sevDesk Integration in WHMCS as Addon

I need a WHMCS integration for the cloud accounting service sevDesk. Cloud Service Homepage: [login to view URL] API: [login to view URL] I need a WHMCS addon based on the current GitHub template from WHMCS. This refers to the use of the namespace and classes function. use WHMCS\Module\Addon\AddonModule\Admin\AdminDispatcher; use WHMCS\Module\Addon\AddonModule\Client\ClientDispatcher; The following functions are required. - Create WHMCS customers in the sevDesk with the complete data set. - Update the sevDesk customer data when updated in the WHMCS. - Upload of WHMCS invoices into the sevDesk as voucher including the PDF file of the invoice. All invoice items must also be uploaded individually in sevDesk. When uploading the individual invoice items, it is important to consider the TAX option of the item. It is also important whether you are a customer in your own country, an EU customer or a non-EU customer. - Update the sevDesk voucher when the invoice has been changed in the WHMCS. In the case of canceled invoices, this must also be canceled in the sevDesk The addon is to get a bootstrap navigation with which you get into the areas (customers, invoices, settings). In the customer area, you can see all WHMCS and sevDesk customers, and WHMCS customers do not have a sevDesk customer. Here is a sync button to start a complete update of the customers in sevDesk. This is e.g. Necessary, after the installation of the addon or if the update of the WHMCS customer by Hook was not successful. In the field of invoices, you can see all WHMCS invoices and whether these are available in the sevDesk. By clicking on the Compare button on each invoice you can see the data of WHMCS and sevDesk in comparison. As with the customer area, there should also be a sync button in this area so that all invoices can be matched at once. In the Settings area, the access data for sevDesk can be stored. The current status of the Sync is to be displayed in the two areas Customer and Invoices via a Bootstrap Modal PopUp. The popup is to synchronize the total number of all customers / invoices, including an upload bar, the customer number and the customer name, and the status of the API requests. For the customer, it is the API Requests contact, addAddress, addPhone, addMobile, and addEmail. The invoices are the API Requests voucher, uploadTempFile for the PDF Upload. The rights to the code are to be transferred completely.