  end
end