// Copyright (c) nano Author. All Rights Reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

package nano

import (
	"bytes"
	"encoding/gob"
	"os"
	"runtime"
	"strings"
)

func serializeOrRaw(v interface{}) ([]byte, error) {
	if data, ok := v.([]byte); ok {
		return data, nil
	}
	data, err := serializer.Marshal(v)
	if err != nil {
		return nil, err
	}
	return data, nil
}

func gobEncode(args ...interface{}) ([]byte, error) {
	buf := bytes.NewBuffer([]byte(nil))
	if err := gob.NewEncoder(buf).Encode(args); err != nil {
		return nil, err
	}
	return buf.Bytes(), nil
}

func gobDecode(reply interface{}, data []byte) error {
	return gob.NewDecoder(bytes.NewReader(data)).Decode(reply)
}

func fileExists(filename string) bool {
	_, err := os.Stat(filename)
	return err == nil || os.IsExist(err)
}

func stack() string {
	buf := make([]byte, 10000)
	n := runtime.Stack(buf, false)
	buf = buf[:n]

	s := string(buf)

	// skip nano frames lines
	const skip = 7
	count := 0
	index := strings.IndexFunc(s, func(c rune) bool {
		if c != '\n' {
			return false
		}
		count++
		return count == skip
	})
	return s[index+1:]
}