/*! © SpryMedia Ltd - datatables.net/license */

import jQuery from 'jquery';
import DataTable from 'datatables.net';

// Allow reassignment of the $ variable
let $ = jQuery;

/**
 * @summary     Download Button
 * @author      SpryMedia Ltd (www.datatables.net)
 * @copyright   Copyright 2018 SpryMedia Ltd.
 *
 * License      MIT - http://datatables.net/license/mit
 *
 * A button that can be used to trigger a server-side action, typically a
 * download of a file generated by the server. If server-side processing
 * is enabled in the host table it will automatically add the last parameters
 * used for a table draw allowing the script to output a file with the same
 * order / search applied as the main table.
 *
 * This is particularly useful when using server-side processing and wishing
 * to allow user export of the data in a table. The default Buttons package
 * will only export the data available on the client-side, while this button
 * can be used to let the server generate the required file and then download
 * it to the client-side.
 *
 * @example
 *   // Download button
 * 	var table = $('#example').DataTable({
 * 		dom: 'Bfrtip',
 * 		buttons: [
 * 			{
 * 				extend: 'download',
 * 				url: '/api/download'
 * 			}
 * 		]
 * 	});
 */
function flattenJson(data, name, flattened) {
    if (!flattened) {
        flattened = {};
    }
    if (!name) {
        name = '';
    }
    if ($.isPlainObject(data) || Array.isArray(data)) {
        $.each(data, function (idx, val) {
            if (name === '') {
                flattenJson(val, idx, flattened);
            }
            else {
                flattenJson(val, name + '[' + idx.toString() + ']', flattened);
            }
        });
    }
    else {
        flattened[name] = data;
    }
    return flattened;
}
DataTable.ext.buttons.download = {
    text: 'Download',
    action: function (e, dt, node, config) {
        // Gather information to be submitted
        var data = {};
        if (dt.page.info().serverSide) {
            $.extend(data, dt.ajax.params());
        }
        if (typeof config.data === 'function') {
            config.data(data);
        }
        else if (typeof config.data === 'object') {
            $.extend(data, config.data);
        }
        // Convert data to a flat structure for submission
        var flattened = flattenJson(data);
        // Create an iframe
        var iframe = $('<iframe/>')
            .css({
            border: 'none',
            height: 0,
            width: 0,
        })
            .appendTo(document.body);
        var contentDoc = iframe[0].contentWindow.document;
        contentDoc.open();
        contentDoc.close();
        var form = $('<form/>', contentDoc)
            .attr('method', config.type)
            .attr('action', config.url)
            .appendTo(contentDoc.body);
        $.each(flattened, function (name, val) {
            $('<input/>', contentDoc)
                .attr('type', 'text')
                .attr('name', name.toString())
                .attr('autocomplete', 'no')
                .val(val)
                .appendTo(form);
        });
        form.submit();
    },
    url: '',
    type: 'POST',
    data: {},
};


export default DataTable;