/*---------------------------------------------------------------------------------------------
 *  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 { Emitter } from 'vs/base/common/event';
import { TernarySearchTree } from 'vs/base/common/map';
import { score } from 'vs/editor/common/modes/languageSelector';
import * as Platform from 'vs/base/common/platform';
import * as errors from 'vs/base/common/errors';
import product from 'vs/platform/node/product';
import pkg from 'vs/platform/node/package';
import { ExtHostFileSystemEventService } from 'vs/workbench/api/node/extHostFileSystemEventService';
import { ExtHostDocumentsAndEditors } from 'vs/workbench/api/node/extHostDocumentsAndEditors';
import { ExtHostDocuments } from 'vs/workbench/api/node/extHostDocuments';
import { ExtHostDocumentContentProvider } from 'vs/workbench/api/node/extHostDocumentContentProviders';
import { ExtHostDocumentSaveParticipant } from 'vs/workbench/api/node/extHostDocumentSaveParticipant';
import { ExtHostConfiguration } from 'vs/workbench/api/node/extHostConfiguration';
import { ExtHostDiagnostics } from 'vs/workbench/api/node/extHostDiagnostics';
import { ExtHostTreeViews } from 'vs/workbench/api/node/extHostTreeViews';
import { ExtHostWorkspace } from 'vs/workbench/api/node/extHostWorkspace';
import { ExtHostQuickOpen } from 'vs/workbench/api/node/extHostQuickOpen';
import { ExtHostProgress } from 'vs/workbench/api/node/extHostProgress';
import { ExtHostSCM } from 'vs/workbench/api/node/extHostSCM';
import { ExtHostHeapService } from 'vs/workbench/api/node/extHostHeapService';
import { ExtHostStatusBar } from 'vs/workbench/api/node/extHostStatusBar';
import { ExtHostCommands } from 'vs/workbench/api/node/extHostCommands';
import { ExtHostOutputService } from 'vs/workbench/api/node/extHostOutputService';
import { ExtHostTerminalService } from 'vs/workbench/api/node/extHostTerminalService';
import { ExtHostMessageService } from 'vs/workbench/api/node/extHostMessageService';
import { ExtHostEditors } from 'vs/workbench/api/node/extHostTextEditors';
import { ExtHostLanguages } from 'vs/workbench/api/node/extHostLanguages';
import { ExtHostLanguageFeatures } from 'vs/workbench/api/node/extHostLanguageFeatures';
import { ExtHostApiCommands } from 'vs/workbench/api/node/extHostApiCommands';
import { ExtHostTask } from 'vs/workbench/api/node/extHostTask';
import { ExtHostDebugService } from 'vs/workbench/api/node/extHostDebugService';
import { ExtHostCredentials } from 'vs/workbench/api/node/extHostCredentials';
import { ExtHostWindow } from 'vs/workbench/api/node/extHostWindow';
import * as extHostTypes from 'vs/workbench/api/node/extHostTypes';
import URI from 'vs/base/common/uri';
import Severity from 'vs/base/common/severity';
import EditorCommon = require('vs/editor/common/editorCommon');
import { IExtensionDescription } from 'vs/platform/extensions/common/extensions';
import { ExtHostExtensionService } from 'vs/workbench/api/node/extHostExtensionService';
import { TPromise } from 'vs/base/common/winjs.base';
import { CancellationTokenSource } from 'vs/base/common/cancellation';
import * as vscode from 'vscode';
import * as paths from 'vs/base/common/paths';
import { MainContext, ExtHostContext, IInitData } from './extHost.protocol';
import * as languageConfiguration from 'vs/editor/common/modes/languageConfiguration';
import { TextEditorCursorStyle } from 'vs/editor/common/config/editorOptions';
import { ExtHostThreadService } from 'vs/workbench/services/thread/node/extHostThreadService';
import { ProxyIdentifier } from 'vs/workbench/services/thread/common/threadService';
import { ExtHostDialogs } from 'vs/workbench/api/node/extHostDialogs';
import { ExtHostFileSystem } from 'vs/workbench/api/node/extHostFileSystem';
import { FileChangeType, FileType } from 'vs/platform/files/common/files';

export interface IExtensionApiFactory {
	(extension: IExtensionDescription): typeof vscode;
}

function proposedApiFunction<T>(extension: IExtensionDescription, fn: T): T {
	if (extension.enableProposedApi) {
		return fn;
	} else {
		return <any>(() => {
			throw new Error(`[${extension.id}]: Proposed API is only available when running out of dev or with the following command line switch: --enable-proposed-api ${extension.id}`);
		});
	}
}

/**
 * This method instantiates and returns the extension API surface
 */
export function createApiFactory(
	initData: IInitData,
	threadService: ExtHostThreadService,
	extHostWorkspace: ExtHostWorkspace,
	extHostConfiguration: ExtHostConfiguration,
	extensionService: ExtHostExtensionService
): IExtensionApiFactory {

	// Addressable instances
	const extHostHeapService = threadService.set(ExtHostContext.ExtHostHeapService, new ExtHostHeapService());
	const extHostDocumentsAndEditors = threadService.set(ExtHostContext.ExtHostDocumentsAndEditors, new ExtHostDocumentsAndEditors(threadService));
	const extHostDocuments = threadService.set(ExtHostContext.ExtHostDocuments, new ExtHostDocuments(threadService, extHostDocumentsAndEditors));
	const extHostDocumentContentProviders = threadService.set(ExtHostContext.ExtHostDocumentContentProviders, new ExtHostDocumentContentProvider(threadService, extHostDocumentsAndEditors));
	const extHostDocumentSaveParticipant = threadService.set(ExtHostContext.ExtHostDocumentSaveParticipant, new ExtHostDocumentSaveParticipant(extHostDocuments, threadService.get(MainContext.MainThreadEditors)));
	const extHostEditors = threadService.set(ExtHostContext.ExtHostEditors, new ExtHostEditors(threadService, extHostDocumentsAndEditors));
	const extHostCommands = threadService.set(ExtHostContext.ExtHostCommands, new ExtHostCommands(threadService, extHostHeapService));
	const extHostTreeViews = threadService.set(ExtHostContext.ExtHostTreeViews, new ExtHostTreeViews(threadService.get(MainContext.MainThreadTreeViews), extHostCommands));
	threadService.set(ExtHostContext.ExtHostWorkspace, extHostWorkspace);
	const extHostDebugService = threadService.set(ExtHostContext.ExtHostDebugService, new ExtHostDebugService(threadService, extHostWorkspace));
	threadService.set(ExtHostContext.ExtHostConfiguration, extHostConfiguration);
	const extHostDiagnostics = threadService.set(ExtHostContext.ExtHostDiagnostics, new ExtHostDiagnostics(threadService));
	const languageFeatures = threadService.set(ExtHostContext.ExtHostLanguageFeatures, new ExtHostLanguageFeatures(threadService, extHostDocuments, extHostCommands, extHostHeapService, extHostDiagnostics));
	const extHostFileSystem = threadService.set(ExtHostContext.ExtHostFileSystem, new ExtHostFileSystem(threadService));
	const extHostFileSystemEvent = threadService.set(ExtHostContext.ExtHostFileSystemEventService, new ExtHostFileSystemEventService());
	const extHostQuickOpen = threadService.set(ExtHostContext.ExtHostQuickOpen, new ExtHostQuickOpen(threadService, extHostWorkspace, extHostCommands));
	const extHostTerminalService = threadService.set(ExtHostContext.ExtHostTerminalService, new ExtHostTerminalService(threadService));
	const extHostSCM = threadService.set(ExtHostContext.ExtHostSCM, new ExtHostSCM(threadService, extHostCommands));
	const extHostTask = threadService.set(ExtHostContext.ExtHostTask, new ExtHostTask(threadService, extHostWorkspace));
	const extHostCredentials = threadService.set(ExtHostContext.ExtHostCredentials, new ExtHostCredentials(threadService));
	const extHostWindow = threadService.set(ExtHostContext.ExtHostWindow, new ExtHostWindow(threadService));
	threadService.set(ExtHostContext.ExtHostExtensionService, extensionService);

	// Check that no named customers are missing
	const expected: ProxyIdentifier<any>[] = Object.keys(ExtHostContext).map((key) => ExtHostContext[key]);
	threadService.assertRegistered(expected);

	// Other instances
	const extHostMessageService = new ExtHostMessageService(threadService);
	const extHostDialogs = new ExtHostDialogs(threadService);
	const extHostStatusBar = new ExtHostStatusBar(threadService);
	const extHostProgress = new ExtHostProgress(threadService.get(MainContext.MainThreadProgress));
	const extHostOutputService = new ExtHostOutputService(threadService);
	const extHostLanguages = new ExtHostLanguages(threadService);

	// Register API-ish commands
	ExtHostApiCommands.register(extHostCommands);

	return function (extension: IExtensionDescription): typeof vscode {

		if (extension.enableProposedApi && !extension.isBuiltin) {

			if (
				!initData.environment.enableProposedApiForAll &&
				initData.environment.enableProposedApiFor.indexOf(extension.id) < 0
			) {
				extension.enableProposedApi = false;
				console.error(`Extension '${extension.id} cannot use PROPOSED API (must started out of dev or enabled via --enable-proposed-api)`);

			} else {
				// proposed api is available when developing or when an extension was explicitly
				// spelled out via a command line argument
				console.warn(`Extension '${extension.id}' uses PROPOSED API which is subject to change and removal without notice.`);
			}
		}

		// namespace: commands
		const commands: typeof vscode.commands = {
			registerCommand<T>(id: string, command: <T>(...args: any[]) => T | Thenable<T>, thisArgs?: any): vscode.Disposable {
				return extHostCommands.registerCommand(id, command, thisArgs);
			},
			registerTextEditorCommand(id: string, callback: (textEditor: vscode.TextEditor, edit: vscode.TextEditorEdit, ...args: any[]) => void, thisArg?: any): vscode.Disposable {
				return extHostCommands.registerCommand(id, (...args: any[]): any => {
					let activeTextEditor = extHostEditors.getActiveTextEditor();
					if (!activeTextEditor) {
						console.warn('Cannot execute ' + id + ' because there is no active text editor.');
						return undefined;
					}

					return activeTextEditor.edit((edit: vscode.TextEditorEdit) => {
						args.unshift(activeTextEditor, edit);
						callback.apply(thisArg, args);

					}).then((result) => {
						if (!result) {
							console.warn('Edits from command ' + id + ' were not applied.');
						}
					}, (err) => {
						console.warn('An error occurred while running command ' + id, err);
					});
				});
			},
			registerDiffInformationCommand: proposedApiFunction(extension, (id: string, callback: (diff: vscode.LineChange[], ...args: any[]) => any, thisArg?: any): vscode.Disposable => {
				return extHostCommands.registerCommand(id, async (...args: any[]) => {
					let activeTextEditor = extHostEditors.getActiveTextEditor();
					if (!activeTextEditor) {
						console.warn('Cannot execute ' + id + ' because there is no active text editor.');
						return undefined;
					}

					const diff = await extHostEditors.getDiffInformation(activeTextEditor.id);
					callback.apply(thisArg, [diff, ...args]);
				});
			}),
			executeCommand<T>(id: string, ...args: any[]): Thenable<T> {
				return extHostCommands.executeCommand<T>(id, ...args);
			},
			getCommands(filterInternal: boolean = false): Thenable<string[]> {
				return extHostCommands.getCommands(filterInternal);
			}
		};

		// namespace: env
		const env: typeof vscode.env = Object.freeze({
			get machineId() { return initData.telemetryInfo.machineId; },
			get sessionId() { return initData.telemetryInfo.sessionId; },
			get language() { return Platform.language; },
			get appName() { return product.nameLong; },
			get appRoot() { return initData.environment.appRoot; },
		});

		// namespace: extensions
		const extensions: typeof vscode.extensions = {
			getExtension(extensionId: string): Extension<any> {
				let desc = extensionService.getExtensionDescription(extensionId);
				if (desc) {
					return new Extension(extensionService, desc);
				}
				return undefined;
			},
			get all(): Extension<any>[] {
				return extensionService.getAllExtensionDescriptions().map((desc) => new Extension(extensionService, desc));
			}
		};

		// namespace: languages
		const languages: typeof vscode.languages = {
			createDiagnosticCollection(name?: string): vscode.DiagnosticCollection {
				return extHostDiagnostics.createDiagnosticCollection(name);
			},
			getLanguages(): TPromise<string[]> {
				return extHostLanguages.getLanguages();
			},
			match(selector: vscode.DocumentSelector, document: vscode.TextDocument): number {
				return score(selector, <any>document.uri, document.languageId);
			},
			registerCodeActionsProvider(selector: vscode.DocumentSelector, provider: vscode.CodeActionProvider): vscode.Disposable {
				return languageFeatures.registerCodeActionProvider(selector, provider);
			},
			registerCodeLensProvider(selector: vscode.DocumentSelector, provider: vscode.CodeLensProvider): vscode.Disposable {
				return languageFeatures.registerCodeLensProvider(selector, provider);
			},
			registerDefinitionProvider(selector: vscode.DocumentSelector, provider: vscode.DefinitionProvider): vscode.Disposable {
				return languageFeatures.registerDefinitionProvider(selector, provider);
			},
			registerImplementationProvider(selector: vscode.DocumentSelector, provider: vscode.ImplementationProvider): vscode.Disposable {
				return languageFeatures.registerImplementationProvider(selector, provider);
			},
			registerTypeDefinitionProvider(selector: vscode.DocumentSelector, provider: vscode.TypeDefinitionProvider): vscode.Disposable {
				return languageFeatures.registerTypeDefinitionProvider(selector, provider);
			},
			registerHoverProvider(selector: vscode.DocumentSelector, provider: vscode.HoverProvider): vscode.Disposable {
				return languageFeatures.registerHoverProvider(selector, provider, extension.id);
			},
			registerDocumentHighlightProvider(selector: vscode.DocumentSelector, provider: vscode.DocumentHighlightProvider): vscode.Disposable {
				return languageFeatures.registerDocumentHighlightProvider(selector, provider);
			},
			registerReferenceProvider(selector: vscode.DocumentSelector, provider: vscode.ReferenceProvider): vscode.Disposable {
				return languageFeatures.registerReferenceProvider(selector, provider);
			},
			registerRenameProvider(selector: vscode.DocumentSelector, provider: vscode.RenameProvider): vscode.Disposable {
				return languageFeatures.registerRenameProvider(selector, provider);
			},
			registerDocumentSymbolProvider(selector: vscode.DocumentSelector, provider: vscode.DocumentSymbolProvider): vscode.Disposable {
				return languageFeatures.registerDocumentSymbolProvider(selector, provider);
			},
			registerWorkspaceSymbolProvider(provider: vscode.WorkspaceSymbolProvider): vscode.Disposable {
				return languageFeatures.registerWorkspaceSymbolProvider(provider);
			},
			registerDocumentFormattingEditProvider(selector: vscode.DocumentSelector, provider: vscode.DocumentFormattingEditProvider): vscode.Disposable {
				return languageFeatures.registerDocumentFormattingEditProvider(selector, provider);
			},
			registerDocumentRangeFormattingEditProvider(selector: vscode.DocumentSelector, provider: vscode.DocumentRangeFormattingEditProvider): vscode.Disposable {
				return languageFeatures.registerDocumentRangeFormattingEditProvider(selector, provider);
			},
			registerOnTypeFormattingEditProvider(selector: vscode.DocumentSelector, provider: vscode.OnTypeFormattingEditProvider, firstTriggerCharacter: string, ...moreTriggerCharacters: string[]): vscode.Disposable {
				return languageFeatures.registerOnTypeFormattingEditProvider(selector, provider, [firstTriggerCharacter].concat(moreTriggerCharacters));
			},
			registerSignatureHelpProvider(selector: vscode.DocumentSelector, provider: vscode.SignatureHelpProvider, ...triggerCharacters: string[]): vscode.Disposable {
				return languageFeatures.registerSignatureHelpProvider(selector, provider, triggerCharacters);
			},
			registerCompletionItemProvider(selector: vscode.DocumentSelector, provider: vscode.CompletionItemProvider, ...triggerCharacters: string[]): vscode.Disposable {
				return languageFeatures.registerCompletionItemProvider(selector, provider, triggerCharacters);
			},
			registerDocumentLinkProvider(selector: vscode.DocumentSelector, provider: vscode.DocumentLinkProvider): vscode.Disposable {
				return languageFeatures.registerDocumentLinkProvider(selector, provider);
			},
			setLanguageConfiguration: (language: string, configuration: vscode.LanguageConfiguration): vscode.Disposable => {
				return languageFeatures.setLanguageConfiguration(language, configuration);
			},
			// proposed API
			registerColorProvider: proposedApiFunction(extension, (selector: vscode.DocumentSelector, provider: vscode.DocumentColorProvider) => {
				return languageFeatures.registerColorProvider(selector, provider);
			})
		};

		// namespace: window
		const window: typeof vscode.window = {
			get activeTextEditor() {
				return extHostEditors.getActiveTextEditor();
			},
			get visibleTextEditors() {
				return extHostEditors.getVisibleTextEditors();
			},
			showTextDocument(documentOrUri: vscode.TextDocument | vscode.Uri, columnOrOptions?: vscode.ViewColumn | vscode.TextDocumentShowOptions, preserveFocus?: boolean): TPromise<vscode.TextEditor> {
				let documentPromise: TPromise<vscode.TextDocument>;
				if (URI.isUri(documentOrUri)) {
					documentPromise = TPromise.wrap(workspace.openTextDocument(documentOrUri));
				} else {
					documentPromise = TPromise.wrap(<vscode.TextDocument>documentOrUri);
				}
				return documentPromise.then(document => {
					return extHostEditors.showTextDocument(document, columnOrOptions, preserveFocus);
				});
			},
			createTextEditorDecorationType(options: vscode.DecorationRenderOptions): vscode.TextEditorDecorationType {
				return extHostEditors.createTextEditorDecorationType(options);
			},
			onDidChangeActiveTextEditor(listener, thisArg?, disposables?) {
				return extHostEditors.onDidChangeActiveTextEditor(listener, thisArg, disposables);
			},
			onDidChangeVisibleTextEditors(listener, thisArg, disposables) {
				return extHostEditors.onDidChangeVisibleTextEditors(listener, thisArg, disposables);
			},
			onDidChangeTextEditorSelection(listener: (e: vscode.TextEditorSelectionChangeEvent) => any, thisArgs?: any, disposables?: extHostTypes.Disposable[]) {
				return extHostEditors.onDidChangeTextEditorSelection(listener, thisArgs, disposables);
			},
			onDidChangeTextEditorOptions(listener: (e: vscode.TextEditorOptionsChangeEvent) => any, thisArgs?: any, disposables?: extHostTypes.Disposable[]) {
				return extHostEditors.onDidChangeTextEditorOptions(listener, thisArgs, disposables);
			},
			onDidChangeTextEditorViewColumn(listener, thisArg?, disposables?) {
				return extHostEditors.onDidChangeTextEditorViewColumn(listener, thisArg, disposables);
			},
			onDidCloseTerminal(listener, thisArg?, disposables?) {
				return extHostTerminalService.onDidCloseTerminal(listener, thisArg, disposables);
			},
			get state() {
				return extHostWindow.state;
			},
			onDidChangeWindowState(listener, thisArg?, disposables?) {
				return extHostWindow.onDidChangeWindowState(listener, thisArg, disposables);
			},
			showInformationMessage(message, first, ...rest) {
				return extHostMessageService.showMessage(extension, Severity.Info, message, first, rest);
			},
			showWarningMessage(message, first, ...rest) {
				return extHostMessageService.showMessage(extension, Severity.Warning, message, first, rest);
			},
			showErrorMessage(message, first, ...rest) {
				return extHostMessageService.showMessage(extension, Severity.Error, message, first, rest);
			},
			showQuickPick(items: any, options: vscode.QuickPickOptions, token?: vscode.CancellationToken) {
				return extHostQuickOpen.showQuickPick(items, options, token);
			},
			showWorkspaceFolderPick(options: vscode.WorkspaceFolderPickOptions) {
				return extHostQuickOpen.showWorkspaceFolderPick(options);
			},
			showInputBox(options?: vscode.InputBoxOptions, token?: vscode.CancellationToken) {
				return extHostQuickOpen.showInput(options, token);
			},
			showOpenDialog(options) {
				return extHostDialogs.showOpenDialog(options);
			},
			showSaveDialog(options) {
				return extHostDialogs.showSaveDialog(options);
			},
			createStatusBarItem(position?: vscode.StatusBarAlignment, priority?: number): vscode.StatusBarItem {
				return extHostStatusBar.createStatusBarEntry(extension.id, <number>position, priority);
			},
			setStatusBarMessage(text: string, timeoutOrThenable?: number | Thenable<any>): vscode.Disposable {
				return extHostStatusBar.setStatusBarMessage(text, timeoutOrThenable);
			},
			withScmProgress<R>(task: (progress: vscode.Progress<number>) => Thenable<R>) {
				console.warn(`[Deprecation Warning] function 'withScmProgress' is deprecated and should no longer be used. Use 'withProgress' instead.`);
				return extHostProgress.withProgress(extension, { location: extHostTypes.ProgressLocation.SourceControl }, (progress, token) => task({ report(n: number) { /*noop*/ } }));
			},
			withProgress<R>(options: vscode.ProgressOptions, task: (progress: vscode.Progress<{ message?: string; percentage?: number }>) => Thenable<R>) {
				return extHostProgress.withProgress(extension, options, task);
			},
			createOutputChannel(name: string): vscode.OutputChannel {
				return extHostOutputService.createOutputChannel(name);
			},
			createTerminal(nameOrOptions: vscode.TerminalOptions | string, shellPath?: string, shellArgs?: string[]): vscode.Terminal {
				if (typeof nameOrOptions === 'object') {
					return extHostTerminalService.createTerminalFromOptions(<vscode.TerminalOptions>nameOrOptions);
				}
				return extHostTerminalService.createTerminal(<string>nameOrOptions, shellPath, shellArgs);
			},
			registerTreeDataProvider(viewId: string, treeDataProvider: vscode.TreeDataProvider<any>): vscode.Disposable {
				return extHostTreeViews.registerTreeDataProvider(viewId, treeDataProvider);
			},
			// proposed API
			sampleFunction: proposedApiFunction(extension, () => {
				return extHostMessageService.showMessage(extension, Severity.Info, 'Hello Proposed Api!', {}, []);
			}),
		};

		// namespace: workspace
		const workspace: typeof vscode.workspace = {
			get rootPath() {
				return extHostWorkspace.getPath();
			},
			set rootPath(value) {
				throw errors.readonly();
			},
			getWorkspaceFolder(resource) {
				return extHostWorkspace.getWorkspaceFolder(resource);
			},
			get workspaceFolders() {
				return extHostWorkspace.getWorkspaceFolders();
			},
			onDidChangeWorkspaceFolders: function (listener, thisArgs?, disposables?) {
				return extHostWorkspace.onDidChangeWorkspace(listener, thisArgs, disposables);
			},
			asRelativePath: (pathOrUri, includeWorkspace) => {
				return extHostWorkspace.getRelativePath(pathOrUri, includeWorkspace);
			},
			findFiles: (include, exclude, maxResults?, token?) => {
				return extHostWorkspace.findFiles(include, exclude, maxResults, token);
			},
			saveAll: (includeUntitled?) => {
				return extHostWorkspace.saveAll(includeUntitled);
			},
			applyEdit(edit: vscode.WorkspaceEdit): TPromise<boolean> {
				return extHostEditors.applyWorkspaceEdit(edit);
			},
			createFileSystemWatcher: (pattern, ignoreCreate, ignoreChange, ignoreDelete): vscode.FileSystemWatcher => {
				return extHostFileSystemEvent.createFileSystemWatcher(pattern, ignoreCreate, ignoreChange, ignoreDelete);
			},
			get textDocuments() {
				return extHostDocuments.getAllDocumentData().map(data => data.document);
			},
			set textDocuments(value) {
				throw errors.readonly();
			},
			openTextDocument(uriOrFileNameOrOptions?: vscode.Uri | string | { language?: string; content?: string; }) {
				let uriPromise: TPromise<URI>;

				let options = uriOrFileNameOrOptions as { language?: string; content?: string; };
				if (typeof uriOrFileNameOrOptions === 'string') {
					uriPromise = TPromise.as(URI.file(uriOrFileNameOrOptions));
				} else if (uriOrFileNameOrOptions instanceof URI) {
					uriPromise = TPromise.as(uriOrFileNameOrOptions);
				} else if (!options || typeof options === 'object') {
					uriPromise = extHostDocuments.createDocumentData(options);
				} else {
					throw new Error('illegal argument - uriOrFileNameOrOptions');
				}

				return uriPromise.then(uri => {
					return extHostDocuments.ensureDocumentData(uri).then(() => {
						const data = extHostDocuments.getDocumentData(uri);
						return data && data.document;
					});
				});
			},
			onDidOpenTextDocument: (listener, thisArgs?, disposables?) => {
				return extHostDocuments.onDidAddDocument(listener, thisArgs, disposables);
			},
			onDidCloseTextDocument: (listener, thisArgs?, disposables?) => {
				return extHostDocuments.onDidRemoveDocument(listener, thisArgs, disposables);
			},
			onDidChangeTextDocument: (listener, thisArgs?, disposables?) => {
				return extHostDocuments.onDidChangeDocument(listener, thisArgs, disposables);
			},
			onDidSaveTextDocument: (listener, thisArgs?, disposables?) => {
				return extHostDocuments.onDidSaveDocument(listener, thisArgs, disposables);
			},
			onWillSaveTextDocument: (listener, thisArgs?, disposables?) => {
				return extHostDocumentSaveParticipant.onWillSaveTextDocumentEvent(listener, thisArgs, disposables);
			},
			onDidChangeConfiguration: (listener: (_: any) => any, thisArgs?: any, disposables?: extHostTypes.Disposable[]) => {
				return extHostConfiguration.onDidChangeConfiguration(listener, thisArgs, disposables);
			},
			getConfiguration: (section?: string, resource?: vscode.Uri): vscode.WorkspaceConfiguration => {
				return extHostConfiguration.getConfiguration(section, resource);
			},
			registerTextDocumentContentProvider(scheme: string, provider: vscode.TextDocumentContentProvider) {
				return extHostDocumentContentProviders.registerTextDocumentContentProvider(scheme, provider);
			},
			registerTaskProvider: (type: string, provider: vscode.TaskProvider) => {
				return extHostTask.registerTaskProvider(extension, provider);
			},
			registerFileSystemProvider: proposedApiFunction(extension, (authority, provider) => {
				return extHostFileSystem.registerFileSystemProvider(authority, provider);
			})
		};

		// namespace: scm
		const scm: typeof vscode.scm = {
			get inputBox() {
				return extHostSCM.getLastInputBox(extension);
			},
			createSourceControl(id: string, label: string, rootUri?: vscode.Uri) {
				return extHostSCM.createSourceControl(extension, id, label, rootUri);
			}
		};

		// namespace: debug
		const debug: typeof vscode.debug = {
			get activeDebugSession() {
				return extHostDebugService.activeDebugSession;
			},
			startDebugging(folder: vscode.WorkspaceFolder | undefined, nameOrConfig: string | vscode.DebugConfiguration) {
				return extHostDebugService.startDebugging(folder, nameOrConfig);
			},
			onDidStartDebugSession(listener, thisArg?, disposables?) {
				return extHostDebugService.onDidStartDebugSession(listener, thisArg, disposables);
			},
			onDidTerminateDebugSession(listener, thisArg?, disposables?) {
				return extHostDebugService.onDidTerminateDebugSession(listener, thisArg, disposables);
			},
			onDidChangeActiveDebugSession(listener, thisArg?, disposables?) {
				return extHostDebugService.onDidChangeActiveDebugSession(listener, thisArg, disposables);
			},
			onDidReceiveDebugSessionCustomEvent(listener, thisArg?, disposables?) {
				return extHostDebugService.onDidReceiveDebugSessionCustomEvent(listener, thisArg, disposables);
			},
			registerDebugConfigurationProvider(debugType: string, provider: vscode.DebugConfigurationProvider) {
				return extHostDebugService.registerDebugConfigurationProvider(debugType, provider);
			},
		};

		// namespace: credentials
		const credentials = {
			readSecret(service: string, account: string): Thenable<string | undefined> {
				return extHostCredentials.readSecret(service, account);
			},
			writeSecret(service: string, account: string, secret: string): Thenable<void> {
				return extHostCredentials.writeSecret(service, account, secret);
			},
			deleteSecret(service: string, account: string): Thenable<boolean> {
				return extHostCredentials.deleteSecret(service, account);
			}
		};


		const api: typeof vscode = {
			version: pkg.version,
			// namespaces
			commands,
			env,
			extensions,
			languages,
			window,
			workspace,
			scm,
			debug,
			// types
			CancellationTokenSource: CancellationTokenSource,
			CodeLens: extHostTypes.CodeLens,
			Color: extHostTypes.Color,
			ColorPresentation: extHostTypes.ColorPresentation,
			ColorInformation: extHostTypes.ColorInformation,
			EndOfLine: extHostTypes.EndOfLine,
			CompletionItem: extHostTypes.CompletionItem,
			CompletionItemKind: extHostTypes.CompletionItemKind,
			CompletionList: extHostTypes.CompletionList,
			CompletionTriggerKind: extHostTypes.CompletionTriggerKind,
			Diagnostic: extHostTypes.Diagnostic,
			DiagnosticSeverity: extHostTypes.DiagnosticSeverity,
			Disposable: extHostTypes.Disposable,
			DocumentHighlight: extHostTypes.DocumentHighlight,
			DocumentHighlightKind: extHostTypes.DocumentHighlightKind,
			DocumentLink: extHostTypes.DocumentLink,
			EventEmitter: Emitter,
			Hover: extHostTypes.Hover,
			IndentAction: languageConfiguration.IndentAction,
			Location: extHostTypes.Location,
			MarkdownString: extHostTypes.MarkdownString,
			OverviewRulerLane: EditorCommon.OverviewRulerLane,
			ParameterInformation: extHostTypes.ParameterInformation,
			Position: extHostTypes.Position,
			Range: extHostTypes.Range,
			Selection: extHostTypes.Selection,
			SignatureHelp: extHostTypes.SignatureHelp,
			SignatureInformation: extHostTypes.SignatureInformation,
			SnippetString: extHostTypes.SnippetString,
			StatusBarAlignment: extHostTypes.StatusBarAlignment,
			SymbolInformation: extHostTypes.SymbolInformation,
			SymbolKind: extHostTypes.SymbolKind,
			TextDocumentSaveReason: extHostTypes.TextDocumentSaveReason,
			TextEdit: extHostTypes.TextEdit,
			TextEditorCursorStyle: TextEditorCursorStyle,
			TextEditorLineNumbersStyle: extHostTypes.TextEditorLineNumbersStyle,
			TextEditorRevealType: extHostTypes.TextEditorRevealType,
			TextEditorSelectionChangeKind: extHostTypes.TextEditorSelectionChangeKind,
			DecorationRangeBehavior: extHostTypes.DecorationRangeBehavior,
			Uri: URI,
			ViewColumn: extHostTypes.ViewColumn,
			WorkspaceEdit: extHostTypes.WorkspaceEdit,
			ProgressLocation: extHostTypes.ProgressLocation,
			TreeItemCollapsibleState: extHostTypes.TreeItemCollapsibleState,
			TreeItem: extHostTypes.TreeItem,
			ThemeColor: extHostTypes.ThemeColor,
			// functions
			TaskRevealKind: extHostTypes.TaskRevealKind,
			TaskPanelKind: extHostTypes.TaskPanelKind,
			TaskGroup: extHostTypes.TaskGroup,
			ProcessExecution: extHostTypes.ProcessExecution,
			ShellExecution: extHostTypes.ShellExecution,
			TaskScope: extHostTypes.TaskScope,
			Task: extHostTypes.Task,
			ConfigurationTarget: extHostTypes.ConfigurationTarget,
			RelativePattern: extHostTypes.RelativePattern,

			// TODO@JOH,remote
			FileChangeType: <any>FileChangeType,
			FileType: <any>FileType
		};
		if (extension.enableProposedApi && extension.isBuiltin) {
			api['credentials'] = credentials;
		}
		return api;
	};
}

class Extension<T> implements vscode.Extension<T> {

	private _extensionService: ExtHostExtensionService;

	public id: string;
	public extensionPath: string;
	public packageJSON: any;

	constructor(extensionService: ExtHostExtensionService, description: IExtensionDescription) {
		this._extensionService = extensionService;
		this.id = description.id;
		this.extensionPath = paths.normalize(description.extensionFolderPath, true);
		this.packageJSON = description;
	}

	get isActive(): boolean {
		return this._extensionService.isActivated(this.id);
	}

	get exports(): T {
		return <T>this._extensionService.getExtensionExports(this.id);
	}

	activate(): Thenable<T> {
		return this._extensionService.activateById(this.id, false).then(() => this.exports);
	}
}

export function initializeExtensionApi(extensionService: ExtHostExtensionService, apiFactory: IExtensionApiFactory): TPromise<void> {
	return extensionService.getExtensionPathIndex().then(trie => defineAPI(apiFactory, trie));
}

function defineAPI(factory: IExtensionApiFactory, extensionPaths: TernarySearchTree<IExtensionDescription>): void {

	// each extension is meant to get its own api implementation
	const extApiImpl = new Map<string, typeof vscode>();
	let defaultApiImpl: typeof vscode;

	const node_module = <any>require.__$__nodeRequire('module');
	const original = node_module._load;
	node_module._load = function load(request, parent, isMain) {
		if (request !== 'vscode') {
			return original.apply(this, arguments);
		}

		// get extension id from filename and api for extension
		const ext = extensionPaths.findSubstr(parent.filename);
		if (ext) {
			let apiImpl = extApiImpl.get(ext.id);
			if (!apiImpl) {
				apiImpl = factory(ext);
				extApiImpl.set(ext.id, apiImpl);
			}
			return apiImpl;
		}

		// fall back to a default implementation
		if (!defaultApiImpl) {
			defaultApiImpl = factory(nullExtensionDescription);
		}
		return defaultApiImpl;
	};
}

const nullExtensionDescription: IExtensionDescription = {
	id: 'nullExtensionDescription',
	name: 'Null Extension Description',
	publisher: 'vscode',
	activationEvents: undefined,
	contributes: undefined,
	enableProposedApi: false,
	engines: undefined,
	extensionDependencies: undefined,
	extensionFolderPath: undefined,
	isBuiltin: false,
	main: undefined,
	version: undefined
};