udemy-go-web-2/cmd/web/handlers.go

package main

import (
	"myapp/internal/cards"
	"myapp/internal/models"
	"net/http"
	"strconv"

	"github.com/go-chi/chi/v5"
)

func (app *application) Home(w http.ResponseWriter, r *http.Request) {
	if err := app.renderTemplate(w, r, "home", &templateData{}); err != nil {
		app.errorLog.Println(err)
	}
}

func (app *application) VirtualTerminal(w http.ResponseWriter, r *http.Request) {
	if err := app.renderTemplate(w, r, "terminal", &templateData{}); err != nil {
		app.errorLog.Println(err)
	}
}

type TransactionData struct {
	FirstName       string
	LastName        string
	Email           string
	PaymentIntentID string
	PaymentMethodID string
	PaymentAmount   int
	PaymentCurrency string
	LastFour        string
	ExpiryMonth     int
	ExpiryYear      int
	BankReturnCode  string
}

func (app *application) GetTransactionData(r *http.Request) (TransactionData, error) {
	var txnData TransactionData

	err := r.ParseForm()
	if err != nil {
		app.errorLog.Println(err)
		return txnData, err
	}

	firstName := r.Form.Get("first_name")
	lastName := r.Form.Get("last_name")
	email := r.Form.Get("cardholder_email")
	paymentIntent := r.Form.Get("payment_intent")
	paymentMethod := r.Form.Get("payment_method")
	paymentAmount := r.Form.Get("payment_amount")
	paymentCurrency := r.Form.Get("payment_currency")
	amount, _ := strconv.Atoi(paymentAmount)

	// TODO: validation of the data

	card := cards.Card{
		Secret: app.config.stripe.secret,
		Key:    app.config.stripe.key,
	}

	pi, err := card.RetrievePaymentIntent(paymentIntent)
	if err != nil {
		app.errorLog.Println(err)
		return txnData, err
	}

	pm, err := card.GetPaymentMethod(paymentMethod)
	if err != nil {
		app.errorLog.Println(err)
		return txnData, err
	}

	lastFour := pm.Card.Last4
	expiryMonth := pm.Card.ExpMonth
	expiryYear := pm.Card.ExpYear

	txnData = TransactionData{
		FirstName:       firstName,
		LastName:        lastName,
		Email:           email,
		PaymentIntentID: paymentIntent,
		PaymentMethodID: paymentMethod,
		PaymentAmount:   amount,
		PaymentCurrency: paymentCurrency,
		LastFour:        lastFour,
		ExpiryMonth:     int(expiryMonth),
		ExpiryYear:      int(expiryYear),
		BankReturnCode:  pi.LatestCharge.ID,
	}
	return txnData, nil
}

func (app *application) PaymentSucceeded(w http.ResponseWriter, r *http.Request) {
	// read posted data
	err := r.ParseForm()
	if err != nil {
		app.errorLog.Println(err)
		return
	}

	widgetID, _ := strconv.Atoi(r.Form.Get("product_id"))

	txnData, err := app.GetTransactionData(r)
	if err != nil {
		app.errorLog.Println(err)
		return
	}

	customerID, err := app.SaveCustomer(txnData.FirstName, txnData.LastName, txnData.Email)
	if err != nil {
		app.errorLog.Println(err)
		return
	}
	app.infoLog.Printf("custumer id: %d", customerID)

	transaction := models.Transaction{
		Amount:              txnData.PaymentAmount,
		Currency:            txnData.PaymentCurrency,
		LastFour:            txnData.LastFour,
		ExpiryMonth:         txnData.ExpiryMonth,
		ExpiryYear:          txnData.ExpiryYear,
		PaymentIntent:       txnData.PaymentIntentID,
		PaymentMethod:       txnData.PaymentMethodID,
		BankReturnCode:      txnData.BankReturnCode,
		TransactionStatusID: 2, // TODO: use an enum
	}

	txnID, err := app.SaveTransaction(transaction)
	if err != nil {
		app.errorLog.Println(err)
		return
	}
	app.infoLog.Printf("transaction id: %d", txnID)

	order := models.Order{
		WidgetID:      widgetID,
		TransactionID: txnID,
		CustomerID:    customerID,
		StatusID:      1,
		Quantity:      1,
		Amount:        txnData.PaymentAmount,
	}
	orderID, err := app.SaveOrder(order)
	if err != nil {
		app.errorLog.Println(err)
		return
	}
	app.infoLog.Printf("order id: %d", orderID)

	app.Session.Put(r.Context(), "txn", txnData)

	http.Redirect(w, r, "/receipt", http.StatusSeeOther)
}

func (app *application) Receipt(w http.ResponseWriter, r *http.Request) {
	txn := app.Session.Pop(r.Context(), "txn").(TransactionData)
	data := make(map[string]interface{})
	data["txn"] = txn
	if err := app.renderTemplate(w, r, "receipt", &templateData{
		Data: data,
	}); err != nil {
		app.errorLog.Println(err)
	}
}

func (app *application) SaveCustomer(firstName, lastName, email string) (int, error) {
	customer := models.Customer{
		FirstName: firstName,
		LastName:  lastName,
		Email:     email,
	}

	id, err := app.DB.InsertCustomer(customer)
	if err != nil {
		return 0, err
	}

	return id, nil
}

func (app *application) SaveTransaction(txn models.Transaction) (int, error) {
	txnID, err := app.DB.InsertTransaction(txn)
	if err != nil {
		app.errorLog.Println(err)
		return 0, err
	}

	return txnID, nil
}

func (app *application) SaveOrder(order models.Order) (int, error) {
	id, err := app.DB.InsertOrder(order)
	if err != nil {
		app.errorLog.Println(err)
		return 0, err
	}

	return id, nil
}

// ChargeOnce displays the page to buy one widget
func (app *application) ChargeOnce(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	widgetID, _ := strconv.Atoi(id)

	widget, err := app.DB.GetWidget(widgetID)
	if err != nil {
		app.errorLog.Println(err)
	}

	data := make(map[string]interface{})
	data["widget"] = widget

	if err := app.renderTemplate(w, r, "buy-once", &templateData{
		Data: data,
	}); err != nil {
		app.errorLog.Println(err)
	}
}