/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

'use strict';

import * as fs from 'fs';
import * as nls from 'vs/nls';
import * as json from 'vs/base/common/json';
import pkg from 'vs/platform/package';
import paths = require('vs/base/common/paths');
import { toErrorMessage } from 'vs/base/common/errorMessage';
import { stringify } from 'vs/base/common/marshalling';
import * as objects from 'vs/base/common/objects';
import URI from 'vs/base/common/uri';
import { TPromise } from 'vs/base/common/winjs.base';
import { isWindows } from 'vs/base/common/platform';
import { findFreePort } from 'vs/base/node/ports';
import { IMessageService, Severity } from 'vs/platform/message/common/message';
import { ILifecycleService, ShutdownEvent } from 'vs/platform/lifecycle/common/lifecycle';
import { IWorkspaceContextService } from 'vs/platform/workspace/common/workspace';
import { IWindowService } from 'vs/workbench/services/window/electron-browser/windowService';
import { ChildProcess, fork } from 'child_process';
import { ipcRenderer as ipc } from 'electron';
import { IEnvironmentService } from 'vs/platform/environment/common/environment';
import { ReloadWindowAction } from 'vs/workbench/electron-browser/actions';
import { IInstantiationService } from 'vs/platform/instantiation/common/instantiation';
import { IExtensionDescription, IMessage } from 'vs/platform/extensions/common/extensions';
import { IExtensionsStorageData, ExtensionsStorageFile } from 'vs/platform/extensionManagement/common/extensionManagement';
import { ExtensionScanner, MessagesCollector } from 'vs/workbench/node/extensionPoints';
import { IMessagePassingProtocol } from 'vs/base/parts/ipc/common/ipc';
import Event, { Emitter } from 'vs/base/common/event';
import { IStorageService } from 'vs/platform/storage/common/storage';

export const EXTENSION_LOG_BROADCAST_CHANNEL = 'vscode:extensionLog';
export const EXTENSION_ATTACH_BROADCAST_CHANNEL = 'vscode:extensionAttach';
export const EXTENSION_TERMINATE_BROADCAST_CHANNEL = 'vscode:extensionTerminate';

const DIRNAME = URI.parse(require.toUrl('./')).fsPath;
const BASE_PATH = paths.normalize(paths.join(DIRNAME, '../../../..'));
const BUILTIN_EXTENSIONS_PATH = paths.join(BASE_PATH, 'extensions');

export interface ILogEntry {
	type: string;
	severity: string;
	arguments: any;
}

export class ExtensionHostProcessWorker {
	private initializeExtensionHostProcess: TPromise<ChildProcess>;
	private extensionHostProcessHandle: ChildProcess;
	private extensionHostProcessReady: boolean;
	private initializeTimer: number;

	private lastExtensionHostError: string;
	private unsentMessages: any[];
	private terminating: boolean;

	private isExtensionDevelopmentHost: boolean;
	private isExtensionDevelopmentTestFromCli: boolean;
	private isExtensionDevelopmentDebugging: boolean;

	private _onMessage = new Emitter<any>();
	public get onMessage(): Event<any> {
		return this._onMessage.event;
	}

	constructor(
		@IWorkspaceContextService private contextService: IWorkspaceContextService,
		@IMessageService private messageService: IMessageService,
		@IWindowService private windowService: IWindowService,
		@ILifecycleService lifecycleService: ILifecycleService,
		@IInstantiationService private instantiationService: IInstantiationService,
		@IEnvironmentService private environmentService: IEnvironmentService,
		@IStorageService private storageService: IStorageService
	) {
		// handle extension host lifecycle a bit special when we know we are developing an extension that runs inside
		this.isExtensionDevelopmentHost = !!environmentService.extensionDevelopmentPath;
		this.isExtensionDevelopmentDebugging = !!environmentService.debugExtensionHost.break;
		this.isExtensionDevelopmentTestFromCli = this.isExtensionDevelopmentHost && !!environmentService.extensionTestsPath && !environmentService.debugExtensionHost.break;

		this.unsentMessages = [];
		this.extensionHostProcessReady = false;
		lifecycleService.onWillShutdown(this._onWillShutdown, this);
		lifecycleService.onShutdown(() => this.terminate());
	}

	public start(): void {
		let opts: any = {
			env: objects.mixin(objects.clone(process.env), {
				AMD_ENTRYPOINT: 'vs/workbench/node/extensionHostProcess',
				PIPE_LOGGING: 'true',
				VERBOSE_LOGGING: true,
				VSCODE_WINDOW_ID: String(this.windowService.getWindowId())
			}),
			// We only detach the extension host on windows. Linux and Mac orphan by default
			// and detach under Linux and Mac create another process group.
			// We detach because we have noticed that when the renderer exits, its child processes
			// (i.e. extension host) is taken down in a brutal fashion by the OS
			detached: !!isWindows,
		};

		// Help in case we fail to start it
		if (!this.environmentService.isBuilt || this.isExtensionDevelopmentHost) {
			this.initializeTimer = setTimeout(() => {
				const msg = this.isExtensionDevelopmentDebugging ? nls.localize('extensionHostProcess.startupFailDebug', "Extension host did not start in 10 seconds, it might be stopped on the first line and needs a debugger to continue.") : nls.localize('extensionHostProcess.startupFail', "Extension host did not start in 10 seconds, that might be a problem.");

				this.messageService.show(Severity.Warning, msg);
			}, 10000);
		}

		// Initialize extension host process with hand shakes
		this.initializeExtensionHostProcess = this.doInitializeExtensionHostProcess(opts);
	}

	public get messagingProtocol(): IMessagePassingProtocol {
		return this;
	}

	private doInitializeExtensionHostProcess(opts: any): TPromise<ChildProcess> {
		return new TPromise<ChildProcess>((c, e) => {
			// Resolve additional execution args (e.g. debug)
			this.resolveDebugPort(this.environmentService.debugExtensionHost.port).then(port => {
				if (port) {
					opts.execArgv = ['--nolazy', (this.isExtensionDevelopmentDebugging ? '--debug-brk=' : '--debug=') + port];
				}

				// Run Extension Host as fork of current process
				this.extensionHostProcessHandle = fork(URI.parse(require.toUrl('bootstrap')).fsPath, ['--type=extensionHost'], opts);

				// Notify debugger that we are ready to attach to the process if we run a development extension
				if (this.isExtensionDevelopmentHost && port) {
					this.windowService.broadcast({
						channel: EXTENSION_ATTACH_BROADCAST_CHANNEL,
						payload: { port }
					}, this.environmentService.extensionDevelopmentPath /* target */);
				}

				// Messages from Extension host
				this.extensionHostProcessHandle.on('message', msg => {
					if (this.onMessaage(msg)) {
						c(this.extensionHostProcessHandle);
					}
				});

				// Lifecycle
				let onExit = () => this.terminate();
				process.once('exit', onExit);
				this.extensionHostProcessHandle.on('error', (err) => this.onError(err));
				this.extensionHostProcessHandle.on('exit', (code: any, signal: any) => this.onExit(code, signal, onExit));
			});
		}, () => this.terminate());
	}

	private resolveDebugPort(extensionHostPort: number): TPromise<number> {
		if (typeof extensionHostPort !== 'number') {
			return TPromise.wrap(void 0);
		}
		return new TPromise<number>((c, e) => {
			findFreePort(extensionHostPort, 10 /* try 10 ports */, 5000 /* try up to 5 seconds */, (port) => {
				if (!port) {
					console.warn('%c[Extension Host] %cCould not find a free port for debugging', 'color: blue', 'color: black');
					c(void 0);
				}
				if (port !== extensionHostPort) {
					console.warn('%c[Extension Host] %cProvided debugging port ' + extensionHostPort + ' is not free, using ' + port + ' instead.', 'color: blue', 'color: black');
				}
				if (this.isExtensionDevelopmentDebugging) {
					console.warn('%c[Extension Host] %cSTOPPED on first line for debugging on port ' + port, 'color: blue', 'color: black');
				} else {
					console.info('%c[Extension Host] %cdebugger listening on port ' + port, 'color: blue', 'color: black');
				}
				return c(port);
			});
		});
	}

	// @return `true` if ready
	private onMessaage(msg: any): boolean {
		// 1) Host is ready to receive messages, initialize it
		if (msg === 'ready') {
			this.initializeExtensionHost();
			return false;
		}

		// 2) Host is initialized
		if (msg === 'initialized') {
			this.unsentMessages.forEach(m => this.send(m));
			this.unsentMessages = [];
			this.extensionHostProcessReady = true;
			return true;
		}

		// Support logging from extension host
		if (msg && (<ILogEntry>msg).type === '__$console') {
			this.logExtensionHostMessage(<ILogEntry>msg);
			return false;
		}

		// Any other message emits event
		this._onMessage.fire(msg);
		return false;
	}

	private initializeExtensionHost() {
		if (this.initializeTimer) {
			window.clearTimeout(this.initializeTimer);
		}
		this.scanExtensions().then(extensionDescriptors => {
			let initPayload = stringify({
				parentPid: process.pid,
				environment: {
					appSettingsHome: this.environmentService.appSettingsHome,
					disableExtensions: this.environmentService.disableExtensions,
					userExtensionsHome: this.environmentService.extensionsPath,
					extensionDevelopmentPath: this.environmentService.extensionDevelopmentPath,
					extensionTestsPath: this.environmentService.extensionTestsPath
				},
				contextService: {
					workspace: this.contextService.getWorkspace()
				},
				workspaceStoragePath: this.storageService.getWorkspaceStoragePath(),
				extensions: extensionDescriptors
			});
			this.extensionHostProcessHandle.send(initPayload);
		});
	}

	private scanExtensions(): TPromise<IExtensionDescription[]> {
		const collector = new MessagesCollector();
		const version = pkg.version;
		const builtinExtensions = ExtensionScanner.scanExtensions(version, collector, BUILTIN_EXTENSIONS_PATH, true);
		const userExtensions = this.environmentService.disableExtensions || !this.environmentService.extensionsPath ? TPromise.as([]) : this.getUserExtensions(version, collector);
		const developedExtensions = this.environmentService.disableExtensions || !this.environmentService.extensionDevelopmentPath ? TPromise.as([]) : ExtensionScanner.scanOneOrMultipleExtensions(version, collector, this.environmentService.extensionDevelopmentPath, false);
		const isDev = !this.environmentService.isBuilt || !!this.environmentService.extensionDevelopmentPath;

		return TPromise.join([builtinExtensions, userExtensions, developedExtensions]).then((extensionDescriptions: IExtensionDescription[][]) => {
			let builtinExtensions = extensionDescriptions[0];
			let userExtensions = extensionDescriptions[1];
			let developedExtensions = extensionDescriptions[2];

			let result: { [extensionId: string]: IExtensionDescription; } = {};
			builtinExtensions.forEach((builtinExtension) => {
				result[builtinExtension.id] = builtinExtension;
			});
			userExtensions.forEach((userExtension) => {
				if (result.hasOwnProperty(userExtension.id)) {
					collector.warn(userExtension.extensionFolderPath, nls.localize('overwritingExtension', "Overwriting extension {0} with {1}.", result[userExtension.id].extensionFolderPath, userExtension.extensionFolderPath));
				}
				result[userExtension.id] = userExtension;
			});
			developedExtensions.forEach(developedExtension => {
				collector.info('', nls.localize('extensionUnderDevelopment', "Loading development extension at {0}", developedExtension.extensionFolderPath));
				if (result.hasOwnProperty(developedExtension.id)) {
					collector.warn(developedExtension.extensionFolderPath, nls.localize('overwritingExtension', "Overwriting extension {0} with {1}.", result[developedExtension.id].extensionFolderPath, developedExtension.extensionFolderPath));
				}
				result[developedExtension.id] = developedExtension;
			});

			return Object.keys(result).map(name => result[name]);
		}).then(null, err => {
			collector.error('', err);
			return [];
		}).then(extensions => {
			collector.getMessages().forEach(entry => this._handleMessage(entry, isDev));
			return extensions;
		});
	}

	private getUserExtensions(version: string, collector: MessagesCollector): TPromise<IExtensionDescription[]> {
		return ExtensionScanner.scanExtensions(version, collector, this.environmentService.extensionsPath, false)
			.then(extensionDescriptions => this.getDisabledExtensions()
				.then(disabledExtensions => extensionDescriptions.filter(e => disabledExtensions.indexOf(`${e.publisher}.${e.name}`) === -1)));
	}

	private getDisabledExtensions(): TPromise<string[]> {
		return this.getWorkspaceDisabledExtensions();
	}

	private getWorkspaceDisabledExtensions(): TPromise<string[]> {
		const workspaceStoragePath = this.storageService.getWorkspaceStoragePath();
		if (!workspaceStoragePath) {
			return TPromise.wrap([]);
		}

		return new TPromise<string[]>((c, e) => {
			fs.readFile(paths.join(workspaceStoragePath, ExtensionsStorageFile), (error, raw) => {
				let result = [];
				if (!error) {
					try {
						const extensionsData: IExtensionsStorageData = json.parse(raw.toString());
						result = extensionsData.disabledExtensions || [];
					} catch (error) {
						// Ignore parsing errors
					}
				}
				return c(result);
			});
		});
	}

	private logExtensionHostMessage(logEntry: ILogEntry) {
		let args = [];
		try {
			let parsed = JSON.parse(logEntry.arguments);
			args.push(...Object.getOwnPropertyNames(parsed).map(o => parsed[o]));
		} catch (error) {
			args.push(logEntry.arguments);
		}

		// If the first argument is a string, check for % which indicates that the message
		// uses substitution for variables. In this case, we cannot just inject our colored
		// [Extension Host] to the front because it breaks substitution.
		let consoleArgs = [];
		if (typeof args[0] === 'string' && args[0].indexOf('%') >= 0) {
			consoleArgs = [`%c[Extension Host]%c ${args[0]}`, 'color: blue', 'color: black', ...args.slice(1)];
		} else {
			consoleArgs = ['%c[Extension Host]', 'color: blue', ...args];
		}

		// Send to local console unless we run tests from cli
		if (!this.isExtensionDevelopmentTestFromCli) {
			console[logEntry.severity].apply(console, consoleArgs);
		}

		// Log on main side if running tests from cli
		if (this.isExtensionDevelopmentTestFromCli) {
			ipc.send('vscode:log', logEntry);
		}

		// Broadcast to other windows if we are in development mode
		else if (!this.environmentService.isBuilt || this.isExtensionDevelopmentHost) {
			this.windowService.broadcast({
				channel: EXTENSION_LOG_BROADCAST_CHANNEL,
				payload: logEntry
			}, this.environmentService.extensionDevelopmentPath /* target */);
		}
	}

	private onError(err: any): void {
		let errorMessage = toErrorMessage(err);
		if (errorMessage === this.lastExtensionHostError) {
			return; // prevent error spam
		}

		this.lastExtensionHostError = errorMessage;

		this.messageService.show(Severity.Error, nls.localize('extensionHostProcess.error', "Error from the extension host: {0}", errorMessage));
	}

	private onExit(code: any, signal: any, onProcessExit: any): void {
		process.removeListener('exit', onProcessExit);

		if (!this.terminating) {

			// Unexpected termination
			if (!this.isExtensionDevelopmentHost) {
				this.messageService.show(Severity.Error, {
					message: nls.localize('extensionHostProcess.crash', "Extension host terminated unexpectedly. Please reload the window to recover."),
					actions: [this.instantiationService.createInstance(ReloadWindowAction, ReloadWindowAction.ID, ReloadWindowAction.LABEL)]
				});
				console.error('Extension host terminated unexpectedly. Code: ', code, ' Signal: ', signal);
			}

			// Expected development extension termination: When the extension host goes down we also shutdown the window
			else if (!this.isExtensionDevelopmentTestFromCli) {
				this.windowService.getWindow().close();
			}

			// When CLI testing make sure to exit with proper exit code
			else {
				ipc.send('vscode:exit', code);
			}
		}
	}

	public send(msg: any): void {
		if (this.extensionHostProcessReady) {
			this.extensionHostProcessHandle.send(msg);
		} else if (this.initializeExtensionHostProcess) {
			this.initializeExtensionHostProcess.done(p => p.send(msg));
		} else {
			this.unsentMessages.push(msg);
		}
	}

	public terminate(): void {
		this.terminating = true;

		if (this.extensionHostProcessHandle) {
			this.extensionHostProcessHandle.send({
				type: '__$terminate'
			});
		}
	}

	private _onWillShutdown(event: ShutdownEvent): void {

		// If the extension development host was started without debugger attached we need
		// to communicate this back to the main side to terminate the debug session
		if (this.isExtensionDevelopmentHost && !this.isExtensionDevelopmentTestFromCli && !this.isExtensionDevelopmentDebugging) {
			this.windowService.broadcast({
				channel: EXTENSION_TERMINATE_BROADCAST_CHANNEL,
				payload: true
			}, this.environmentService.extensionDevelopmentPath /* target */);

			event.veto(TPromise.timeout(100 /* wait a bit for IPC to get delivered */).then(() => false));
		}
	}

	private _handleMessage(message: IMessage, isDev: boolean): void {
		let messageShown = false;
		if (message.type === Severity.Error || message.type === Severity.Warning) {
			if (isDev) {
				// Only show nasty intrusive messages if doing extension development.
				this.messageService.show(message.type, (message.source ? '[' + message.source + ']: ' : '') + message.message);
				messageShown = true;
			}
		}
		if (!messageShown) {
			switch (message.type) {
				case Severity.Error:
					console.error(message);
					break;
				case Severity.Warning:
					console.warn(message);
					break;
				default:
					console.log(message);
			}
		}
	}
}