Copyright (c) Microsoft Corporation. All rights reserved.
Licensed under the MIT License. See License.txt in the project root for
license information.
/**
 * Copyright (c) Microsoft Corporation. All rights reserved.
 * Licensed under the MIT License. See License.txt in the project root for
 * license information.
 */

package com.microsoft.azure.management.resources.fluentcore.utils;

import org.joda.time.DateTime;
import org.joda.time.DateTimeZone;

import java.util.Random;
import java.util.UUID;

The ResourceNamer to generate random name.
/**
 * The ResourceNamer to generate random name.
 */
public class ResourceNamer {
    private final String randName;
    private static final Random RANDOM = new Random();

    
Creates ResourceNamer.
Params:
name – the randName/**
     * Creates ResourceNamer.
     *
     * @param name the randName
     */
    public ResourceNamer(String name) {
        this.randName = name.toLowerCase() + UUID.randomUUID().toString().replace("-", "").substring(0, 3).toLowerCase();
    }

    
Gets a random name.
Params:
prefix – the prefix to be used if possible
maxLen – the max length for the random generated name
Returns:
the random name/**
     * Gets a random name.
     *
     * @param prefix the prefix to be used if possible
     * @param maxLen the max length for the random generated name
     * @return the random name
     */
    public String randomName(String prefix, int maxLen) {
        prefix = prefix.toLowerCase();
        int minRandomnessLength = 5;
        if (maxLen <= minRandomnessLength) {
            return randomString(maxLen);
        }

        if (maxLen < prefix.length() + minRandomnessLength) {
            return randomString(maxLen);
        }

        String minRandomString = String.format("%05d", Math.abs(RANDOM.nextInt() % 100000));

        if (maxLen <= prefix.length() + randName.length() + minRandomnessLength) {
            String str = prefix + minRandomString;
            return str + randomString((maxLen - str.length()) / 2);
        }

        String str = prefix + randName + minRandomString;
        return str + randomString((maxLen - str.length()) / 2);
    }

    
Creates a random UUID.
Returns:
the UUID string./**
     * Creates a random UUID.
     * @return the UUID string.
     */
    public String randomUuid() {
        return UUID.randomUUID().toString();
    }

    
Returns:
the current time./**
     * @return the current time.
     */
    public DateTime dateTimeNow() {
        return DateTime.now(DateTimeZone.UTC);
    }

    private String randomString(int length) {
        StringBuilder str = new StringBuilder();
        while (str.length() < length) {
            str.append(UUID.randomUUID()
                    .toString()
                    .replace("-", "")
                    .substring(0, Math.min(32, length)).toLowerCase());
        }
        return str.toString();
    }
}