<?php
/**
 * Bulk import of customers.
 *
 * @package HostKhata
 */

namespace HostKhata\Domain\Customers;

defined( 'ABSPATH' ) || exit;

use HostKhata\Support\Errors;
use WP_Error;

/**
 * Creates customers from rows prepared by the admin app (a parsed CSV).
 *
 * Columns: email, first_name, last_name, company, phone, address_1, address_2,
 * city, state, postcode, country, status, tags. A dry run checks every row and
 * saves nothing. Imported customers get a random password and no welcome email
 * unless `send_welcome` is true; they can use "lost password" to set their own.
 *
 * @since 0.1.0
 */
final class CustomerImportService {

	const MAX_ROWS = 500;

	/**
	 * Customers.
	 *
	 * @var CustomerService
	 */
	private $customers;

	/**
	 * Constructor.
	 *
	 * @param CustomerService $customers Customer service.
	 */
	public function __construct( CustomerService $customers ) {
		$this->customers = $customers;
	}

	/**
	 * Imports customers.
	 *
	 * @since 0.1.0
	 *
	 * @param array<int, mixed> $rows         Rows keyed by column name.
	 * @param bool              $dry_run      Only check the rows.
	 * @param bool              $send_welcome Send the welcome email to each new customer.
	 * @return array<string, mixed>|WP_Error
	 */
	public function import( array $rows, bool $dry_run, bool $send_welcome = false ) {
		$rows = array_values( $rows );

		if ( array() === $rows ) {
			return Errors::invalid( array( 'rows' => __( 'The file has no rows.', 'hostkhata' ) ) );
		}

		if ( count( $rows ) > self::MAX_ROWS ) {
			/* translators: %d: maximum number of rows. */
			return Errors::invalid( array( 'rows' => sprintf( __( 'Import at most %d rows at a time.', 'hostkhata' ), self::MAX_ROWS ) ) );
		}

		if ( ! $send_welcome ) {
			add_filter( 'hostkhata_send_welcome_email', '__return_false' );
		}

		$results = array();
		$ok      = 0;
		$seen    = array();

		foreach ( $rows as $index => $row ) {
			$result = $this->one( $row, $dry_run, $seen );

			if ( is_wp_error( $result ) ) {
				$data      = (array) $result->get_error_data();
				$results[] = array(
					'row'    => $index + 1,
					'ok'     => false,
					'errors' => isset( $data['errors'] ) ? (array) $data['errors'] : array( 'row' => $result->get_error_message() ),
				);
				continue;
			}

			++$ok;
			$results[] = array(
				'row'    => $index + 1,
				'ok'     => true,
				'errors' => array(),
				'id'     => $dry_run ? 0 : (int) ( $result['id'] ?? 0 ),
			);
		}

		if ( ! $send_welcome ) {
			remove_filter( 'hostkhata_send_welcome_email', '__return_false' );
		}

		return array(
			'dry_run' => $dry_run,
			'created' => $dry_run ? 0 : $ok,
			'valid'   => $ok,
			'failed'  => count( $rows ) - $ok,
			'results' => $results,
		);
	}

	/**
	 * Checks or creates one row.
	 *
	 * @param mixed               $row     Row.
	 * @param bool                $dry_run Dry run.
	 * @param array<string, true> $seen    Email addresses already used earlier in the file.
	 * @return array<string, mixed>|WP_Error
	 */
	private function one( $row, bool $dry_run, array &$seen ) {
		if ( ! is_array( $row ) ) {
			return Errors::invalid( array( 'row' => __( 'This row is not valid.', 'hostkhata' ) ) );
		}

		// The export writes tags separated by semicolons, so the import accepts them too.
		if ( isset( $row['tags'] ) && is_string( $row['tags'] ) ) {
			$row['tags'] = str_replace( array( ';', '|' ), ',', $row['tags'] );
		}

		$email = isset( $row['email'] ) && is_string( $row['email'] ) ? strtolower( trim( $row['email'] ) ) : '';

		if ( '' !== $email && isset( $seen[ $email ] ) ) {
			return Errors::invalid( array( 'email' => __( 'This email address appears twice in the file.', 'hostkhata' ) ) );
		}

		if ( $dry_run ) {
			$clean = CustomerInput::clean( $row, true );

			if ( $clean['errors'] ) {
				return Errors::invalid( $clean['errors'] );
			}

			if ( email_exists( $clean['data']['email'] ) ) {
				return Errors::invalid( array( 'email' => __( 'A user with this email address already exists.', 'hostkhata' ) ) );
			}

			$seen[ $email ] = true;

			return array( 'id' => 0 );
		}

		$result = $this->customers->create( $row );

		if ( ! is_wp_error( $result ) && '' !== $email ) {
			$seen[ $email ] = true;
		}

		return $result;
	}
}