Feat/create

app/controllers/api/v1/merchants/coupons_controller.rb

@@ -0,0 +1,29 @@
+class Api::V1::Merchants::CouponsController < ApplicationController
+
+  def show 
+    coupon = Coupon.find(params[:id])
+    render json: CouponSerializer.new(coupon)
+  end
+
+  def index
+    merchant = Merchant.find(params[:merchant_id])
+    coupons = merchant.coupons
+    render json: CouponSerializer.new(coupons)
+  end
+
+  def create
+    merchant = Merchant.find(params[:merchant_id])
+    coupon = merchant.coupons.new(coupon_params)
+    if coupon.save 
+      render json: CouponSerializer.new(coupon), status: :created 
+    else
+      render json: { errors: coupon.errors.full_messages }, status: :unprocessable_entity 
+    end
+  end
+
+  private
+
+  def coupon_params
+    params.require(:coupon).permit(:name, :code, :discount_value, :active)
+  end
+end

app/models/coupon.rb

@@ -0,0 +1,7 @@
+class Coupon < ApplicationRecord
+  belongs_to :merchant
+  has_many :invoices
+  validates :code, uniqueness: { scope: :merchant_id, message: "has already been taken" }
+  validates :name, :code, presence: true
+  validates :active, inclusion: { in: [true, false] }
+end

app/models/invoice.rb

@@ -1,6 +1,7 @@
 class Invoice < ApplicationRecord
   belongs_to :customer
   belongs_to :merchant
+  belongs_to :coupon, optional: true
   has_many :invoice_items, dependent: :destroy
   has_many :transactions, dependent: :destroy
 

app/models/merchant.rb

@@ -3,6 +3,7 @@ class Merchant < ApplicationRecord
   has_many :items, dependent: :destroy
   has_many :invoices, dependent: :destroy
   has_many :customers, through: :invoices
+  has_many :coupons
   # has_many :invoice_items, through: :invoices
   # has_many :transactions, through: :invoices
 

app/serializers/coupon_serializer.rb

@@ -0,0 +1,4 @@
+class CouponSerializer
+  include JSONAPI::Serializer
+  attributes :id, :name, :code, :discount_value, :active, :merchant_id
+end

config/routes.rb

@@ -24,6 +24,7 @@
         resources :items, only: :index, controller: "merchants/items"
         resources :customers, only: :index, controller: "merchants/customers"
         resources :invoices, only: :index, controller: "merchants/invoices"
+        resources :coupons, only: [:index, :show, :create], controller: "merchants/coupons"
       end
     end
   end

db/migrate/20240919204137_create_coupons.rb

@@ -0,0 +1,14 @@
+class CreateCoupons < ActiveRecord::Migration[7.1]
+  def change
+    create_table :coupons do |t|
+      t.string :name
+      t.string :code
+      t.decimal :discount_value
+      t.boolean :active
+      t.references :merchant, null: false, foreign_key: true
+
+      t.timestamps
+    end
+    add_index :coupons, :code, unique: true
+  end
+end

db/migrate/20240919204828_add_coupon_to_invoices.rb

@@ -0,0 +1,5 @@
+class AddCouponToInvoices < ActiveRecord::Migration[7.1]
+  def change
+    add_reference :invoices, :coupon, null: true, foreign_key: true
+  end
+end

spec/factories/coupons.rb

@@ -0,0 +1,9 @@
+FactoryBot.define do
+  factory :coupon do
+    name { "MyString" }
+    code { "MyString" }
+    discount_value { "9.99" }
+    active { false }
+    merchant 
+  end
+end

spec/models/coupon_spec.rb

@@ -0,0 +1,24 @@
+require 'rails_helper'
+
+require 'rails_helper'
+
+RSpec.describe Coupon, type: :model do
+  before do
+    @merchant = Merchant.create(name: "Test Merchant")
+  end
+
+  it { should belong_to(:merchant) }
+  it { should have_many(:invoices) }
+
+  it { should validate_presence_of(:name) }
+  it { should validate_presence_of(:code) }
+  it { should validate_inclusion_of(:active).in_array([true, false]) }
+
+  it 'validates uniqueness of code scoped to merchant_id' do
+    Coupon.create!(name: "Existing Coupon", code: "UNIQUECODE", active: true, merchant: @merchant)
+    new_coupon = Coupon.new(name: "New Coupon", code: "UNIQUECODE", active: true, merchant: @merchant)
+
+    expect(new_coupon).not_to be_valid
+    expect(new_coupon.errors[:code]).to include("has already been taken")
+  end
+end

spec/models/invoice_spec.rb

@@ -3,5 +3,8 @@
 RSpec.describe Invoice do
   it { should belong_to :merchant }
   it { should belong_to :customer }
+  it { should belong_to(:coupon).optional}
+  it { should have_many(:invoice_items).dependent(:destroy) }
+  it { should have_many(:transactions).dependent(:destroy) }
   it { should validate_inclusion_of(:status).in_array(%w(shipped packaged returned)) }
 end

spec/models/merchant_spec.rb

@@ -9,6 +9,7 @@
     it { should have_many :items }
     it { should have_many :invoices }
     it { should have_many(:customers).through(:invoices) }
+    it { should have_many(:coupons)}
   end
 
   describe "class methods" do

spec/requests/api/v1/merchant/coupons_request_spec.rb

@@ -0,0 +1,101 @@
+require 'rails_helper'
+
+RSpec.describe "Coupons", type: :request do
+  describe "GET /show" do
+    it 'return one coupon by id' do 
+      merchant = Merchant.create!(id: 1, name: "Sample Merchant")
+      coupon = Coupon.create!(name: "Buy One Get One 50", code: "BOGO50", discount_value: 50, active: true, merchant_id: merchant.id)
+
+      get "/api/v1/merchants/#{merchant.id}/coupons/#{coupon.id}"
+
+      expect(response).to have_http_status(200)
+      expect(response).to be_successful
+
+      json_response = JSON.parse(response.body)
+
+      expect(json_response['data']['id']).to eq(coupon.id.to_s)
+      expect(json_response['data']['type']).to eq('coupon')
+      expect(json_response['data']['attributes']['name']).to eq(coupon.name)
+      expect(json_response['data']['attributes']['code']).to eq(coupon.code)
+      expect(json_response['data']['attributes']['discount_value']).to be_a(String)
+      expect(json_response['data']['attributes']['active']).to eq(coupon.active?)
+      expect(json_response['data']['attributes']['merchant_id']).to eq(coupon.merchant_id)
+    end
+
+    it 'returns a 404 when a coupon does not exist' do
+      merchant = Merchant.create!(id: 1, name: "Sample Merchant")
+
+      get "/api/v1/merchants/#{merchant.id}/coupons/9999"
+
+      expect(response).to have_http_status(404)
+      json_response = JSON.parse(response.body)
+
+      expect(json_response['message']).to include("Your query could not be completed")
+      expect(json_response['errors']).to include("Couldn't find Coupon with 'id'=9999")
+    end
+  end
+
+  describe 'GET/index' do
+    it 'returns all coupons for certain merchant id' do 
+      merchant = Merchant.create!(id: 1, name: "Sample Merchant")
+      Coupon.create!(name: "Buy One Get One 50", code: "BOGO50", discount_value: 50, active: true, merchant_id: merchant.id)
+      Coupon.create!(name: "Buy One Get One 40", code: "BOGO40", discount_value: 40, active: true, merchant_id: merchant.id)
+      Coupon.create!(name: "Buy One Get One 30", code: "BOGO30", discount_value: 30, active: false, merchant_id: merchant.id)
+      Coupon.create!(name: "Buy One Get One 20", code: "BOGO20", discount_value: 20, active: false, merchant_id: merchant.id)
+
+      get "/api/v1/merchants/#{merchant.id}/coupons"
+
+      expect(response).to be_successful
+
+      json_response = JSON.parse(response.body, symbolize_names: true)[:data]
+      expect(json_response.size).to eq(4)
+
+      json_response.each do |coupon|
+        expect(coupon[:id]).to be_a(String)
+        expect(coupon[:type]).to eq('coupon')
+        expect(coupon[:attributes]).to have_key(:id)
+        expect(coupon[:attributes][:id]).to be_an(Integer)
+        expect(coupon[:attributes][:name]).to be_a(String)
+        expect(coupon[:attributes][:code]).to be_a(String)
+        expect(coupon[:attributes][:discount_value]).to be_a(String)
+        expect([true, false]).to include(coupon[:attributes][:active])
+        expect(coupon[:attributes][:merchant_id]).to be_an(Integer)
+      end
+    end
+
+      it 'returns an error is there is no merchant with that id' do 
+        merchant = Merchant.create!(id: 1, name: "Sample Merchant")
+        Coupon.create!(name: "Buy One Get One 50", code: "BOGO50", discount_value: 50, active: true, merchant_id: merchant.id)
+        Coupon.create!(name: "Buy One Get One 40", code: "BOGO40", discount_value: 40, active: true, merchant_id: merchant.id)
+        Coupon.create!(name: "Buy One Get One 30", code: "BOGO30", discount_value: 30, active: false, merchant_id: merchant.id)
+        Coupon.create!(name: "Buy One Get One 20", code: "BOGO20", discount_value: 20, active: false, merchant_id: merchant.id)
+
+        get "/api/v1/merchants/9999/coupons"
+
+        expect(response).to have_http_status(404)
+
+        json_response = JSON.parse(response.body)
+
+        expect(json_response['message']).to include("Your query could not be completed")
+        expect(json_response['errors']).to include("Couldn't find Merchant with 'id'=9999")
+      end
+    end
+
+    describe 'POST' do 
+      it 'creates a new coupon' do 
+        merchant = Merchant.create!(name: "Sample Merchant")
+        coupon_params = { name: "Buy One Get One 50", code: "BOGO50", discount_value: 50, active: true }
+
+        post "/api/v1/merchants/#{merchant.id}/coupons", params: { coupon: coupon_params }
+
+        expect(response).to have_http_status(201)
+
+        created_coupon = Coupon.last
+        expect(created_coupon.name).to eq("Buy One Get One 50")
+        expect(created_coupon.code).to eq("BOGO50")
+        expect(created_coupon.discount_value).to eq(50)
+        expect(created_coupon.active).to be_truthy
+        expect(created_coupon.merchant_id).to eq(merchant.id)
+      end
+    end
+end