Add MealPlan & Meal model

app/models/meal.rb

@@ -0,0 +1,4 @@
+class Meal < ApplicationRecord
+  belongs_to :meal_plan
+  belongs_to :recipe
+end

app/models/meal_plan.rb

@@ -0,0 +1,24 @@
+class MealPlan < ApplicationRecord
+  belongs_to :user
+  has_many :meals
+
+  validates :start_date, presence: true
+  validates :end_date, presence: true
+  validates :user, presence: true
+
+  def build_meals
+    user_recipe_ids = user.recipes.pluck(:id)
+
+    (start_date..end_date).each do |date|
+      unused_recipe_ids = user_recipe_ids - meals.map(&:recipe_id)
+
+      if unused_recipe_ids.empty?
+        available_recipe_ids = user_recipe_ids
+      else
+        available_recipe_ids = unused_recipe_ids
+      end
+
+      meals.build(date: date, recipe_id: available_recipe_ids.sample)
+    end
+  end
+end

config/application.rb

@@ -15,7 +15,7 @@
 # you've limited to :test, :development, or :production.
 Bundler.require(*Rails.groups)
 
-module MealPlan
+module MealPlanner
   class Application < Rails::Application
     # Settings in config/environments/* take precedence over those specified here.
     # Application configuration should go into files in config/initializers

db/migrate/20161205095851_create_meal_plans.rb

@@ -0,0 +1,10 @@
+class CreateMealPlans < ActiveRecord::Migration[5.0]
+  def change
+    create_table :meal_plans do |t|
+      t.date :start_date, null: false
+      t.date :end_date, null: false
+      t.references :user, null: false, foreign_key: true
+      t.timestamps null: false
+    end
+  end
+end

db/migrate/20161205100045_create_meals.rb

@@ -0,0 +1,10 @@
+class CreateMeals < ActiveRecord::Migration[5.0]
+  def change
+    create_table :meals do |t|
+      t.date :date, null: false
+      t.references :meal_plan, null: false, foreign_key: true
+      t.references :recipe, null: false, foreign_key: true
+      t.timestamps null: false
+    end
+  end
+end

db/schema.rb

@@ -10,11 +10,30 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20161119203421) do
+ActiveRecord::Schema.define(version: 20161205100045) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
+  create_table "meal_plans", force: :cascade do |t|
+    t.date     "start_date", null: false
+    t.date     "end_date",   null: false
+    t.integer  "user_id",    null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["user_id"], name: "index_meal_plans_on_user_id", using: :btree
+  end
+
+  create_table "meals", force: :cascade do |t|
+    t.date     "date",         null: false
+    t.integer  "meal_plan_id", null: false
+    t.integer  "recipe_id",    null: false
+    t.datetime "created_at",   null: false
+    t.datetime "updated_at",   null: false
+    t.index ["meal_plan_id"], name: "index_meals_on_meal_plan_id", using: :btree
+    t.index ["recipe_id"], name: "index_meals_on_recipe_id", using: :btree
+  end
+
   create_table "recipes", force: :cascade do |t|
     t.string   "name",        null: false
     t.text     "description", null: false
@@ -36,5 +55,8 @@
     t.index ["remember_token"], name: "index_users_on_remember_token", using: :btree
   end
 
+  add_foreign_key "meal_plans", "users"
+  add_foreign_key "meals", "meal_plans"
+  add_foreign_key "meals", "recipes"
   add_foreign_key "recipes", "users"
 end

test/factories/meal_plans.rb

@@ -0,0 +1,8 @@
+FactoryGirl.define do
+  factory :meal_plan do
+    start_date { Date.today }
+    end_date { 6.days.from_now.to_date }
+
+    association(:user)
+  end
+end

test/factories/meals.rb

@@ -0,0 +1,5 @@
+FactoryGirl.define do
+  factory :meal do
+
+  end
+end

test/models/meal_plan_test.rb

@@ -0,0 +1,64 @@
+require "test_helper"
+
+describe MealPlan do
+  describe "validity" do
+    let(:meal_plan) { MealPlan.new }
+
+    before do
+      meal_plan.valid?
+    end
+
+    it "requires a start date" do
+      meal_plan.errors[:start_date].must_include "can't be blank"
+    end
+
+    it "requires an end date" do
+      meal_plan.errors[:end_date].must_include "can't be blank"
+    end
+
+    it "requires a user" do
+      meal_plan.errors[:user].must_include "can't be blank"
+    end
+  end
+
+  describe "generating a weekly plan" do
+    let(:meal_plan) { build(:meal_plan) }
+
+    before do
+      7.times do
+        create(:recipe, user: meal_plan.user)
+      end
+    end
+
+    it "populates a meal for each day between the start date and the end date" do
+      meal_plan.meals.size.must_equal 0
+
+      meal_plan.build_meals
+
+      meal_plan.meals.size.must_equal 7
+    end
+
+    it "builds valid meals" do
+      meal_plan.build_meals
+
+      meal_plan.meals.all?(&:valid?).must_equal true
+    end
+
+    describe "with more days than recipes" do
+      let(:meal_plan) { build(:meal_plan, end_date: 8.days.from_now) }
+
+      it "build valid meals" do
+        meal_plan.build_meals
+
+        meal_plan.meals.all?(&:valid?).must_equal true
+      end
+
+      it "reuses recipes where necessary" do
+        meal_plan.build_meals
+
+        uniq_ids = meal_plan.meals.map(&:recipe_id).uniq
+        uniq_ids.size.must_equal 7
+      end
+    end
+  end
+end