/*******************************************************************************

    uBlock Origin - a browser extension to block requests.
    Copyright (C) 2015-present Raymond Hill

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see {http://www.gnu.org/licenses/}.

    Home: https://github.com/gorhill/uBlock
*/

'use strict';

/******************************************************************************/

µBlock.staticFilteringReverseLookup = (( ) => {

/******************************************************************************/

const workerTTL = 5 * 60 * 1000;
const pendingResponses = new Map();

let worker = null;
let workerTTLTimer;
let needLists = true;
let messageId = 1;

/******************************************************************************/

const onWorkerMessage = function(e) {
    const msg = e.data;
    const callback = pendingResponses.get(msg.id);
    pendingResponses.delete(msg.id);
    callback(msg.response);
};

/******************************************************************************/

const stopWorker = function() {
    if ( workerTTLTimer !== undefined ) {
        clearTimeout(workerTTLTimer);
        workerTTLTimer = undefined;
    }
    if ( worker === null ) { return; }
    worker.terminate();
    worker = null;
    needLists = true;
    pendingResponses.clear();
};

/******************************************************************************/

const initWorker = function() {
    if ( worker === null ) {
        worker = new Worker('js/reverselookup-worker.js');
        worker.onmessage = onWorkerMessage;
    }

    // The worker will be shutdown after n minutes without being used.
    if ( workerTTLTimer !== undefined ) {
        clearTimeout(workerTTLTimer);
    }
    workerTTLTimer = vAPI.setTimeout(stopWorker, workerTTL);

    if ( needLists === false ) {
        return Promise.resolve();
    }
    needLists = false;

    const entries = new Map();

    const onListLoaded = function(details) {
        const entry = entries.get(details.assetKey);

        // https://github.com/gorhill/uBlock/issues/536
        // Use assetKey when there is no filter list title.

        worker.postMessage({
            what: 'setList',
            details: {
                assetKey: details.assetKey,
                title: entry.title || details.assetKey,
                supportURL: entry.supportURL,
                content: details.content
            }
        });
    };

    const µb = µBlock;
    for ( const listKey in µb.availableFilterLists ) {
        if ( µb.availableFilterLists.hasOwnProperty(listKey) === false ) {
            continue;
        }
        const entry = µb.availableFilterLists[listKey];
        if ( entry.off === true ) { continue; }
        entries.set(listKey, {
            title: listKey !== µb.userFiltersPath ?
                entry.title :
                vAPI.i18n('1pPageName'),
            supportURL: entry.supportURL || ''
        });
    }
    if ( entries.size === 0 ) {
        return Promise.resolve();
    }

    const promises = [];
    for ( const listKey of entries.keys() ) {
        promises.push(
            µb.getCompiledFilterList(listKey).then(details => {
                onListLoaded(details);
            })
        );
    }
    return Promise.all(promises);
};

/******************************************************************************/

const fromNetFilter = async function(compiledFilter, rawFilter, callback) {
    if ( typeof callback !== 'function' ) {
        return;
    }

    if ( compiledFilter === '' || rawFilter === '' ) {
        callback();
        return;
    }

    await initWorker();

    const id = messageId++;
    const message = {
        what: 'fromNetFilter',
        id: id,
        compiledFilter: compiledFilter,
        rawFilter: rawFilter
    };
    pendingResponses.set(id, callback);
    worker.postMessage(message);
};

/******************************************************************************/

const fromCosmeticFilter = async function(details, callback) {
    if ( typeof callback !== 'function' ) { return; }

    if ( details.rawFilter === '' ) {
        callback();
        return;
    }

    await initWorker();

    const id = messageId++;
    const hostname = µBlock.URI.hostnameFromURI(details.url);
    pendingResponses.set(id, callback);
    worker.postMessage({
        what: 'fromCosmeticFilter',
        id: id,
        domain: µBlock.URI.domainFromHostname(hostname),
        hostname: hostname,
        ignoreGeneric: µBlock.staticNetFilteringEngine
                             .matchStringGenericHide(details.url) === 2,
        rawFilter: details.rawFilter
    });
};

/******************************************************************************/

// This tells the worker that filter lists may have changed.

const resetLists = function() {
    needLists = true;
    if ( worker === null ) { return; }
    worker.postMessage({ what: 'resetLists' });
};

/******************************************************************************/

return {
    fromNetFilter,
    fromCosmeticFilter,
    resetLists,
    shutdown: stopWorker
};

/******************************************************************************/

})();

/******************************************************************************/