import { Conversion } from "../Conversion";
import { ConversionContext } from "../ConversionContext";
import { PluginApi } from "./PluginApi";
/**
 * A plugin that hooks into the {@link EuropaCore} conversion process.
 *
 * Any declared converters will override any previously associated tag name to converter mappings when the plugin is
 * added to {@link EuropaCore}.
 */
export interface Plugin {
    /**
     * Called whenever a text node is being converted with the specified `value`, allowing this plugin to perform any
     * alternative conversion of the text by the given `conversion`.
     *
     * It is extremely important that, if this plugin does perform any alternative conversion of the specified `value`,
     * that this method returns `true` in order to prevent `conversion` from also processing `value` which would result in
     * duplication and would likely have other unexpected and unwanted side effects.
     *
     * @param value - The text value to potentially be converted.
     * @param conversion - The current {@link Conversion}.
     * @return `true` if `value` has been converted by this plugin; otherwise `false`.
     */
    readonly convertText?: PluginTextConverter;
    /**
     * A map containing tag name to converter pairs.
     */
    readonly converters?: {
        readonly [key: string]: PluginConverter;
    };
    /**
     * Called after all nodes have been converted for a single input, allowing this plugin to perform any necessary clean
     * up or tear down steps.
     *
     * @param conversion - The current {@link Conversion}.
     */
    readonly endConversion?: (conversion: Conversion) => void;
    /**
     * Called whenever a text node is being converted with the specified `value`, allowing this plugin to perform any
     * additional escaping of special characters within the text which has been taken by the given `conversion`.
     *
     * It's important to note that `value` will have already been escaped by `conversion` (or another plugin) and that
     * only additional escaping should be applied, and with extra care as to not double-escape characters.
     *
     * @param value - The text value to be escaped.
     * @param conversion - The current {@link Conversion}.
     * @return The escaped `str` or `str` if no escaping is required.
     */
    readonly escapeText?: PluginTextEscaper;
    /**
     * Called before any nodes are converted for a single input, allowing this plugin to perform any necessary setup
     * steps.
     *
     * @param conversion - The current {@link Conversion}.
     */
    readonly startConversion?: (conversion: Conversion) => void;
}
/**
 * Responsible for converting an individual element to Markdown as defined in a plugin.
 */
export interface PluginConverter {
    /**
     * Called at the end of the current element within the specified `conversion` and only once all children elements have
     * been converted as well, provided they weren't skipped.
     *
     * `context` can be used to receive any state that may have been passed at the start of the single element conversion
     * by this converter.
     *
     * @param conversion - The current {@link Conversion}.
     * @param context - The context for the current element within the {@link Conversion}.
     */
    readonly endTag?: (conversion: Conversion, context: ConversionContext) => void;
    /**
     * Called at the start of the current element within the specified `conversion` which can be used to provide control
     * over the conversion and returns whether the children of the element should be converted.
     *
     * `context` can be used to pass any state for a single element conversion from start to end, limited to this
     * converter.
     *
     * @param conversion - The current {@link Conversion}.
     * @param context - The context for the current element within the {@link Conversion}.
     * @return `true` if the children of the current element should be converted; otherwise `false`.
     */
    readonly startTag?: (conversion: Conversion, context: ConversionContext) => boolean;
}
/**
 * The name of a hook on a {@link PluginConverter}.
 */
export declare type PluginConverterHook = keyof PluginConverter;
/**
 * The name of a hook on a {@link Plugin}.
 */
export declare type PluginHook = Exclude<keyof Plugin, 'convertText' | 'converters' | 'escapeText'>;
/**
 * Provides a plugin compatible with {@link EuropaCore}.
 *
 * Invoked internally by {@link PluginManager#addPlugin} in order to get the plugin and is passed an `api`, which it can
 * choose to use or not.
 *
 * Any error that is thrown will bubble up and prevent the plugin from being added.
 *
 * @param api - The {@link PluginApi} that provides useful methods for plugin providers.
 * @return The provided {@link Plugin}.
 * @throws If a problem occurs while providing the plugin.
 */
export declare type PluginProvider = (api: PluginApi) => Plugin;
/**
 * Conditionally performs an alternative conversion of the specified `value` which has been taken from a text node being
 * converted by the given `conversion`.
 *
 * It is extremely important that, if any alternative conversion of the specified `value` is performed, that this method
 * returns `true` in order to prevent `conversion` from also processing `value` which would result in duplication and
 * would likely have other unexpected and unwanted side effects.
 *
 * @param value - The text value to potentially be converted.
 * @param conversion - The current {@link Conversion}.
 * @return `true` if `value` has been converted by this method; otherwise `false`.
 */
export declare type PluginTextConverter = (value: string, conversion: Conversion) => boolean;
/**
 * Conditionally performs additional escaping of special characters within the specified `value` which has been taken
 * from a text node being converted by the given `conversion`.
 *
 * It's important to note that `value` will have already been escaped by `conversion` (or another plugin) and that only
 * additional escaping should be applied, and with extra care as to not double-escape characters.
 *
 * @param value - The text value to be escaped.
 * @param conversion - The current {@link Conversion}.
 * @return The escaped `str` or `str` if no escaping is required.
 */
export declare type PluginTextEscaper = (value: string, conversion: Conversion) => string;