1 files changed, 120 insertions, 0 deletions
diff --git a/internal/templatemanager/templatemanager.go b/internal/templatemanager/templatemanager.go
new file mode 100644
index 0000000..75309e4
--- /dev/null
+++ b/internal/templatemanager/templatemanager.go
@@ -0,0 +1,120 @@
+package templatemanager
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"path/filepath"
+	"strings"
+)
+
+type TemplateManager struct {
+	templates map[string]templateManagerRender
+}
+
+type templateManagerRender struct {
+	Main string
+	Tmpl *template.Template
+}
+
+type TemplateManagerTemplates struct {
+	Name  string
+	Files []string
+}
+
+var templateFuncMap = template.FuncMap{
+	"contains": strings.Contains,
+	"iterate": func(count uint) []uint {
+		items := make([]uint, count)
+		for i := range count {
+			items[i] = i
+		}
+		return items
+	},
+	"replace": strings.ReplaceAll,
+}
+
+func NewTemplateManager(templates ...TemplateManagerTemplates) (*TemplateManager, error) {
+	templateMap := make(map[string]templateManagerRender)
+
+	for _, tmplStruct := range templates {
+		tmpl := template.New(tmplStruct.Name).Funcs(templateFuncMap)
+		if len(tmplStruct.Files) == 0 {
+			templateMap[tmplStruct.Name] = templateManagerRender{
+				Main: "",
+				Tmpl: tmpl,
+			}
+			continue
+		}
+		tmpl, err := tmpl.ParseFiles(tmplStruct.Files...)
+		if err != nil {
+			return nil, err
+		}
+
+		templateMap[tmplStruct.Name] = templateManagerRender{
+			Main: filepath.Base(tmplStruct.Files[0]),
+			Tmpl: tmpl,
+		}
+	}
+
+	return &TemplateManager{
+		templates: templateMap,
+	}, nil
+}
+
+func (tm *TemplateManager) Render(name string, data any, files ...string) ([]byte, error) {
+	tmpl, exists := tm.templates[name]
+	if !exists {
+		return nil, fmt.Errorf("template %s not found", name)
+	}
+
+	var err error
+	var tempTmpl *template.Template
+	var mainTmpl string = tmpl.Main
+	if len(files) == 0 {
+		if mainTmpl == "" {
+			return []byte{}, nil
+		}
+		tempTmpl = tmpl.Tmpl
+	} else {
+		tempTmpl, err = tmpl.Tmpl.Clone()
+		if err != nil {
+			return nil, fmt.Errorf("couldn't clone existing template for rendering: %w", err)
+		}
+		tempTmpl, err = tempTmpl.ParseFiles(files...)
+		if err != nil {
+			return nil, fmt.Errorf("couldn't include additional files in template rendering: %w", err)
+		}
+		if mainTmpl == "" {
+			mainTmpl = filepath.Base(files[0])
+		}
+	}
+
+	var buf bytes.Buffer
+	err = tempTmpl.ExecuteTemplate(&buf, mainTmpl, data)
+	return buf.Bytes(), err
+}
+
+func (tm *TemplateManager) Add(name string, files ...string) error {
+	tmpl := template.New(name).Funcs(templateFuncMap)
+
+	if len(files) == 0 {
+		tm.templates[name] = templateManagerRender{
+			Main: "",
+			Tmpl: tmpl,
+		}
+		return nil
+	}
+
+	tmpl, err := tmpl.ParseFiles(files...)
+	if err != nil {
+		return fmt.Errorf("failed to add template into manager: %w", err)
+	}
+
+	tm.templates[name] = templateManagerRender{
+		Main: filepath.Base(files[0]),
+		Tmpl: tmpl,
+	}
+
+	return nil
+}