/*
DESCRIPTION
  utils.go houses generic vidforward utilities and helper functions.

AUTHORS
  Saxon A. Nelson-Milton <saxon@ausocean.org>

LICENSE
  Copyright (C) 2022 the Australian Ocean Lab (AusOcean)

  It is free software: you can redistribute it and/or modify them
  under the terms of the GNU General Public License as published by the
  Free Software Foundation, either version 3 of the License, or (at your
  option) any later version.

  It is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  for more details.

  You should have received a copy of the GNU General Public License
  along with revid in gpl.txt. If not, see http://www.gnu.org/licenses.
*/

package main

import (
	"fmt"
	"net/http"
	"strconv"

	"bitbucket.org/ausocean/utils/logging"
)

// writeError logs an error and writes to w in JSON format.
func (m *broadcastManager) errorLogWrite(log logging.Logger, w http.ResponseWriter, msg string, args ...interface{}) {
	log.Error(msg, args...)
	w.Header().Add("Content-Type", "application/json")
	fmt.Fprint(w, `{"er":"`+msg+`"}`)
}

// isMac returns true if the provided string is a valid mac address.
func isMac(m string) bool {
	if len(m) != 17 || m == "00:00:00:00:00:00" {
		return false
	}

	for i := 0; i <= 15; i++ {
		if (i+1)%3 == 0 && m[i] != ':' {
			return false
		}

		if (3-i)%3 != 0 {
			continue
		}

		_, err := strconv.ParseUint(m[i:i+2], 16, 64)
		if err != nil {
			return false
		}
	}
	return true
}