import type {ChromiumOptions, LogLevel, openBrowser} from '@remotion/renderer';
import {RenderInternals} from '@remotion/renderer';
import type {
	Await,
	CloudProvider,
	ProviderSpecifics,
} from '@remotion/serverless-client';
import {VERSION} from '@remotion/serverless-client';
import type {
	ForgetBrowserEventLoop,
	GetBrowserInstance,
	InsideFunctionSpecifics,
} from './provider-implementation';

export type LaunchedBrowser = {
	instance: Await<ReturnType<typeof openBrowser>>;
	configurationString: string;
};

const makeConfigurationString = (
	options: ChromiumOptions,
	logLevel: LogLevel,
): string => {
	return [
		`web-security-${Boolean(options.disableWebSecurity)}`,
		`multi-process-${Boolean(options.enableMultiProcessOnLinux)}`,
		`ignore-certificate-errors-${Boolean(options.ignoreCertificateErrors)}`,
		`log-level-${logLevel}`,
		`gl-${options.gl ?? null}`,
		`userAgent-${options.userAgent ?? null}`,
		`headless-${options.headless ?? false}`,
	].join('/');
};

let _browserInstance: LaunchedBrowser | null;

let launching = false;

const waitForLaunched = () => {
	return new Promise<void>((resolve, reject) => {
		const check = () =>
			setTimeout(() => {
				if (launching) {
					check();
				} else {
					resolve();
				}
			}, 16);

		setTimeout(() => reject(new Error('Timeout launching browser')), 5000);
		check();
	});
};

export const forgetBrowserEventLoopImplementation: ForgetBrowserEventLoop = ({
	logLevel,
	launchedBrowser,
}) => {
	RenderInternals.Log.info(
		{indent: false, logLevel},
		'Keeping browser open for next invocation',
	);
	launchedBrowser.instance.runner.forgetEventLoop();
	launchedBrowser.instance.runner.deleteBrowserCaches();
};

export const getBrowserInstanceImplementation: GetBrowserInstance = async <
	Provider extends CloudProvider,
>({
	logLevel,
	indent,
	chromiumOptions,
	providerSpecifics,
	insideFunctionSpecifics,
}: {
	logLevel: LogLevel;
	indent: boolean;
	chromiumOptions: ChromiumOptions;
	providerSpecifics: ProviderSpecifics<Provider>;
	insideFunctionSpecifics: InsideFunctionSpecifics<Provider>;
}): Promise<LaunchedBrowser> => {
	const actualChromiumOptions: Required<ChromiumOptions> = {
		...chromiumOptions,
		darkMode: chromiumOptions.darkMode ?? false,
		disableWebSecurity: chromiumOptions.disableWebSecurity ?? false,
		headless: chromiumOptions.headless ?? true,
		userAgent: chromiumOptions.userAgent ?? null,
		ignoreCertificateErrors: chromiumOptions.ignoreCertificateErrors ?? false,
		// Override the `null` value, which might come from CLI with swANGLE
		gl: chromiumOptions.gl ?? 'swangle',
		enableMultiProcessOnLinux: false,
	};
	const configurationString = makeConfigurationString(
		actualChromiumOptions,
		logLevel,
	);
	RenderInternals.Log.info(
		{indent: false, logLevel},
		`Rendering with Remotion v${VERSION}.`,
	);

	if (launching) {
		RenderInternals.Log.info(
			{indent: false, logLevel},
			'Already waiting for browser launch...',
		);
		await waitForLaunched();
		if (!_browserInstance) {
			throw new Error('expected to launch');
		}
	}

	if (!_browserInstance) {
		RenderInternals.Log.info(
			{indent: false, logLevel},
			'Cold function, launching new browser instance',
		);
		launching = true;

		const execPath = providerSpecifics.getChromiumPath();

		const instance = await RenderInternals.internalOpenBrowser({
			browser: 'chrome',
			browserExecutable: execPath,
			chromiumOptions: actualChromiumOptions,
			forceDeviceScaleFactor: undefined,
			indent: false,
			viewport: null,
			logLevel,
			onBrowserDownload: () => {
				throw new Error('Should not download a browser in serverless');
			},
			chromeMode: 'headless-shell',
		});
		instance.on('disconnected', () => {
			RenderInternals.Log.info(
				{indent: false, logLevel},
				'Browser disconnected or crashed.',
			);
			insideFunctionSpecifics.forgetBrowserEventLoop({
				logLevel,
				launchedBrowser: _browserInstance as LaunchedBrowser,
			});
			_browserInstance?.instance?.close({silent: true}).catch((err) => {
				RenderInternals.Log.info(
					{indent: false, logLevel},
					'Could not close browser instance',
					err,
				);
			});
			_browserInstance = null;
		});
		_browserInstance = {
			instance,
			configurationString,
		};

		launching = false;
		return _browserInstance;
	}

	if (_browserInstance.configurationString !== configurationString) {
		RenderInternals.Log.info(
			{indent: false, logLevel},
			'Warm function, but Browser configuration changed. Killing old browser instance.',
		);
		_browserInstance.instance.runner.rememberEventLoop();
		await _browserInstance.instance.close({silent: true});
		_browserInstance = null;
		return insideFunctionSpecifics.getBrowserInstance({
			logLevel,
			indent,
			chromiumOptions,
			providerSpecifics,
			insideFunctionSpecifics,
		});
	}

	RenderInternals.Log.info(
		{indent: false, logLevel},
		'Warm function, reusing browser instance',
	);
	_browserInstance.instance.runner.rememberEventLoop();
	return _browserInstance;
};