golang-template/internal/handlers/handler.go

package handlers

import (
	"context"
	"go-backend/internal/auth"
	"go-backend/internal/database/sqlc"
	"go-backend/internal/services"
	"log"
	"net/http"
	"text/template"
)

// UserService and AuthService are defined here, on the consumer side, so
// handlers depend only on the methods they actually use and tests can swap
// in fakes without touching the services package.

type UserService interface {
	FindByID(ctx context.Context, id string) (*sqlc.UserAuth, error)
	FindByUsername(ctx context.Context, username string) (*sqlc.UserAuth, error)
	CreateUser(ctx context.Context, userInput sqlc.InsertUserParams) (*sqlc.UserAuth, error)
}

type AuthService interface {
	CreateSession(ctx context.Context, userID string) (*services.SessionWithToken, error)
	ValidateSessionToken(ctx context.Context, token string) (*sqlc.UserSession, bool, error)
	DeleteSession(ctx context.Context, token string) error
}

type Handler struct {
	users UserService
	auth  AuthService
}

func NewHandler(users UserService, auth AuthService) *Handler {
	return &Handler{
		users: users,
		auth:  auth,
	}
}

func (h *Handler) HomeHandler(w http.ResponseWriter, r *http.Request) {
	cookie, err := r.Cookie("session")

	if err != nil {
		http.Redirect(w, r, "/login", http.StatusSeeOther)
		return
	}

	session, bump, err := h.auth.ValidateSessionToken(r.Context(), cookie.Value)

	if err != nil {
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}

	if session == nil {
		http.Redirect(w, r, "/login", http.StatusSeeOther)
		return
	}

	if bump {
		http.SetCookie(w, auth.NewSessionCookie(cookie.Value, false))
	}

	user, err := h.users.FindByID(r.Context(), session.UserID)

	if err != nil {
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}

	files := []string{
		"./ui/html/base.tmpl",
		"./ui/html/pages/index.tmpl",
	}

	ts, err := template.ParseFiles(files...)
	if err != nil {
		log.Print(err.Error())
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}

	err = ts.ExecuteTemplate(w, "base", user.Username)
	if err != nil {
		log.Print(err.Error())
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
	}
}

func (h *Handler) LoginPageHandler(w http.ResponseWriter, r *http.Request) {
	cookie, err := r.Cookie("session")

	if cookie != nil {
		session, bump, err := h.auth.ValidateSessionToken(r.Context(), cookie.Value)

		if err != nil {
			log.Print(err.Error())
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			return
		}

		if bump {
			http.SetCookie(w, auth.NewSessionCookie(cookie.Value, false))
		}

		if session != nil {
			http.Redirect(w, r, "/", http.StatusSeeOther)
			return
		}
	}

	files := []string{
		"./ui/html/base.tmpl",
		"./ui/html/pages/login.tmpl",
	}

	ts, err := template.ParseFiles(files...)
	if err != nil {
		log.Print(err.Error())
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}

	err = ts.ExecuteTemplate(w, "base", nil)
	if err != nil {
		log.Print(err.Error())
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
	}
}

func (h *Handler) SignUpPageHandler(w http.ResponseWriter, r *http.Request) {
	cookie, err := r.Cookie("session")

	if cookie != nil {
		session, bump, err := h.auth.ValidateSessionToken(r.Context(), cookie.Value)

		if err != nil {
			log.Print(err.Error())
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			return
		}

		if bump {
			http.SetCookie(w, auth.NewSessionCookie(cookie.Value, false))
		}

		if session != nil {
			http.Redirect(w, r, "/", http.StatusSeeOther)
			return
		}
	}

	files := []string{
		"./ui/html/base.tmpl",
		"./ui/html/pages/signup.tmpl",
	}

	ts, err := template.ParseFiles(files...)
	if err != nil {
		log.Print(err.Error())
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}

	err = ts.ExecuteTemplate(w, "base", nil)
	if err != nil {
		log.Print(err.Error())
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
	}
}