/**
 * D1 Database Query Helpers
 *
 * Type-safe wrappers for common D1 query patterns.
 * "Less, but better" - one place for database typing.
 */
import type { Paper } from '../types/paper.js';
export interface CategoryStat {
    name: string;
    slug: string;
    count: number;
}
export interface CategoryRow {
    category: string;
    count: number;
}
export interface ExperimentStats {
    total_executions: number;
    completed_count: number;
    avg_time_seconds: number;
    avg_errors: number;
    total_errors: number;
    completion_rate?: number;
    fastest_time?: number;
    slowest_time?: number;
}
type D1Database = {
    prepare(query: string): D1PreparedStatement;
};
type D1PreparedStatement = {
    bind(...values: unknown[]): D1PreparedStatement;
    all<T = unknown>(): Promise<D1Result<T>>;
    first<T = unknown>(colName?: string): Promise<T | null>;
    run(): Promise<D1Result<unknown>>;
};
type D1Result<T> = {
    results?: T[];
    success: boolean;
    meta: object;
};
/**
 * Standard columns for Paper queries.
 * Matches the Paper interface from types/paper.ts
 */
export declare const PAPER_COLUMNS = "\n\tid, title, category, content, html_content, reading_time,\n\tdifficulty_level, technical_focus, published_on, excerpt_short,\n\texcerpt_long, slug, featured, published, is_hidden, archived,\n\tdate, excerpt, description, thumbnail_image, featured_card_image,\n\tfeatured_image, video_walkthrough_url, interactive_demo_url,\n\tresource_downloads, prerequisites, meta_title, meta_description,\n\tfocus_keywords, ascii_art, ascii_thumbnail, created_at, updated_at,\n\tpublished_at, pathway, \"order\", summary, code_snippet\n";
/**
 * Fetch all published papers
 */
export declare function fetchPublishedPapers(db: D1Database): Promise<Paper[]>;
/**
 * Fetch a single paper by slug
 */
export declare function fetchPaperBySlug(db: D1Database, slug: string): Promise<Paper | null>;
/**
 * Fetch related papers by category, excluding current paper
 */
export declare function fetchRelatedPapers(db: D1Database, category: string, excludeId: string, limit?: number): Promise<Paper[]>;
/**
 * Fetch papers by category
 */
export declare function fetchPapersByCategory(db: D1Database, category: string): Promise<Paper[]>;
/**
 * Fetch category statistics
 */
export declare function fetchCategoryStats(db: D1Database): Promise<CategoryStat[]>;
/**
 * Fetch experiment execution statistics
 */
export declare function fetchExperimentStats(db: D1Database, paperId: string): Promise<ExperimentStats | null>;
/**
 * Safe query wrapper that handles errors gracefully
 */
export declare function safeQuery<T>(queryFn: () => Promise<T>, fallback: T): Promise<T>;
export {};