<?php
/**
 * AKSRT Payment Gateway — 支付网关适配器层
 *
 * 定义支付网关统一接口和基础实现。
 * 具体网关（支付宝、微信支付等）通过子类实现。
 *
 * @package AKSRT
 */

defined('ABSPATH') || exit;

/**
 * 支付网关统一接口
 */
interface AKSRT_Payment_Gateway_Interface {
    /**
     * 创建支付单
     *
     * @param array $order 订单数据
     * @return array{success: bool, payment_url?: string, payment_data?: array, message?: string}
     */
    public function create_payment(array $order): array;

    /**
     * 验证回调
     *
     * @param WP_REST_Request $request 回调请求
     * @return array{success: bool, order_number?: string, amount?: float, transaction_id?: string, message?: string}
     */
    public function verify_callback(WP_REST_Request $request): array;

    /**
     * 查询支付状态
     *
     * @param string $order_number 订单号
     * @return array{success: bool, status?: string, transaction_id?: string, message?: string}
     */
    public function query_status(string $order_number): array;

    /**
     * 退款
     *
     * @param string $order_number 订单号
     * @param float  $amount       退款金额
     * @return array{success: bool, refund_id?: string, message?: string}
     */
    public function refund(string $order_number, float $amount): array;

    /**
     * 获取网关显示名称
     */
    public function get_name(): string;

    /**
     * 获取网关标识
     */
    public function get_id(): string;

    /**
     * 网关是否已配置
     */
    public function is_configured(): bool;
}

/**
 * 支付网关管理器
 */
class AKSRT_Payment_Gateway {

    private static $instance = null;
    private $gateways = [];

    public static function get_instance(): self {
        if (null === self::$instance) self::$instance = new self();
        return self::$instance;
    }

    /**
     * 注册网关
     */
    public function register(string $id, AKSRT_Payment_Gateway_Interface $gateway): void {
        $this->gateways[$id] = $gateway;
    }

    /**
     * 获取网关
     */
    public function get_gateway(string $id): ?AKSRT_Payment_Gateway_Interface {
        return $this->gateways[$id] ?? null;
    }

    /**
     * 获取所有已注册网关
     *
     * @return AKSRT_Payment_Gateway_Interface[]
     */
    public function get_all(): array {
        return $this->gateways;
    }

    /**
     * 获取可用网关列表（已配置的）
     */
    public function get_available(): array {
        $available = [];
        foreach ($this->gateways as $id => $gateway) {
            if ($gateway->is_configured()) {
                $available[$id] = $gateway;
            }
        }
        return $available;
    }

    /**
     * 获取网关状态摘要（用于后台展示）
     */
    public function get_status_summary(): array {
        $summary = [];
        foreach ($this->gateways as $id => $gateway) {
            $summary[] = [
                'id'          => $id,
                'name'        => $gateway->get_name(),
                'configured'  => $gateway->is_configured(),
                'available'   => $gateway->is_configured(),
            ];
        }
        return $summary;
    }

    /**
     * 绑定支付回调路由。必须在 functions.php 中初始化。
     *
     * 此前网关 create_payment() 把 notify_url/return_url 指向
     * /wp-json/aksrt/v1/payment/{gateway}/{notify|return|cancel}，但这些路由
     * 从未注册，导致所有跳转型网关（支付宝/微信/PayPal/Stripe）无法完成支付。
     */
    public function init(): void {
        add_action('rest_api_init', [$this, 'register_routes']);
    }

    public function register_routes(): void {
        $args = [
            'methods'             => ['GET', 'POST'],
            'permission_callback' => '__return_true', // 真实性由各网关签名校验保证
            'args'                => [
                'gateway' => ['sanitize_callback' => 'sanitize_key'],
            ],
        ];

        register_rest_route('aksrt/v1', '/payment/(?P<gateway>[a-z0-9_]+)/notify', array_merge($args, [
            'callback' => [$this, 'handle_notify'],
        ]));
        register_rest_route('aksrt/v1', '/payment/(?P<gateway>[a-z0-9_]+)/return', array_merge($args, [
            'callback' => [$this, 'handle_return'],
        ]));
        register_rest_route('aksrt/v1', '/payment/(?P<gateway>[a-z0-9_]+)/cancel', array_merge($args, [
            'callback' => [$this, 'handle_cancel'],
        ]));
    }

    /**
     * 异步通知（服务器到服务器）。验签 → 到账 → 输出网关期望的 ACK。
     */
    public function handle_notify(WP_REST_Request $request) {
        $gateway_id = sanitize_key((string) $request->get_param('gateway'));
        $gateway = $this->get_gateway($gateway_id);
        if (!$gateway) {
            return new WP_REST_Response('gateway not found', 404);
        }

        $verify   = $gateway->verify_callback($request);
        $verified = !empty($verify['success']);
        $paid     = $verified && ($verify['status'] ?? '') === 'paid';

        if ($paid) {
            $this->complete_order($gateway_id, $verify);
        }

        // 网关各自要求的 ACK 格式
        if ($gateway_id === 'wechatpay' && method_exists($gateway, 'output_callback_response')) {
            $gateway->output_callback_response(['success' => $verified]); // exit
        }
        if ($gateway_id === 'alipay') {
            // 支付宝异步通知要求返回纯文本 success，否则会重复通知
            header('Content-Type: text/plain; charset=utf-8');
            echo $verified ? 'success' : 'fail';
            exit;
        }

        // Stripe / PayPal webhook：200 表示已接收；验签失败返回 400 触发重试
        return new WP_REST_Response(['received' => $verified], $verified ? 200 : 400);
    }

    /**
     * 用户浏览器同步返回。尽力确认到账（兜底异步通知延迟），再跳回订单中心。
     */
    public function handle_return(WP_REST_Request $request) {
        $gateway_id   = sanitize_key((string) $request->get_param('gateway'));
        $order_number = sanitize_text_field((string) ($request->get_param('order')
            ?: $request->get_param('out_trade_no')
            ?: ''));
        $gateway = $this->get_gateway($gateway_id);
        $status  = 'pending';

        if ($gateway) {
            if ($gateway_id === 'alipay') {
                // 支付宝同步返回带签名参数，可直接验签作为到账兜底
                $verify = $gateway->verify_callback($request);
                if (!empty($verify['success'])) {
                    $order_number = $order_number ?: sanitize_text_field((string) ($verify['order_number'] ?? ''));
                    if (($verify['status'] ?? '') === 'paid' && $this->complete_order($gateway_id, $verify)) {
                        $status = 'success';
                    }
                }
            } elseif ($gateway_id === 'paypal' && method_exists($gateway, 'capture_order')) {
                // PayPal v2：用户批准后在 return 时捕获（token = PayPal 订单号）
                $paypal_order_id = sanitize_text_field((string) ($request->get_param('token') ?: ''));
                if ($paypal_order_id !== '') {
                    $cap = $gateway->capture_order($paypal_order_id);
                    if (!empty($cap['success']) && ($cap['status'] ?? '') === 'paid') {
                        $order_number = $order_number ?: sanitize_text_field((string) ($cap['order_number'] ?? ''));
                        $cap['order_number'] = $order_number;
                        if ($this->complete_order($gateway_id, $cap)) {
                            $status = 'success';
                        }
                    }
                }
            } elseif ($order_number !== '') {
                // 其余网关：主动查询订单状态兜底
                $q = $gateway->query_status($order_number);
                if (!empty($q['success']) && ($q['status'] ?? '') === 'paid') {
                    $done = $this->complete_order($gateway_id, [
                        'order_number'   => $order_number,
                        'amount'         => 0, // 由网关 API 已确认到账，金额校验交给 notify 路径
                        'transaction_id' => $q['transaction_id'] ?? '',
                        'status'         => 'paid',
                    ]);
                    if ($done) {
                        $status = 'success';
                    }
                }
            }
        }

        $this->redirect_to_orders($order_number, $status);
        return null;
    }

    /**
     * 用户取消支付，跳回订单中心。
     */
    public function handle_cancel(WP_REST_Request $request) {
        $order_number = sanitize_text_field((string) ($request->get_param('order')
            ?: $request->get_param('out_trade_no')
            ?: ''));
        $this->redirect_to_orders($order_number, 'cancelled');
        return null;
    }

    /**
     * 幂等、带金额校验的订单完成。仅由验签通过的回调调用。
     *
     * @param string $gateway_id 网关 ID
     * @param array  $verify     网关 verify_callback / query 结果
     * @return bool
     */
    public function complete_order(string $gateway_id, array $verify): bool {
        $order_number = sanitize_text_field((string) ($verify['order_number'] ?? ''));
        if ($order_number === '' || !class_exists('AKSRT_Order_Repository')) {
            return false;
        }

        $repo  = AKSRT_Order_Repository::get_instance();
        $order = $repo->get($order_number);
        if (!$order) {
            return false;
        }

        $current = (string) ($order['status'] ?? '');

        // 幂等：已支付/已交付/已完成视为成功，不重复处理（回调可能多次到达）
        if (in_array($current, ['paid', 'delivered', 'completed'], true)) {
            return true;
        }
        // 只允许从未支付态完成
        if (!in_array($current, ['created', 'pending'], true)) {
            return false;
        }

        // 金额校验，防止前端/回调金额被篡改
        $expected    = (float) ($order['amount'] ?? 0);
        $paid_amount = (float) ($verify['amount'] ?? 0);
        if ($expected > 0 && $paid_amount > 0 && abs($expected - $paid_amount) > 0.01) {
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log(sprintf('[AKSRT Payment] amount mismatch order=%s expected=%.2f paid=%.2f gateway=%s', $order_number, $expected, $paid_amount, $gateway_id));
            }
            return false;
        }

        return $repo->update_status($order_number, AKSRT_Order::STATUS_PAID, [
            'payment_method'         => $gateway_id,
            'payment_transaction_id' => sanitize_text_field((string) ($verify['transaction_id'] ?? '')),
            'note'                   => __('支付网关回调确认到账。', 'aksrt'),
        ]);
    }

    private function redirect_to_orders(string $order_number, string $status): void {
        $url = add_query_arg(array_filter([
            'payment' => sanitize_key($status),
            'order'   => $order_number,
        ]), $this->orders_page_url());

        nocache_headers();
        wp_safe_redirect($url);
        exit;
    }

    private function orders_page_url(): string {
        $pages = get_posts([
            'post_type'      => 'page',
            'post_status'    => 'publish',
            'posts_per_page' => 1,
            'meta_key'       => '_wp_page_template',
            'meta_value'     => 'templates/pages/page-orders.php',
            'fields'         => 'ids',
            'no_found_rows'  => true,
        ]);

        if (!empty($pages)) {
            return (string) get_permalink((int) $pages[0]);
        }

        return home_url('/orders/');
    }
}

/**
 * 站内余额支付网关（内置实现）
 *
 * 优先扣现金钱包（AKSRT_Balance / pay_balance）；未启用时回退到积分。
 */
class AKSRT_Balance_Gateway implements AKSRT_Payment_Gateway_Interface {

    public function get_id(): string {
        return 'balance';
    }

    public function get_name(): string {
        return __('站内余额', 'aksrt');
    }

    public function is_configured(): bool {
        $wallet_on = class_exists('AKSRT_Balance') && AKSRT_Balance::enabled();
        $credits_on = class_exists('AKSRT_Credits');
        if (!$wallet_on && !$credits_on) {
            return false;
        }
        if (class_exists('AKSRT_Settings_Payment_Runtime')) {
            return AKSRT_Settings_Payment_Runtime::is_gateway_enabled('balance');
        }
        return true;
    }

    public function create_payment(array $order): array {
        $user_id = (int) ($order['user_id'] ?? 0);
        $amount = round((float) ($order['amount'] ?? 0), 2);
        $order_number = (string) ($order['order_number'] ?? '');

        // Prefer cash wallet when pay_balance_s is on.
        if (class_exists('AKSRT_Balance') && AKSRT_Balance::enabled()) {
            if ($user_id <= 0) {
                return ['success' => false, 'message' => __('请先登录', 'aksrt')];
            }
            $balance = AKSRT_Balance::balance($user_id);
            if ($balance < $amount) {
                return ['success' => false, 'message' => __('余额不足', 'aksrt')];
            }
            $result = AKSRT_Balance::deduct(
                $user_id,
                $amount,
                'order_payment',
                ['type' => 'order', 'id' => 0, 'order' => $order_number],
                sprintf(__('订单 %s 支付', 'aksrt'), $order_number)
            );
            if (is_wp_error($result)) {
                return ['success' => false, 'message' => $result->get_error_message() ?: __('扣款失败', 'aksrt')];
            }
            return [
                'success'        => true,
                'transaction_id' => 'BAL_' . ($order_number !== '' ? $order_number : (string) time()),
                'message'        => __('余额支付成功', 'aksrt'),
            ];
        }

        // Fallback: legacy points-as-balance (1 元 = 100 积分).
        if (!class_exists('AKSRT_Credits')) {
            return ['success' => false, 'message' => __('积分系统未启用', 'aksrt')];
        }

        $credits_cost = (int) ceil($amount * 100);
        $balance = AKSRT_Credits::balance($user_id);
        if ($balance < $credits_cost) {
            return ['success' => false, 'message' => __('余额不足', 'aksrt')];
        }

        $result = AKSRT_Credits::deduct(
            $user_id,
            $credits_cost,
            'order_payment',
            ['order' => $order_number],
            sprintf(__('订单 %s 支付', 'aksrt'), $order_number)
        );

        if (is_wp_error($result)) {
            return ['success' => false, 'message' => $result->get_error_message() ?: __('扣款失败', 'aksrt')];
        }

        return [
            'success'        => true,
            'transaction_id' => 'BAL_' . ($order_number !== '' ? $order_number : (string) time()),
            'message'        => __('余额支付成功', 'aksrt'),
        ];
    }

    public function verify_callback(WP_REST_Request $request): array {
        // Balance payment is synchronous — no callback needed
        return ['success' => false, 'message' => __('余额支付无需回调验证', 'aksrt')];
    }

    public function query_status(string $order_number): array {
        $order_repo = AKSRT_Order_Repository::get_instance();
        $order = $order_repo->get($order_number);

        if (!$order) {
            return ['success' => false, 'message' => __('订单不存在', 'aksrt')];
        }

        return [
            'success'        => true,
            'status'         => $order['status'],
            'transaction_id' => $order['payment_transaction_id'] ?? '',
        ];
    }

    public function refund(string $order_number, float $amount): array {
        $order_repo = AKSRT_Order_Repository::get_instance();
        $order = $order_repo->get($order_number);

        if (!$order) {
            return ['success' => false, 'message' => __('订单不存在', 'aksrt')];
        }

        $user_id = (int) $order['user_id'];
        $amount = round((float) $amount, 2);

        if (class_exists('AKSRT_Balance') && AKSRT_Balance::enabled()) {
            $result = AKSRT_Balance::add(
                $user_id,
                $amount,
                'order_refund',
                ['type' => 'order', 'order' => $order_number],
                sprintf(__('订单 %s 退款', 'aksrt'), $order_number)
            );
            if (is_wp_error($result)) {
                return ['success' => false, 'message' => $result->get_error_message() ?: __('退款失败', 'aksrt')];
            }
            return ['success' => true, 'refund_id' => 'BAL_REF_' . $order_number, 'message' => __('退款成功', 'aksrt')];
        }

        if (!class_exists('AKSRT_Credits')) {
            return ['success' => false, 'message' => __('积分系统未启用', 'aksrt')];
        }

        $credits_refund = (int) ceil($amount * 100);
        $result = AKSRT_Credits::add(
            $user_id,
            $credits_refund,
            'order_refund',
            ['order' => $order_number],
            sprintf(__('订单 %s 退款', 'aksrt'), $order_number)
        );

        if (is_wp_error($result)) {
            return ['success' => false, 'message' => $result->get_error_message() ?: __('退款失败', 'aksrt')];
        }

        return ['success' => true, 'refund_id' => 'BAL_REF_' . $order_number, 'message' => __('退款成功', 'aksrt')];
    }
}