Ingredient CSV import input validation

app/controllers/ingredients_controller.rb

@@ -1,4 +1,6 @@
 class IngredientsController < ApplicationController
+  require 'csv'
+
   before_action :find_project_by_project_id, only: [:index, :create, :import]
   before_action :find_ingredient, only: [:destroy]
   before_action :authorize
@@ -30,6 +32,78 @@ class IngredientsController < ApplicationController
   end
 
   def import
+    warnings = []
+
+    if params.has_key?(:file)
+      quantities = @project.quantities.map { |q| [q.name, q] }.to_h
+      units = @project.units.map { |u| [u.shortname, u] }.to_h
+      ingredients = []
+      column_units = {}
+
+      CSV.foreach(params[:file].path, headers: true).with_index(2) do |row, line|
+        r = row.to_h
+        i = {
+          name: r.delete('Name'),
+          group: r.delete('Group') || :other,
+          nutrients_attributes: []
+        }
+        r.each do |col, val|
+          if col.blank?
+            warnings << "Line 1: column header missing" if line == 2
+            next
+          end
+          quantity, quantity_unit_sn, * = col.rstrip.partition(/\[.*\]$/)
+          quantity.strip!
+          if line == 2
+            unless quantities[quantity]
+              warnings << "Line 1: unknown quantity name #{quantity}"
+            end
+            if quantity_unit_sn.present?
+              column_units[quantity] = units[quantity_unit_sn[1..-2]]
+              warnings << "Line 1: unknown unit #{quantity_unit_sn}" \
+                " in column #{col}" unless column_units[quantity]
+            end
+          end
+          next if quantities[quantity].blank? || val.blank?
+
+          amount, amount_unit_sn, * = val.rstrip.partition(/\[.*\]$/)
+          unit = nil
+          if amount_unit_sn.present?
+            unit = units[amount_unit_sn[1..-2]]
+            warnings << "Line #{line}: unknown unit name #{amount_unit_sn}" \
+              " in column #{col}" unless unit
+          else
+            unit = column_units[quantity]
+            # Suppress row warning if column unit error has been reported eariler
+            unless unit || column_units.has_key?(quantity)
+              warnings << "Line #{line}: unknown unit for column #{col}"
+            end
+          end
+
+          if quantity == 'Reference'
+            i.update({
+              ref_amount: amount.to_d,
+              ref_unit: unit
+            })
+          else
+            i[:nutrients_attributes] << {
+              quantity: quantities[quantity],
+              amount: amount.to_d,
+              unit: unit
+            }
+          end
+        end
+        ingredients << i
+      end
+    else
+      warnings << 'No file selected'
+    end
+
+    if warnings.present?
+      warnings.unshift("Problems encountered during import - fix and try again:")
+      flash[:warning] = warnings.join("<br>").truncate(1024, omission: '...(and other)')
+    end
+    redirect_to project_ingredients_url(@project)
   end
 
   private

config/locales/en.yml

@@ -40,8 +40,13 @@ en:
       heading_new_ingredient: 'New ingredient'
       label_import_select_csv_file: 'Select CSV file'
       import_hints: 'CSV file has to include header with column names. Recognized column
-        names are: (1) ingredient attributes (name, ref_amount, ref_unit, group),
-        (2) quantities names with units short names in square brackets (e.g. proteins [g])'
+        names are:
+        (1) ingredient attributes, case sensitive:
+        "Name" - required, "Reference" - defaults to 100[g], "Group" - defaults to "other",
+        (2) quantities'' names with unit short name in square brackets.
+        Sample header: "Name,Reference,Group,Proteins[g],Fats[g],Carbohydrates[g]".
+        Sample data row: "Brussels,100[g],other,3.4,300[mg],9".
+        Unit given in data row has precedence over that specified in header.'
     form:
       button_add_nutrient: 'Add nutrient'
       button_delete_nutrient: 'Delete'