<?php
namespace Academy\Classes;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}


class ExportBase {
	public function array_to_xml( $data, &$xml ) {
		foreach ( $data as $key => $value ) {
			if ( is_array( $value ) ) {
				$subNode = $xml->addChild( $key );
				$this->array_to_xml( $value, $subNode );
			} else {
				$xml->addChild( $key, htmlspecialchars( $value ) );
			}
		}
	}

	public function flatten_array( $array, $prefix = '' ) {
		if ( ! is_iterable( $array ) ) {
			return [];
		}
		$result = array();
		foreach ( $array as $key => $value ) {
			if ( is_array( $value ) ) {
				$result = array_merge( $result, $this->flatten_array( $value, $prefix . $key . '_' ) );
			} else {
				$result[ $prefix . $key ] = $value;
			}
		}
		return $result;
	}

	/**
	 * Neutralise spreadsheet formula injection: a text cell starting with
	 * = + - @ (or a tab / carriage return) is prefixed with a single quote so
	 * Excel/Sheets treat it as text. Numbers and non-strings are untouched.
	 *
	 * @param mixed $value Cell value.
	 * @return mixed
	 */
	public static function csv_safe_cell( $value ) {
		if ( is_string( $value ) && '' !== $value && in_array( $value[0], array( '=', '+', '-', '@', "\t", "\r" ), true ) && ! is_numeric( $value ) ) {
			return "'" . $value;
		}
		return $value;
	}

	/**
	 * Undo csv_safe_cell() when an exported file is imported back, so a title
	 * such as "-Intro" does not come back as "'-Intro".
	 *
	 * @param mixed $value Cell value read from a CSV file.
	 * @return mixed
	 */
	public static function csv_restore_cell( $value ) {
		if ( is_string( $value ) && isset( $value[1] ) && "'" === $value[0] && self::csv_safe_cell( substr( $value, 1 ) ) === $value ) {
			return substr( $value, 1 );
		}
		return $value;
	}

	public function write_nested_csv( $array, $fp ) {
		foreach ( $array as $row ) {
			$flattenRow = array_map( array( __CLASS__, 'csv_safe_cell' ), $this->flatten_array( $row ) );
			fputcsv( $fp, $flattenRow, ',', '"', '\\' ); // phpcs:ignore WordPressVIPMinimum.Functions.RestrictedFunctions.file_ops_fputcsv -- writes to php://output (download stream), not the filesystem
		}
	}

	public function array_to_csv_download( $data, $filename = 'export.csv', $allow_header = true, $utf8_bom = false ) {
		header( 'Content-Type: application/csv' );
		header( 'Content-Disposition: attachment; filename="' . $filename . '";' );
		$f = fopen( 'php://output', 'w' );

		if ( $utf8_bom ) {
			fwrite( $f, "\xEF\xBB\xBF" ); // phpcs:ignore WordPressVIPMinimum.Functions.RestrictedFunctions.file_ops_fwrite, WordPress.WP.AlternativeFunctions.file_system_operations_fwrite -- writes to php://output (download stream), not the filesystem
		}

		// Write the CSV header row
		if ( $allow_header ) {
			$headerRow = array_keys( $this->flatten_array( $data[0] ) );
			fputcsv( $f, $headerRow, ',', '"', '\\' ); // phpcs:ignore WordPressVIPMinimum.Functions.RestrictedFunctions.file_ops_fputcsv -- writes to php://output (download stream), not the filesystem
		}

		// Write the nested array data to CSV
		$this->write_nested_csv( $data, $f );
		// Close the output stream
		// phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_read_fclose, WordPress.WP.AlternativeFunctions.file_system_operations_fclose -- php://output download stream
		fclose( $f );
	}
}