/**
 * OpenAlex (https://openalex.org): CC0 metadata for about 250 million works.
 *
 * `search=` matches title, abstract and full text, with quoted phrases and
 * AND / OR / NOT. Without a key the API gives 1000 credits a day: a search
 * costs 10, a lookup by ID or DOI costs nothing. A free key from
 * openalex.org/settings/api raises that; set OPENALEX_API_KEY or put it in the
 * keychain (see apiKey in core.ts).
 */
import { type PaperContext } from "./core.js";
import type { PaperRecord } from "./records.js";
type Location = {
    landing_page_url?: string | null;
    pdf_url?: string | null;
    license?: string | null;
    version?: string | null;
    is_oa?: boolean;
    source?: {
        display_name?: string | null;
        type?: string | null;
    } | null;
    raw_source_name?: string | null;
};
export type OpenAlexWork = {
    id: string;
    doi?: string | null;
    display_name?: string | null;
    publication_year?: number | null;
    publication_date?: string | null;
    type?: string | null;
    authorships?: Array<{
        author?: {
            display_name?: string | null;
        } | null;
        raw_author_name?: string | null;
    }>;
    primary_location?: Location | null;
    locations?: Location[];
    best_oa_location?: Location | null;
    open_access?: {
        is_oa?: boolean;
        oa_status?: string | null;
    } | null;
    cited_by_count?: number | null;
    abstract_inverted_index?: Record<string, number[]> | null;
};
/** OpenAlex ships abstracts as word -> positions. Put the words back in order. */
export declare function rebuildAbstract(index: Record<string, number[]> | null | undefined): string | undefined;
export declare function fromOpenAlex(work: OpenAlexWork): PaperRecord;
/** A note when the day's free credits run low, read from the reply headers. */
export declare function creditNote(headers: Headers): string | undefined;
export type OpenAlexSearch = {
    records: PaperRecord[];
    total: number;
    note?: string;
};
export declare function searchOpenAlex(ctx: PaperContext, query: string, options: {
    limit: number;
    yearFrom?: number;
    yearTo?: number;
}): Promise<OpenAlexSearch>;
/** Look up one work by DOI or OpenAlex ID (free of credits). Null when OpenAlex has no record. */
export declare function getOpenAlexWork(ctx: PaperContext, id: {
    doi: string;
} | {
    openalex: string;
}): Promise<PaperRecord | null>;
export {};