/**
 * @module natural-time-js/validators
 * @description Validation utilities for natural time calculations.
 * This module provides functions to validate inputs for natural time operations,
 * ensuring that values are within acceptable ranges and of the correct types.
 */
import { NaturalDate } from '../core/NaturalDate';
/**
 * Validates if a value is a finite number.
 *
 * This is a utility function that checks if a value is a valid number
 * (not NaN, not Infinity, and actually a number type).
 *
 * @param value - Value to validate
 * @returns True if value is a valid number
 *
 * @example
 * isValidNumber(42); // true
 * isValidNumber('42'); // false (string, not number)
 * isValidNumber(NaN); // false
 * isValidNumber(Infinity); // false
 */
export declare const isValidNumber: (value: unknown) => value is number;
/**
 * Validates if a latitude value is within the valid range.
 *
 * Latitude must be a number between -90° (South Pole) and 90° (North Pole).
 *
 * @param latitude - Latitude in degrees to validate
 * @returns True if latitude is valid
 *
 * @example
 * isValidLatitude(45.5); // true
 * isValidLatitude(-90); // true (South Pole)
 * isValidLatitude(90); // true (North Pole)
 * isValidLatitude(91); // false (out of range)
 */
export declare const isValidLatitude: (latitude: unknown) => latitude is number;
/**
 * Validates if a longitude value is within the valid range.
 *
 * Longitude must be a number between -180° and 180°, where:
 * - 0° is the Prime Meridian (Greenwich)
 * - Positive values are East longitude
 * - Negative values are West longitude
 *
 * @param longitude - Longitude in degrees to validate
 * @returns True if longitude is valid
 *
 * @example
 * isValidLongitude(0); // true (Prime Meridian)
 * isValidLongitude(180); // true (International Date Line)
 * isValidLongitude(-180); // true (International Date Line)
 * isValidLongitude(181); // false (out of range)
 */
export declare const isValidLongitude: (longitude: unknown) => longitude is number;
/**
 * Validates if an angle value is within the valid range.
 *
 * Angles in natural time are measured in degrees from 0° to 360°,
 * representing a full circle. This is used for time of day and
 * celestial positions.
 *
 * @param angle - Angle in degrees to validate
 * @returns True if angle is valid
 *
 * @example
 * isValidAngle(180); // true (half circle)
 * isValidAngle(360); // true (full circle)
 * isValidAngle(0); // true (beginning of circle)
 * isValidAngle(361); // false (out of range)
 * isValidAngle(-1); // false (out of range)
 */
export declare const isValidAngle: (angle: unknown) => angle is number;
/**
 * Validates if a timestamp is a valid Unix time.
 *
 * Unix timestamps represent the number of milliseconds since
 * January 1, 1970, 00:00:00 UTC (the Unix epoch).
 * Valid timestamps must be positive numbers.
 *
 * @param timestamp - Unix timestamp in milliseconds
 * @returns True if timestamp is valid
 *
 * @example
 * isValidTimestamp(Date.now()); // true
 * isValidTimestamp(0); // false (Unix epoch exactly)
 * isValidTimestamp(-1); // false (before Unix epoch)
 */
export declare const isValidTimestamp: (timestamp: unknown) => timestamp is number;
/**
 * Validates if an object is a properly initialized NaturalDate instance.
 *
 * This function performs a comprehensive check of a NaturalDate object,
 * verifying that all properties are present and within valid ranges.
 * It's used to ensure that only valid NaturalDate objects are used in calculations.
 *
 * @param date - Value to validate
 * @returns True if value is a valid NaturalDate instance
 *
 * @example
 * const naturalDate = new NaturalDate(new Date(), 0);
 * isValidNaturalDate(naturalDate); // true
 *
 * isValidNaturalDate({}); // false (not a NaturalDate instance)
 * isValidNaturalDate(null); // false
 */
export declare const isValidNaturalDate: (date: unknown) => date is NaturalDate;
/**
 * Validates if a string is a valid cache key.
 *
 * Cache keys are used for storing and retrieving calculated values
 * to improve performance. Valid keys must be non-empty strings.
 *
 * @param key - Cache key to validate
 * @returns True if key is valid
 *
 * @example
 * isValidCacheKey('SUN_2023_45.5_0'); // true
 * isValidCacheKey(''); // false (empty string)
 * isValidCacheKey(123); // false (not a string)
 */
export declare const isValidCacheKey: (key: unknown) => key is string;
/**
 * Throws a formatted error for invalid parameters.
 *
 * This utility function creates consistent error messages for validation failures,
 * making it easier to identify and fix issues with invalid inputs.
 *
 * @param paramName - Name of the invalid parameter
 * @param value - Invalid value
 * @param expectedType - Description of expected type/format
 * @throws {Error} Formatted validation error
 *
 * @example
 * // If latitude is invalid:
 * throwValidationError('latitude', 95, 'number between -90 and 90');
 * // Throws: "Error: Invalid latitude: 95. Expected number between -90 and 90"
 */
export declare const throwValidationError: (paramName: string, value: unknown, expectedType: string) => never;