<?php

declare(strict_types=1);

namespace App\Services\Auth;

use App\Models\Client;
use App\Services\LogService;
use Illuminate\Support\Facades\Redis;
use Illuminate\Support\Str;

class TokenService
{
    private const AUTH_TOKEN_PREFIX = 'auth_token:';
    private const ACCESS_TOKEN_PREFIX = 'access_token:';
    private const BLACKLIST_PREFIX = 'token_blacklist:';
    private const MAX_AUTH_TOKEN_HOURS = 8; // 最大 8 小時有效期
    private const ACCESS_TOKEN_TTL = 3600; // 1 小時有效期

    public function __construct(
        private readonly LogService $logService
    ) {}

    /**
     * 生成認證令牌
     *
     * @return array{auth_token: string, expires_at: string, client_id: int}
     */
    public function generateAuthToken(Client $client, ?int $expiresInHours = null): array
    {
        // 確保不超過最大有效期
        $effectiveHours = min($expiresInHours ?? self::MAX_AUTH_TOKEN_HOURS, self::MAX_AUTH_TOKEN_HOURS);
        $effectiveSeconds = $effectiveHours * 3600;

        // 生成新令牌
        $token = Str::random(64);
        $expiresAt = now()->addHours($effectiveHours);

        // 存儲到 Redis
        Redis::setex(
            self::AUTH_TOKEN_PREFIX . $token,
            $effectiveSeconds,
            json_encode([
                'client_id' => $client->id,
                'token' => $token,
                'created_at' => now()->toIso8601String(),
                'expires_at' => $expiresAt->toIso8601String(),
            ])
        );

        // 記錄操作日誌
        $this->logService->logOperation(
            'client',
            $client->id,
            'Generated new auth token'
        );

        return [
            'auth_token' => $token,
            'expires_at' => $expiresAt->toIso8601String(),
            'client_id' => $client->id,
        ];
    }

    /**
     * 驗證認證令牌
     *
     * @return array{client_id: int, token: string, created_at: string, expires_at: string}|null
     */
    public function validateAuthToken(string $token): ?array
    {
        // 檢查黑名單
        if (Redis::exists(self::BLACKLIST_PREFIX . $token)) {
            return null;
        }

        // 檢查令牌是否存在且有效
        $tokenData = Redis::get(self::AUTH_TOKEN_PREFIX . $token);
        if (!$tokenData) {
            return null;
        }

        $data = json_decode($tokenData, true);
        if (!$data || now()->isAfter($data['expires_at'])) {
            Redis::del(self::AUTH_TOKEN_PREFIX . $token);
            return null;
        }

        return $data;
    }

    /**
     * 生成訪問令牌
     *
     * @return array{access_token: string, expires_in: int}
     */
    public function generateAccessToken(array $authTokenData): array
    {
        $accessToken = Str::random(64);

        // 存儲到 Redis，包含更多信息以便追蹤
        Redis::setex(
            self::ACCESS_TOKEN_PREFIX . $accessToken,
            self::ACCESS_TOKEN_TTL,
            json_encode([
                'client_id' => $authTokenData['client_id'],
                'auth_token' => $authTokenData['token'],
                'created_at' => now()->toIso8601String(),
            ])
        );

        // 記錄操作日誌
        $this->logService->logOperation(
            'client',
            $authTokenData['client_id'],
            'Generated new access token'
        );

        return [
            'access_token' => $accessToken,
            'expires_in' => self::ACCESS_TOKEN_TTL,
        ];
    }

    /**
     * 驗證訪問令牌
     *
     * @return array{client_id: int, auth_token: string, created_at: string}|null
     */
    public function validateAccessToken(string $token): ?array
    {
        $tokenData = Redis::get(self::ACCESS_TOKEN_PREFIX . $token);
        if (!$tokenData) {
            return null;
        }

        return json_decode($tokenData, true);
    }

    /**
     * 撤銷訪問令牌
     */
    public function revokeAccessToken(string $token): void
    {
        $tokenData = Redis::get(self::ACCESS_TOKEN_PREFIX . $token);
        if ($tokenData) {
            $data = json_decode($tokenData, true);
            if ($data) {
                // 記錄操作日誌
                $this->logService->logOperation(
                    'client',
                    $data['client_id'],
                    'Access token revoked'
                );
            }
            // 從 Redis 中刪除
            Redis::del(self::ACCESS_TOKEN_PREFIX . $token);
        }
    }

    /**
     * 撤銷認證令牌
     */
    public function revokeAuthToken(string $token): void
    {
        $tokenData = Redis::get(self::AUTH_TOKEN_PREFIX . $token);
        if ($tokenData) {
            $data = json_decode($tokenData, true);
            if ($data) {
                // 計算剩餘有效期
                $expiresAt = now()->parse($data['expires_at']);
                $remainingSeconds = max(1, $expiresAt->diffInSeconds(now()));

                // 加入黑名單
                Redis::setex(
                    self::BLACKLIST_PREFIX . $token,
                    $remainingSeconds,
                    'revoked'
                );

                // 記錄操作日誌
                $this->logService->logOperation(
                    'client',
                    $data['client_id'],
                    'Auth token revoked'
                );
            }
            // 從 Redis 中刪除
            Redis::del(self::AUTH_TOKEN_PREFIX . $token);
        }
    }
}