<?php
declare(strict_types=1);

namespace addon\paycenter\service;

use addon\paycenter\library\AlipayChannel;
use addon\paycenter\library\contract\Channel;
use addon\paycenter\library\PayException;
use addon\paycenter\library\PayFactory;
use addon\paycenter\library\TradeLog;
use addon\paycenter\library\WechatChannel;
use think\facade\Event;
use think\facade\Log;
use think\Response;

/**
 * 支付门面（业务侧唯一入口）。
 *
 * 业务只做两件事：
 *   1) Payment::create(...) 拉起支付；
 *   2) 监听 PayPaid 事件发货（应用市场见 app\appmall\listener\OrderPaid）。
 * 验签、查单、退款、回调应答全部在插件内，业务代码里不该出现任何 `Pay::alipay()`。
 *
 * 业务侧调用前用 class_exists(Payment::class) 判一下：插件未安装时不致命。
 */
class Payment
{
    /** 渠道登记表：新增渠道只改这里 */
    public const CHANNELS = [
        'alipay' => AlipayChannel::class,
        'wechat' => WechatChannel::class,
    ];

    /** 支付成功事件名（业务在 app/event.php 监听） */
    public const EVENT_PAID = 'PayPaid';

    /**
     * 取渠道实例
     * @throws PayException 未知渠道
     */
    public static function channel(string $code): Channel
    {
        $class = self::CHANNELS[$code] ?? null;
        if ($class === null) {
            throw new PayException('不支持的支付渠道：' . $code, 400);
        }

        return new $class();
    }

    /**
     * 可用支付方式（供前台收银台渲染）：只返回「后台启用 + 商户参数已配置」的渠道。
     * @return array<int,array{code:string,name:string,scenes:array,scene:string}>
     */
    public static function methods(): array
    {
        $list = [];
        foreach (self::CHANNELS as $code => $class) {
            if (!self::enabled($code)) {
                continue;
            }
            /** @var Channel $ch */
            $ch     = new $class();
            $list[] = [
                'code'   => $ch->code(),
                'name'   => $ch->name(),
                'scenes' => $ch->scenes(),
                'scene'  => self::defaultScene($code),
            ];
        }

        return $list;
    }

    /** 渠道是否可用（后台开关 + 商户参数齐备 + SDK 已安装） */
    public static function enabled(string $code): bool
    {
        if (!isset(self::CHANNELS[$code]) || !PayFactory::available()) {
            return false;
        }
        if ((string) self::cfg($code . '_enable', '1') !== '1') {
            return false;
        }

        return self::channel($code)->configured();
    }

    /** 是否有任意一个渠道可用（业务据此决定「能否真实支付 / 只能 mock」） */
    public static function anyEnabled(): bool
    {
        foreach (array_keys(self::CHANNELS) as $code) {
            if (self::enabled($code)) {
                return true;
            }
        }

        return false;
    }

    public static function defaultChannel(): string
    {
        $channel = (string) self::cfg('default_channel', 'alipay');

        return isset(self::CHANNELS[$channel]) ? $channel : 'alipay';
    }

    public static function defaultScene(string $code): string
    {
        $key    = $code === 'wechat' ? 'wechat_scene' : 'alipay_scene';
        $scene  = (string) self::cfg($key, $code === 'wechat' ? 'qr' : 'web');
        $scenes = self::channel($code)->scenes();

        return in_array($scene, $scenes, true) ? $scene : ($scenes[0] ?? 'web');
    }

    /**
     * 插件统一回调地址（业务不传 notify 时用）。
     * 形如 https://host/paycenter/api/notify?channel=alipay
     */
    public static function notifyUrl(string $code): string
    {
        return self::domain() . '/paycenter/api/notify?channel=' . $code;
    }

    /**
     * 拉起支付。
     *
     * @param string $channel alipay / wechat
     * @param array  $order   ['trade_no','amount','subject','biz','biz_id','attach','openid'?]
     * @param string $scene   留空则用后台配置的默认场景
     * @param array  $urls    ['notify'=>..., 'return'=>...]；notify 留空用插件统一回调地址
     * @return array{type:string,content:mixed,trade_no:string}
     * @throws PayException 渠道不可用 / 下单失败
     */
    public static function create(string $channel, array $order, string $scene = '', array $urls = []): array
    {
        if (!self::enabled($channel)) {
            throw new PayException('该支付方式未启用或尚未配置商户参数（' . $channel . '）', 400);
        }
        if (empty($order['trade_no'])) {
            throw new PayException('缺少订单号 trade_no', 400);
        }

        $scene = $scene !== '' ? $scene : self::defaultScene($channel);
        $urls  = [
            'notify' => (string) ($urls['notify'] ?? '') ?: self::notifyUrl($channel),
            'return' => (string) ($urls['return'] ?? ''),
        ];

        // 下单前先落流水：即便网关调用失败，后台也能看到「谁在什么时候试图付哪笔钱」
        TradeLog::record($order, $channel, $scene);

        try {
            return self::channel($channel)->create($order, $scene, $urls);
        } catch (PayException $e) {
            throw $e;
        } catch (\Throwable $e) {
            Log::error('[paycenter] 下单失败 ' . $channel . '/' . $scene . '：' . $e->getMessage());
            throw new PayException('支付发起失败：' . $e->getMessage(), 500);
        }
    }

    /**
     * 主动查单（回调丢失 / 用户跳回落地页时兜底）。
     * 查询失败一律按「未支付」处理：宁可让用户多轮询一次，也不能凭一次失败的响应发货。
     *
     * @return array{paid:bool,amount:float,gateway_no:string}
     */
    public static function query(string $channel, string $tradeNo): array
    {
        try {
            if (!self::enabled($channel)) {
                return ['paid' => false, 'amount' => 0.0, 'gateway_no' => ''];
            }

            return self::channel($channel)->query($tradeNo);
        } catch (\Throwable $e) {
            Log::warning('[paycenter] 主动查单失败：' . $e->getMessage(), ['trade_no' => $tradeNo, 'channel' => $channel]);

            return ['paid' => false, 'amount' => 0.0, 'gateway_no' => ''];
        }
    }

    /**
     * 异步回调入口：验签 → 记流水 → 触发 PayPaid → 应答网关。
     *
     * 业务侧（应用市场）在 app/event.php 监听 PayPaid 完成发货；
     * 本方法只保证「钱确实收到了」，不关心收到钱之后做什么。
     */
    public static function notify(string $channel): Response
    {
        $ch = self::channel($channel);
        try {
            $data = $ch->notify();
        } catch (\Throwable $e) {
            Log::warning('[paycenter] 回调验签失败：' . $e->getMessage(), ['channel' => $channel]);

            return $ch->ack(false);
        }

        if (empty($data['trade_no'])) {
            return $ch->ack(false);
        }

        $trade = TradeLog::touchNotify($data, $channel);

        // 非「支付成功」的通知（如退款通知、待支付通知）也要正常应答，否则网关会一直重试
        if (empty($data['paid'])) {
            return $ch->ack(true);
        }

        $trade = TradeLog::markPaid($data) ?: $trade;

        Event::trigger(self::EVENT_PAID, [
            'trade_no'   => (string) $data['trade_no'],
            'channel'    => $channel,
            'amount'     => (float) $data['amount'],
            'gateway_no' => (string) ($data['gateway_no'] ?? ''),
            'biz'        => (string) ($trade['biz'] ?? ''),
            'biz_id'     => (int) ($trade['biz_id'] ?? 0),
            'attach'     => $trade['attach'] ?? '',
            'scene'      => (string) ($trade['scene'] ?? ''),
            'trade'      => $trade,
        ]);

        return $ch->ack(true);
    }

    /**
     * 退款（按流水查渠道，业务无需知道这笔单当初用的哪个渠道）。
     * @return array{ok:bool,message:string}
     */
    public static function refund(string $tradeNo, ?float $amount = null): array
    {
        $trade = TradeLog::find($tradeNo);
        if (!$trade) {
            return ['ok' => false, 'message' => '支付流水不存在：' . $tradeNo];
        }
        $channel = (string) $trade['channel'];
        if (!isset(self::CHANNELS[$channel])) {
            return ['ok' => false, 'message' => '未知的支付渠道：' . $channel];
        }

        $total  = (float) $trade['amount'];
        $amount = $amount === null || $amount <= 0 ? $total : $amount;
        $result = self::channel($channel)->refund($tradeNo, $amount, $total);

        if (!empty($result['ok'])) {
            TradeLog::markRefunded($tradeNo);
        }

        return $result;
    }

    /** 读插件配置（后台开关优先，其次 config.php 默认值） */
    private static function cfg(string $key, $default = null)
    {
        static $conf = null;
        if ($conf === null) {
            $conf = \ywxapp\AddonBase::readConfig('paycenter');
        }

        return $conf[$key] ?? $default;
    }

    /** 当前站点根地址（CLI 下取 APP_HOST） */
    private static function domain(): string
    {
        $req = function_exists('request') ? request() : null;
        if ($req) {
            try {
                $domain = (string) $req->domain(true);
                if ($domain !== '') {
                    return rtrim($domain, '/');
                }
            } catch (\Throwable) {
                // CLI 下 request() 可能不可用
            }
        }

        return rtrim((string) env('APP_HOST', ''), '/');
    }
}