/**
 * Spreads Resource
 *
 * Access oil & product spread analytics: crack spreads, basis spreads,
 * curve-structure (contango/backwardation), refining margins, and physical
 * premiums. Each spread type supports the latest value, full history, and an
 * `all` listing.
 */
import type { OilPriceAPI } from "../client.js";
/**
 * Supported spread types.
 *
 * - `crack` — refining crack spread (e.g., 3:2:1)
 * - `basis` — regional basis differential vs benchmark
 * - `curve-structure` — contango / backwardation structure
 * - `margin` — refining margin
 * - `physical-premium` — physical-vs-paper premium
 */
export type SpreadType = "crack" | "basis" | "curve-structure" | "margin" | "physical-premium";
/**
 * A single spread data point.
 */
export interface SpreadValue {
    /** Spread type slug */
    type: string;
    /** Spread name / label */
    name?: string;
    /** Spread value */
    value: number;
    /** Unit (e.g., "USD/bbl") */
    unit?: string;
    /** Region or market */
    region?: string;
    /** Benchmark or components */
    components?: string[];
    /** ISO timestamp */
    timestamp: string;
    /** Additional metadata */
    metadata?: Record<string, unknown>;
}
/**
 * Historical spread data point.
 */
export interface HistoricalSpreadValue {
    /** ISO date */
    date: string;
    /** Spread value */
    value: number;
    /** Unit */
    unit?: string;
}
/**
 * Options for a historical spread query.
 */
export interface HistoricalSpreadOptions {
    /** Start date (YYYY-MM-DD) */
    startDate?: string;
    /** End date (YYYY-MM-DD) */
    endDate?: string;
}
/**
 * Spreads Resource
 *
 * @example
 * ```typescript
 * import { OilPriceAPI } from 'oilpriceapi';
 *
 * const client = new OilPriceAPI({ apiKey: 'your_key' });
 *
 * // Latest crack spread
 * const crack = await client.spreads.crack();
 * console.log(`Crack spread: ${crack.value} ${crack.unit}`);
 *
 * // Historical basis spreads
 * const history = await client.spreads.historical('basis', {
 *   startDate: '2024-01-01',
 *   endDate: '2024-12-31',
 * });
 *
 * // All margin spreads
 * const all = await client.spreads.all('margin');
 * ```
 */
export declare class SpreadsResource {
    private client;
    constructor(client: OilPriceAPI);
    /**
     * Get the latest value for a spread type.
     *
     * @param type - Spread type slug.
     * @returns Latest spread value.
     * @throws {ValidationError} If the type is invalid.
     */
    get(type: SpreadType): Promise<SpreadValue>;
    /**
     * Get historical data for a spread type.
     *
     * @param type - Spread type slug.
     * @param options - Optional date range filters.
     * @returns Array of historical spread values.
     */
    historical(type: SpreadType, options?: HistoricalSpreadOptions): Promise<HistoricalSpreadValue[]>;
    /**
     * Get all spread values for a spread type.
     *
     * @param type - Spread type slug.
     * @returns Array of spread values.
     */
    all(type: SpreadType): Promise<SpreadValue[]>;
    /** Latest crack spread. */
    crack(): Promise<SpreadValue>;
    /** Latest basis spread. */
    basis(): Promise<SpreadValue>;
    /** Latest curve-structure (contango / backwardation). */
    curveStructure(): Promise<SpreadValue>;
    /** Latest refining margin. */
    margin(): Promise<SpreadValue>;
    /** Latest physical premium. */
    physicalPremium(): Promise<SpreadValue>;
    private validateType;
}