whmcsServiceAddon/serviceAddon.php

<?php

if (!defined("WHMCS")) {
    die("This file cannot be accessed directly");
}

function serviceAddon_CreateAccount(array $params) {
    if($params['Create_Mail'] > 0) {
        $result = localAPI('SendEmail', ['id' => $params['Create_Mail']]);
    }

    logModuleCall(
        'iServiceAddon',
        __FUNCTION__,
        $params,
        'Debug',
        $result
    );
    return 'success';
}

function serviceAddon_SuspendAccount(array $params) {
    return 'success';
}

function serviceAddon_UnsuspendAccount(array $params) {
    return 'success';
}

function serviceAddon_TerminateAccount(array $params) {
    return 'success';
}

function serviceAddon_ChangePackage(array $params) {
    return 'success';
}

function serviceAddon_TestConnection(array $params) {
    return 'success';
}

function serviceAddon_UsageUpdate(array $params) {
    return 'success';
}

function serviceAddon_ConfigOptions(array $params) {
    $response = localAPI('GetEmailTemplates');
    $emailTemplates = array('none');
    foreach ($response['emailtemplates']['emailtemplate'] as $emailTemplate) {
        if ($emailTemplate['custom'] == 1) {
            $emailTemplates[$emailTemplate['id']] = $emailTemplate['name'];
        }
    }
    $configOptions = array(
        "Create_Mail" => [
            "Type" => "dropdown", # Dropdown Choice of Options
            "Options" => $emailTemplates,
            "Description" => "E-Mail Template auswählen",
            "Default" => "option1"
        ],
        "Suspend_Mail" => [
            "Type" => "dropdown", # Dropdown Choice of Options
            "Options" => $emailTemplates,
            "Description" => "E-Mail Template auswählen",
            "Default" => "option1"
        ],
        "Unsuspend_Mail" => [
            "Type" => "dropdown", # Dropdown Choice of Options
            "Options" => $emailTemplates,
            "Description" => "E-Mail Template auswählen",
            "Default" => "option1"
        ],
        "ChangePackage_Mail" => [
            "Type" => "dropdown", # Dropdown Choice of Options
            "Options" => $emailTemplates,
            "Description" => "E-Mail Template auswählen",
            "Default" => "option1"
        ],
        "Terminate_Mail" => [
            "Type" => "dropdown", # Dropdown Choice of Options
            "Options" => $emailTemplates,
            "Description" => "E-Mail Template auswählen",
            "Default" => "option1"
        ],
    );
    return $configOptions;
}

function serviceAddon_MetaData() {
}

function serviceAddon_AdminCustomButtonArray($params) {
}

function serviceAddon_AdminServicesTabFields($params) {
}

function serviceAddon_ClientArea($params) {
    return array(
        'tabOverviewReplacementTemplate' => 'templates/clientarea',
        'vars' => array(
            'test1' => 'hello',
            'test2' => 'world',
        ),
    );
}