<?php
/**
 * CSV import/export of redirects.
 *
 * @package Unbreak
 */

namespace Unbreak\Redirects;

defined( 'ABSPATH' ) || exit;

/**
 * Columns: source,target,code,match_mode,enabled.
 */
final class Csv {

	public const HEADER = array( 'source', 'target', 'code', 'match_mode', 'enabled' );

	/**
	 * Export every rule as CSV text.
	 *
	 * @param RedirectRepository $repo Repository.
	 */
	public static function export( RedirectRepository $repo ): string {
		$lines = array( implode( ',', self::HEADER ) );
		$page  = 1;
		do {
			$batch = $repo->paginate( '', $page, 500 );
			foreach ( $batch['items'] as $rule ) {
				$lines[] = implode(
					',',
					array_map(
						array( self::class, 'cell' ),
						array( $rule['source_path'], $rule['target_url'], (string) $rule['code'], $rule['match_mode'], $rule['enabled'] ? '1' : '0' )
					)
				);
			}
			++$page;
			$fetched = count( $batch['items'] );
		} while ( 500 === $fetched );
		return implode( "\n", $lines ) . "\n";
	}

	/**
	 * Import CSV text. Existing sources are updated; invalid rows are reported.
	 *
	 * @param RedirectRepository $repo Repository.
	 * @param string             $csv  CSV text.
	 * @return array{created:int,updated:int,errors:array<int,string>}
	 */
	public static function import( RedirectRepository $repo, string $csv ): array {
		$result = array(
			'created' => 0,
			'updated' => 0,
			'errors'  => array(),
		);
		$csv    = (string) preg_replace( '/^\xEF\xBB\xBF/', '', $csv );
		$lines  = preg_split( '/\r\n|\r|\n/', $csv );
		foreach ( (array) $lines as $index => $line ) {
			if ( '' === trim( (string) $line ) ) {
				continue;
			}
			$cells = str_getcsv( (string) $line, ',', '"', '\\' );
			if ( 0 === $index && isset( $cells[0] ) && 'source' === strtolower( trim( (string) $cells[0] ) ) ) {
				continue;
			}
			if ( count( $cells ) < 2 ) {
				/* translators: %d: line number. */
				$result['errors'][] = sprintf( __( 'Line %d: expected at least a source and a target.', 'unbreak' ), $index + 1 );
				continue;
			}
			$input    = array(
				'source_path' => (string) $cells[0],
				'target_url'  => (string) $cells[1],
				'code'        => isset( $cells[2] ) && '' !== $cells[2] ? (int) $cells[2] : 301,
				'match_mode'  => isset( $cells[3] ) && '' !== $cells[3] ? (string) $cells[3] : '404',
				'enabled'     => isset( $cells[4] ) && '' !== $cells[4] ? (int) $cells[4] : 1,
			);
			$source   = Path::normalize( $input['source_path'], true );
			$existing = null !== $source ? $repo->find_by_source( $source ) : null;
			$saved    = $repo->save( $input, null !== $existing ? (int) $existing['id'] : 0 );
			if ( is_wp_error( $saved ) ) {
				/* translators: 1: line number, 2: error message. */
				$result['errors'][] = sprintf( __( 'Line %1$d: %2$s', 'unbreak' ), $index + 1, $saved->get_error_message() );
				continue;
			}
			++$result[ null !== $existing ? 'updated' : 'created' ];
		}
		return $result;
	}

	/**
	 * Quote a CSV cell when needed (and neutralize spreadsheet formulas).
	 *
	 * @param string $value Value.
	 */
	private static function cell( string $value ): string {
		if ( '' !== $value && in_array( $value[0], array( '=', '+', '-', '@' ), true ) ) {
			$value = "'" . $value;
		}
		if ( preg_match( '/[",\r\n]/', $value ) ) {
			return '"' . str_replace( '"', '""', $value ) . '"';
		}
		return $value;
	}
}