<?php
/**
 * Phone number importer.
 *
 * @package Aslansheed\OTP
 */

namespace Aslansheed\OTP\Tools;

use Aslansheed\OTP\Auth\Identity_Store;
use Aslansheed\OTP\Auth\Phone_Normalizer;
use Aslansheed\OTP\Core\Options;

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

/**
 * Reads phone numbers from user meta, for example from a previous login
 * plugin, and links them as verified phone identities.
 */
final class Importer {

	const SOURCE_DIGITS = 'digits';
	const SOURCE_META   = 'meta';
	const BATCH         = 500;

	/**
	 * Runs one pass over all users.
	 *
	 * @param string $source  SOURCE_DIGITS or SOURCE_META.
	 * @param string $meta    Meta key for SOURCE_META.
	 * @param bool   $dry_run When true nothing is written.
	 * @return array{scanned: int, imported: int, skipped_invalid: int, skipped_taken: int, skipped_existing: int}
	 */
	public static function run( $source, $meta = '', $dry_run = true ) {
		global $wpdb;

		$result  = array(
			'scanned'          => 0,
			'imported'         => 0,
			'skipped_invalid'  => 0,
			'skipped_taken'    => 0,
			'skipped_existing' => 0,
		);
		$country = (string) Options::get( 'general.default_country' );
		$last_id = 0;

		do {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- One-off admin tool reading core ids.
			$ids = $wpdb->get_col( $wpdb->prepare( "SELECT ID FROM {$wpdb->users} WHERE ID > %d ORDER BY ID ASC LIMIT %d", $last_id, self::BATCH ) );

			$fetched = count( $ids );

			foreach ( $ids as $id ) {
				$last_id = (int) $id;
				++$result['scanned'];

				$raw = self::read_number( (int) $id, $source, $meta );

				if ( '' === $raw ) {
					continue;
				}

				$phone = Phone_Normalizer::to_e164( $raw, $country );

				if ( null === $phone ) {
					++$result['skipped_invalid'];
					continue;
				}

				if ( array() !== Identity_Store::find_for_user( (int) $id, 'phone' ) ) {
					++$result['skipped_existing'];
					continue;
				}

				$owner = Identity_Store::find( 'phone', $phone );

				if ( $owner && (int) $owner->user_id > 0 && (int) $owner->user_id !== (int) $id ) {
					++$result['skipped_taken'];
					continue;
				}

				if ( ! $dry_run ) {
					Identity_Store::save( (int) $id, 'phone', $phone );
				}

				++$result['imported'];
			}
		} while ( self::BATCH === $fetched );

		return $result;
	}

	/**
	 * Reads the stored phone number of one user.
	 *
	 * @param int    $user_id User id.
	 * @param string $source  Source type.
	 * @param string $meta    Meta key for SOURCE_META.
	 * @return string
	 */
	private static function read_number( $user_id, $source, $meta ) {
		if ( self::SOURCE_META === $source ) {
			return '' === $meta ? '' : trim( (string) get_user_meta( $user_id, $meta, true ) );
		}

		// Digits keeps the full number in one key and, in some versions, splits it into country code and national number.
		$country_code = trim( (string) get_user_meta( $user_id, 'digt_countrycode', true ) );
		$national     = trim( (string) get_user_meta( $user_id, 'digits_phone_no', true ) );

		if ( '' !== $country_code && '' !== $national ) {
			return '+' . ltrim( $country_code, '+' ) . ltrim( $national, '0' );
		}

		return trim( (string) get_user_meta( $user_id, 'digits_phone', true ) );
	}
}