<?php
/**
 * WooCommerce Customer/Order CSV Export
 *
 * This source file is subject to the GNU General Public License v3.0
 * that is bundled with this package in the file license.txt.
 * It is also available through the world-wide-web at this URL:
 * http://www.gnu.org/licenses/gpl-3.0.html
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@skyverge.com so we can send you a copy immediately.
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade WooCommerce Customer/Order CSV Export to newer
 * versions in the future. If you wish to customize WooCommerce Customer/Order CSV Export for your
 * needs please refer to http://docs.woothemes.com/document/ordercustomer-csv-exporter/
 *
 * @package     WC-Customer-Order-CSV-Export/Generator
 * @author      SkyVerge
 * @copyright   Copyright (c) 2012-2016, SkyVerge, Inc.
 * @license     http://www.gnu.org/licenses/gpl-3.0.html GNU General Public License v3.0
 */

defined( 'ABSPATH' ) or exit;

/**
 * Customer/Order CSV Export Generator
 *
 * Converts customer/order data into CSV
 *
 * @since 3.0
 */
class WC_Customer_Order_CSV_Export_Generator {

	/** @var array order IDs or customer IDs */
	public $ids;

	/** @var array CSV header fields */
	public $headers;

	/** @var string order export format */
	public $order_format;

	/** @var resource output stream containing CSV */
	private $stream;


	/**
	 * Setup the IDs to export and CSV options
	 *
	 * @since 3.0
	 * @param $ids
	 * @return \WC_Customer_Order_CSV_Export_Generator
	 */
	public function __construct( $ids ) {

		/**
		 * Filter the order/customer IDs
		 *
		 * @since 3.9.1
		 * @param array $id, order IDs or customer IDs
		 * @param \WC_Customer_Order_CSV_Export_Generator $this, generator instance
		 */
		$this->ids = apply_filters( 'wc_customer_order_csv_export_ids', $ids, $this );

		$this->order_format = get_option( 'wc_customer_order_csv_export_order_format' );

		/**
		 * CSV Delimiter.
		 *
		 * Filter the delimiter used for the CSV file
		 *
		 * @since 3.0.0
		 * @param string $delimiter, defaults to comma (,)
		 * @param \WC_Customer_Order_CSV_Export_Generator $this, generator instance
		 */
		$this->delimiter = apply_filters( 'wc_customer_order_csv_export_delimiter', ',', $this );

		/**
		 * CSV Enclosure.
		 *
		 * Filter the enclosure used for the CSV file
		 *
		 * @since 3.0.0
		 * @param string $enclosure, defaults to double quote (")
		 * @param \WC_Customer_Order_CSV_Export_Generator $this, generator instance
		 */
		$this->enclosure = apply_filters( 'wc_customer_order_csv_export_enclosure', '"', $this );

		// open output buffer to write CSV to
		$this->stream = fopen( 'php://output', 'w' );
		ob_start();

		/**
		 * CSV BOM (Byte order mark).
		 *
		 * Enable adding a BOM to the exported CSV
		 *
		 * @since 3.0
		 * @param bool $enable_bom true to add the BOM, false otherwise. Defaults to false.
		 * @param \WC_Customer_Order_CSV_Export_Generator $this, generator instance
		 */
		if ( apply_filters( 'wc_customer_order_csv_export_enable_bom', false, $this ) ) {

			fputs( $this->stream, ( chr(0xEF) . chr(0xBB) . chr(0xBF) ) );
		}
	}


	/**
	 * Get the CSV for orders
	 *
	 * @since 3.0
	 * @return string CSV data
	 */
	public function get_orders_csv() {

		// order headers
		$this->headers = $this->get_orders_csv_headers();

		// write headers
		$this->write( $this->headers );

		$order_data = array();

		// iterate through order IDs
		foreach ( $this->ids as $order_id ) {

			// get data for each order
			$data = $this->get_orders_csv_row( $order_id );
			$order_data[] = $data;

			// data can be an array of arrays when each line item is it's own row
			$first_element = reset( $data );
			if ( is_array( $first_element ) ) {

				// iterate through each line item row and write it
				foreach( $data as $row ) {

					$this->write( $row );
				}

			} else {

				// otherwise simply write the single order row
				$this->write( $data );
			}
		}

		/**
		 * Filter the generated orders CSV
		 *
		 * @since 3.8.0
		 * @param string $csv_data The CSV data
		 * @param array $order_data An array of the order data to write to to the CSV
		 * @param array $order_ids The order ids.
		 * @param string $order_format The order export format.
		 */
		return apply_filters( 'wc_customer_order_csv_export_get_orders_csv', $this->get_csv(), $order_data, $this->ids, $this->order_format );
	}


	/**
	 * Get the column headers for the orders CSV
	 *
	 * Note that the headers are keyed in column_key => column_name format so that plugins can control the output
	 * format using only the column headers and row data is not required to be in the exact same order, as the row data
	 * is matched on the column key
	 *
	 * @since 3.0
	 * @return array column headers in column_key => column_name format
	 */
	private function get_orders_csv_headers() {

		$column_headers = array(
			'order_id'            => 'order_id',
			'order_number'        => 'order_number',
			'order_date'          => 'date',
			'status'              => 'status',
			'shipping_total'      => 'shipping_total',
			'shipping_tax_total'  => 'shipping_tax_total',
			'fee_total'           => 'fee_total',
			'fee_tax_total'       => 'fee_tax_total',
			'tax_total'           => 'tax_total',
			'discount_total'      => 'discount_total',
			'order_total'         => 'order_total',
			'refunded_total'      => 'refunded_total',
			'order_currency'      => 'order_currency',
			'payment_method'      => 'payment_method',
			'shipping_method'     => 'shipping_method',
			'customer_id'         => 'customer_id',
			'billing_first_name'  => 'billing_first_name',
			'billing_last_name'   => 'billing_last_name',
			'billing_company'     => 'billing_company',
			'billing_email'       => 'billing_email',
			'billing_phone'       => 'billing_phone',
			'billing_address_1'   => 'billing_address_1',
			'billing_address_2'   => 'billing_address_2',
			'billing_postcode'    => 'billing_postcode',
			'billing_city'        => 'billing_city',
			'billing_state'       => 'billing_state',
			'billing_country'     => 'billing_country',
			'shipping_first_name' => 'shipping_first_name',
			'shipping_last_name'  => 'shipping_last_name',
			'shipping_address_1'  => 'shipping_address_1',
			'shipping_address_2'  => 'shipping_address_2',
			'shipping_postcode'   => 'shipping_postcode',
			'shipping_city'       => 'shipping_city',
			'shipping_state'      => 'shipping_state',
			'shipping_country'    => 'shipping_country',
			'shipping_company'    => 'shipping_company',
			'customer_note'       => 'customer_note',
		);

		if ( 'default_one_row_per_item' == $this->order_format ) {
			$column_headers['item_name']         = 'item_name';
			$column_headers['item_sku']          = 'item_sku';
			$column_headers['item_quantity']     = 'item_quantity';
			$column_headers['item_tax']          = 'item_tax';
			$column_headers['item_total']        = 'item_total';
			$column_headers['item_refunded']     = 'item_refunded';
			$column_headers['item_refunded_qty'] = 'item_refunded_qty';
			$column_headers['item_meta']         = 'item_meta';
		} else {
			$column_headers['line_items'] = 'line_items';
		}

		$column_headers['shipping_items']       = 'shipping_items';
		$column_headers['fee_items']            = 'fee_items';
		$column_headers['tax_items']            = 'tax_items';
		$column_headers['coupon_items']         = 'coupons';
		$column_headers['order_notes']          = 'order_notes';
		$column_headers['download_permissions'] = 'download_permissions_granted';

		/**
		 * CSV Order Export Column Headers.
		 *
		 * Filter the column headers for the order export
		 *
		 * @since 3.0
		 * @param array $column_headers {
		 *     column headers in key => name format
		 *     to modify the column headers, ensure the keys match these and set your own values
		 * }
		 * @param \WC_Customer_Order_CSV_Export_Generator $this, generator instance
		 */
		return apply_filters( 'wc_customer_order_csv_export_order_headers', $column_headers, $this );
	}


	/**
	 * Get the order data for a single CSV row
	 *
	 * Note items are keyed according to the column header keys above so these can be modified using
	 * the provider filter without needing to worry about the array order
	 *
	 * @since 3.0
	 * @param int $order_id the WC_Order ID
	 * @return array order data in the format key => content
	 */
	private function get_orders_csv_row( $order_id ) {

		$order      = wc_get_order( $order_id );
		$is_json    = 'import' == $this->order_format;
		$line_items = $shipping_items = $fee_items = $tax_items = $coupon_items = array();

		// get line items
		foreach ( $order->get_items() as $item_id => $item ) {

			$product = $order->get_product_from_item( $item );

			if ( ! is_object( $product ) ) {
				$product = new WC_Product( 0 );
			}

			$item_meta = new WC_Order_Item_Meta( $item );

			if ( $is_json ) {

				$meta = array();

				foreach ( $item_meta->get_formatted( '_' ) as $meta_key => $formatted_meta ) {
					$meta[ $formatted_meta['key'] ] = $formatted_meta['value'];
				}

			} else {

				add_filter( 'woocommerce_attribute_label',               array( $this, 'escape_reserved_meta_chars' ) );
				add_filter( 'woocommerce_order_item_display_meta_value', array( $this, 'escape_reserved_meta_chars' ) );

				$meta = $item_meta->display( true, true );

				remove_filter( 'woocommerce_attribute_label',               array( $this, 'escape_reserved_meta_chars' ) );
				remove_filter( 'woocommerce_order_item_display_meta_value', array( $this, 'escape_reserved_meta_chars' ) );

				if ( $meta ) {

					// replace key-value sperator (': ') with our own - equals sign (=)
					$meta = str_replace( ': ', '=', $meta );

					// remove any newlines generated by WC_Order_Item_Meta::display()
					$meta = str_replace( array( ", \r\n", ", \r", ", \n" ), ',', $meta );

					// re-insert colons and newlines
					$meta = str_replace( array( '[INSERT_COLON_HERE]', '[INSERT_NEWLINE_HERE]' ), array( ':', "\n" ), $meta );
				}
			}

			$product     = $order->get_product_from_item( $item );
			$product_id  = null;
			$product_sku = null;

			// Check if the product exists.
			if ( is_object( $product ) ) {
				$product_id  = ( isset( $product->variation_id ) ) ? $product->variation_id : $product->id;
				$product_sku = $product->get_sku();
			}

			if ( $is_json ) {

				$line_item = array(
					// fields following WC API conventions, see WC_API_Orders
					'id'           => $item_id,
					'subtotal'     => wc_format_decimal( $order->get_line_subtotal( $item ), 2 ),
					'subtotal_tax' => wc_format_decimal( $item['line_subtotal_tax'], 2 ),
					'total'        => wc_format_decimal( $order->get_line_total( $item ), 2 ),
					'total_tax'    => wc_format_decimal( $order->get_line_tax( $item ), 2 ),
					'quantity'     => (int) $item['qty'],
					'name'         => $item['name'],
					'product_id'   => $product_id,
					'sku'          => $product_sku,
					'meta'         => $meta,
					'tax_data'     => isset( $item['line_tax_data'] ) ? maybe_unserialize( $item['line_tax_data'] ) : '',
				);

			} else {

				$line_item = array(
					'name'          => html_entity_decode( $item['name'], ENT_NOQUOTES, 'UTF-8' ),
					'sku'           => $product_sku,
					'quantity'      => (int) $item['qty'],
					'total'         => wc_format_decimal( $order->get_line_total( $item ), 2 ),
					'refunded'      => wc_format_decimal( $order->get_total_refunded_for_item( $item_id ), 2 ),
					'refunded_qty'  => $order->get_qty_refunded_for_item( $item_id ),
					'meta'          => is_string( $meta ) ? html_entity_decode( $meta, ENT_NOQUOTES, 'UTF-8' ) : $meta,
				);

				// add line item tax
				$line_tax_data    = isset( $item['line_tax_data'] ) ? $item['line_tax_data'] : array();
				$tax_data         = maybe_unserialize( $line_tax_data );
				$line_item['tax'] = isset( $tax_data['total'] ) ? wc_format_decimal( wc_round_tax_total( array_sum( (array) $tax_data['total'] ) ), 2 ) : '';
			}

			/**
			 * CSV Order Export Line Item.
			 *
			 * Filter the individual line item entry for the default export
			 *
			 * @since 3.0.6
			 * @param array $line_item {
			 *     line item data in key => value format
			 *     the keys are for convenience and not used for exporting. Make
			 *     sure to prefix the values with the desired line item entry name
			 * }
			 *
			 * @param array $item WC order item data
			 * @param WC_Product $product the product
			 * @param WC_Order $order the order
			 * @param \WC_Customer_Order_CSV_Export_Generator $this, generator instance
			 */
			$line_item = apply_filters( 'wc_customer_order_csv_export_order_line_item', $line_item, $item, $product, $order, $this );

			if ( ! in_array( $this->order_format, array( 'default_one_row_per_item', 'import' ) ) && is_array( $line_item ) ) {

				foreach ( $line_item as $name => $value ) {
					$name  = $this->escape_reserved_item_chars( $name );
					$value = $this->escape_reserved_item_chars( $value );
					$line_item[ $name ] = $name . ':' . $value;
				}

				$line_item = implode( '|', $line_item );
			}

			if ( $line_item ) {
				$line_items[] = $line_item;
			}
		}

		foreach ( $order->get_shipping_methods() as $shipping_item_id => $shipping_item ) {

			$shipping_item = array(
				'id'           => $shipping_item_id,
				'method_id'    => $shipping_item['method_id'],
				'method_title' => $shipping_item['name'],
				'total'        => wc_format_decimal( $shipping_item['cost'], 2 ),
				'taxes'        => isset( $shipping_item['taxes'] ) ? maybe_unserialize( $shipping_item['taxes'] ) : '',
			);

			if ( $is_json ) {
				$shipping_items[] = $shipping_item;
			} else {
				$shipping_items[] = implode( '|', array(
					'method:' . $this->escape_reserved_item_chars( $shipping_item['method_title'] ),
					'total:' . $shipping_item['total'],
				) );
			}
		}

		// get fee items & total
		$fee_total = 0;
		$fee_tax_total = 0;

		foreach ( $order->get_fees() as $fee_item_id => $fee_item ) {

			$fee = array(
				'id'        => $fee_item_id,
				'title'     => $fee_item['name'],
				'tax_class' => ( ! empty( $fee_item['tax_class'] ) ) ? $fee_item['tax_class'] : null,
				'total'     => wc_format_decimal( $order->get_line_total( $fee_item ), 2 ),
				'total_tax' => wc_format_decimal( $order->get_line_tax( $fee_item ), 2 ),
				'tax_data'  => isset( $fee_item['line_tax_data'] ) ? maybe_unserialize( $fee_item['line_tax_data'] ) : '',
			);

			if ( $is_json ) {

				if ( null !== $fee['tax_class'] ) {
					$fee['taxable'] = true;
				}

				$fee_items[] = $fee;

			} else {

				$fee_items[] = implode( '|', array(
					'name:' . $this->escape_reserved_item_chars( $fee['title'] ),
					'total:' . $fee['total'],
					'tax:' . $fee['total_tax'],
				) );
			}

			$fee_total     += $fee_item['line_total'];
			$fee_tax_total += $fee_item['line_tax'];
		}

		// get tax items
		foreach ( $order->get_tax_totals() as $tax_code => $tax ) {

			$tax_item = array(
				'id'       => $tax->id,
				'rate_id'  => $tax->rate_id,
				'code'     => $tax_code,
				'title'    => $tax->label,
				'total'    => wc_format_decimal( $tax->amount, 2 ),
				'compound' => (bool) $tax->is_compound,
			);

			if ( $is_json ) {
				$tax_items[] = $tax_item;
			} else {
				$tax_items[] = implode( '|', array(
					'code:'  . $this->escape_reserved_item_chars( $tax_code ),
					'total:' . $tax->amount,
				) );
			}

		}

		// add coupons
		foreach ( $order->get_items( 'coupon' ) as $coupon_item_id => $coupon_item ) {

			$coupon_item = array(
				'id'     => $coupon_item_id,
				'code'   => $coupon_item['name'],
				'amount' => wc_format_decimal( $coupon_item['discount_amount'], 2 ),
			);

			if ( $is_json ) {
				$coupon_items[] = $coupon_item;
			} else {

				$coupon      = new WC_Coupon( $coupon_item['code'] );
				$coupon_post = get_post( $coupon->id );

				$coupon_items[] = implode( '|', array(
					'code:' . $this->escape_reserved_item_chars( $coupon_item['code'] ),
					'description:' . $this->escape_reserved_item_chars( is_object( $coupon_post ) ? $coupon_post->post_excerpt : '' ),
					'amount:' . $coupon_item['amount'],
				) );
			}
		}

		$order_data = array(
			'order_id'             => $order->id,
			'order_number'         => $order->get_order_number(),
			'order_date'           => $order->order_date,
			'status'               => $order->get_status(),
			'shipping_total'       => $order->get_total_shipping(),
			'shipping_tax_total'   => wc_format_decimal( $order->get_shipping_tax(), 2 ),
			'fee_total'            => wc_format_decimal( $fee_total, 2 ),
			'fee_tax_total'        => wc_format_decimal( $fee_tax_total, 2 ),
			'tax_total'            => wc_format_decimal( $order->get_total_tax(), 2 ),
			'discount_total'       => wc_format_decimal( $order->get_total_discount(), 2 ),
			'order_total'          => wc_format_decimal( $order->get_total(), 2 ),
			'refunded_total'       => wc_format_decimal( $order->get_total_refunded(), 2 ),
			'order_currency'       => $order->get_order_currency(),
			'payment_method'       => $order->payment_method,
			'shipping_method'      => $order->get_shipping_method(),
			'customer_id'          => $order->get_user_id(),
			'billing_first_name'   => $order->billing_first_name,
			'billing_last_name'    => $order->billing_last_name,
			'billing_company'      => $order->billing_company,
			'billing_email'        => $order->billing_email,
			'billing_phone'        => $order->billing_phone,
			'billing_address_1'    => $order->billing_address_1,
			'billing_address_2'    => $order->billing_address_2,
			'billing_postcode'     => $order->billing_postcode,
			'billing_city'         => $order->billing_city,
			'billing_state'        => $order->billing_state,
			'billing_country'      => $order->billing_country,
			'shipping_first_name'  => $order->shipping_first_name,
			'shipping_last_name'   => $order->shipping_last_name,
			'shipping_company'     => $order->shipping_company,
			'shipping_address_1'   => $order->shipping_address_1,
			'shipping_address_2'   => $order->shipping_address_2,
			'shipping_postcode'    => $order->shipping_postcode,
			'shipping_city'        => $order->shipping_city,
			'shipping_state'       => $order->shipping_state,
			'shipping_country'     => $order->shipping_country,
			'customer_note'        => $order->customer_note,
			'shipping_items'       => $is_json && ! empty( $shipping_items ) ? json_encode( $shipping_items ) : implode( ';', $shipping_items ),
			'fee_items'            => $is_json && ! empty( $fee_items ) ? json_encode( $fee_items ) : implode( ';', $fee_items ),
			'tax_items'            => $is_json && ! empty( $tax_items ) ? json_encode( $tax_items ) : implode( ';', $tax_items ),
			'coupon_items'         => $is_json && ! empty( $coupon_items ) ? json_encode( $coupon_items ) : implode( ';', $coupon_items ),
			'order_notes'          => implode( '|', $this->get_order_notes( $order ) ),
			'download_permissions' => $order->download_permissions_granted ? $order->download_permissions_granted : 0,
		);

		if ( 'default_one_row_per_item' === $this->order_format ) {

			$new_order_data = array();

			foreach ( $line_items as $item ) {
				$order_data['item_name']         = $item['name'];
				$order_data['item_sku']          = $item['sku'];
				$order_data['item_quantity']     = $item['quantity'];
				$order_data['item_tax']          = $item['tax'];
				$order_data['item_total']        = $item['total'];
				$order_data['item_refunded']     = $item['refunded'];
				$order_data['item_refunded_qty'] = $item['refunded_qty'];
				$order_data['item_meta']         = $item['meta'];

				/**
				 * CSV Order Export Row for One Row per Item.
				 *
				 * Filter the individual row data for the order export
				 *
				 * @since 3.3.0
				 * @param array $order_data {
				 *     order data in key => value format
				 *     to modify the row data, ensure the key matches any of the header keys and set your own value
				 * }
				 * @param array $item
				 * @param \WC_Order $order WC Order object
				 * @param \WC_Customer_Order_CSV_Export_Generator $this, generator instance
				 */
				$new_order_data[] = apply_filters( 'wc_customer_order_csv_export_order_row_one_row_per_item', $order_data, $item, $order, $this );
			}

			$order_data = $new_order_data;
		} else {

			$order_data['line_items'] = $is_json ? json_encode( $line_items ) : implode( ';', $line_items );
		}

		/**
		 * CSV Order Export Row.
		 *
		 * Filter the individual row data for the order export
		 *
		 * @since 3.0
		 * @param array $order_data {
		 *     order data in key => value format
		 *     to modify the row data, ensure the key matches any of the header keys and set your own value
		 * }
		 * @param \WC_Order $order WC Order object
		 * @param \WC_Customer_Order_CSV_Export_Generator $this, generator instance
		 */
		return apply_filters( 'wc_customer_order_csv_export_order_row', $order_data, $order, $this );
	}


	/**
	 * Get the order notes for given order
	 *
	 * @since 3.0
	 * @param WC_Order $order
	 * @return array order notes
	 */
	private function get_order_notes( $order ) {

		$callback = array( 'WC_Comments', 'exclude_order_comments' );

		$args = array(
			'post_id' => $order->id,
			'approve' => 'approve',
			'type'    => 'order_note'
		);

		remove_filter( 'comments_clauses', $callback );

		$notes = get_comments( $args );

		add_filter( 'comments_clauses', $callback );

		$order_notes = array();

		foreach ( $notes as $note ) {

			$order_notes[] = str_replace( array( "\r", "\n" ), ' ', $note->comment_content );
		}

		return $order_notes;
	}


	/**
	 * Escape reserved meta chars in a string (commas and equals signs)
	 *
	 * Will also replace colons and newlines with a placeholder, which should
	 * be replaced later with actual characters.
	 *
	 * @since 3.12.0
	 * @param string $input Input string
	 * @return string
	 */
	public function escape_reserved_meta_chars( $input ) {

		// commas delimit meta fields, equals sign delimits key-value pairs,
		// colons need to be replaced with a placeholder so that we can safely
		// replace the key-value separator (colon + space) with our own (equals sign)
		$input = str_replace(
			array( '=',  ',',  ':' ),
			array( '\=', '\,', '[INSERT_COLON_HERE]' ),
			$input
		);

		// newlines are legal in CSV, but we want to remove the newlines generated
		// by WC_Order_Item_Meta::display(), so we replace them with a placeholder temporarily
		return str_replace( array( "\r\n", "\r", "\n" ), '[INSERT_NEWLINE_HERE]', $input );
	}


	/**
	 * Escape reserved item chars in a string (semicolons, colons and pipes)
	 *
	 * @since 3.12.0
	 * @param string $input Input string
	 * @return string
	 */
	private function escape_reserved_item_chars( $input ) {

		// colons separate key-value pairs, pipes separate fields/properties,
		// and semicolons separate line items themselves
		return str_replace(
			array( ':',  '|',  ';' ),
			array( '\:', '\|', '\;' ),
			$input
		);
	}


	/**
	 * Get the CSV for customers
	 *
	 * @since 3.0
	 * @return string CSV data
	 */
	public function get_customers_csv() {

		// customer headers
		$this->headers = $this->get_customers_csv_headers();

		// write headers
		$this->write( $this->headers );

		$customers = array();

		// get customers to export based on orders
		foreach ( $this->ids as $order_id ) {

			$billing_email = get_post_meta( $order_id, '_billing_email', true );

			// skip orders without a billing email
			if ( ! $billing_email ) {
				continue;
			}

			$customers[ $order_id ] = $billing_email;
		}

		// customer date filtering requires a bit of a hack as WP_User_Query does not support the same `date_query`
		// arguments as WP_Query (as of WP 3.8.1) and so must be done with raw SQL
		add_action( 'pre_user_query', array( $this, 'modify_user_query' ) );

		// get customers to export based on role
		$users = get_users( array( 'role' => 'customer' ) );

		remove_action( 'pre_user_query', array( $this, 'modify_user_query' ) );

		foreach ( $users as $user ) {

			if ( ! isset( $user->user_email ) ) {
				continue;
			}

			$customers[ 'user_id_' . $user->ID ] = $user->user_email;
		}

		// ensure each customer has a unique billing email
		$customers = array_unique( $customers );

		$customer_data = array();

		foreach ( $customers as $order_id => $customer_email ) {

			// get data for each customer
			$data = $this->get_customers_csv_row( $customer_email, $order_id );
			$customer_data[] = $data;

			// data can be an array of arrays when customer meta is it's own row
			$first_element = reset( $data );
			if ( is_array( $first_element ) ) {

				// iterate through each customer meta row and write it
				foreach( $data as $row ) {

					$this->write( $row );
				}

			} else {

				// otherwise simply write the single customer row
				$this->write( $data );
			}
		}

		/**
		 * Filter the generated customers CSV
		 *
		 * @since 3.8.0
		 * @param string $csv_data The CSV data
		 * @param array $customer_data An array of the customer data to write to the CSV
		 * @param array $customers An associative array of customers in the format array( $order_id => $customer_email ).
		 */
		return apply_filters( 'wc_customer_order_csv_export_get_customers_csv', $this->get_csv(), $customer_data, $customers );
	}


	/**
	 * Modify the WP_User_Query to support filtering on the date the customer was created
	 *
	 * @since 3.0.5
	 * @param WP_User_Query $query
	 */
	public function modify_user_query( $query ) {

		if ( wc_customer_order_csv_export()->get_admin_instance()->customer_export_start_date ) {
			$query->query_where .= sprintf( " AND user_registered >= STR_TO_DATE( '%s', '%%Y-%%m-%%d %%h:%%i' )", esc_sql( wc_customer_order_csv_export()->get_admin_instance()->customer_export_start_date ) );
		}

		if ( wc_customer_order_csv_export()->get_admin_instance()->customer_export_end_date ) {
			$query->query_where .= sprintf( " AND user_registered <= STR_TO_DATE( '%s', '%%Y-%%m-%%d %%h:%%i' )", esc_sql( wc_customer_order_csv_export()->get_admin_instance()->customer_export_end_date ) );
		}
	}


	/**
	 * Get the column headers for the customers CSV
	 *
	 * Note that the headers are keyed in column_key => column_name format so that plugins can control the output
	 * format using only the column headers and row data is not required to be in the exact same order, as the row data
	 * is matched on the column key
	 *
	 * @since 3.0
	 * @return array column headers in column_key => column_name format
	 */
	public function get_customers_csv_headers() {

		$column_headers = array(
			'customer_id'         => 'customer_id',
			'first_name'          => 'first_name',
			'last_name'           => 'last_name',
			'email'               => 'email',
			'date_registered'     => 'date_registered',
			'billing_first_name'  => 'billing_first_name',
			'billing_last_name'   => 'billing_last_name',
			'billing_company'     => 'billing_company',
			'billing_email'       => 'billing_email',
			'billing_phone'       => 'billing_phone',
			'billing_address_1'   => 'billing_address_1',
			'billing_address_2'   => 'billing_address_2',
			'billing_postcode'    => 'billing_postcode',
			'billing_city'        => 'billing_city',
			'billing_state'       => 'billing_state',
			'billing_country'     => 'billing_country',
			'shipping_first_name' => 'shipping_first_name',
			'shipping_last_name'  => 'shipping_last_name',
			'shipping_company'    => 'shipping_company',
			'shipping_address_1'  => 'shipping_address_1',
			'shipping_address_2'  => 'shipping_address_2',
			'shipping_postcode'   => 'shipping_postcode',
			'shipping_city'       => 'shipping_city',
			'shipping_state'      => 'shipping_state',
			'shipping_country'    => 'shipping_country',
		);

		/**
		 * CSV Customer Export Column Headers.
		 *
		 * Filter the column headers for the customer export
		 *
		 * @since 3.0
		 * @param array $column_headers {
		 *     column headers in key => name format
		 *     to modify the column headers, ensure the keys match these and set your own values
		 * }
		 * @param \WC_Customer_Order_CSV_Export_Generator $this, generator instance
		 */
		return apply_filters( 'wc_customer_order_csv_export_customer_headers', $column_headers, $this );
	}


	/**
	 * Get the customer data for a single CSV row
	 *
	 * Note items are keyed according to the column header keys above so these can be modified using
	 * the provider filter without needing to worry about the array order
	 *
	 * @since 3.0
	 * @param string $customer_email the customer's email
	 * @param int $order_id a valid order ID for the customer
	 * @return array customer data in the format key => content
	 */
	private function get_customers_csv_row( $customer_email, $order_id ) {

		$user = get_user_by( 'email', $customer_email );

		// guest, get info from order
		if ( ! $user && is_numeric( $order_id ) ) {

			$order = wc_get_order( $order_id );

			// create blank user
			$user = new stdClass();

			// set properties on user
			$user->ID                  = 0;
			$user->first_name          = $order->billing_first_name;
			$user->last_name           = $order->billing_last_name;
			$user->user_email          = $order->billing_email;
			$user->user_registered     = $order->order_date;
			$user->billing_first_name  = $order->billing_first_name;
			$user->billing_last_name   = $order->billing_last_name;
			$user->billing_company     = $order->billing_company;
			$user->billing_email       = $order->billing_email;
			$user->billing_phone       = $order->billing_phone;
			$user->billing_address_1   = $order->billing_address_1;
			$user->billing_address_2   = $order->billing_address_2;
			$user->billing_postcode    = $order->billing_postcode;
			$user->billing_city        = $order->billing_city;
			$user->billing_state       = $order->billing_state;
			$user->billing_country     = $order->billing_country;
			$user->shipping_first_name = $order->shipping_first_name;
			$user->shipping_last_name  = $order->shipping_last_name;
			$user->shipping_company    = $order->shipping_company;
			$user->shipping_address_1  = $order->shipping_address_1;
			$user->shipping_address_2  = $order->shipping_address_2;
			$user->shipping_postcode   = $order->shipping_postcode;
			$user->shipping_city       = $order->shipping_city;
			$user->shipping_state      = $order->shipping_state;
			$user->shipping_country    = $order->shipping_country;
		}

		$customer_data = array(
			'customer_id'         => $user->ID,
			'first_name'          => $user->first_name,
			'last_name'           => $user->last_name,
			'email'               => $user->user_email,
			'date_registered'     => $user->user_registered,
			'billing_first_name'  => $user->billing_first_name,
			'billing_last_name'   => $user->billing_last_name,
			'billing_company'     => $user->billing_company,
			'billing_email'       => $user->billing_email,
			'billing_phone'       => $user->billing_phone,
			'billing_address_1'   => $user->billing_address_1,
			'billing_address_2'   => $user->billing_address_2,
			'billing_postcode'    => $user->billing_postcode,
			'billing_city'        => $user->billing_city,
			'billing_state'       => $user->billing_state,
			'billing_country'     => $user->billing_country,
			'shipping_first_name' => $user->shipping_first_name,
			'shipping_last_name'  => $user->shipping_last_name,
			'shipping_company'    => $user->shipping_company,
			'shipping_address_1'  => $user->shipping_address_1,
			'shipping_address_2'  => $user->shipping_address_2,
			'shipping_postcode'   => $user->shipping_postcode,
			'shipping_city'       => $user->shipping_city,
			'shipping_state'      => $user->shipping_state,
			'shipping_country'    => $user->shipping_country,
		);

		/**
		 * CSV Customer Export Row.
		 *
		 * Filter the individual row data for the customer export
		 *
		 * @since 3.0
		 * @param array $customer_data {
		 *     order data in key => value format
		 *     to modify the row data, ensure the key matches any of the header keys and set your own value
		 * }
		 * @param \WP_User $user WP User object
		 * @param int $order_id an order ID for the customer
		 * @param \WC_Customer_Order_CSV_Export_Generator $this, generator instance
		 */
		return apply_filters( 'wc_customer_order_csv_export_customer_row', $customer_data, $user, $order_id, $this );
	}


	/**
	 * Write the given row to the CSV
	 *
	 * This is abstracted so the provided data can be matched to the CSV headers set and the CSV delimiter and
	 * enclosure can be controlled from a single method
	 *
	 * @since 3.0
	 * @param array $row
	 */
	private function write( $row ) {

		if ( empty( $row ) ) {
			return;
		}

		$data = array();

		foreach ( $this->headers as $header_key => $_ ) {

			if ( ! isset( $row[ $header_key ] ) ) {
				$row[ $header_key ] = '';
			}

			// strict string comparison, as values like '0' are valid
			$value = ( '' !== $row[ $header_key ] ) ? $row[ $header_key ] : '';

			// escape leading equals sign character with a single quote to prevent CSV injections, see http://www.contextis.com/resources/blog/comma-separated-vulnerabilities/
			if ( SV_WC_Helper::str_starts_with( $value, '=' ) ) {
				$value = "'" . $value;
			}

			$data[] = $value;
		}

		fputcsv( $this->stream, $data, $this->delimiter, $this->enclosure );
	}


	/**
	 * Return the CSV data by closing the output buffer and stream
	 *
	 * @since 3.0
	 * @return string CSV
	 */
	private function get_csv() {

		$csv = ob_get_clean();

		fclose( $this->stream );

		/**
		 * Allow actors to change the generated CSV, such as removing headers.
		 *
		 * @since 3.0.6
		 * @param string $csv - generated CSV file
		 * @param \WC_Customer_Order_CSV_Export_Generator $this - generator class instance
		 */
		return apply_filters( 'wc_customer_order_csv_export_generated_csv', $csv, $this );
	}


} //end \WC_Customer_Order_CSV_Export_Generator class