/*
 * Copyright 2020 The Knative Authors
 * 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 sender

import (
	"math/rand"
	"time"

	"knative.dev/eventing/test/upgrade/prober/wathola/config"
)

// New creates new Sender
func New() Sender {
	config.ReadIfPresent()
	return &sender{
		eventsSent: 0,
	}
}

// NewEventID creates new event ID
func NewEventID() string {
	return randString(16)
}

const charset = "abcdefghijklmnopqrstuvwxyz" +
	"ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"

var seededRand = rand.New(
	rand.NewSource(time.Now().UnixNano()))

func randStringWithCharset(length int, charset string) string {
	b := make([]byte, length)
	for i := range b {
		b[i] = charset[seededRand.Intn(len(charset))]
	}
	return string(b)
}

func randString(length int) string {
	return randStringWithCharset(length, charset)
}
