/**
 * Custom Handlebars Helpers for Template Rendering
 *
 * Provides helpers for:
 * - Currency formatting
 * - Date formatting
 * - Number formatting
 * - Percentage formatting
 * - Conditional logic
 * - Mathematical operations
 * - String manipulation
 * - Invoice calculations
 */
import type Handlebars from 'handlebars';
import type { StorageTemplateInvoiceTotalArgs } from '@plyaz/types/storage';
/**
 * Format a number as currency
 *
 * @example
 * {{formatCurrency 1234.56}} -> $1,234.56
 * {{formatCurrency 1000 'EUR' 'de-DE'}} -> 1.000,00 €
 */
export declare function formatCurrency(value: number, currency?: string | Handlebars.HelperOptions, locale?: string | Handlebars.HelperOptions): string;
/**
 * Format a date
 *
 * @example
 * {{formatDate myDate}} -> January 1, 2025
 * {{formatDate myDate 'short'}} -> 1/1/2025
 * {{formatDate myDate 'long' 'es-ES'}} -> 1 de enero de 2025
 */
export declare function formatDate(value: Date | string | number, style?: 'full' | 'long' | 'medium' | 'short' | Handlebars.HelperOptions, locale?: string | Handlebars.HelperOptions): string;
/**
 * Format a number with thousands separators
 *
 * @example
 * {{formatNumber 1234567}} -> 1,234,567
 * {{formatNumber 1234.5 2}} -> 1,234.50
 */
export declare function formatNumber(value: number, decimals?: number | Handlebars.HelperOptions, locale?: string | Handlebars.HelperOptions): string;
/**
 * Format a number as percentage
 *
 * @example
 * {{formatPercentage 0.15}} -> 15%
 * {{formatPercentage 0.1234 2}} -> 12.34%
 */
export declare function formatPercentage(value: number, decimals?: number | Handlebars.HelperOptions, locale?: string | Handlebars.HelperOptions): string;
/**
 * Add two numbers
 *
 * @example
 * {{add 5 3}} -> 8
 */
export declare function add(a: number, b: number): number;
/**
 * Subtract two numbers
 *
 * @example
 * {{subtract 10 3}} -> 7
 */
export declare function subtract(a: number, b: number): number;
/**
 * Multiply two numbers
 *
 * @example
 * {{multiply 5 3}} -> 15
 */
export declare function multiply(a: number, b: number): number;
/**
 * Divide two numbers
 *
 * @example
 * {{divide 10 2}} -> 5
 */
export declare function divide(a: number, b: number): number;
/**
 * Check if value equals another value
 *
 * @example
 * {{#eq status 'paid'}}Payment received{{/eq}}
 */
export declare function eq(this: unknown, a: unknown, b: unknown, options: Handlebars.HelperOptions): string;
/**
 * Check if value does not equal another value
 *
 * @example
 * {{#neq status 'paid'}}Payment pending{{/neq}}
 */
export declare function neq(this: unknown, a: unknown, b: unknown, options: Handlebars.HelperOptions): string;
/**
 * Check if value is greater than another value
 *
 * @example
 * {{#gt total 1000}}Large order{{/gt}}
 */
export declare function gt(this: unknown, a: number, b: number, options: Handlebars.HelperOptions): string;
/**
 * Check if value is less than another value
 *
 * @example
 * {{#lt total 100}}Small order{{/lt}}
 */
export declare function lt(this: unknown, a: number, b: number, options: Handlebars.HelperOptions): string;
/**
 * Check if value is greater than or equal to another value
 *
 * @example
 * {{#gte total 1000}}Eligible for discount{{/gte}}
 */
export declare function gte(this: unknown, a: number, b: number, options: Handlebars.HelperOptions): string;
/**
 * Check if value is less than or equal to another value
 *
 * @example
 * {{#lte items.length 5}}Few items{{/lte}}
 */
export declare function lte(this: unknown, a: number, b: number, options: Handlebars.HelperOptions): string;
/**
 * Logical AND
 *
 * @example
 * {{#and isPaid isShipped}}Order complete{{/and}}
 */
export declare function and(this: unknown, a: unknown, b: unknown, options: Handlebars.HelperOptions): string;
/**
 * Logical OR
 *
 * @example
 * {{#or isPending isFailed}}Needs attention{{/or}}
 */
export declare function or(this: unknown, a: unknown, b: unknown, options: Handlebars.HelperOptions): string;
/**
 * Uppercase a string
 *
 * @example
 * {{uppercase 'hello'}} -> HELLO
 */
export declare function uppercase(value: string): string;
/**
 * Lowercase a string
 *
 * @example
 * {{lowercase 'HELLO'}} -> hello
 */
export declare function lowercase(value: string): string;
/**
 * Capitalize first letter
 *
 * @example
 * {{capitalize 'hello world'}} -> Hello world
 */
export declare function capitalize(value: string): string;
/**
 * Calculate invoice totals (subtotal, discount, tax, or total)
 *
 * This helper is designed for Handlebars templates and accepts positional arguments.
 *
 * @example
 * {{invoiceTotal items taxRate discountPercent shippingCost "subtotal"}}
 * {{invoiceTotal items taxRate discountPercent shippingCost "discount"}}
 * {{invoiceTotal items taxRate discountPercent shippingCost "tax"}}
 * {{invoiceTotal items taxRate discountPercent shippingCost "total"}}
 */
export declare function invoiceTotal(...args: StorageTemplateInvoiceTotalArgs): number;
/**
 * Truncate string to length
 *
 * @example
 * {{truncate description 50}} -> Truncates to 50 characters...
 */
export declare function truncate(value: string, length?: number | Handlebars.HelperOptions): string;
/**
 * Get default helpers map
 *
 * @returns Map of helper name to function
 */
export declare function getDefaultHelpers(): Record<string, Handlebars.HelperDelegate>;