// Copyright 2018 ThousandEyes Inc.
//
// 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 utils

import (
	"fmt"
	"net"
	"path/filepath"
	"strings"
)

// Filter receives a slide of strings and a function that receives a string
// and returns a bool, and returns a slide that has only the strings that
// returned true when they were applied the received function.
func Filter(files []string, fn func(string) bool) []string {
	var ret []string
	for _, f := range files {
		if fn(f) {
			ret = append(ret, f)
		}
	}

	return ret
}

// StringInSlice receives a string and a slice of strings and returns true if it exists
// there.
func StringInSlice(a string, list []string) bool {
	for _, b := range list {
		if b == a {
			return true
		}
	}
	return false
}

// KeyInMap checks wheter the received key exists in the received map.
func KeyInMap(key string, mapInput map[string]interface{}) bool {
	_, found := mapInput[key]
	return found
}

// MapToString provides a string representation of a map of strings.
func MapToString(mapInput map[string]interface{}) string {
	result := ""
	for k, v := range mapInput {
		if len(result) > 0 {
			result += ", "
		}
		result += fmt.Sprintf("%s:%v", k, v)
	}
	return result
}

// BaseURLforEnvName provides an environment-sensitive method for returning
// the BaseURL of the application.
func BaseURLforEnvName(baseURL, environment string) string {
	if environment != "" {
		return filepath.Join(baseURL, "env", environment)
	}
	return baseURL
}

// ResolveHostname receives an IP and returns the resolved PTR. It returns an
// empty string in case the DNS lookup fails.
func ResolveHostname(ip string) (host string) {
	hosts, err := net.LookupAddr(ip)
	if err != nil {
		return ""
	}
	return hosts[0]
}

// IsValidIP returns whether or not an IP is well-formed.
func IsValidIP(ip string) bool {
	return net.ParseIP(ip) != nil
}

// IsValidMAC returns whether or not a MAC address is well-formed.
func IsValidMAC(mac string) bool {
	_, err := net.ParseMAC(mac)
	return err == nil
}

// MacColonToDash receives a mac address and replace its colons by dashes
func MacColonToDash(mac string) string {
	return strings.Replace(mac, ":", "-", -1)
}

// MacDashToColon receives a mac address and replace its dashes by colons
func MacDashToColon(mac string) string {
	return strings.Replace(mac, "-", ":", -1)
}