/**
 * DocumentParser — SPI interface + MarkdownParser implementation.
 *
 * Parses structured documents into sections for downstream extraction.
 * Supports frontmatter metadata extraction and heading-based sectioning.
 */
import type { KnowledgeSource } from '../types/index.js';
export interface ParsedSection {
    title: string;
    content: string;
    level: number;
    metadata: Record<string, unknown>;
}
export interface Frontmatter {
    title?: string;
    tags?: string[];
    domain?: string;
    [key: string]: unknown;
}
/**
 * SPI: Any document parser must implement this interface.
 */
export interface DocumentParser {
    parse(content: string, source: KnowledgeSource): ParsedSection[];
}
/**
 * MarkdownParser — Parses markdown documents into heading-based sections.
 *
 * Extracts YAML frontmatter (---) and splits content by headings.
 * Each heading becomes a ParsedSection with its body content.
 */
/**
 * PlainTextParser — Splits plain text into sections by double-newline paragraphs.
 *
 * Used for plain text, web page content, and pre-converted formats (PDF→text, EPUB→text).
 * Each paragraph becomes a ParsedSection at level 0.
 */
export declare class PlainTextParser implements DocumentParser {
    parse(content: string, _source: KnowledgeSource): ParsedSection[];
}
/**
 * MarkdownParser — Parses markdown documents into heading-based sections.
 *
 * Extracts YAML frontmatter (---) and splits content by headings.
 * Each heading becomes a ParsedSection with its body content.
 */
export declare class MarkdownParser implements DocumentParser {
    parse(content: string, source: KnowledgeSource): ParsedSection[];
    /**
     * Extract YAML frontmatter delimited by --- lines.
     */
    extractFrontmatter(content: string): {
        frontmatter: Frontmatter;
        body: string;
    };
    /**
     * Minimal YAML parser for frontmatter (key: value pairs, arrays with - prefix).
     */
    private parseYamlSimple;
    /**
     * Split markdown body into sections by headings.
     * Content before the first heading becomes a level-0 section.
     */
    private splitByHeadings;
}
//# sourceMappingURL=document-parser.d.ts.map