parsley/app/controllers/ingredients_controller.rb

class IngredientsController < ApplicationController
  before_action :set_ingredient, only: [:edit, :update, :destroy]

  # GET /ingredients
  # GET /ingredients.json
  def index
    @ingredients = Ingredient.all.order(:name)
  end

  # GET /ingredients/new
  def new
    @ingredient = Ingredient.new
  end

  # GET /ingredients/1/edit
  def edit
  end

  # POST /ingredients
  # POST /ingredients.json
  def create
    @ingredient = Ingredient.new(ingredient_params)

    respond_to do |format|
      if @ingredient.save
        format.html { redirect_to ingredients_path, notice: 'Ingredient was successfully created.' }
        format.json { render :show, status: :created, location: @ingredient }
      else
        format.html { render :new }
        format.json { render json: @ingredient.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /ingredients/1
  # PATCH/PUT /ingredients/1.json
  def update
    respond_to do |format|
      if @ingredient.update(ingredient_params)
        format.html { redirect_to @ingredient, notice: 'Ingredient was successfully updated.' }
        format.json { render :show, status: :ok, location: @ingredient }
      else
        format.html { render :edit }
        format.json { render json: @ingredient.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /ingredients/1
  # DELETE /ingredients/1.json
  def destroy
    @ingredient.destroy
    respond_to do |format|
      format.html { redirect_to ingredients_url, notice: 'Ingredient was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  def prefetch
    @ingredients = Ingredient.all.order(:name)
    render :search
  end

  def search
    query = params[:query] + '%'
    @ingredients = Ingredient.where("name LIKE ?", query).order(:name)
  end

  def convert
    @conversion = Conversion.new(conversion_params)

    if @conversion.valid?
      @output_quantity = @conversion.output_quantity
      @conversion = Conversion.new
    else
      @output_quantity = ''
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_ingredient
      @ingredient = Ingredient.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def ingredient_params
      params.require(:ingredient).permit(:name, :density, :notes)
    end

    def conversion_params
      params.require(:conversion).permit(:input_quantity, :input_units, :scale, :output_units, :density)
    end
end