<?php

namespace addons\shopro\library\commission;

use addons\shopro\model\User as UserModel;

/**
 * 邀请码
 */
class InviteCode
{
    /**
     * 生成唯一邀请码
     */
    public static function generate($userId = 0)
    {
        $chars = 'ABCDEFGHJKLMNPQRSTUVWXYZ23456789';
        do {
            $code = '';
            for ($i = 0; $i < 6; $i++) {
                $code .= $chars[mt_rand(0, strlen($chars) - 1)];
            }
            if ($userId) {
                $code = substr($code, 0, 4) . str_pad($userId % 10000, 4, '0', STR_PAD_LEFT);
            }
            $exists = UserModel::where('invite_code', $code)->find();
        } while ($exists);

        return $code;
    }

    /**
     * 为用户生成并保存邀请码
     */
    public static function ensureForUser($userId)
    {
        $user = UserModel::get($userId);
        if (!$user) {
            return null;
        }
        if (!empty($user->invite_code)) {
            return $user->invite_code;
        }
        $code = self::generate($userId);
        $user->invite_code = $code;
        $user->save();
        return $code;
    }

    /**
     * 通过邀请码查找用户
     */
    public static function findUserByCode($code)
    {
        if (empty($code)) {
            return null;
        }
        return UserModel::where('invite_code', strtoupper(trim($code)))->find();
    }
}