package utils

import (
	"io"
	"os"
	"text/template"
)

// TemplateRenderer holds cached templates for rendering
type TemplateRenderer struct {
	baseTemplate *template.Template
	templateMap  map[string]*template.Template
}

// NewTemplateRenderer constructs a template renderer with a base file
func NewTemplateRenderer(baseFile string) *TemplateRenderer {
	return &TemplateRenderer{
		baseTemplate: template.Must(template.ParseFiles("./views/" + baseFile)),
		templateMap:  make(map[string]*template.Template),
	}
}

// Render the template
func (t *TemplateRenderer) Render(w io.Writer, name string, data interface{}) error {
	tmpl := t.templateMap[name]

	if os.Getenv("MODE") == "development" || tmpl == nil {
		tmpl = template.Must(t.baseTemplate.Clone())
		tmpl.ParseFiles("./views/" + name)
		t.templateMap[name] = tmpl
	}

	return tmpl.ExecuteTemplate(w, "base", data)
}