V2 alpha - initial version (#172)

Initial alpha codebase for version 2 of WireGuard Portal.
This version is considered unstable and incomplete (for example, no public REST API)! 
Use with care!


Fixes/Implements the following issues:
 - OAuth support #154, #1 
 - New Web UI with internationalisation support #98, #107, #89, #62
 - Postgres Support #49 
 - Improved Email handling #47, #119 
 - DNS Search Domain support #46 
 - Bugfixes #94, #48 

---------

Co-authored-by: Fabian Wechselberger <wechselbergerf@hotmail.com>

internal/app/mail/template.go

@@ -0,0 +1,93 @@
+package mail
+
+import (
+	"bytes"
+	"embed"
+	"fmt"
+	htmlTemplate "html/template"
+	"io"
+	"text/template"
+
+	"github.com/h44z/wg-portal/internal/domain"
+)
+
+//go:embed tpl_files/*
+var TemplateFiles embed.FS
+
+type TemplateHandler struct {
+	portalUrl     string
+	htmlTemplates *htmlTemplate.Template
+	textTemplates *template.Template
+}
+
+func newTemplateHandler(portalUrl string) (*TemplateHandler, error) {
+	htmlTemplateCache, err := htmlTemplate.New("Html").ParseFS(TemplateFiles, "tpl_files/*.gohtml")
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse html template files: %w", err)
+	}
+
+	txtTemplateCache, err := template.New("Txt").ParseFS(TemplateFiles, "tpl_files/*.gotpl")
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse text template files: %w", err)
+	}
+
+	handler := &TemplateHandler{
+		portalUrl:     portalUrl,
+		htmlTemplates: htmlTemplateCache,
+		textTemplates: txtTemplateCache,
+	}
+
+	return handler, nil
+}
+
+func (c TemplateHandler) GetConfigMail(user *domain.User, link string) (io.Reader, io.Reader, error) {
+	var tplBuff bytes.Buffer
+	var htmlTplBuff bytes.Buffer
+
+	err := c.textTemplates.ExecuteTemplate(&tplBuff, "mail_with_link.gotpl", map[string]interface{}{
+		"User":      user,
+		"Link":      link,
+		"PortalUrl": c.portalUrl,
+	})
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to execute template mail_with_link.gotpl: %w", err)
+	}
+
+	err = c.htmlTemplates.ExecuteTemplate(&htmlTplBuff, "mail_with_link.gohtml", map[string]interface{}{
+		"User":      user,
+		"Link":      link,
+		"PortalUrl": c.portalUrl,
+	})
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to execute template mail_with_link.gohtml: %w", err)
+	}
+
+	return &tplBuff, &htmlTplBuff, nil
+}
+
+func (c TemplateHandler) GetConfigMailWithAttachment(user *domain.User, cfgName, qrName string) (io.Reader, io.Reader, error) {
+	var tplBuff bytes.Buffer
+	var htmlTplBuff bytes.Buffer
+
+	err := c.textTemplates.ExecuteTemplate(&tplBuff, "mail_with_attachment.gotpl", map[string]interface{}{
+		"User":           user,
+		"ConfigFileName": cfgName,
+		"QrcodePngName":  qrName,
+		"PortalUrl":      c.portalUrl,
+	})
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to execute template mail_with_attachment.gotpl: %w", err)
+	}
+
+	err = c.htmlTemplates.ExecuteTemplate(&htmlTplBuff, "mail_with_attachment.gohtml", map[string]interface{}{
+		"User":           user,
+		"ConfigFileName": cfgName,
+		"QrcodePngName":  qrName,
+		"PortalUrl":      c.portalUrl,
+	})
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to execute template mail_with_attachment.gohtml: %w", err)
+	}
+
+	return &tplBuff, &htmlTplBuff, nil
+}