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

import * as DOM from 'vs/base/browser/dom';
import { CancellationToken } from 'vs/base/common/cancellation';
import { Emitter, Event } from 'vs/base/common/event';
import { IDisposable } from 'vs/base/common/lifecycle';
import { URI } from 'vs/base/common/uri';
import { IContextKeyService } from 'vs/platform/contextkey/common/contextkey';
import { IInstantiationService } from 'vs/platform/instantiation/common/instantiation';
import { ITelemetryService } from 'vs/platform/telemetry/common/telemetry';
import { IThemeService } from 'vs/platform/theme/common/themeService';
import { IWorkspaceContextService } from 'vs/platform/workspace/common/workspace';
import { EditorOptions } from 'vs/workbench/common/editor';
import { WebviewEditorInput } from 'vs/workbench/parts/webview/electron-browser/webviewEditorInput';
import { IEditorService } from 'vs/workbench/services/editor/common/editorService';
import { IEditorGroup } from 'vs/workbench/services/group/common/editorGroupsService';
import { IPartService, Parts } from 'vs/workbench/services/part/common/partService';
import { BaseWebviewEditor, KEYBINDING_CONTEXT_WEBVIEW_FIND_WIDGET_VISIBLE } from './baseWebviewEditor';
import { WebviewElement } from './webviewElement';
import { IWindowService } from 'vs/platform/windows/common/windows';
import { IStorageService } from 'vs/platform/storage/common/storage';

export class WebviewEditor extends BaseWebviewEditor {

	public static readonly ID = 'WebviewEditor';

	private _editorFrame: HTMLElement;
	private _content: HTMLElement;
	private _webviewContent: HTMLElement | undefined;

	private _webviewFocusTracker?: DOM.IFocusTracker;
	private _webviewFocusListenerDisposable?: IDisposable;
	private _onFocusWindowHandler?: IDisposable;

	private readonly _onDidFocusWebview = new Emitter<void>();

	constructor(
		@ITelemetryService telemetryService: ITelemetryService,
		@IThemeService themeService: IThemeService,
		@IContextKeyService private _contextKeyService: IContextKeyService,
		@IPartService private readonly _partService: IPartService,
		@IWorkspaceContextService private readonly _contextService: IWorkspaceContextService,
		@IInstantiationService private readonly _instantiationService: IInstantiationService,
		@IEditorService private readonly _editorService: IEditorService,
		@IWindowService private readonly _windowService: IWindowService,
		@IStorageService storageService: IStorageService
	) {
		super(WebviewEditor.ID, telemetryService, themeService, _contextKeyService, storageService);
	}

	protected createEditor(parent: HTMLElement): void {
		this._editorFrame = parent;
		this._content = document.createElement('div');
		parent.appendChild(this._content);
	}

	private doUpdateContainer() {
		const webviewContainer = this.input && (this.input as WebviewEditorInput).container;
		if (webviewContainer && webviewContainer.parentElement) {
			const frameRect = this._editorFrame.getBoundingClientRect();
			const containerRect = webviewContainer.parentElement.getBoundingClientRect();

			webviewContainer.style.position = 'absolute';
			webviewContainer.style.top = `${frameRect.top - containerRect.top}px`;
			webviewContainer.style.left = `${frameRect.left - containerRect.left}px`;
			webviewContainer.style.width = `${frameRect.width}px`;
			webviewContainer.style.height = `${frameRect.height}px`;
		}
	}

	public layout(dimension: DOM.Dimension): void {
		if (this._webview) {
			this.doUpdateContainer();
		}
		super.layout(dimension);
	}

	public focus() {
		super.focus();
		if (this._onFocusWindowHandler) {
			return;
		}

		// Make sure we restore focus when switching back to a VS Code window
		this._onFocusWindowHandler = this._windowService.onDidChangeFocus(focused => {
			if (focused && this._editorService.activeControl === this) {
				this.focus();
			}
		});
	}

	public dispose(): void {
		// Let the editor input dispose of the webview.
		this._webview = undefined;
		this._webviewContent = undefined;

		if (this._content && this._content.parentElement) {
			this._content.parentElement.removeChild(this._content);
			this._content = undefined;
		}

		this._onDidFocusWebview.dispose();

		if (this._webviewFocusTracker) {
			this._webviewFocusTracker.dispose();
			this._webviewFocusTracker = undefined;
		}

		if (this._webviewFocusListenerDisposable) {
			this._webviewFocusListenerDisposable.dispose();
			this._webviewFocusListenerDisposable = undefined;
		}

		if (this._onFocusWindowHandler) {
			this._onFocusWindowHandler.dispose();
		}

		super.dispose();
	}

	public sendMessage(data: any): void {
		if (this._webview) {
			this._webview.sendMessage(data);
		}
	}

	public get onDidFocus(): Event<any> {
		return this._onDidFocusWebview.event;
	}

	protected setEditorVisible(visible: boolean, group: IEditorGroup): void {
		if (this.input && this.input instanceof WebviewEditorInput) {
			if (visible) {
				this.input.claimWebview(this);
			} else {
				this.input.releaseWebview(this);
			}

			this.updateWebview(this.input as WebviewEditorInput);
		}

		if (this._webviewContent) {
			if (visible) {
				this._webviewContent.style.visibility = 'visible';
				this.doUpdateContainer();
			} else {
				this._webviewContent.style.visibility = 'hidden';
			}
		}

		super.setEditorVisible(visible, group);
	}

	public clearInput() {
		if (this.input && this.input instanceof WebviewEditorInput) {
			this.input.releaseWebview(this);
		}

		this._webview = undefined;
		this._webviewContent = undefined;

		super.clearInput();
	}

	setInput(input: WebviewEditorInput, options: EditorOptions, token: CancellationToken): Thenable<void> {
		if (this.input) {
			(this.input as WebviewEditorInput).releaseWebview(this);
			this._webview = undefined;
			this._webviewContent = undefined;
		}
		return super.setInput(input, options, token)
			.then(() => input.resolve())
			.then(() => {
				if (token.isCancellationRequested) {
					return;
				}

				input.updateGroup(this.group.id);
				this.updateWebview(input);
			});
	}

	private updateWebview(input: WebviewEditorInput) {
		const webview = this.getWebview(input);
		input.claimWebview(this);
		webview.update(input.html, {
			allowScripts: input.options.enableScripts,
			allowSvgs: true,
			enableWrappedPostMessage: true,
			useSameOriginForRoot: false,
			localResourceRoots: input.options.localResourceRoots || this.getDefaultLocalResourceRoots(),
			extensionLocation: input.extensionLocation
		}, input.options.retainContextWhenHidden);

		if (this._webviewContent) {
			this._webviewContent.style.visibility = 'visible';
		}

		this.doUpdateContainer();
	}

	private getDefaultLocalResourceRoots(): URI[] {
		const rootPaths = this._contextService.getWorkspace().folders.map(x => x.uri);
		if ((this.input as WebviewEditorInput).extensionLocation) {
			rootPaths.push((this.input as WebviewEditorInput).extensionLocation);
		}
		return rootPaths;
	}

	private getWebview(input: WebviewEditorInput): WebviewElement {
		if (this._webview) {
			return this._webview;
		}

		this._webviewContent = input.container;

		this.trackFocus();

		const existing = input.webview;
		if (existing) {
			this._webview = existing;
			return existing;
		}

		if (input.options.enableFindWidget) {
			this._contextKeyService = this._register(this._contextKeyService.createScoped(this._webviewContent));
			this.findWidgetVisible = KEYBINDING_CONTEXT_WEBVIEW_FIND_WIDGET_VISIBLE.bindTo(this._contextKeyService);
		}

		this._webview = this._instantiationService.createInstance(WebviewElement,
			this._partService.getContainer(Parts.EDITOR_PART),
			{
				enableWrappedPostMessage: true,
				useSameOriginForRoot: false,
				extensionLocation: input.extensionLocation
			});
		this._webview.mountTo(this._webviewContent);
		input.webview = this._webview;

		if (input.options.tryRestoreScrollPosition) {
			this._webview.initialScrollProgress = input.scrollYPercentage;
		}

		this._webview.state = input.webviewState;

		this._content.setAttribute('aria-flowto', this._webviewContent.id);

		this.doUpdateContainer();
		return this._webview;
	}

	private trackFocus() {
		if (this._webviewFocusTracker) {
			this._webviewFocusTracker.dispose();
		}
		if (this._webviewFocusListenerDisposable) {
			this._webviewFocusListenerDisposable.dispose();
		}

		this._webviewFocusTracker = DOM.trackFocus(this._webviewContent);
		this._webviewFocusListenerDisposable = this._webviewFocusTracker.onDidFocus(() => {
			this._onDidFocusWebview.fire();
		});
	}
}