From 2f1f1ef7d66523abf1f9f89e8a19d135431f52e3 Mon Sep 17 00:00:00 2001
From: Vladimir Zagainov <mrixs@mrixs.ru>
Date: Thu, 4 Jun 2026 06:51:11 +0300
Subject: [PATCH] fix: embed HTML templates into binary via go:embed
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Switched from runtime file-based template loading (os.Stat + ParseGlob)
to compile-time embedding (embed.FS + ParseFS). Templates are now
bundled into the binary — no need to COPY them into Docker image.

This fixes the fallback response issue where h.loaded was always false
because templates weren't present in the container filesystem.
---
 internal/templates/templates.go | 77 +++++++++------------------------
 1 file changed, 21 insertions(+), 56 deletions(-)

diff --git a/internal/templates/templates.go b/internal/templates/templates.go
index 60c2a8f..041efcf 100644
--- a/internal/templates/templates.go
+++ b/internal/templates/templates.go
@@ -2,16 +2,18 @@
 package templates
 
 import (
+	"embed"
 	"html/template"
 	"log"
 	"net/http"
-	"os"
-	"path/filepath"
 
 	"gitea.mrixs.me/Mrixs/MrixsCraft-server/internal/config"
 	"gitea.mrixs.me/Mrixs/MrixsCraft-server/internal/database"
 )
 
+//go:embed html/*.html
+var templateFS embed.FS
+
 // pageData is passed to all templates.
 type pageData struct {
 	Title    string
@@ -21,13 +23,12 @@ type pageData struct {
 
 // Handler serves template-rendered pages.
 type Handler struct {
-	db     *database.DB
-	cfg    *config.Config
-	tmpl   *template.Template
-	loaded bool
+	db   *database.DB
+	cfg  *config.Config
+	tmpl *template.Template
 }
 
-// NewHandler creates a new templates handler and parses on-disk templates.
+// NewHandler creates a new templates handler and parses embedded templates.
 func NewHandler(db *database.DB, cfg *config.Config) *Handler {
 	h := &Handler{db: db, cfg: cfg}
 	h.parseTemplates()
@@ -49,79 +50,43 @@ func (h *Handler) index(w http.ResponseWriter, r *http.Request) {
 		http.NotFound(w, r)
 		return
 	}
-	if !h.loaded {
-		fallback(w, "MrixsCraft")
-		return
-	}
 	h.render(w, "index.html", pageData{Title: "Главная"})
 }
 
 func (h *Handler) loginPage(w http.ResponseWriter, r *http.Request) {
-	if !h.loaded {
-		fallback(w, "Login")
-		return
-	}
 	h.render(w, "login.html", pageData{Title: "Вход"})
 }
 
 func (h *Handler) registerPage(w http.ResponseWriter, r *http.Request) {
-	if !h.loaded {
-		fallback(w, "Register")
-		return
-	}
 	h.render(w, "register.html", pageData{Title: "Регистрация"})
 }
 
 func (h *Handler) profilePage(w http.ResponseWriter, r *http.Request) {
-	if !h.loaded {
-		fallback(w, "Profile")
-		return
-	}
 	h.render(w, "profile.html", pageData{Title: "Профиль"})
 }
 
-// render executes the base layout template with the given content page.
-// The base.html layout calls {{template "content" .}} which is defined in each page file.
+// render executes the base layout template which calls {{template "content" .}}
+// to inject the named page content.
 func (h *Handler) render(w http.ResponseWriter, page string, data pageData) {
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	if h.tmpl == nil {
+		http.Error(w, "Templates not loaded", http.StatusInternalServerError)
+		return
+	}
 	if err := h.tmpl.ExecuteTemplate(w, "base.html", data); err != nil {
 		log.Printf("Template error (base.html → %s): %v", page, err)
-		// Fallback: render the page without layout
-		if err2 := h.tmpl.ExecuteTemplate(w, page, data); err2 != nil {
-			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
-		}
+		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
 	}
 }
 
-// fallback writes a minimal placeholder when templates are missing.
-func fallback(w http.ResponseWriter, title string) {
-	w.WriteHeader(http.StatusOK)
-	w.Write([]byte("<h1>" + title + "</h1>"))
-}
-
 // ── Template parsing ───────────────────────────────────────────
 
 func (h *Handler) parseTemplates() {
-	dirs := []string{
-		filepath.Join("internal", "templates", "html"),
-		"templates",
+	tmpl, err := template.New("").Funcs(template.FuncMap{}).ParseFS(templateFS, "html/*.html")
+	if err != nil {
+		log.Printf("Template parse error: %v", err)
+		return
 	}
-	for _, dir := range dirs {
-		if _, err := os.Stat(dir); err != nil {
-			continue
-		}
-		pattern := filepath.Join(dir, "*.html")
-		tmpl, err := template.New("").Funcs(template.FuncMap{}).ParseGlob(pattern)
-		if err != nil {
-			log.Printf("Template parse error in %s: %v", dir, err)
-			continue
-		}
-		if tmpl != nil {
-			h.tmpl = tmpl
-			h.loaded = true
-			log.Printf("Loaded templates from %s", dir)
-			return
-		}
-	}
-	log.Println("No HTML templates found; using placeholder responses")
+	h.tmpl = tmpl
+	log.Println("Loaded embedded HTML templates")
 }