package resource

import (
	"bytes"
	"fmt"
	"log"
	"text/template"
)


// DefaultRenderTemplate is an adapter to implement the builtin golang text template renderer as resource.RenderTemplate.
func DefaultRenderTemplate(r Resource, sym string, values map[string]string, idx uint16, sizer *Sizer) (string, error) {
	v, err := r.GetTemplate(sym, nil)
	if err != nil {
		return "", err
	}

	if sizer != nil {
		values, err = sizer.GetAt(values, idx)
	} else if idx > 0 {
		return "", fmt.Errorf("sizer needed for indexed render")
	}
	log.Printf("render for index: %v", idx)

	if err != nil {
		return "", err
	}
	
	tp, err := template.New("tester").Option("missingkey=error").Parse(v)
	if err != nil {
		return "", err
	}

	b := bytes.NewBuffer([]byte{})
	err = tp.Execute(b, values)
	if err != nil {
		return "", err
	}
	return b.String(), err
}