/**
 * Content Screening Service - Phase 1 Security Layer
 * Provides security checkpoint for inbound file processing with threat detection
 */
export interface ScreenOptions {
    checkExtensionMismatch?: boolean;
    checkExecutableContent?: boolean;
    checkSuspiciousPatterns?: boolean;
    strictMode?: boolean;
}
export interface ScreenIssue {
    type: "extension_mismatch" | "executable_disguised" | "suspicious_pattern" | "unknown_type";
    severity: "warning" | "error";
    message: string;
    details?: Record<string, any>;
}
export interface ScreenResult {
    filePath: string;
    passed: boolean;
    threatLevel: "none" | "low" | "medium" | "high";
    detectedType: string;
    declaredExtension: string;
    issues: ScreenIssue[];
    timestamp: Date;
}
export interface ScreeningReport {
    totalFiles: number;
    passedCount: number;
    failedCount: number;
    threatSummary: {
        none: number;
        low: number;
        medium: number;
        high: number;
    };
    issuesByType: Record<string, number>;
    timestamp: Date;
    results: ScreenResult[];
}
export declare class ContentScreeningService {
    private readonly maxHeaderBytes;
    /**
     * Screen a single file for security threats
     */
    screen(filePath: string, options?: ScreenOptions): Promise<ScreenResult>;
    /**
     * Screen multiple files in parallel
     */
    screenBatch(filePaths: string[], options?: ScreenOptions): Promise<ScreenResult[]>;
    /**
     * Check if a file is allowed based on type restrictions
     */
    isAllowed(filePath: string, allowedTypes?: string[]): Promise<boolean>;
    /**
     * Generate a comprehensive screening report
     */
    generateScreeningReport(results: ScreenResult[]): ScreeningReport;
    /**
     * Read the header and trailer bytes of a file for magic number detection
     */
    private readFileHeaderAndTrailer;
    /**
     * Read the header bytes of a file for magic number detection (backward compatibility)
     */
    private readFileHeader;
    /**
     * Detect file type from magic number
     */
    private detectFileType;
    /**
     * Check if file extension matches detected type
     */
    private checkExtensionMismatch;
    /**
     * Check for executable files masquerading as documents or images
     */
    private checkExecutableMasquerading;
    /**
     * Check for suspicious filename patterns
     */
    private checkSuspiciousPatterns;
    /**
     * Update threat level based on issues
     */
    private updateThreatLevel;
    /**
     * Extract extension from detected type string
     */
    private extractExtensionFromType;
}
export declare const contentScreeningService: ContentScreeningService;
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