import { elements, type XinStyleSheet } from 'tosijs';
import type { JSONSchema } from './json-schema.js';
/** What a plugin is handed. `set` writes the model — the plugin never owns the value. */
export interface FieldPluginContext {
    schema: JSONSchema;
    /** dotted path into the form's value, e.g. `scores.0.threshold` */
    path: string;
    label: string;
    required: boolean;
    value: unknown;
    /** write this field's value; the form fires `change`, exactly as for a built-in control */
    set: (value: unknown) => void;
    elements: typeof elements;
}
export interface FieldPlugin {
    /**
     * Build the control. Called ONCE per field; the form wraps it in the usual labelled field
     * with the error slot, so a plugin renders the control and nothing else.
     */
    render: (context: FieldPluginContext) => HTMLElement;
    /**
     * Put a value into an already-rendered control — the form's `value` can change without the
     * schema changing, and rebuilding the element instead would take focus off a slider the
     * user is dragging.
     *
     * Required, deliberately: a control that cannot accept a value back is not compatible with
     * a form whose model owns the data, and finding that out at authoring time beats finding it
     * out when a save silently reverts.
     */
    sync: (element: HTMLElement, value: unknown) => void;
    /** injected under `tosi-schema-form-plugin-<format>` when the plugin registers */
    styles?: XinStyleSheet;
}
/**
 * Claim a schema `format`.
 *
 * Registering the same format twice replaces the plugin — last one wins, which is what lets
 * an application override a library's default for its own pages.
 */
export declare function registerFieldPlugin(format: string, plugin: FieldPlugin): void;
export declare function fieldPlugin(format: string | undefined): FieldPlugin | undefined;
/** Called with the newly-claimed format, so live forms using it can pick it up. */
export declare function onFieldPluginsChanged(listener: (format: string) => void): void;
/** Does this schema use `format` anywhere? What decides whether a form cares about a plugin. */
export declare function schemaUsesFormat(schema: JSONSchema | undefined, format: string): boolean;