/*
 * Copyright 2010-2019 Gildas Lormeau
 * contact : gildas.lormeau <at> gmail.com
 * 
 * This file is part of SingleFile.
 *
 *   The code in this file is free software: you can redistribute it and/or 
 *   modify it under the terms of the GNU Affero General Public License 
 *   (GNU AGPL) as published by the Free Software Foundation, either version 3
 *   of the License, or (at your option) any later version.
 * 
 *   The code in this file 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 Affero 
 *   General Public License for more details.
 *
 *   As additional permission under GNU AGPL version 3 section 7, you may 
 *   distribute UNMODIFIED VERSIONS OF THIS file without the copy of the GNU 
 *   AGPL normally required by section 4, provided you include this license 
 *   notice and a URL through which recipients can access the Corresponding 
 *   Source.
 */

/* global singlefile */

singlefile.extension.core.bg.business = (() => {

	const ERROR_CONNECTION_ERROR_CHROMIUM = "Could not establish connection. Receiving end does not exist.";
	const ERROR_CONNECTION_LOST_CHROMIUM = "The message port closed before a response was received.";
	const ERROR_CONNECTION_LOST_GECKO = "Message manager disconnected";
	const INJECT_SCRIPTS_STEP = 1;
	const EXECUTE_SCRIPTS_STEP = 2;

	const extensionScriptFiles = [
		"common/index.js",
		"common/ui/content/content-infobar.js",
		"extension/lib/single-file/index.js",
		"extension/core/index.js",
		"extension/ui/index.js",
		"extension/core/content/content-main.js",
		"extension/core/content/content-download.js",
		"extension/ui/content/content-ui-main.js"
	];

	const pendingSaves = new Map();

	return {
		isSavingTab: tab => pendingSaves.has(tab.id),
		saveTabs,
		saveLink,
		cancelTab,
		cancelAllTabs: () => Array.from(pendingSaves).forEach(([tabId]) => cancelTab(tabId)),
		getTabsInfo: () => Array.from(pendingSaves).map(mapSaveInfo),
		getTabInfo: tabId => pendingSaves.get(tabId),
		setCancelCallback: (tabId, cancelCallback) => {
			const saveInfo = pendingSaves.get(tabId);
			if (saveInfo) {
				saveInfo.cancel = cancelCallback;
			}
		},
		onSaveEnd: tabId => {
			const saveInfo = pendingSaves.get(tabId);
			if (saveInfo) {
				saveInfo.resolve();
			}
		},
		onTabUpdated: cancelTab,
		onTabRemoved: cancelTab
	};

	async function saveTabs(tabs, options = {}) {
		const config = singlefile.extension.core.bg.config;
		const maxParallelWorkers = (await config.get()).maxParallelWorkers;
		const autosave = singlefile.extension.core.bg.autosave;
		const ui = singlefile.extension.ui.bg.main;
		await Promise.all(tabs.map(async tab => {
			const tabId = tab.id;
			const tabOptions = await config.getOptions(tab.url);
			Object.keys(options).forEach(key => tabOptions[key] = options[key]);
			tabOptions.tabId = tabId;
			tabOptions.tabIndex = tab.index;
			tabOptions.extensionScriptFiles = extensionScriptFiles;
			if (options.autoSave) {
				if (autosave.isEnabled(tab)) {
					pendingSaves.set(tab.id, { status: "pending", tab, options: tabOptions, method: "content.autosave" });
				}
			} else {
				ui.onStart(tabId, INJECT_SCRIPTS_STEP);
				const scriptsInjected = await singlefile.extension.injectScript(tabId, tabOptions);
				if (scriptsInjected) {
					ui.onStart(tabId, EXECUTE_SCRIPTS_STEP);
					pendingSaves.set(tab.id, { status: "pending", tab, options: tabOptions, method: "content.save" });
				} else {
					ui.onForbiddenDomain(tab);
				}
			}
		}));
		const processingCount = Array.from(pendingSaves).filter(([, saveInfo]) => saveInfo.status == "processing").length;
		for (let index = 0; index < Math.min(tabs.length, (maxParallelWorkers - processingCount)); index++) {
			runTask();
		}
	}

	function runTask() {
		const nextPendingSave = Array.from(pendingSaves).find(([, saveInfo]) => saveInfo.status == "pending");
		if (nextPendingSave) {
			const [tabId, saveInfo] = nextPendingSave;
			return new Promise((resolve, reject) => {
				saveInfo.status = "processing";
				saveInfo.resolve = async () => {
					if (saveInfo.options.autoClose && !saveInfo.cancelled) {
						singlefile.extension.core.bg.tabs.remove(tabId);
					}
					pendingSaves.delete(tabId);
					resolve();
					await runTask();
				};
				saveInfo.reject = async error => {
					pendingSaves.delete(tabId);
					reject(error);
					await runTask();
				};
				singlefile.extension.core.bg.tabs.sendMessage(tabId, { method: saveInfo.method, options: saveInfo.options })
					.catch(error => {
						if (error && (!error.message || (error.message != ERROR_CONNECTION_LOST_CHROMIUM && error.message != ERROR_CONNECTION_ERROR_CHROMIUM && error.message != ERROR_CONNECTION_LOST_GECKO))) {
							console.log(error); // eslint-disable-line no-console
							singlefile.extension.ui.bg.main.onError(tabId);
							saveInfo.reject(error);
						}
					});
			});
		}
	}

	async function saveLink(url, options = {}) {
		const tabs = singlefile.extension.core.bg.tabs;
		const tab = await tabs.create({ url, active: false });
		options.autoClose = true;
		await saveTabs([tab], options);
	}

	function cancelTab(tabId) {
		if (pendingSaves.has(tabId)) {
			const saveInfo = pendingSaves.get(tabId);
			saveInfo.cancelled = true;
			singlefile.extension.core.bg.tabs.sendMessage(tabId, { method: "content.cancelSave" });
			if (saveInfo.cancel) {
				saveInfo.cancel();
			}
			if (saveInfo.method == "content.autosave") {
				singlefile.extension.ui.bg.main.onEnd(tabId, true);
			}
			singlefile.extension.ui.bg.main.onCancelled(saveInfo.tab);
			pendingSaves.delete(tabId);
			saveInfo.resolve();
		}
	}

	function mapSaveInfo([tabId, saveInfo]) {
		return [tabId, { index: saveInfo.tab.index, url: saveInfo.tab.url, title: saveInfo.tab.title, cancelled: saveInfo.cancelled, status: saveInfo.status }];
	}

})();