Autodetect CSV columns

app/models/gobierto_common/scrutinizer/column.rb

@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+module GobiertoCommon
+  module Scrutinizer
+    class Column
+
+      attr_reader :original_name, :db_name, :type
+
+      def initialize(name)
+        @original_name = name
+        @db_name = name.parameterize(separator: "_").tr("-", "_")
+        @type = nil
+        @date_parser = nil
+      end
+
+      def detect_type(value)
+        update_type(value)
+      end
+
+      def parsed_value(value)
+        return if value.nil?
+
+        case type
+        when :date
+          @date_parser.call(value)
+        when :float
+          Float(value)
+        when :integer
+          Integer(value)
+        else
+          value
+        end
+      end
+
+      private
+
+      def is_date?(value)
+        @date_parser ||= if Date.strptime(value, "%m/%d/%Y").present?
+                           ->(orig) { orig.blank? ? nil : Date.strptime(orig, "%m/%d/%Y") }
+                         else
+                           ->(orig) { orig.blank? ? nil : Date.parse(orig) }
+                         end
+        parsed_date = @date_parser.call(value)
+
+        parsed_date.present? && parsed_date.year > 1900
+      rescue ArgumentError
+        false
+      end
+
+      def is_float?(value)
+        return false if %w(, .).any { |c| value.count(c) > 1 }
+
+        value = value.tr(",", ".")
+        Float(value).present?
+      rescue ArgumentError
+        false
+      end
+
+      def is_integer?(value)
+        Integer(value).present?
+      rescue ArgumentError
+        false
+      end
+
+      def update_type(value)
+        return if value.nil? || @type.present? && (@type == :string || send("is_#{@type}?", value))
+
+        @type = if @type.present?
+                  @type == :integer && is_float?(value) ? :float : :string
+                else
+                  [:date, :integer, :float].find { |t| send("is_#{t}?", value) } || :string
+                end
+      end
+    end
+  end
+end