<?php

namespace App\Module\OpenAPI\Services;

use App\Module\OpenAPI\Models\OpenApiApp;
use App\Module\OpenAPI\Enums\APP_STATUS;
use App\Module\OpenAPI\Enums\AUTH_TYPE;
use App\Module\OpenAPI\Enums\SCOPE_TYPE;
use App\Module\OpenAPI\Events\AppCreatedEvent;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Event;
use Illuminate\Support\Facades\Hash;

/**
 * OpenAPI核心服务
 */
class OpenApiService
{
    /**
     * 创建新应用
     *
     * @param array $data
     * @return OpenApiApp
     */
    public function createApp(array $data): OpenApiApp
    {
        // 验证必填字段
        $this->validateRequiredFields($data);

        // 生成应用ID和密钥
        $data['app_id'] = OpenApiApp::generateAppId();
        $data['app_secret'] = OpenApiApp::generateAppSecret();

        // 设置默认值
        $data['status'] = $data['status'] ?? config('openapi.app.default_status', APP_STATUS::PENDING->value);
        $data['auth_type'] = $data['auth_type'] ?? config('openapi.auth.default_type', AUTH_TYPE::API_KEY->value);
        $data['scopes'] = $data['scopes'] ?? config('openapi.scopes.default', []);

        // 设置过期时间
        if (!isset($data['expires_at'])) {
            $expireDays = config('openapi.app.expire_days', 365);
            $data['expires_at'] = now()->addDays($expireDays);
        }

        // 加密应用密钥
        if (config('openapi.security.encrypt_secrets', true)) {
            $data['app_secret'] = encrypt($data['app_secret']);
        }

        // 创建应用
        $app = OpenApiApp::create($data);

        // 触发应用创建事件
        Event::dispatch(new AppCreatedEvent($app));

        return $app;
    }

    /**
     * 验证必填字段
     *
     * @param array $data
     * @throws \InvalidArgumentException
     */
    protected function validateRequiredFields(array $data): void
    {
        $requiredFields = config('openapi.app.required_fields', ['name', 'description', 'callback_url']);

        foreach ($requiredFields as $field) {
            if (empty($data[$field])) {
                throw new \InvalidArgumentException("字段 {$field} 是必填的");
            }
        }
    }

    /**
     * 审核应用
     *
     * @param int $appId
     * @param bool $approved
     * @param string $note
     * @param int $approvedBy
     * @return OpenApiApp
     */
    public function approveApp(int $appId, bool $approved, string $note = '', int $approvedBy = null): OpenApiApp
    {
        $app = OpenApiApp::findOrFail($appId);

        if ($app->status !== APP_STATUS::PENDING->value) {
            throw new \InvalidArgumentException('只能审核待审核状态的应用');
        }

        $app->update([
            'status' => $approved ? APP_STATUS::APPROVED->value : APP_STATUS::REJECTED->value,
            'approved_at' => now(),
            'approved_by' => $approvedBy,
            'approved_note' => $note,
        ]);

        // 清除缓存
        $this->clearAppCache($app->app_id);

        return $app;
    }

    /**
     * 激活应用
     *
     * @param int $appId
     * @return OpenApiApp
     */
    public function activateApp(int $appId): OpenApiApp
    {
        $app = OpenApiApp::findOrFail($appId);

        if (!in_array($app->status, [APP_STATUS::APPROVED->value, APP_STATUS::SUSPENDED->value])) {
            throw new \InvalidArgumentException('只能激活已审核或已暂停的应用');
        }

        $app->update(['status' => APP_STATUS::ACTIVE->value]);

        // 清除缓存
        $this->clearAppCache($app->app_id);

        return $app;
    }

    /**
     * 暂停应用
     *
     * @param int $appId
     * @param string $reason
     * @return OpenApiApp
     */
    public function suspendApp(int $appId, string $reason = ''): OpenApiApp
    {
        $app = OpenApiApp::findOrFail($appId);

        if ($app->status !== APP_STATUS::ACTIVE->value) {
            throw new \InvalidArgumentException('只能暂停激活状态的应用');
        }

        $app->update([
            'status' => APP_STATUS::SUSPENDED->value,
            'approved_note' => $reason,
        ]);

        // 清除缓存
        $this->clearAppCache($app->app_id);

        return $app;
    }

    /**
     * 禁用应用
     *
     * @param int $appId
     * @param string $reason
     * @return OpenApiApp
     */
    public function disableApp(int $appId, string $reason = ''): OpenApiApp
    {
        $app = OpenApiApp::findOrFail($appId);

        $app->update([
            'status' => APP_STATUS::DISABLED->value,
            'approved_note' => $reason,
        ]);

        // 清除缓存
        $this->clearAppCache($app->app_id);

        return $app;
    }

    /**
     * 重新生成应用密钥
     *
     * @param int $appId
     * @return OpenApiApp
     */
    public function regenerateSecret(int $appId): OpenApiApp
    {
        $app = OpenApiApp::findOrFail($appId);

        if (!config('openapi.api_key.allow_regenerate', true)) {
            throw new \InvalidArgumentException('不允许重新生成密钥');
        }

        $newSecret = OpenApiApp::generateAppSecret();

        // 加密应用密钥
        if (config('openapi.security.encrypt_secrets', true)) {
            $newSecret = encrypt($newSecret);
        }

        $app->update(['app_secret' => $newSecret]);

        // 清除缓存
        $this->clearAppCache($app->app_id);

        return $app;
    }

    /**
     * 更新应用权限
     *
     * @param int $appId
     * @param array $scopes
     * @return OpenApiApp
     */
    public function updateScopes(int $appId, array $scopes): OpenApiApp
    {
        $app = OpenApiApp::findOrFail($appId);

        // 验证权限范围
        $this->validateScopes($scopes);

        $app->update(['scopes' => $scopes]);

        // 清除缓存
        $this->clearAppCache($app->app_id);

        return $app;
    }

    /**
     * 验证权限范围
     *
     * @param array $scopes
     * @throws \InvalidArgumentException
     */
    protected function validateScopes(array $scopes): void
    {
        $validScopes = array_column(SCOPE_TYPE::cases(), 'value');
        $validScopes[] = '*'; // 允许通配符

        foreach ($scopes as $scope) {
            if (!in_array($scope, $validScopes)) {
                throw new \InvalidArgumentException("无效的权限范围: {$scope}");
            }
        }
    }

    /**
     * 通过应用ID获取应用信息
     *
     * @param string $appId
     * @return OpenApiApp|null
     */
    public function getAppByAppId(string $appId): ?OpenApiApp
    {
        $cacheKey = config('openapi.cache.keys.app_info');
        $cacheKey = str_replace('{app_id}', $appId, $cacheKey);

        return Cache::remember($cacheKey, config('openapi.cache.default_ttl', 300), function () use ($appId) {
            return OpenApiApp::where('app_id', $appId)->first();
        });
    }

    /**
     * 验证应用认证
     *
     * @param string $appId
     * @param string $appSecret
     * @return OpenApiApp|null
     */
    public function validateApp(string $appId, string $appSecret): ?OpenApiApp
    {
        $app = $this->getAppByAppId($appId);

        if (!$app) {
            return null;
        }

        // 检查应用状态
        if (!$app->can_call_api) {
            return null;
        }

        // 检查应用是否过期
        if ($app->is_expired) {
            return null;
        }

        // 验证密钥
        $storedSecret = $app->app_secret;
        if (config('openapi.security.encrypt_secrets', true)) {
            $storedSecret = decrypt($storedSecret);
        }

        if (!hash_equals($storedSecret, $appSecret)) {
            return null;
        }

        return $app;
    }

    /**
     * 检查应用权限
     *
     * @param OpenApiApp $app
     * @param string $scope
     * @return bool
     */
    public function checkScope(OpenApiApp $app, string $scope): bool
    {
        return $app->hasScope($scope);
    }

    /**
     * 检查IP白名单
     *
     * @param OpenApiApp $app
     * @param string $ip
     * @return bool
     */
    public function checkIpWhitelist(OpenApiApp $app, string $ip): bool
    {
        return $app->isIpAllowed($ip);
    }

    /**
     * 更新应用最后使用时间
     *
     * @param OpenApiApp $app
     * @return void
     */
    public function updateLastUsed(OpenApiApp $app): void
    {
        $app->updateLastUsed();
    }

    /**
     * 获取应用统计信息
     *
     * @param string $appId
     * @param string $period
     * @return array
     */
    public function getAppStats(string $appId, string $period = 'day'): array
    {
        $startTime = $this->getStatsPeriodStart($period);

        // 获取基础统计
        $stats = \App\Module\OpenAPI\Models\OpenApiStats::where('app_id', $appId)
            ->where('created_at', '>=', $startTime)
            ->selectRaw('
                SUM(request_count) as total_requests,
                SUM(success_count) as total_success,
                SUM(error_count) as total_errors,
                AVG(avg_response_time) as avg_response_time,
                MAX(max_response_time) as max_response_time,
                MIN(min_response_time) as min_response_time,
                SUM(rate_limit_hits) as total_rate_limit_hits,
                SUM(unique_ips) as total_unique_ips
            ')
            ->first();

        $successRate = $stats->total_requests > 0
            ? round(($stats->total_success / $stats->total_requests) * 100, 2)
            : 0;

        $errorRate = $stats->total_requests > 0
            ? round(($stats->total_errors / $stats->total_requests) * 100, 2)
            : 0;

        return [
            'period' => $period,
            'start_time' => $startTime,
            'total_requests' => $stats->total_requests ?? 0,
            'total_success' => $stats->total_success ?? 0,
            'total_errors' => $stats->total_errors ?? 0,
            'success_rate' => $successRate,
            'error_rate' => $errorRate,
            'avg_response_time' => round($stats->avg_response_time ?? 0, 2),
            'max_response_time' => $stats->max_response_time ?? 0,
            'min_response_time' => $stats->min_response_time ?? 0,
            'total_rate_limit_hits' => $stats->total_rate_limit_hits ?? 0,
            'total_unique_ips' => $stats->total_unique_ips ?? 0,
        ];
    }

    /**
     * 清除应用缓存
     *
     * @param string $appId
     * @return void
     */
    protected function clearAppCache(string $appId): void
    {
        $cacheKey = config('openapi.cache.keys.app_info');
        $cacheKey = str_replace('{app_id}', $appId, $cacheKey);
        Cache::forget($cacheKey);
    }

    /**
     * 批量处理过期应用
     *
     * @return int
     */
    public function handleExpiredApps(): int
    {
        $expiredApps = OpenApiApp::where('expires_at', '<', now())
                                 ->where('status', '!=', APP_STATUS::EXPIRED->value)
                                 ->get();

        $count = 0;
        foreach ($expiredApps as $app) {
            $app->update(['status' => APP_STATUS::EXPIRED->value]);
            $this->clearAppCache($app->app_id);
            $count++;
        }

        return $count;
    }

    /**
     * 获取用户的应用列表
     *
     * @param int $userId
     * @return \Illuminate\Database\Eloquent\Collection
     */
    public function getUserApps(int $userId)
    {
        return OpenApiApp::byUser($userId)->orderBy('created_at', 'desc')->get();
    }

    /**
     * 检查用户是否可以创建更多应用
     *
     * @param int $userId
     * @return bool
     */
    public function canCreateMoreApps(int $userId): bool
    {
        $maxApps = config('openapi.app.max_apps_per_user', 10);
        $currentCount = OpenApiApp::byUser($userId)->count();

        return $currentCount < $maxApps;
    }

    /**
     * 更新应用信息
     *
     * @param int $appId
     * @param array $data
     * @return OpenApiApp
     */
    public function updateApp(int $appId, array $data): OpenApiApp
    {
        $app = OpenApiApp::findOrFail($appId);

        // 过滤允许更新的字段
        $allowedFields = ['name', 'description', 'website', 'logo', 'callback_url', 'contact_email'];
        $updateData = array_intersect_key($data, array_flip($allowedFields));

        $app->update($updateData);

        // 清除缓存
        $this->clearAppCache($app->app_id);

        return $app->fresh();
    }

    /**
     * 重新生成应用密钥
     *
     * @param int $appId
     * @return string
     */
    public function regenerateAppSecret(int $appId): string
    {
        $app = OpenApiApp::findOrFail($appId);

        $newSecret = OpenApiApp::generateAppSecret();
        $app->update(['app_secret' => $newSecret]);

        // 清除缓存
        $this->clearAppCache($app->app_id);

        return $newSecret;
    }

    /**
     * 获取应用配额信息
     *
     * @param string $appId
     * @return array
     */
    public function getAppQuota(string $appId): array
    {
        $app = OpenApiApp::where('app_id', $appId)->firstOrFail();

        // 获取今日使用量
        $todayUsage = \App\Module\OpenAPI\Models\OpenApiStats::where('app_id', $appId)
            ->where('date', now()->toDateString())
            ->sum('request_count');

        // 获取本月使用量
        $monthUsage = \App\Module\OpenAPI\Models\OpenApiStats::where('app_id', $appId)
            ->whereBetween('date', [
                now()->startOfMonth()->toDateString(),
                now()->endOfMonth()->toDateString()
            ])
            ->sum('request_count');

        // 获取配额限制
        $rateLimits = $app->rate_limits ?? [];
        $dailyLimit = $rateLimits['requests_per_day'] ?? 0;
        $monthlyLimit = $rateLimits['requests_per_month'] ?? 0;

        return [
            'today' => [
                'used' => $todayUsage,
                'limit' => $dailyLimit,
                'remaining' => max(0, $dailyLimit - $todayUsage),
                'percentage' => $dailyLimit > 0 ? round(($todayUsage / $dailyLimit) * 100, 2) : 0,
            ],
            'month' => [
                'used' => $monthUsage,
                'limit' => $monthlyLimit,
                'remaining' => max(0, $monthlyLimit - $monthUsage),
                'percentage' => $monthlyLimit > 0 ? round(($monthUsage / $monthlyLimit) * 100, 2) : 0,
            ],
        ];
    }

    /**
     * 获取统计周期的开始时间
     *
     * @param string $period
     * @return \Carbon\Carbon
     */
    protected function getStatsPeriodStart(string $period): \Carbon\Carbon
    {
        return match ($period) {
            'hour' => now()->subHour(),
            'day' => now()->subDay(),
            'week' => now()->subWeek(),
            'month' => now()->subMonth(),
            default => now()->subDay(),
        };
    }
}