<?php
/**
 * @package AKSRT
 */

namespace AKSRT\Payment\Gateways;

defined('ABSPATH') || exit;

class StripeGateway implements \AKSRT\Payment\GatewayInterface {

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

    public function get_name(): string {
        return __('Stripe', 'aksrt');
    }

    public function is_configured(): bool {
        if (class_exists('\AKSRT\Settings\PaymentRuntime')
            && !\AKSRT\Settings\PaymentRuntime::is_gateway_enabled('stripe')) {
            return false;
        }
        $config = $this->get_config();
        return !empty($config['secret_key'])
            && !empty($config['publishable_key'])
            && !empty($config['webhook_secret']);
    }

    public function create_payment(array $order): array {
        if (!$this->is_configured()) {
            return ['success' => false, 'message' => __('Stripe 未配置', 'aksrt')];
        }

        $config = $this->get_config();
        $order_number = (string) ($order['order_number'] ?? '');
        // Re-pay attempts carry a fresh provider number; the callback resolves it back.
        $out_trade_no = (string) ($order['out_trade_no'] ?? '');
        if ($out_trade_no === '') {
            $out_trade_no = class_exists('\AKSRT\Payment\OrderRepository')
                ? \AKSRT\Payment\OrderRepository::provider_out_trade_no($order)
                : $order_number;
        }
        $amount = is_string($order['amount'] ?? null) ? trim($order['amount']) : '';
        $subject = $order['subject'] ?? __('订单支付', 'aksrt');
        $order_currency = strtoupper((string) ($order['currency'] ?? ''));
        $currency = strtolower($config['currency'] ?? 'usd');
        if ($order_currency === '' || !hash_equals($order_currency, strtoupper($currency))) {
            return ['success' => false, 'message' => __('Stripe 币种与订单币种不一致', 'aksrt')];
        }
		$smallest_amount = $this->to_smallest_unit($amount, $currency);
		if ($order_number === '' || $out_trade_no === '' || $smallest_amount === null || $smallest_amount <= 0) {
			return ['success' => false, 'message' => __('订单金额无效', 'aksrt')];
		}

        try {
            $stripe = $this->create_client($config);

            // 创建 Checkout Session
            $session_params = [
                'payment_method_types' => $this->get_payment_methods($config),
                'line_items' => [[
                    'price_data' => [
                        'currency'     => $currency,
                        'product_data' => [
                            'name' => $subject,
                        ],
                        'unit_amount'  => $smallest_amount,
                    ],
                    'quantity' => 1,
                ]],
                'mode' => 'payment',
                'client_reference_id' => $out_trade_no,
                'success_url' => home_url('/wp-json/aksrt/v1/payment/stripe/return?session_id={CHECKOUT_SESSION_ID}&order=' . rawurlencode($out_trade_no)),
                'cancel_url'  => home_url('/wp-json/aksrt/v1/payment/stripe/cancel?order=' . rawurlencode($out_trade_no)),
                'metadata'    => [
                    'order_number' => $out_trade_no,
                ],
            ];

            // 启用自动支付方式（Apple Pay, Google Pay 等）
            if (!empty($config['auto_payment_methods'])) {
                $session_params['automatic_payment_methods'] = [
                    'enabled' => true,
                ];
            }

            $session = \Stripe\Checkout\Session::create($session_params, [
                'api_key' => $config['secret_key'],
            ]);

            // Persist the session id before returning the redirect. Without this,
            // status/refund lookup may miss older sessions after traffic exceeds 100.
            if ($order_number !== '' && class_exists('\AKSRT\Payment\OrderRepository')) {
                $persisted = \AKSRT\Payment\OrderRepository::get_instance()->merge_meta($order_number, [
                    'stripe_session_id' => (string) $session->id,
                    'stripe_sessions'   => $this->append_session_mapping($order, $out_trade_no, (string) $session->id),
                ]);
                if (!$persisted) {
                    try {
                        \Stripe\Checkout\Session::expire((string) $session->id, [
                            'api_key' => $config['secret_key'],
                        ]);
                    } catch (\Throwable $e) {
                        // Best-effort cleanup; do not return an untraceable session.
                    }
                    return ['success' => false, 'message' => __('Stripe 支付会话保存失败，请重试', 'aksrt')];
                }
            }

            return [
                'success'      => true,
                'payment_url'  => $session->url,
                'payment_data' => [
                    'order_number' => $order_number,
                    'out_trade_no' => $out_trade_no,
                    'session_id'   => $session->id,
                ],
                'message'      => __('Stripe 支付页面已创建', 'aksrt'),
            ];
        } catch (\Stripe\Exception\ApiErrorException $e) {
            return ['success' => false, 'message' => $e->getMessage()];
        } catch (\Exception $e) {
            return ['success' => false, 'message' => $e->getMessage()];
        }
    }

    public function verify_callback(\WP_REST_Request $request): array {
        $config = $this->get_config();

        try {
            $stripe = $this->create_client($config);

            $payload = $request->get_body();
            $sigHeader = $_SERVER['HTTP_STRIPE_SIGNATURE'] ?? '';

            // 验证 Webhook 签名
            $event = \Stripe\Webhook::constructEvent(
                $payload,
                $sigHeader,
                $config['webhook_secret'] ?? ''
            );

            if ($event->type !== 'checkout.session.completed') {
                return ['success' => false, 'message' => __('非支付完成事件', 'aksrt')];
            }

            $session = $event->data->object;
            $orderNumber = $session->metadata->order_number ?? '';
            $currency = strtolower((string) ($session->currency ?? $config['currency'] ?? 'usd'));
            $amount = $this->from_smallest_unit((int) ($session->amount_total ?? 0), $currency);

            return [
                'success'        => true,
                'order_number'   => $orderNumber,
                'amount'         => $amount,
                'currency'       => strtoupper($currency),
                'transaction_id' => $session->payment_intent ?? $session->id,
                'status'         => $session->payment_status === 'paid' ? 'paid' : 'pending',
            ];
        } catch (\Stripe\Exception\SignatureVerificationException $e) {
            return ['success' => false, 'message' => __('Webhook 签名验证失败', 'aksrt')];
        } catch (\Exception $e) {
            return ['success' => false, 'message' => $e->getMessage()];
        }
    }

    public function query_status(string $order_number): array {
        if (!$this->is_configured()) {
            return ['success' => false, 'message' => __('Stripe 未配置', 'aksrt')];
        }

        $config = $this->get_config();

        try {
            $this->create_client($config);
            $found = $this->find_session($order_number, $config, true);

            if ($found) {
                $status = 'pending';
                if ($found->payment_status === 'paid') {
                    $status = 'paid';
                } elseif ($found->status === 'expired') {
                    $status = 'cancelled';
                }

                $transaction_id = is_string($found->payment_intent)
                    ? $found->payment_intent
                    : (string) ($found->payment_intent->id ?? '');

                return [
                    'success'        => true,
                    'order_number'   => (string) ($found->metadata->order_number ?? $order_number),
                    'amount'         => $this->from_smallest_unit(
                        (int) ($found->amount_total ?? 0),
                        strtolower((string) ($found->currency ?? $config['currency'] ?? 'usd'))
                    ),
                    'currency'       => strtoupper((string) ($found->currency ?? $config['currency'] ?? 'usd')),
                    'status'         => $status,
                    'transaction_id' => $transaction_id,
                ];
            }

            return ['success' => true, 'status' => 'pending', 'message' => __('未找到支付记录', 'aksrt')];
        } catch (\Exception $e) {
            return ['success' => false, 'message' => $e->getMessage()];
        }
    }

	public function refund(string $order_number, string $amount, string $request_id = ''): array {
		try {
			$refund_amount = \AKSRT\Ledger\AssetAmount::balance($amount);
		} catch (\InvalidArgumentException $e) {
			return ['success' => false, 'message' => __('退款金额无效', 'aksrt')];
		}
		if ($refund_amount->minor() <= 0) {
			return ['success' => false, 'message' => __('退款金额无效', 'aksrt')];
		}
        if (!$this->is_configured()) {
            return ['success' => false, 'message' => __('Stripe 未配置', 'aksrt')];
        }

        $config = $this->get_config();

        try {
            $this->create_client($config);
            $found = $this->find_session($order_number, $config, true);

            if (!$found) {
                return ['success' => false, 'message' => __('未找到支付记录', 'aksrt')];
            }

            $paymentIntentId = is_string($found->payment_intent)
                ? $found->payment_intent
                : (string) ($found->payment_intent->id ?? '');

            if ($paymentIntentId === '') {
                return ['success' => false, 'message' => __('未找到支付意图', 'aksrt')];
            }

            $currency = strtolower((string) ($found->currency ?? $config['currency'] ?? 'usd'));
			$refund_smallest = $this->to_smallest_unit($refund_amount->decimal(), $currency);
			if ($refund_smallest === null || $refund_smallest <= 0) {
				return ['success' => false, 'message' => __('退款金额与币种精度不匹配', 'aksrt')];
			}

            $options = ['api_key' => $config['secret_key']];
            if ($request_id !== '') {
                $options['idempotency_key'] = $request_id;
            }
            $refund = \Stripe\Refund::create([
                'payment_intent' => $paymentIntentId,
				'amount'         => $refund_smallest,
                'reason'         => 'requested_by_customer',
                'metadata'       => [
                    'aksrt_request_id' => $request_id,
                    'order_number'     => $order_number,
                ],
            ], $options);

            return [
                'success'    => true,
                'status'     => ($refund->status ?? '') === 'succeeded' ? 'succeeded' : 'pending',
                'refund_id'  => $refund->id,
                'request_id' => $request_id,
                'message'    => __('退款请求已提交', 'aksrt'),
            ];
        } catch (\Stripe\Exception\ApiErrorException $e) {
            return ['success' => false, 'message' => $e->getMessage()];
        } catch (\Exception $e) {
            return ['success' => false, 'message' => $e->getMessage()];
        }
    }

    public function query_refund(string $request_id, string $order_number = ''): array {
        if (!$this->is_configured() || $request_id === '') {
            return ['success' => false, 'status' => 'failed', 'message' => __('Stripe 退款查询参数无效', 'aksrt')];
        }

        try {
            $config = $this->get_config();
            $this->create_client($config);
            $refunds = \Stripe\Refund::all(['limit' => 100], ['api_key' => $config['secret_key']]);
            foreach ($refunds->data as $refund) {
                if (($refund->metadata->aksrt_request_id ?? '') !== $request_id) {
                    continue;
                }
                $status = ($refund->status ?? '') === 'succeeded'
                    ? 'succeeded'
                    : (($refund->status ?? '') === 'failed' ? 'failed' : 'pending');
                return [
                    'success'   => true,
                    'status'    => $status,
                    'refund_id' => (string) ($refund->id ?? ''),
                ];
            }
            return ['success' => true, 'status' => 'unknown', 'message' => __('未找到 Stripe 退款记录', 'aksrt')];
        } catch (\Exception $e) {
            return ['success' => false, 'status' => 'unknown', 'message' => $e->getMessage()];
        }
    }

    /**
     * 获取 Stripe Publishable Key（前端使用）。
     */
    public function get_publishable_key(): string {
        $config = $this->get_config();
        return $config['publishable_key'] ?? '';
    }

    /**
     * @param array<string,mixed> $order
     * @return array<string,string>
     */
    private function append_session_mapping(array $order, string $out_trade_no, string $session_id): array {
        $meta = is_array($order['meta_payload'] ?? null) ? $order['meta_payload'] : [];
        $map  = is_array($meta['stripe_sessions'] ?? null) ? $meta['stripe_sessions'] : [];
        $map[$out_trade_no] = $session_id;
        if (count($map) > 20) {
            $map = array_slice($map, -20, null, true);
        }
        return $map;
    }

    /**
     * Locate the Checkout Session for an order. Prefers the session id persisted
     * at create time; falls back to scanning recent sessions for legacy orders.
     *
     * @return \Stripe\Checkout\Session|null
     */
    private function find_session(string $order_number, array $config, bool $allow_legacy_scan = false) {
        $session_id = '';
        if ($order_number !== '' && class_exists('\AKSRT\Payment\OrderRepository')) {
            $repo  = \AKSRT\Payment\OrderRepository::get_instance();
            $order = $repo->resolve_by_out_trade_no($order_number) ?: $repo->get($order_number);
            if ($order) {
                $meta = is_array($order['meta_payload'] ?? null) ? $order['meta_payload'] : [];
                $sessions = is_array($meta['stripe_sessions'] ?? null) ? $meta['stripe_sessions'] : [];
                $session_id = sanitize_text_field((string) ($sessions[$order_number] ?? ''));
                if ($session_id === '' && $repo->get($order_number)) {
                    $current_ref = \AKSRT\Payment\OrderRepository::provider_out_trade_no($order);
                    $session_id = sanitize_text_field((string) ($sessions[$current_ref] ?? $meta['stripe_session_id'] ?? ''));
                }
            }
        }

        if ($session_id !== '') {
            try {
                return \Stripe\Checkout\Session::retrieve($session_id, ['api_key' => $config['secret_key']]);
            } catch (\Exception $e) {
                // Fall through to the scan below.
            }
        }

        if (!$allow_legacy_scan) {
            return null;
        }

        // Legacy orders created before session-id persistence can only be found
        // through Stripe's recent-session window.
        $sessions = \Stripe\Checkout\Session::all(['limit' => 100], ['api_key' => $config['secret_key']]);
        foreach ($sessions->data as $session) {
            if (($session->metadata->order_number ?? '') === $order_number) {
                return $session;
            }
        }

        return null;
    }

    private function get_config(): array {
        if (!class_exists('\AKSRT\Settings\Settings')) {
            return [];
        }
        $all = \AKSRT\Settings\Settings::get_all();
        return [
            'secret_key'      => (string) ($all['stripe_secret_key'] ?? ''),
            'publishable_key' => (string) ($all['stripe_publishable_key'] ?? ''),
            'webhook_secret'  => (string) ($all['stripe_webhook_secret'] ?? ''),
            'currency'        => (string) ($all['stripe_currency'] ?? 'usd'),
            'mode'            => !empty($all['stripe_test_mode']) ? 'test' : 'live',
        ];
    }

    private function create_client(array $config): void {
        \Stripe\Stripe::setApiKey($config['secret_key']);

        // 设置 API 版本
        \Stripe\Stripe::setApiVersion('2023-10-16');

        // 启用遥测（可选）
        if (!empty($config['enable_telemetry'])) {
            \Stripe\Stripe::setEnableTelemetry(true);
        }
    }

    /**
     * 获取支持的支付方式。
     */
    private function get_payment_methods(array $config): array {
        $methods = $config['payment_methods'] ?? ['card'];

        // 验证支付方式
        $valid = ['card', 'alipay', 'wechat_pay', 'sepa_debit', 'ideal', 'bancontact', 'giropay', 'sofort'];
        return array_values(array_intersect($methods, $valid)) ?: ['card'];
    }

    private function from_smallest_unit(int $amount, string $currency): string {
		if ($amount < 0) {
			return '0.00';
		}
        $zero_decimal = ['bif', 'clp', 'djf', 'gnf', 'jpy', 'kmf', 'krw', 'mga', 'pyg', 'rwf', 'ugx', 'vnd', 'vuv', 'xaf', 'xof', 'xpf'];
        if (in_array(strtolower($currency), $zero_decimal, true)) {
			if ($amount > intdiv(PHP_INT_MAX, 100)) {
				return '0.00';
			}
			return \AKSRT\Ledger\AssetAmount::from_minor(\AKSRT\Ledger\AssetType::BALANCE, $amount * 100)->decimal();
        }

		return \AKSRT\Ledger\AssetAmount::from_minor(\AKSRT\Ledger\AssetType::BALANCE, $amount)->decimal();
    }

    /**
     * 将金额转换为最小单位（分/cent）。
     */
    private function to_smallest_unit(string $amount, string $currency): ?int {
		try {
			$parsed = \AKSRT\Ledger\AssetAmount::balance($amount);
		} catch (\InvalidArgumentException $e) {
			return null;
		}
        // 零小数货币（日元、韩元等）
        $zeroDecimal = ['bif', 'clp', 'djf', 'gnf', 'jpy', 'kmf', 'krw', 'mga', 'pyg', 'rwf', 'ugx', 'vnd', 'vuv', 'xaf', 'xof', 'xpf'];

        if (in_array(strtolower($currency), $zeroDecimal, true)) {
			return $parsed->minor() % 100 === 0 ? intdiv($parsed->minor(), 100) : null;
        }

		return $parsed->minor();
    }
}