<?php

namespace App\Services\Payments\Danal;

use App\Models\GcPaymentAttempt;
use App\Services\Payments\Danal\Gateways\DanalCardGateway;
use App\Services\Payments\Danal\Gateways\DanalVactGateway;
use App\Services\Payments\Danal\Clients\DanalTeleditClient;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Str;

final class DanalPaymentService
{
    public function __construct(
        private readonly DanalCardGateway $card,
        private readonly DanalVactGateway $vact,
        private readonly DanalTeleditClient $teledit,
    ) {}

    /**
     * 결제 시작: card/vact/phone 분기
     */
    public function start(int $memNo, array $data): array
    {
        $oid = (string)$data['oid'];
        $payMethod = (string)$data['pay_method'];

        // TODO: 여기서 CI3처럼 주문정보를 DB에서 조회해서 변조 방지해야 함
        // - 필요한 값: amount, itemName, stat_pay(w), mid(환금성 판단), mem_no 일치 등
        // - 현재는 최소값만 받되, 반드시 네 주문 테이블에 맞게 연결할 것.
        $order = $this->loadOrderForPaymentOrFail($oid, $memNo);

        return DB::transaction(function () use ($memNo, $data, $order, $payMethod, $oid) {
            [$attempt, $token] = $this->upsertAttempt($memNo, $order, $data);

            if ($payMethod === 'card') {
                $kind = $data['card_kind'] ?? 'general'; // general|exchange
                $start = $this->card->auth($attempt, $token, $order, $kind);
            } elseif ($payMethod === 'vact') {
                $kind = $data['vact_kind'] ?? 'a'; // a|v (기본 a)
                $start = $this->vact->auth($attempt, $token, $order, $kind);
            } else { // phone
                $start = $this->teledit->ready($attempt, $token, $order);
            }

            $attempt->status = 'redirected';
            $attempt->redirected_at = now();
            $attempt->save();

            return $start;
        });
    }

    public function handleCardReturn(string $oid, string $token, array $all, array $post): array
    {
        return DB::transaction(function () use ($oid, $token, $post) {
            $attempt = $this->findAttemptOrFail('card', $oid, $token);
            $order = $this->loadOrderForPaymentOrFail($attempt->oid, (int)$attempt->mem_no);

            $ret = $this->card->billOnReturn($attempt, $token, $order, $post);

            return $ret;
        });
    }

    public function handleVactReturn(string $token, array $post): array
    {
        return DB::transaction(function () use ($token, $post) {
            $attempt = $this->findAttemptByTokenOrFail('vact', $token);
            $order = $this->loadOrderForPaymentOrFail($attempt->oid, (int)$attempt->mem_no);

            return $this->vact->issueVaccountOnReturn($attempt, $token, $order, $post);
        });
    }

    public function handleVactNoti(array $post): void
    {
        // NOTI는 idempotent하게: 이미 paid면 그냥 OK
        DB::transaction(function () use ($post) {
            $this->vact->handleNoti($post, function (string $oid, string $tid, int $amount, array $payload) {
                // TODO: 여기서 주문 paid 처리 + 장부 처리
                // $this->markOrderPaid($oid, $tid, $amount, $payload);

                // attempt도 paid로
                $attempt = GcPaymentAttempt::query()
                    ->where('provider','danal')->where('oid',$oid)->where('pay_method','vact')
                    ->lockForUpdate()->first();

                if ($attempt) {
                    if ($attempt->status !== 'paid') {
                        $attempt->status = 'paid';
                        $attempt->pg_tid = $tid ?: $attempt->pg_tid;
                        $attempt->amount = $amount ?: $attempt->amount;
                        $attempt->noti_payload = $payload;
                        $attempt->noti_at = now();
                        $attempt->save();
                    }
                }
            });
        });
    }

    public function handlePhoneReturn(array $post): array
    {
        return DB::transaction(function () use ($post) {

            // Order 복호화로 oid/mem_no/token 확보
            [$oid, $amount, $memNo, $token] = $this->teledit->decryptOrder((string)($post['Order'] ?? ''));

            $order = $this->loadOrderForPaymentOrFail($oid, (int)$memNo);

            return $this->teledit->confirmAndBillOnReturn($post, $order, function (string $oid, string $tid, int $amount, array $payload) {
                // TODO: 주문 paid 처리 + 장부 처리
                // $this->markOrderPaid($oid, $tid, $amount, $payload);

                $attempt = GcPaymentAttempt::query()
                    ->where('provider','danal')->where('oid',$oid)->where('pay_method','phone')
                    ->lockForUpdate()->first();

                if ($attempt) {
                    $attempt->status = 'paid';
                    $attempt->pg_tid = $tid;
                    $attempt->returned_at = now();
                    $attempt->return_payload = $payload;
                    $attempt->save();
                }
            });
        });
    }


    public function handlePhoneCancel(array $post): array
    {
        return DB::transaction(function () use ($post) {

            return $this->teledit->handleCancel($post, function (string $oid, array $payload) {
                // TODO: 주문 cancel 처리
                // $this->cancelOrder($oid, 'C999', '사용자 결제 취소', $payload);

                $attempt = GcPaymentAttempt::query()
                    ->where('provider','danal')->where('oid',$oid)->where('pay_method','phone')
                    ->lockForUpdate()->first();

                if ($attempt) {
                    $attempt->status = 'cancelled';
                    $attempt->return_payload = $payload;
                    $attempt->returned_at = now();
                    $attempt->save();
                }
            });
        });
    }


    public function handleCancel(string $oid, string $token): array
    {
        return DB::transaction(function () use ($oid, $token) {
            $attempt = $this->findAttemptAnyMethodOrFail($oid, $token);

            // TODO: 주문 cancel 처리
            // $this->cancelOrder($oid, 'USER_CANCEL', '사용자 결제 취소', []);

            $attempt->status = 'cancelled';
            $attempt->returned_at = now();
            $attempt->save();

            return [
                'status' => 'cancel',
                'message' => '구매를 취소했습니다.',
                'redirectUrl' => url('/mypage/usage'),
            ];
        });
    }

    private function upsertAttempt(int $memNo, array $order, array $data): array
    {
        $token = bin2hex(random_bytes(32));
        $tokenHash = hash('sha256', $token);

        $attempt = GcPaymentAttempt::query()
            ->where('provider','danal')
            ->where('oid', (string)$order['oid'])
            ->where('pay_method', (string)$data['pay_method'])
            ->lockForUpdate()
            ->first();

        if (!$attempt) {
            $attempt = new GcPaymentAttempt();
            $attempt->provider = 'danal';
            $attempt->oid = (string)$order['oid'];
            $attempt->mem_no = $memNo;
            $attempt->pay_method = (string)$data['pay_method'];
            $attempt->amount = (int)$order['amount'];
            $attempt->currency = 'KRW';
            $attempt->ready_at = now();
        }

        $attempt->status = 'ready';
        $attempt->token_hash = $tokenHash;
        $attempt->card_kind = $data['card_kind'] ?? null;
        $attempt->vact_kind = $data['vact_kind'] ?? null;
        $attempt->user_agent = request()->userAgent();
        $attempt->user_ip = inet_pton(request()->ip() ?: '127.0.0.1');
        $attempt->save();

        return [$attempt, $token];
    }

    private function findAttemptOrFail(string $method, string $oid, string $token): GcPaymentAttempt
    {
        $tokenHash = hash('sha256', $token);

        $attempt = GcPaymentAttempt::query()
            ->where('provider','danal')
            ->where('oid',$oid)
            ->where('pay_method',$method)
            ->lockForUpdate()
            ->first();

        if (!$attempt) abort(404);
        if (!hash_equals((string)$attempt->token_hash, $tokenHash)) abort(403);

        return $attempt;
    }

    private function findAttemptByTokenOrFail(string $method, string $token): GcPaymentAttempt
    {
        $tokenHash = hash('sha256', $token);

        $attempt = GcPaymentAttempt::query()
            ->where('provider','danal')
            ->where('pay_method',$method)
            ->where('token_hash',$tokenHash)
            ->lockForUpdate()
            ->first();

        if (!$attempt) abort(404);

        return $attempt;
    }

    private function findAttemptAnyMethodOrFail(string $oid, string $token): GcPaymentAttempt
    {
        $tokenHash = hash('sha256', $token);

        $attempt = GcPaymentAttempt::query()
            ->where('provider','danal')
            ->where('oid',$oid)
            ->where('token_hash',$tokenHash)
            ->lockForUpdate()
            ->first();

        if (!$attempt) abort(404);
        return $attempt;
    }

    /**
     * TODO: 네 주문테이블에 맞게 구현해야 하는 핵심 함수
     * - CI3 Product.php payment_danal_ready()에서 하던 검증(oid/mem_no/stat_pay/amount 등)
     */
    private function loadOrderForPaymentOrFail(string $oid, int $memNo): array
    {
        // ✅ 여기만 너 DB 구조에 맞게 바꾸면 나머지 다날 연동은 그대로 감
        // 예시 형태:
        // $row = DB::table('gc_orders')->where('oid',$oid)->first();
        // if (!$row) abort(404);
        // if ((int)$row->mem_no !== $memNo) abort(403);
        // if ($row->stat_pay !== 'w') abort(409);
        // return ['oid'=>$row->oid,'amount'=>(int)$row->pay_money,'itemName'=>$row->pin_name,'mid'=>$row->mid];

        return [
            'oid' => $oid,
            'amount' => (int) request('amount', 0),     // 임시
            'itemName' => (string) request('itemName', '상품권'),
            'mid' => (string) request('mid', ''),
        ];
    }
}