export type List<T> = T | T[];
export interface Definition {
    query?: Operation;
    mutation?: Operation;
    subscription?: Operation;
    fragments?: List<FragmentDeclarations>;
}
export interface FragmentProps {
    /**
     * Spread named fragments.
     */
    $spread?: List<string | {
        name: string;
        directives?: Directives;
    }>;
    /**
     * Inline fragments.
     */
    $on?: {
        [typeName: string]: List<Field>;
    };
}
export interface Operation extends FragmentProps {
    /**
     * Optional operation name.
     */
    $name?: string;
    /**
     * Optional variable definitions.
     *
     * @example
     * {
     *   $status: "Int",
     *   $codes: "[String!] = []"
     * }
     */
    $variables?: Record<string, string>;
    /**
     * Optional directives.
     *
     * @example
     * {
     *   name: '@skip',
     *   args: { if: true }
     * }
     */
    $directives?: Directives;
    /**
     * Optional fields.
     */
    $fields?: ({
        [key: string]: FieldValue;
    } & FragmentProps)[];
    /**
     * Any other selection.
     */
    [key: string]: FieldValue;
}
export interface Field extends FragmentProps {
    /**
     * Alias for the field.
     */
    $alias?: string;
    /**
     * Arguments for the field.
     */
    $args?: Args;
    /**
     * Directives for the field.
     */
    $directives?: Directives;
    /**
     * The content to replace the entire field (including the key).
     */
    $content?: string;
    /**
     * The content to replace the body of the field.
     */
    $body?: string;
    /**
     * Any other selection.
     */
    [key: string]: FieldValue;
}
export type FieldValue = boolean | null | number | object | string | undefined | Field | Field[];
export type Args = Record<string, ArgValue>;
export type ArgValue = boolean | null | number | string | undefined | ArgValue[] | {
    /**
     * @example { $enum: 'DESC' }
     */
    $enum: string | null | undefined;
} | {
    /**
     * @example { $var: '$keyword' }
     */
    $var: string | null | undefined;
} | {
    /**
     * @example { $raw: '{}' }
     */
    $raw: string | number | boolean | null | undefined;
} | {
    /**
     * A flag to keep the value even it is an empty object.
     */
    $keep?: ArgValue;
    /**
     * Nested arguments.
     */
    [key: string]: ArgValue;
};
export type Directives = List<string | Directive>;
export interface Directive {
    /**
     * Directive name, must start with `@`. Example: `@skip`.
     */
    name: string;
    /**
     * Optional directive arguments.
     */
    args?: Args;
}
export interface FragmentDeclarations {
    [name: string]: FragmentDefinition;
}
export interface FragmentDefinition extends FragmentProps {
    $onType: string;
    $directives?: Directives;
    [key: string]: FieldValue;
}
export interface Options {
    indent?: number;
    indentChar?: string;
}
export declare const generateQuery: <T = Definition>(definition: T, options?: Options) => string;