/*
Copyright 2016-2019 Balena

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
import * as BalenaSdk from 'balena-sdk';
import { CommandDefinition } from 'capitano';
import { stripIndent } from 'common-tags';

import { BalenaApplicationNotFound, BalenaDeviceNotFound } from 'balena-errors';
import {
	validateApplicationName,
	validateDotLocalUrl,
	validateIPAddress,
	validateShortUuid,
	validateUuid,
} from '../utils/validation';

enum SSHTarget {
	APPLICATION,
	DEVICE,
	LOCAL_DEVICE,
}

async function getSSHTarget(
	sdk: BalenaSdk.BalenaSDK,
	applicationOrDevice: string,
): Promise<{
	target: SSHTarget;
	deviceChecked?: boolean;
	applicationChecked?: boolean;
	device?: BalenaSdk.Device;
} | null> {
	if (
		validateDotLocalUrl(applicationOrDevice) ||
		validateIPAddress(applicationOrDevice)
	) {
		return { target: SSHTarget.LOCAL_DEVICE };
	}

	const appTest = validateApplicationName(applicationOrDevice);
	const uuidTest = validateUuid(applicationOrDevice);
	if (appTest || uuidTest) {
		// Do some further processing to work out which it is
		if (appTest && !uuidTest) {
			return {
				target: SSHTarget.APPLICATION,
				applicationChecked: false,
			};
		}
		if (uuidTest && !appTest) {
			return {
				target: SSHTarget.DEVICE,
				deviceChecked: false,
			};
		}

		// This is the harder part, we have a string that
		// fulfills both the uuid and application name
		// requirements. We should go away and test for both a
		// device with that uuid, and an application with that
		// name, and choose the appropriate one
		try {
			await sdk.models.application.get(applicationOrDevice);
			return { target: SSHTarget.APPLICATION, applicationChecked: true };
		} catch (e) {
			if (e instanceof BalenaApplicationNotFound) {
				// Here we want to check for a device with that UUID
				try {
					const device = await sdk.models.device.get(applicationOrDevice, {
						$select: ['id', 'uuid', 'supervisor_version', 'is_online'],
					});
					return { target: SSHTarget.DEVICE, deviceChecked: true, device };
				} catch (err) {
					if (err instanceof BalenaDeviceNotFound) {
						throw new Error(
							`Device or application not found: ${applicationOrDevice}`,
						);
					}
					throw err;
				}
			}
			throw e;
		}
	}
	return null;
}

async function getContainerId(
	sdk: BalenaSdk.BalenaSDK,
	uuid: string,
	serviceName: string,
	sshOpts: {
		port?: number;
		proxyCommand?: string;
		proxyUrl: string;
		username: string;
	},
	version?: string,
	id?: number,
): Promise<string> {
	const semver = await import('resin-semver');

	if (version == null || id == null) {
		const device = await sdk.models.device.get(uuid, {
			$select: ['id', 'supervisor_version'],
		});
		version = device.supervisor_version;
		id = device.id;
	}

	let containerId: string | undefined;
	if (semver.gte(version, '8.6.0')) {
		const apiUrl = await sdk.settings.get('apiUrl');
		// TODO: Move this into the SDKs device model
		const request = await sdk.request.send({
			method: 'POST',
			url: '/supervisor/v2/containerId',
			baseUrl: apiUrl,
			body: {
				method: 'GET',
				deviceId: id,
			},
		});
		if (request.status !== 200) {
			throw new Error(
				`There was an error connecting to device ${uuid}, HTTP response code: ${
					request.status
				}.`,
			);
		}
		const body = request.body;
		if (body.status !== 'success') {
			throw new Error(
				`There was an error communicating with device ${uuid}.\n\tError: ${
					body.message
				}`,
			);
		}
		containerId = body.services[serviceName];
	} else {
		console.log(stripIndent`
			Using legacy method to detect container ID. This will be slow.
			To speed up this process, please update your device to an OS
			which has a supervisor version of at least v8.6.0.
		`);
		// We need to execute a balena ps command on the device,
		// and parse the output, looking for a specific
		// container
		const { child_process } = await import('mz');
		const escapeRegex = await import('lodash/escapeRegExp');
		const { getSubShellCommand } = await import('../utils/helpers');
		const { deviceContainerEngineBinary } = await import('../utils/device/ssh');

		const command = generateVpnSshCommand({
			uuid,
			verbose: false,
			port: sshOpts.port,
			command: `host ${uuid} '"${deviceContainerEngineBinary}" ps --format "{{.ID}} {{.Names}}"'`,
			proxyCommand: sshOpts.proxyCommand,
			proxyUrl: sshOpts.proxyUrl,
			username: sshOpts.username,
		});

		const subShellCommand = getSubShellCommand(command);
		const subprocess = child_process.spawn(
			subShellCommand.program,
			subShellCommand.args,
			{
				stdio: [null, 'pipe', null],
			},
		);
		const containers = await new Promise<string>((resolve, reject) => {
			let output = '';
			subprocess.stdout.on('data', chunk => (output += chunk.toString()));
			subprocess.on('close', (code: number) => {
				if (code !== 0) {
					reject(
						new Error(
							`Non-zero error code when looking for service container: ${code}`,
						),
					);
				} else {
					resolve(output);
				}
			});
		});

		const lines = containers.split('\n');
		const regex = new RegExp(`\\/?${escapeRegex(serviceName)}_\\d+_\\d+`);
		for (const container of lines) {
			const [cId, name] = container.split(' ');
			if (regex.test(name)) {
				containerId = cId;
				break;
			}
		}
	}

	if (containerId == null) {
		throw new Error(
			`Could not find a service ${serviceName} on device ${uuid}.`,
		);
	}
	return containerId;
}

function generateVpnSshCommand(opts: {
	uuid: string;
	command: string;
	verbose: boolean;
	port?: number;
	username: string;
	proxyUrl: string;
	proxyCommand?: string;
}) {
	return (
		`ssh ${
			opts.verbose ? '-vvv' : ''
		} -t -o LogLevel=ERROR -o StrictHostKeyChecking=no ` +
		`-o UserKnownHostsFile=/dev/null ` +
		`${opts.proxyCommand != null ? opts.proxyCommand : ''} ` +
		`${opts.port != null ? `-p ${opts.port}` : ''} ` +
		`${opts.username}@ssh.${opts.proxyUrl} ${opts.command}`
	);
}

export const ssh: CommandDefinition<
	{
		applicationOrDevice: string;
		serviceName?: string;
	},
	{
		port: string;
		service: string;
		verbose: true | undefined;
		noProxy: boolean;
	}
> = {
	signature: 'ssh <applicationOrDevice> [serviceName]',
	description: 'SSH into the host or application container of a device',
	primary: true,
	help: stripIndent`
		This command can be used to start a shell on a local or remote device.

		If a service name is not provided, a shell will be opened on the host OS.

		If an application name is provided, all online devices in the application
		will be presented, and the chosen device will then have a shell opened on
		in it's service container or host OS.

		For local devices, the ip address and .local domain name are supported.

		Examples:
			balena ssh MyApp

			balena ssh f49cefd
			balena ssh f49cefd my-service
			balena ssh f49cefd --port <port>

			balena ssh 192.168.0.1 --verbose
			balena ssh f49cefd.local my-service

		Warning: 'balena ssh' requires an openssh-compatible client to be correctly
		installed in your shell environment. For more information (including Windows
		support) please check:
			https://github.com/balena-io/balena-cli/blob/master/INSTALL.md#additional-dependencies`,
	options: [
		{
			signature: 'port',
			parameter: 'port',
			description: 'SSH gateway port',
			alias: 'p',
		},
		{
			signature: 'verbose',
			boolean: true,
			description: 'Increase verbosity',
			alias: 'v',
		},
		{
			signature: 'noproxy',
			boolean: true,
			description: stripIndent`
				Don't use the proxy configuration for this connection. This flag
				only make sense if you've configured a proxy globally.`,
		},
	],
	action: async (params, options) => {
		const map = await import('lodash/map');
		const bash = await import('bash');
		// TODO: Make this typed
		const hasbin = require('hasbin');
		const { getSubShellCommand } = await import('../utils/helpers');
		const { child_process } = await import('mz');
		const { exitIfNotLoggedIn } = await import('../utils/patterns');

		const { exitWithExpectedError, selectFromList } = await import(
			'../utils/patterns'
		);
		const sdk = BalenaSdk.fromSharedOptions();

		const verbose = options.verbose === true;
		// ugh TODO: Fix this
		const proxyConfig = (global as any).PROXY_CONFIG;
		const useProxy = !!proxyConfig && !options.noProxy;
		const port = options.port != null ? parseInt(options.port, 10) : undefined;

		const getSshProxyCommand = (hasTunnelBin: boolean) => {
			if (!useProxy) {
				return '';
			}

			if (!hasTunnelBin) {
				console.warn(stripIndent`
					Proxy is enabled but the \`proxytunnel\` binary cannot be found.
					Please install it if you want to route the \`balena ssh\` requests through the proxy.
					Alternatively you can pass \`--noproxy\` param to the \`balena ssh\` command to ignore the proxy config
					for the \`ssh\` requests.

					Attempting the unproxied request for now.`);
				return '';
			}

			let tunnelOptions: Dictionary<string> = {
				proxy: `${proxyConfig.host}:${proxyConfig.port}`,
				dest: '%h:%p',
			};
			const { proxyAuth } = proxyConfig;
			if (proxyAuth) {
				const i = proxyAuth.indexOf(':');
				tunnelOptions = {
					user: proxyAuth.substring(0, i),
					pass: proxyAuth.substring(i + 1),
					...tunnelOptions,
				};
			}

			const proxyCommand = `proxytunnel ${bash.args(tunnelOptions, '--', '=')}`;
			return `-o ${bash.args({ ProxyCommand: proxyCommand }, '', '=')}`;
		};

		// Detect what type of SSH we're doing
		const maybeParamChecks = await getSSHTarget(
			sdk,
			params.applicationOrDevice,
		);
		if (maybeParamChecks == null) {
			exitWithExpectedError(
				new Error(stripIndent`
					Could not parse SSH target.
					You can provide an application name, IP address or .local address`),
			);
		}
		const paramChecks = maybeParamChecks!;

		switch (paramChecks.target) {
			case SSHTarget.APPLICATION:
				exitIfNotLoggedIn();
				// Here what we want to do is fetch all device which
				// are part of this application, and online
				try {
					const devices = await sdk.models.device.getAllByApplication(
						params.applicationOrDevice,
						{ $filter: { is_online: true }, $select: ['device_name', 'uuid'] },
					);
					const choice = await selectFromList(
						'Please choose an online device to SSH into:',
						map(devices, ({ device_name, uuid: uuidToChoose }) => ({
							name: `${device_name}  [${uuidToChoose.substr(0, 7)}]`,
							uuid: uuidToChoose,
						})),
					);
					// A little bit hacky, but it means we can fall
					// through to the next handling mechanism
					params.applicationOrDevice = choice.uuid;
				} catch (e) {
					if (e instanceof BalenaApplicationNotFound) {
						exitWithExpectedError(
							`Could not find an application named ${
								params.applicationOrDevice
							}`,
						);
					}
					throw e;
				}
			case SSHTarget.DEVICE:
				exitIfNotLoggedIn();
				// We want to do two things here; firstly, check
				// that the device exists and is accessible, and
				// also convert a short uuid to a long one if
				// necessary
				let uuid = params.applicationOrDevice;
				let version: string | undefined;
				let id: number | undefined;
				let isOnline: boolean | undefined;
				// We also want to avoid checking for a device if we
				// know it exists
				if (!paramChecks.deviceChecked || validateShortUuid(uuid)) {
					try {
						const device = await sdk.models.device.get(uuid, {
							$select: ['id', 'uuid', 'supervisor_version', 'is_online'],
						});
						uuid = device.uuid;
						version = device.supervisor_version;
						id = device.id;
						isOnline = device.is_online;
					} catch (e) {
						if (e instanceof BalenaDeviceNotFound) {
							exitWithExpectedError(`Could not find device: ${uuid}`);
						}
					}
				} else {
					version = paramChecks.device!.supervisor_version;
					uuid = paramChecks.device!.uuid;
					id = paramChecks.device!.id;
					isOnline = paramChecks.device!.is_online;
				}

				if (!isOnline) {
					throw new Error(`Device ${uuid} is not online.`);
				}

				const [hasTunnelBin, username, proxyUrl] = await Promise.all([
					useProxy ? await hasbin('proxytunnel') : undefined,
					sdk.auth.whoami(),
					sdk.settings.get('proxyUrl'),
				]);
				const proxyCommand = getSshProxyCommand(hasTunnelBin);

				if (username == null) {
					exitWithExpectedError(
						`Opening an SSH connection to a remote device requires you to be logged in.`,
					);
				}

				// At this point, we have a long uuid with a device
				// that we know exists and is accessible
				let containerId: string | undefined;
				if (params.serviceName != null) {
					containerId = await getContainerId(
						sdk,
						uuid,
						params.serviceName,
						{
							port,
							proxyCommand,
							proxyUrl,
							username: username!,
						},
						version,
						id,
					);
				}

				let accessCommand: string;
				if (containerId != null) {
					accessCommand = `enter ${uuid} ${containerId}`;
				} else {
					accessCommand = `host ${uuid}`;
				}

				const command = generateVpnSshCommand({
					uuid,
					command: accessCommand,
					verbose,
					port,
					proxyCommand,
					proxyUrl,
					username: username!,
				});

				const subShellCommand = getSubShellCommand(command);
				await child_process.spawn(
					subShellCommand.program,
					subShellCommand.args,
					{
						stdio: 'inherit',
					},
				);

				break;
			case SSHTarget.LOCAL_DEVICE:
				const { performLocalDeviceSSH } = await import('../utils/device/ssh');
				await performLocalDeviceSSH({
					address: params.applicationOrDevice,
					port,
					verbose,
					service: params.serviceName,
				});
				break;
		}
	},
};