<?php

namespace App\Module\OpenAPI\Services;

use App\Module\OpenAPI\Models\OpenApiApp;
use App\Module\OpenAPI\Models\OpenApiScope;
use App\Module\OpenAPI\Enums\SCOPE_TYPE;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Log;

/**
 * 权限范围服务
 * 
 * 提供API权限范围管理和验证功能
 */
class ScopeService
{
    /**
     * 检查应用是否具有指定权限
     *
     * @param OpenApiApp $app
     * @param string $requiredScope
     * @return bool
     */
    public function hasScope(OpenApiApp $app, string $requiredScope): bool
    {
        // 获取应用的权限范围
        $appScopes = $this->getAppScopes($app);

        // 如果应用没有配置权限范围，拒绝访问
        if (empty($appScopes)) {
            return false;
        }

        // 检查是否有管理员权限（拥有所有权限）
        if (in_array('ADMIN', $appScopes)) {
            return true;
        }

        // 检查是否直接拥有所需权限
        if (in_array($requiredScope, $appScopes)) {
            return true;
        }

        // 检查通配符权限
        if (in_array('*', $appScopes)) {
            return true;
        }

        // 检查权限依赖关系
        return $this->checkScopeDependencies($appScopes, $requiredScope);
    }

    /**
     * 检查多个权限
     *
     * @param OpenApiApp $app
     * @param array $requiredScopes
     * @param bool $requireAll 是否需要全部权限，false表示只需要其中一个
     * @return bool
     */
    public function hasScopes(OpenApiApp $app, array $requiredScopes, bool $requireAll = true): bool
    {
        if ($requireAll) {
            // 需要全部权限
            foreach ($requiredScopes as $scope) {
                if (!$this->hasScope($app, $scope)) {
                    return false;
                }
            }
            return true;
        } else {
            // 只需要其中一个权限
            foreach ($requiredScopes as $scope) {
                if ($this->hasScope($app, $scope)) {
                    return true;
                }
            }
            return false;
        }
    }

    /**
     * 获取应用的权限范围
     *
     * @param OpenApiApp $app
     * @return array
     */
    public function getAppScopes(OpenApiApp $app): array
    {
        // 优先从缓存获取
        $cacheKey = "app_scopes:{$app->app_id}";
        $scopes = Cache::get($cacheKey);

        if ($scopes === null) {
            $scopes = $app->scopes ?? [];
            
            // 缓存权限信息
            Cache::put($cacheKey, $scopes, 3600); // 缓存1小时
        }

        return $scopes;
    }

    /**
     * 更新应用权限范围
     *
     * @param OpenApiApp $app
     * @param array $scopes
     * @return bool
     */
    public function updateAppScopes(OpenApiApp $app, array $scopes): bool
    {
        // 验证权限范围
        $validationResult = $this->validateScopes($scopes);
        if (!$validationResult['valid']) {
            Log::warning('Invalid scopes provided', [
                'app_id' => $app->app_id,
                'invalid_scopes' => $validationResult['invalid_scopes'],
            ]);
            return false;
        }

        // 更新应用权限
        $app->update(['scopes' => $scopes]);

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

        // 记录权限变更日志
        $this->logScopeChange($app, $scopes);

        return true;
    }

    /**
     * 验证权限范围
     *
     * @param array $scopes
     * @return array ['valid' => bool, 'invalid_scopes' => array]
     */
    public function validateScopes(array $scopes): array
    {
        $validScopes = $this->getAllValidScopes();
        $invalidScopes = [];

        foreach ($scopes as $scope) {
            if (!in_array($scope, $validScopes)) {
                $invalidScopes[] = $scope;
            }
        }

        return [
            'valid' => empty($invalidScopes),
            'invalid_scopes' => $invalidScopes,
        ];
    }

    /**
     * 获取所有有效的权限范围
     *
     * @return array
     */
    public function getAllValidScopes(): array
    {
        $scopes = array_column(SCOPE_TYPE::cases(), 'value');
        
        // 添加特殊权限
        $scopes[] = '*';     // 通配符权限
        $scopes[] = 'ADMIN'; // 管理员权限

        return $scopes;
    }

    /**
     * 获取权限范围的详细信息
     *
     * @param string $scope
     * @return array|null
     */
    public function getScopeInfo(string $scope): ?array
    {
        // 特殊权限处理
        if ($scope === '*') {
            return [
                'name' => '全部权限',
                'description' => '拥有所有API的访问权限',
                'risk_level' => 'HIGH',
                'category' => 'SPECIAL',
            ];
        }

        if ($scope === 'ADMIN') {
            return [
                'name' => '管理员权限',
                'description' => '拥有管理员级别的所有权限',
                'risk_level' => 'CRITICAL',
                'category' => 'SPECIAL',
            ];
        }

        // 从枚举中获取权限信息
        foreach (SCOPE_TYPE::cases() as $scopeType) {
            if ($scopeType->value === $scope) {
                return [
                    'name' => $scopeType->getLabel(),
                    'description' => $scopeType->getDescription(),
                    'risk_level' => $scopeType->getRiskLevel(),
                    'category' => $scopeType->getCategory(),
                ];
            }
        }

        return null;
    }

    /**
     * 检查权限依赖关系
     *
     * @param array $appScopes
     * @param string $requiredScope
     * @return bool
     */
    protected function checkScopeDependencies(array $appScopes, string $requiredScope): bool
    {
        // 权限依赖关系映射
        $dependencies = [
            'USER_WRITE' => ['USER_READ'],
            'GAME_WRITE' => ['GAME_READ'],
            'ITEM_WRITE' => ['ITEM_READ'],
            'FUND_WRITE' => ['FUND_READ'],
            'TRADE_WRITE' => ['TRADE_READ'],
            'ADMIN_WRITE' => ['ADMIN_READ'],
        ];

        // 如果需要的权限有依赖，检查是否满足依赖
        if (isset($dependencies[$requiredScope])) {
            foreach ($dependencies[$requiredScope] as $dependency) {
                if (!in_array($dependency, $appScopes)) {
                    return false;
                }
            }
        }

        // 检查是否有更高级的权限包含所需权限
        $hierarchies = [
            'USER_READ' => ['USER_WRITE', 'ADMIN'],
            'USER_WRITE' => ['ADMIN'],
            'GAME_READ' => ['GAME_WRITE', 'ADMIN'],
            'GAME_WRITE' => ['ADMIN'],
            'ITEM_READ' => ['ITEM_WRITE', 'ADMIN'],
            'ITEM_WRITE' => ['ADMIN'],
            'FUND_READ' => ['FUND_WRITE', 'ADMIN'],
            'FUND_WRITE' => ['ADMIN'],
            'TRADE_READ' => ['TRADE_WRITE', 'ADMIN'],
            'TRADE_WRITE' => ['ADMIN'],
        ];

        if (isset($hierarchies[$requiredScope])) {
            foreach ($hierarchies[$requiredScope] as $higherScope) {
                if (in_array($higherScope, $appScopes)) {
                    return true;
                }
            }
        }

        return false;
    }

    /**
     * 清除应用权限缓存
     *
     * @param string $appId
     * @return void
     */
    protected function clearAppScopeCache(string $appId): void
    {
        $cacheKey = "app_scopes:{$appId}";
        Cache::forget($cacheKey);
    }

    /**
     * 记录权限变更日志
     *
     * @param OpenApiApp $app
     * @param array $newScopes
     * @return void
     */
    protected function logScopeChange(OpenApiApp $app, array $newScopes): void
    {
        $oldScopes = $app->getOriginal('scopes') ?? [];

        Log::info('App scopes updated', [
            'app_id' => $app->app_id,
            'old_scopes' => $oldScopes,
            'new_scopes' => $newScopes,
            'added_scopes' => array_diff($newScopes, $oldScopes),
            'removed_scopes' => array_diff($oldScopes, $newScopes),
        ]);
    }

    /**
     * 获取权限范围的分组信息
     *
     * @return array
     */
    public function getScopeGroups(): array
    {
        $groups = [];

        foreach (SCOPE_TYPE::cases() as $scope) {
            $category = $scope->getCategory();
            if (!isset($groups[$category])) {
                $groups[$category] = [
                    'name' => $category,
                    'scopes' => [],
                ];
            }

            $groups[$category]['scopes'][] = [
                'value' => $scope->value,
                'label' => $scope->getLabel(),
                'description' => $scope->getDescription(),
                'risk_level' => $scope->getRiskLevel(),
            ];
        }

        return $groups;
    }
}