import { fetch } from 'meteor/fetch';
import { OAuth } from 'meteor/oauth';
import { ServiceConfiguration } from 'meteor/service-configuration';

export const Linkedin = {};

const getImage = (profilePicture) => {
	const image = [];
	if (profilePicture !== undefined) {
		for (const element of profilePicture['displayImage~'].elements) {
			for (const identifier of element.identifiers) {
				image.push(identifier.identifier);
			}
		}
	}
	return {
		displayImage: profilePicture ? profilePicture.displayImage : null,
		identifiersUrl: image,
	};
};

// Request for email, returns array
const getEmails = async function (accessToken) {
	const url = encodeURI(
		`https://api.linkedin.com/v2/emailAddress?q=members&projection=(elements*(handle~))&oauth2_access_token=${accessToken}`,
	);
	const data = await fetch(url);
	const response = await data.json();
	const emails = [];
	for (const element of response.elements) {
		emails.push(element['handle~'].emailAddress);
	}
	return emails;
};

// checks whether a string parses as JSON
const isJSON = function (str) {
	try {
		JSON.parse(str);
		return true;
	} catch (e) {
		return false;
	}
};

// returns an object containing:
// - accessToken
// - expiresIn: lifetime of token in seconds
const getTokenResponse = async function (query) {
	const config = await ServiceConfiguration.configurations.findOneAsync({ service: 'linkedin' });
	if (!config) throw new ServiceConfiguration.ConfigError('Service not configured');

	let responseContent;
	try {
		// Request an access token
		const request = await fetch('https://api.linkedin.com/uas/oauth2/accessToken', {
			method: 'POST',
			body: JSON.stringify({
				grant_type: 'authorization_code',
				client_id: config.clientId,
				client_secret: OAuth.openSecret(config.secret),
				code: query.code,
				redirect_uri: OAuth._redirectUri('linkedin', config),
			}),
		});
		responseContent = await request.text();
	} catch (err) {
		throw new Error(`Failed to complete OAuth handshake with Linkedin. ${err.message}`);
	}

	// If 'responseContent' does not parse as JSON, it is an error.
	if (!isJSON(responseContent)) {
		throw new Error(`Failed to complete OAuth handshake with Linkedin. ${responseContent}`);
	}

	// Success! Extract access token and expiration
	const parsedResponse = JSON.parse(responseContent);
	const accessToken = parsedResponse.access_token;
	const expiresIn = parsedResponse.expires_in;

	if (!accessToken) {
		throw new Error(`Failed to complete OAuth handshake with Linkedin -- can't find access token in HTTP response. ${responseContent}`);
	}

	return {
		accessToken,
		expiresIn,
	};
};

// Request available fields from r_liteprofile
const getIdentity = async function (accessToken) {
	try {
		const url = encodeURI(
			`https://api.linkedin.com/v2/me?projection=(id,firstName,lastName,profilePicture(displayImage~:playableStreams))&oauth2_access_token=${accessToken}`,
		);
		const request = await fetch(url);
		return request.json();
	} catch (err) {
		throw new Error(`Failed to fetch identity from Linkedin. ${err.message}`);
	}
};

OAuth.registerService('linkedin', 2, null, async (query) => {
	const response = await getTokenResponse(query);
	const { accessToken } = response;
	const identity = await getIdentity(accessToken);

	const { id, firstName, lastName, profilePicture } = identity;

	if (!id) {
		throw new Error('Linkedin did not provide an id');
	}

	const emails = await getEmails(accessToken);

	const fields = {
		linkedinId: id,
		firstName,
		lastName,
		profilePicture: getImage(profilePicture),
		emails,
	};

	if (emails.length) {
		const primaryEmail = emails[0];
		fields.emailAddress = primaryEmail; // for backward compatibility with previous versions of this package
		fields.email = primaryEmail;
	}

	const serviceData = {
		id,
		accessToken,
		expiresAt: +new Date() + 1000 * response.expiresIn,
		...fields,
	};

	return {
		serviceData,
		options: {
			profile: fields,
		},
	};
});

Linkedin.retrieveCredential = function (credentialToken, credentialSecret) {
	return OAuth.retrieveCredential(credentialToken, credentialSecret);
};