// Copyright 2015 Prometheus Team
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package notification

import (
	"bytes"
	"strings"
)

var (
	defaultFuncs = map[string]interface{}{
		"toUpper":  strings.ToUpper,
		"toLower":  strings.ToLower,
		"markdown": markdownEscapeString,
	}
	isMarkdownSpecial [128]bool
)

func init() {
	for _, c := range "_*`" {
		isMarkdownSpecial[c] = true
	}
}

func markdownEscapeString(s string) string {
	b := make([]byte, 0, len(s))
	buf := bytes.NewBuffer(b)

	for _, c := range s {
		if c < 128 && isMarkdownSpecial[c] {
			buf.WriteByte('\\')
		}
		buf.WriteRune(c)
	}
	return buf.String()
}
