package common

import (
	"bytes"
	"text/template"
)

func isalphanumeric(b byte) bool {
	if '0' <= b && b <= '9' {
		return true
	}
	if 'a' <= b && b <= 'z' {
		return true
	}
	if 'A' <= b && b <= 'Z' {
		return true
	}
	return false
}

// Clean up AMI name by replacing invalid characters with "-"
func templateCleanAMIName(s string) string {
	allowed := []byte{'(', ')', ',', '/', '-', '_', ' '}
	b := []byte(s)
	newb := make([]byte, len(b))
	for i, c := range b {
		if isalphanumeric(c) || bytes.IndexByte(allowed, c) != -1 {
			newb[i] = c
		} else {
			newb[i] = '-'
		}
	}
	return string(newb[:])
}

var TemplateFuncs = template.FuncMap{
	"clean_ami_name": templateCleanAMIName,
}