<?php

namespace app\common\service;

use app\common\model\account\TransferAuthorizations;
use app\common\traits\ServiceTrait;
use think\Log;

/**
 * 免确认收款授权（商家转账-用户确认模式的前置授权）
 * 流程：
 *  1. 用户发起提现时，前端调本服务 apply() 发起授权申请，
 *     拿到 package_info 后用 wx.requestMerchantTransfer 拉起授权页；
 *  2. 用户授权成功后，微信异步回调 transferAuthorizationNotify，
 *     本服务记录 authorization_id 并将状态置为 TAKING_EFFECT；
 *  3. 后台审核提现时，校验授权为 TAKING_EFFECT 后走
 *     /v3/fund-app/mch-transfer/transfer-bills/transfer 完成免确认转账。
 * 文档（2026.05.08）：
 *  - 申请有效期 24 小时，过期未确认须换 out_authorization_no 重新发起
 *  - 未确认记录保留 30 天，超期后原单号可复用
 *  - 同一微信号在当前商户转账场景下，WAIT_USER_CONFIRM + TAKING_EFFECT 最多 5 个
 *  - 一个用户账号对应唯一一个生效中的授权；授权成功后长期有效，须保存单号
 * 文档：https://pay.weixin.qq.com/doc/v3/merchant/4015901167
 */
class TransferAuthorizationService
{
    use ServiceTrait;

    /** @var TransferAuthorizations */
    public static $Model = TransferAuthorizations::class;

    // 授权状态（与微信查询授权单接口 state 取值一致）
    const STATE_WAIT_USER_CONFIRM = 'WAIT_USER_CONFIRM'; //已受理，待用户确认
    const STATE_TAKING_EFFECT = 'TAKING_EFFECT'; //已授权，生效中（长期有效，直至主动解除）
    const STATE_CLOSED = 'CLOSED'; //已关闭，无法转账至该授权对应的用户

    /**
     * 生成商户侧授权单号：一个用户固定一个单号。
     * 微信规则：未确认的授权单 30 天后单号可复用重新发起，因此复用同一单号即可
     * @param int $userId
     * @return string 仅含字母数字，最长 32 位
     */
    public static function generateAuthNo($userId): string
    {
        return 'TXAUTH' . str_pad((string)intval($userId), 10, '0', STR_PAD_LEFT);
    }

    /**
     * 生成新的商户侧授权单号：授权已被关闭/申请过期时使用。
     * 已关闭单号 30 天内不可复用；WAIT 过期也须换号重新申请。
     * @param int $userId
     * @return string
     */
    public static function generateAuthNoUnique($userId): string
    {
        return self::generateAuthNo($userId) . strtoupper(substr(md5(uniqid('', true)), 0, 6));
    }

    /**
     * 获取用户的授权记录
     * @param int $userId
     * @return TransferAuthorizations|null
     */
    public static function getByUserId($userId)
    {
        //优先取生效中的授权记录（历史被关闭的记录仍保留，故按状态+时间取最新的）
        $record = self::getOne(['user_id' => $userId, 'state' => self::STATE_TAKING_EFFECT], [], ['id', 'desc']);

        return $record ?: self::getOne(['user_id' => $userId], [], ['id', 'desc']);
    }

    /**
     * 用户是否已完成免确认收款授权
     * @param int $userId
     * @return bool
     */
    public static function isAuthorized($userId): bool
    {
        $record = self::getByUserId($userId);

        //授权生效后即可凭 out_authorization_no 发起免确认转账；authorization_id 仅作留存
        return $record && $record->state == self::STATE_TAKING_EFFECT;
    }

    /**
     * 发起/获取免确认收款授权，供前端拉起授权页
     * @param \app\common\model\Users $user 用户（需含 openid）
     * @param string $displayName 授权详情中展示的开通账号名称
     * @return array {authorized: bool, state, package_info?, mch_id?, app_id?}
     * @throws \Exception
     */
    public static function apply($user, string $displayName = ''): array
    {
        $userId = $user->id;
        if (empty($user->openid)) {
            throw new \Exception('无法获取用户微信身份，请先登录小程序');
        }

        $wechat = new EasyWeChatService();
        $record = self::getByUserId($userId);
        //必须查本地当前单号，不能每次都用固定单号：固定单号一旦 CLOSED，
        //再换新号申请会把同一 openid 下未确认单堆到 5 笔上限
        $authNo = ($record && $record->out_authorization_no)
            ? (string)$record->out_authorization_no
            : self::generateAuthNo($userId);
        $displayName = self::sanitizeDisplayName($displayName ?: ($user->nickname ?: ('用户' . $userId)));

        $query = $wechat->queryTransferAuthorization($authNo, true);
        $resolved = self::resolveByWechatState($userId, $authNo, $query, $wechat, $record);
        if ($resolved !== null) {
            return $resolved;
        }

        $queryState = (string)($query['state'] ?? '');
        $renew = false;
        //CLOSED：过期未确认/用户或商户关闭后须换单号；30 天内原单号不可再用
        if ($queryState === self::STATE_CLOSED) {
            $authNo = self::generateAuthNoUnique($userId);
            $renew = true;
        }

        return self::requestAuthorization($user, $authNo, $displayName, $wechat, $renew);
    }

    /**
     * 按微信查询结果决定是否直接返回，无需再申请
     * @return array|null 非空表示已可返回给前端；null 表示继续申请
     */
    private static function resolveByWechatState($userId, string $authNo, array $query, EasyWeChatService $wechat, $record)
    {
        $queryState = (string)($query['state'] ?? '');
        if ($queryState !== '') {
            self::saveAuthorization(
                $userId,
                $authNo,
                $queryState,
                (string)($query['authorization_id'] ?? ''),
                (string)($query['package_info'] ?? '')
            );
            if ($queryState === self::STATE_TAKING_EFFECT) {
                return [
                    'authorized' => true,
                    'state'      => $queryState,
                ];
            }
            if ($queryState === self::STATE_WAIT_USER_CONFIRM) {
                //待确认单有效期内必须复用，禁止再申请（计入 5 笔上限）
                return self::pendingPackageResponse($wechat, $query, $record ?: self::getByUserId($userId));
            }
            //CLOSED 走换号申请
            return null;
        }

        //NOT_FOUND：超期未确认超过 30 天或单号从未存在，可用当前单号重新申请
        if (self::isWechatNotFound($query)) {
            return null;
        }

        //查询失败时禁止再开新单，避免把同一 openid 的待确认/已生效单堆到 5 笔上限
        if ($record && $record->state === self::STATE_TAKING_EFFECT) {
            throw new \Exception('查询授权状态失败，请稍后重试');
        }
        if ($record && $record->state === self::STATE_WAIT_USER_CONFIRM && !empty($record->package_info)) {
            return self::pendingAuthResponse($wechat, self::STATE_WAIT_USER_CONFIRM, (string)$record->package_info);
        }
        if (!empty($query['message'])) {
            throw new \Exception('查询授权状态失败，请稍后重试');
        }

        return null;
    }

    /**
     * 向微信发起授权申请
     */
    private static function requestAuthorization($user, string $authNo, string $displayName, EasyWeChatService $wechat, bool $renew): array
    {
        $userId = $user->id;
        $res = $wechat->applyTransferAuthorization($authNo, $user->openid, $displayName);

        //当前单已受理/已终结：改为查单，禁止换号重试
        if (self::isApplyConflict($res)) {
            $query = $wechat->queryTransferAuthorization($authNo, true);
            $resolved = self::resolveByWechatState($userId, $authNo, $query, $wechat, self::getByUserId($userId));
            if ($resolved !== null) {
                return $resolved;
            }
        }

        if (self::isQuantityLimit($res)) {
            $record = self::getByUserId($userId);
            if ($record && $record->state === self::STATE_WAIT_USER_CONFIRM && !empty($record->package_info)) {
                return self::pendingAuthResponse($wechat, $record->state, (string)$record->package_info);
            }
            throw new \Exception('当前微信账号在本转账场景下待确认/已生效的授权已达上限（最多5个）。请先在微信中完成已发起的授权确认，或等待24小时未确认申请关闭后再试。');
        }

        if (empty($res['package_info'])) {
            throw new \Exception($res['message'] ?? '发起免确认收款授权失败');
        }

        self::saveAuthorization(
            $userId,
            $authNo,
            $res['state'] ?? self::STATE_WAIT_USER_CONFIRM,
            '',
            $res['package_info'],
            $renew
        );

        return self::pendingAuthResponse(
            $wechat,
            $res['state'] ?? self::STATE_WAIT_USER_CONFIRM,
            $res['package_info']
        );
    }

    /**
     * 待确认：优先用查询返回的 package，否则用本地上次申请保存的 package
     */
    private static function pendingPackageResponse(EasyWeChatService $wechat, array $query, $record): array
    {
        $package = (string)($query['package_info'] ?? '');
        if ($package === '' && $record) {
            $package = (string)($record->package_info ?? '');
        }
        if ($package === '') {
            throw new \Exception('授权申请待用户确认，请在微信中完成授权，勿重复发起');
        }

        return self::pendingAuthResponse($wechat, self::STATE_WAIT_USER_CONFIRM, $package);
    }

    private static function pendingAuthResponse(EasyWeChatService $wechat, string $state, string $package): array
    {
        return [
            'authorized'   => false,
            'state'        => $state,
            'package_info' => $package,
            'mch_id'       => (string)$wechat->payApp->getMerchant()->getMerchantId(),
            'app_id'       => $wechat->config['app_id'],
        ];
    }

    private static function sanitizeDisplayName(string $displayName): string
    {
        $displayName = preg_replace('/[\x{10000}-\x{10FFFF}]/u', '', $displayName) ?: '';
        $displayName = trim($displayName);

        return mb_substr($displayName !== '' ? $displayName : '用户', 0, 32);
    }

    private static function isWechatNotFound(array $res): bool
    {
        $code = (string)($res['code'] ?? '');
        $message = (string)($res['message'] ?? '');

        return $code === 'NOT_FOUND' || mb_strpos($message, '不存在') !== false;
    }

    private static function isQuantityLimit(array $res): bool
    {
        $message = (string)($res['message'] ?? '');

        return mb_strpos($message, '授权数量达到限制') !== false || mb_strpos($message, '数量达到限制') !== false;
    }

    private static function isApplyConflict(array $res): bool
    {
        $message = (string)($res['message'] ?? '');

        return mb_strpos($message, '已解除或已授权成功') !== false;
    }

    /**
     * 保存/更新授权记录
     * @param int $userId
     * @param string $authNo 商户侧授权单号
     * @param string $state 授权状态
     * @param string $authorizationId 微信侧授权单号(可为空)
     * @param string $packageInfo 拉起授权页的 package(可为空)
     * @param bool $renew 是否关闭后换号重新授权(覆盖 out_authorization_no 并清空旧 authorization_id)
     * @return void
     */
    private static function saveAuthorization($userId, string $authNo, string $state, string $authorizationId = '', string $packageInfo = '', bool $renew = false)
    {
        //表上存在 uniq_user_id 唯一索引，一个用户只允许一条授权记录，只能更新不能新增
        $record = self::getByUserId($userId);
        $data = [
            'state'                => $state,
            'out_authorization_no' => $authNo,
        ];
        if ($renew) {
            //授权已被关闭/解除：换新单号重新发起，旧的 authorization_id 已失效需清空
            $data['authorization_id'] = '';
        } elseif ($authorizationId !== '') {
            $data['authorization_id'] = $authorizationId;
        }
        if ($packageInfo !== '') {
            $data['package_info'] = $packageInfo;
        }

        if ($record) {
            $record->save($data);

            return;
        }

        try {
            self::create(array_merge([
                'user_id'              => $userId,
                'out_authorization_no' => $authNo,
                'authorization_id'     => $authorizationId,
                'package_info'         => $packageInfo,
            ], $data));
        } catch (\Exception $e) {
            //并发下可能撞 uniq_user_id / uniq_out_auth_no，回退为更新已有记录
            $exists = self::getByUserId($userId);
            if (!$exists) {
                throw $e;
            }
            $exists->save(array_merge($data, ['out_authorization_no' => $authNo]));
        }
    }

    /**
     * 处理免确认收款授权结果回调（用户确认或关闭后微信异步通知）
     * @param array $message 解密后的授权结果，含 out_authorization_no / authorization_id / state
     * @return bool
     */
    public static function handleAuthorizationNotify(array $message): bool
    {
        $outAuthNo = trim((string)($message['out_authorization_no'] ?? ''));
        $authorizationId = trim((string)($message['authorization_id'] ?? ''));
        $state = trim((string)($message['state'] ?? ''));
        if (!$outAuthNo || !$state) {
            Log::error('免确认收款授权回调参数缺失:' . json_encode($message, JSON_UNESCAPED_UNICODE));
            return false;
        }

        $record = self::getOne(['out_authorization_no' => $outAuthNo]);
        if (!$record) {
            Log::error('免确认收款授权回调找不到授权记录:' . $outAuthNo);
            return false;
        }

        if ($authorizationId !== '') {
            $record->authorization_id = $authorizationId;
        }
        $record->state = $state;
        $record->save();
        Log::info('免确认收款授权回调已同步:' . json_encode([
            'user_id' => $record->user_id,
            'state'   => $record->state,
        ], JSON_UNESCAPED_UNICODE));

        return true;
    }
}