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

import * as cp from 'child_process';
import * as os from 'os';
import * as playwright from 'playwright';
import { IElement, ILocaleInfo, ILocalizedStrings, ILogFile } from './driver';
import { Logger, measureAndLog } from './logger';
import { launch as launchPlaywrightBrowser } from './playwrightBrowser';
import { PlaywrightDriver } from './playwrightDriver';
import { launch as launchPlaywrightElectron } from './playwrightElectron';
import { teardown } from './processes';
import { Quality } from './application';

export interface LaunchOptions {
	// Allows you to override the Playwright instance
	playwright?: typeof playwright;
	codePath?: string;
	readonly workspacePath: string;
	userDataDir?: string;
	readonly extensionsPath?: string;
	readonly logger: Logger;
	logsPath: string;
	crashesPath: string;
	readonly videosPath?: string;
	verbose?: boolean;
	useInMemorySecretStorage?: boolean;
	readonly extraArgs?: string[];
	readonly remote?: boolean;
	readonly web?: boolean;
	readonly tracing?: boolean;
	snapshots?: boolean;
	readonly headless?: boolean;
	readonly browser?: 'chromium' | 'webkit' | 'firefox' | 'chromium-msedge' | 'chromium-chrome';
	readonly quality: Quality;
	version: { major: number; minor: number; patch: number };
}

interface ICodeInstance {
	kill: () => Promise<void>;
}

const instances = new Set<ICodeInstance>();

function registerInstance(process: cp.ChildProcess, logger: Logger, type: 'electron' | 'server'): { safeToKill: Promise<void> } {
	const instance = { kill: () => teardown(process, logger) };
	instances.add(instance);

	const safeToKill = new Promise<void>(resolve => {
		process.stdout?.on('data', data => {
			const output = data.toString();
			if (output.indexOf('calling app.quit()') >= 0 && type === 'electron') {
				setTimeout(() => resolve(), 500 /* give Electron some time to actually terminate fully */);
			}
			logger.log(`[${type}] stdout: ${output}`);
		});
		process.stderr?.on('data', error => logger.log(`[${type}] stderr: ${error}`));
	});

	process.once('exit', (code, signal) => {
		logger.log(`[${type}] Process terminated (pid: ${process.pid}, code: ${code}, signal: ${signal})`);

		instances.delete(instance);
	});

	return { safeToKill };
}

async function teardownAll(signal?: number) {
	stopped = true;

	for (const instance of instances) {
		await instance.kill();
	}

	if (typeof signal === 'number') {
		process.exit(signal);
	}
}

let stopped = false;
process.on('exit', () => teardownAll());
process.on('SIGINT', () => teardownAll(128 + 2)); 	 // https://nodejs.org/docs/v14.16.0/api/process.html#process_signal_events
process.on('SIGTERM', () => teardownAll(128 + 15)); // same as above

export async function launch(options: LaunchOptions): Promise<Code> {
	if (stopped) {
		throw new Error('Smoke test process has terminated, refusing to spawn Code');
	}

	// Browser smoke tests
	if (options.web) {
		const { serverProcess, driver } = await measureAndLog(() => launchPlaywrightBrowser(options), 'launch playwright (browser)', options.logger);
		registerInstance(serverProcess, options.logger, 'server');

		return new Code(driver, options.logger, serverProcess, undefined, options.quality, options.version);
	}

	// Electron smoke tests (playwright)
	else {
		const { electronProcess, driver } = await measureAndLog(() => launchPlaywrightElectron(options), 'launch playwright (electron)', options.logger);
		const { safeToKill } = registerInstance(electronProcess, options.logger, 'electron');

		return new Code(driver, options.logger, electronProcess, safeToKill, options.quality, options.version);
	}
}

export class Code {

	readonly driver: PlaywrightDriver;

	constructor(
		driver: PlaywrightDriver,
		readonly logger: Logger,
		private readonly mainProcess: cp.ChildProcess,
		private readonly safeToKill: Promise<void> | undefined,
		readonly quality: Quality,
		readonly version: { major: number; minor: number; patch: number }
	) {
		this.driver = new Proxy(driver, {
			get(target, prop) {
				if (typeof prop === 'symbol') {
					throw new Error('Invalid usage');
				}

				// eslint-disable-next-line local/code-no-any-casts
				const targetProp = (target as any)[prop];
				if (typeof targetProp !== 'function') {
					return targetProp;
				}

				return function (this: any, ...args: any[]) {
					logger.log(`${prop}`, ...args.filter(a => typeof a === 'string'));
					return targetProp.apply(this, args);
				};
			}
		});
	}

	get editContextEnabled(): boolean {
		return !(this.quality === Quality.Stable && this.version.major === 1 && this.version.minor < 101);
	}

	async startTracing(name?: string): Promise<void> {
		return await this.driver.startTracing(name);
	}

	async stopTracing(name?: string, persist: boolean = false): Promise<void> {
		return await this.driver.stopTracing(name, persist);
	}

	/**
	 * Dispatch a keybinding to the application.
	 * @param keybinding The keybinding to dispatch, e.g. 'ctrl+shift+p'.
	 * @param accept The acceptance function to await before returning. Wherever
	 * possible this should verify that the keybinding did what was expected,
	 * otherwise it will likely be a cause of difficult to investigate race
	 * conditions. This is particularly insidious when used in the automation
	 * library as it can surface across many test suites.
	 *
	 * This requires an async function even when there's no implementation to
	 * force the author to think about the accept callback and prevent mistakes
	 * like not making it async.
	 */
	async dispatchKeybinding(keybinding: string, accept: () => Promise<void>): Promise<void> {
		await this.driver.sendKeybinding(keybinding, accept);
	}

	async didFinishLoad(): Promise<void> {
		return this.driver.didFinishLoad();
	}

	async exit(): Promise<void> {
		return measureAndLog(() => new Promise<void>(resolve => {
			const pid = this.mainProcess.pid!;

			let done = false;

			// Start the exit flow via driver
			this.driver.close();

			let safeToKill = false;
			this.safeToKill?.then(() => {
				this.logger.log('Smoke test exit(): safeToKill() called');
				safeToKill = true;
			});

			// Await the exit of the application
			(async () => {
				let retries = 0;
				while (!done) {
					retries++;

					if (safeToKill) {
						this.logger.log('Smoke test exit(): call did not terminate the process yet, but safeToKill is true, so we can kill it');
						this.kill(pid);
					}

					switch (retries) {

						// after 10 seconds: forcefully kill
						case 20: {
							this.logger.log('Smoke test exit(): call did not terminate process after 10s, forcefully exiting the application...');
							this.kill(pid);
							break;
						}

						// after 20 seconds: give up
						case 40: {
							this.logger.log('Smoke test exit(): call did not terminate process after 20s, giving up');
							this.kill(pid);
							done = true;
							resolve();
							break;
						}
					}

					try {
						process.kill(pid, 0); // throws an exception if the process doesn't exist anymore.
						await this.wait(500);
					} catch (error) {
						this.logger.log('Smoke test exit(): call terminated process successfully');

						done = true;
						resolve();
					}
				}
			})();
		}), 'Code#exit()', this.logger);
	}

	private kill(pid: number): void {
		try {
			process.kill(pid, 0); // throws an exception if the process doesn't exist anymore.
		} catch (e) {
			this.logger.log('Smoke test kill(): returning early because process does not exist anymore');
			return;
		}

		try {
			this.logger.log(`Smoke test kill(): Trying to SIGTERM process: ${pid}`);
			process.kill(pid);
		} catch (e) {
			this.logger.log('Smoke test kill(): SIGTERM failed', e);
		}
	}

	async getElement(selector: string): Promise<IElement | undefined> {
		return (await this.driver.getElements(selector))?.[0];
	}

	async getElements(selector: string, recursive: boolean): Promise<IElement[] | undefined> {
		return this.driver.getElements(selector, recursive);
	}

	async waitForTextContent(selector: string, textContent?: string, accept?: (result: string) => boolean, retryCount?: number): Promise<string> {
		accept = accept || (result => textContent !== undefined ? textContent === result : !!result);

		return await this.poll(
			() => this.driver.getElements(selector).then(els => els.length > 0 ? Promise.resolve(els[0].textContent) : Promise.reject(new Error('Element not found for textContent'))),
			s => accept!(typeof s === 'string' ? s : ''),
			`get text content '${selector}'`,
			retryCount
		);
	}

	async waitAndClick(selector: string, xoffset?: number, yoffset?: number, retryCount: number = 200): Promise<void> {
		await this.poll(() => this.driver.click(selector, xoffset, yoffset), () => true, `click '${selector}'`, retryCount);
	}

	async waitForSetValue(selector: string, value: string): Promise<void> {
		await this.poll(() => this.driver.setValue(selector, value), () => true, `set value '${selector}'`);
	}

	async waitForElements(selector: string, recursive: boolean, accept: (result: IElement[]) => boolean = result => result.length > 0): Promise<IElement[]> {
		return await this.poll(() => this.driver.getElements(selector, recursive), accept, `get elements '${selector}'`);
	}

	async waitForElement(selector: string, accept: (result: IElement | undefined) => boolean = result => !!result, retryCount: number = 200): Promise<IElement> {
		return await this.poll<IElement>(() => this.driver.getElements(selector).then(els => els[0]), accept, `get element '${selector}'`, retryCount);
	}

	async waitForActiveElement(selector: string, retryCount: number = 200): Promise<void> {
		await this.poll(() => this.driver.isActiveElement(selector), r => r, `is active element '${selector}'`, retryCount);
	}

	async waitForTitle(accept: (title: string) => boolean): Promise<void> {
		await this.poll(() => this.driver.getTitle(), accept, `get title`);
	}

	async waitForTypeInEditor(selector: string, text: string): Promise<void> {
		await this.poll(() => this.driver.typeInEditor(selector, text), () => true, `type in editor '${selector}'`);
	}

	async waitForEditorSelection(selector: string, accept: (selection: { selectionStart: number; selectionEnd: number }) => boolean): Promise<void> {
		await this.poll(() => this.driver.getEditorSelection(selector), accept, `get editor selection '${selector}'`);
	}

	async waitForTerminalBuffer(selector: string, accept: (result: string[]) => boolean): Promise<void> {
		await this.poll(() => this.driver.getTerminalBuffer(selector), accept, `get terminal buffer '${selector}'`);
	}

	async writeInTerminal(selector: string, value: string): Promise<void> {
		await this.poll(() => this.driver.writeInTerminal(selector, value), () => true, `writeInTerminal '${selector}'`);
	}

	async whenWorkbenchRestored(): Promise<void> {
		await this.poll(() => this.driver.whenWorkbenchRestored(), () => true, `when workbench restored`);
	}

	getLocaleInfo(): Promise<ILocaleInfo> {
		return this.driver.getLocaleInfo();
	}

	getLocalizedStrings(): Promise<ILocalizedStrings> {
		return this.driver.getLocalizedStrings();
	}

	getLogs(): Promise<ILogFile[]> {
		return this.driver.getLogs();
	}

	wait(millis: number): Promise<void> {
		return this.driver.wait(millis);
	}

	private async poll<T>(
		fn: () => Promise<T>,
		acceptFn: (result: T) => boolean,
		timeoutMessage: string,
		retryCount = 200,
		retryInterval = 100 // millis
	): Promise<T> {
		let trial = 1;
		let lastError: string = '';

		while (true) {
			if (trial > retryCount) {
				this.logger.log('Timeout!');
				this.logger.log(lastError);
				this.logger.log(`Timeout: ${timeoutMessage} after ${(retryCount * retryInterval) / 1000} seconds.`);

				throw new Error(`Timeout: ${timeoutMessage} after ${(retryCount * retryInterval) / 1000} seconds.`);
			}

			let result;
			try {
				result = await fn();
				if (acceptFn(result)) {
					return result;
				} else {
					lastError = 'Did not pass accept function';
				}
			} catch (e: any) {
				lastError = Array.isArray(e.stack) ? e.stack.join(os.EOL) : e.stack;
			}

			await this.wait(retryInterval);
			trial++;
		}
	}
}

export function findElement(element: IElement, fn: (element: IElement) => boolean): IElement | null {
	const queue = [element];

	while (queue.length > 0) {
		const element = queue.shift()!;

		if (fn(element)) {
			return element;
		}

		queue.push(...element.children);
	}

	return null;
}

export function findElements(element: IElement, fn: (element: IElement) => boolean): IElement[] {
	const result: IElement[] = [];
	const queue = [element];

	while (queue.length > 0) {
		const element = queue.shift()!;

		if (fn(element)) {
			result.push(element);
		}

		queue.push(...element.children);
	}

	return result;
}
