import type { z } from "zod";
import type { AttachmentFileSchema, AttachmentsSchema } from "../../core/csl-json/types.js";
/**
 * Attachment file metadata stored in reference's custom field.
 * Derived from AttachmentFileSchema (Zod) to ensure single source of truth.
 */
export type AttachmentFile = z.infer<typeof AttachmentFileSchema>;
/**
 * Attachments container stored in reference's custom.attachments field.
 * Derived from AttachmentsSchema (Zod) to ensure single source of truth.
 */
export type Attachments = z.infer<typeof AttachmentsSchema>;
/**
 * Reserved role identifiers with special constraints
 */
export declare const RESERVED_ROLES: readonly ["fulltext", "supplement", "notes", "draft", "archive"];
export type ReservedRole = (typeof RESERVED_ROLES)[number];
/**
 * Check if a role is a reserved role
 */
export declare function isReservedRole(role: string): role is ReservedRole;
/**
 * Get file extension from filename (without leading dot)
 */
export declare function getExtension(filename: string): string;
/**
 * Check if fulltext files satisfy the constraint: max 2 files (1 PDF + 1 Markdown)
 */
export declare function isValidFulltextFiles(files: AttachmentFile[]): boolean;
/**
 * Check if archive files satisfy the constraint: max 1 file
 */
export declare function isValidArchiveFiles(files: AttachmentFile[]): boolean;
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