const { Promise, Immutable } = require('gitbook-core');
const { List } = Immutable;
const TYPES = require('./types');

/**
 * Start a search query
 * @param {String} q
 * @return {Action}
 */
function query(q) {
    return (dispatch, getState) => {
        const handlers = getState().search;

        dispatch({ type: TYPES.UPDATE_QUERY, query: q });

        return Promise.reduce(handlers, (results, handler) => {
            return Promise(handler(q))
            .then(handlerResults => results.concat(handlerResults));
        }, List())
        .then(results => {
            dispatch({ type: TYPES.UPDATE_RESULTS, query: q });
        });
    };
}

/**
 * Register a search handler
 * @param {String} name
 * @param {Function} handler
 * @return {Action}
 */
function registerHandler(name, handler) {
    return { type: TYPES.REGISTER_HANDLER, name, handler };
}

/**
 * Unregister a search handler
 * @param {String} name
 * @return {Action}
 */
function unregisterHandler(name) {
    return { type: TYPES.UNREGISTER_HANDLER, name };
}

module.exports = {
    query,
    registerHandler,
    unregisterHandler
};