/*
 * 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 browser, singlefile, fetch, TextDecoder */

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

	let contentScript, frameScript, modulesScript;

	const contentScriptFiles = [
		"/index.js",
		"/lib/hooks/content/content-hooks.js",
		"/lib/browser-polyfill/chrome-browser-polyfill.js",
		"/lib/single-file/vendor/css-tree.js",
		"/lib/single-file/vendor/html-srcset-parser.js",
		"/lib/single-file/single-file-util.js",
		"/lib/single-file/single-file-helper.js",
		"/lib/fetch/content/content-fetch-resources.js",
		"/lib/single-file/single-file-core.js",
		"/lib/single-file/single-file.js",
		"/extension/ui/content/content-ui-main.js",
		"/extension/core/content/content-main.js"
	];

	const frameScriptFiles = [
		"/index.js",
		"/lib/hooks/content/content-hooks-frames.js",
		"/lib/browser-polyfill/chrome-browser-polyfill.js",
		"/lib/single-file/single-file-helper.js",
		"/lib/fetch/content/content-fetch-resources.js",
		"/lib/frame-tree/content/content-frame-tree.js"
	];

	const modulesScriptFiles = [
		"/lib/single-file/modules/html-minifier.js",
		"/lib/single-file/modules/html-serializer.js",
		"/lib/single-file/vendor/css-minifier.js",
		"/lib/lazy/content/content-lazy-loader.js",
		"/lib/single-file/modules/html-images-alt-minifier.js",
		"/lib/single-file/vendor/css-font-property-parser.js",
		"/lib/single-file/modules/css-fonts-minifier.js",
		"/lib/single-file/modules/css-fonts-alt-minifier.js",
		"/lib/single-file/modules/css-matched-rules.js",
		"/lib/single-file/modules/css-rules-minifier.js",
		"/lib/single-file/vendor/css-media-query-parser.js",
		"/lib/single-file/modules/css-medias-alt-minifier.js"
	];

	initScripts();

	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 pendingSaves = new Map();
	const currentSaves = new Map();
	let maxParallelWorkers;

	return {
		isSavingTab: tab => currentSaves.has(tab.id),
		saveTab,
		cancelTab
	};

	async function saveTab(tab, options = {}) {
		const config = singlefile.extension.core.bg.config;
		const autosave = singlefile.extension.core.bg.autosave;
		const tabs = singlefile.extension.core.bg.tabs;
		const ui = singlefile.extension.ui.bg.main;
		maxParallelWorkers = (await config.get()).maxParallelWorkers;
		await initScripts();
		const tabId = tab.id;
		options.tabId = tabId;
		options.tabIndex = tab.index;
		try {
			if (options.autoSave) {
				const tabOptions = await config.getOptions(tab.url, true);
				if (autosave.isEnabled(tab)) {
					await requestSaveTab(tabId, "content.autosave", tabOptions);
				}
			} else {
				ui.onStart(tabId, INJECT_SCRIPTS_STEP);
				const tabOptions = await config.getOptions(tab.url);
				Object.keys(options).forEach(key => tabOptions[key] = options[key]);
				let scriptsInjected;
				if (!tabOptions.removeFrames) {
					try {
						await tabs.executeScript(tabId, { code: frameScript, allFrames: true, matchAboutBlank: true, runAt: "document_start" });
					} catch (error) {
						// ignored
					}
				}
				try {
					await initScripts();
					await tabs.executeScript(tabId, { code: modulesScript + "\n" + contentScript, allFrames: false, runAt: "document_idle" });
					scriptsInjected = true;
				} catch (error) {
					// ignored
				}
				if (scriptsInjected) {
					ui.onStart(tabId, EXECUTE_SCRIPTS_STEP);
					if (tabOptions.frameId) {
						await tabs.executeScript(tabId, { code: "document.documentElement.dataset.requestedFrameId = true", frameId: tabOptions.frameId, matchAboutBlank: true, runAt: "document_start" });
					}
					await requestSaveTab(tabId, "content.save", tabOptions);
				} else {
					ui.onForbiddenDomain(tab);
				}
			}
		} 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
				ui.onError(tabId);
			}
		}
	}

	async function cancelTab(tab) {
		try {
			singlefile.extension.core.bg.tabs.sendMessage(tab.id, { method: "content.cancelSave" });
		} catch (error) {
			// ignored;
		}
	}

	function requestSaveTab(tabId, method, options) {
		return new Promise((resolve, reject) => requestSaveTab(tabId, method, options, resolve, reject));

		async function requestSaveTab(tabId, method, options, resolve, reject) {
			if (currentSaves.size < maxParallelWorkers) {
				currentSaves.set(tabId, { options, resolve, reject });
				try {
					await singlefile.extension.core.bg.tabs.sendMessage(tabId, { method, options });
					resolve();
				} catch (error) {
					reject(error);
				} finally {
					currentSaves.delete(tabId);
					next();
				}
			} else {
				pendingSaves.set(tabId, { options, resolve, reject });
			}
		}

		function next() {
			if (pendingSaves.size) {
				const [tabId, { resolve, reject, options }] = Array.from(pendingSaves)[0];
				pendingSaves.delete(tabId);
				requestSaveTab(tabId, method, options, resolve, reject);
			}
		}
	}

	async function initScripts() {
		if (!contentScript && !frameScript && !modulesScript) {
			[contentScript, frameScript, modulesScript] = await Promise.all([
				getScript(contentScriptFiles),
				getScript(frameScriptFiles),
				getScript(modulesScriptFiles)
			]);
		}
	}

	async function getScript(scriptFiles) {
		const scriptsPromises = scriptFiles.map(async scriptFile => {
			if (typeof scriptFile == "function") {
				return "(" + scriptFile.toString() + ")();";
			} else {
				const scriptResource = await fetch(browser.runtime.getURL(scriptFile));
				return new TextDecoder().decode(await scriptResource.arrayBuffer());
			}
		});
		let content = "";
		for (const scriptPromise of scriptsPromises) {
			content += await scriptPromise;
		}
		return content;
	}

})();
