From 3f10f7b912bb2b46980e0d07a57c1842d30b4392 Mon Sep 17 00:00:00 2001
From: Nikita Tokarchuk <nikita@tokarch.uk>
Date: Tue, 4 Jan 2022 22:32:06 +0100
Subject: [PATCH] Implement template funcs controller instead of simple funcs
 map

---
 cmd/renderer/main.go       |  3 +-
 pkg/templates/funcs.go     | 78 +++++++++++++++++++++++++++++---------
 pkg/templates/templates.go |  7 ++--
 3 files changed, 65 insertions(+), 23 deletions(-)

diff --git a/cmd/renderer/main.go b/cmd/renderer/main.go
index 854d923..46419a7 100644
--- a/cmd/renderer/main.go
+++ b/cmd/renderer/main.go
@@ -52,7 +52,8 @@ func main() {
 		logrus.Fatal(err)
 	}
 
-	err = templates.Load()
+	templateFuncs := &templates.Funcs{Version: Version}
+	err = templates.Load(templateFuncs)
 	if err != nil {
 		logrus.Fatal(err)
 	}
diff --git a/pkg/templates/funcs.go b/pkg/templates/funcs.go
index aedbf17..41d1927 100644
--- a/pkg/templates/funcs.go
+++ b/pkg/templates/funcs.go
@@ -1,24 +1,66 @@
 package templates
 
-import "html/template"
+import (
+	"html/template"
+	"net/url"
+	"sync"
+)
 
-// UseFuncs returns a func map with template helpers functions
-func UseFuncs() template.FuncMap {
+type Funcs struct {
+	Version string
+
+	compiledJSAppURL string
+
+	initOnce sync.Once
+}
+
+func (f *Funcs) init() {
+
+	jsAppURL, err := url.Parse(URLJSApp)
+	if err != nil {
+		panic(err)
+	}
+
+	{
+		q := jsAppURL.Query()
+		q.Add("version", f.Version)
+
+		jsAppURL.RawQuery = q.Encode()
+	}
+
+	f.compiledJSAppURL = jsAppURL.String()
+}
+
+func (f *Funcs) add(i int) int {
+	return i + 1
+}
+
+func (f *Funcs) sub(i int) int {
+	return i - 1
+}
+
+func (f *Funcs) getJSAppURL() string {
+
+	f.initOnce.Do(f.init)
+
+	return f.compiledJSAppURL
+}
+
+func (f *Funcs) getIndexURL() string {
+	return URLIndex
+}
+
+func (f *Funcs) getBlogURL() string {
+	return URLBlog
+}
+
+// Use returns a func map with template helpers functions
+func (f *Funcs) Use() template.FuncMap {
 	return template.FuncMap{
-		"add": func(i int) int {
-			return i + 1
-		},
-		"sub": func(i int) int {
-			return i - 1
-		},
-		"getJSAppURL": func() string {
-			return URLJSApp
-		},
-		"getIndexURL": func() string {
-			return URLIndex
-		},
-		"getBlogURL": func() string {
-			return URLBlog
-		},
+		"add":         f.add,
+		"sub":         f.sub,
+		"getJSAppURL": f.getJSAppURL,
+		"getIndexURL": f.getIndexURL,
+		"getBlogURL":  f.getBlogURL,
 	}
 }
diff --git a/pkg/templates/templates.go b/pkg/templates/templates.go
index 9cece2c..90c27d6 100644
--- a/pkg/templates/templates.go
+++ b/pkg/templates/templates.go
@@ -21,13 +21,12 @@ import (
 var content embed.FS
 
 // List of compiled go-templates
-var Templates *template.Template
+var Templates *template.Template = template.New("")
 
 // Load embeded templates
-func Load() (err error) {
+func Load(funcs *Funcs) (err error) {
 
-	Templates = template.New("")
-	Templates.Funcs(UseFuncs())
+	Templates.Funcs(funcs.Use())
 
 	tmplNames, err := fs.Glob(content, "*.go.tmpl")
 	if err != nil {