const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);
exports.sendNotification = functions.database.ref('/Messages/{user_id}/{dest_uid}/{message_id}').onWrite(event => {
	const user_id = event.params.user_id;
	const dest_uid = event.params.dest_uid;
	const message_id = event.params.message_id;
	console.log('We have a notification to send to ',dest_uid,' from ',user_id);
	if(!event.data.val()) {
		return console.log('A notification has been deleted from the database ',message_id);
	}
	const nameFinder = admin.database().ref(`/Users/${dest_uid}/name`).once('value');
	return nameFinder.then(nameRes => {
		const name = nameRes.val();
		const messagefinder = admin.database().ref(`/Messages/${user_id}/${dest_uid}/${message_id}/message`).once('value');
		return messagefinder.then(messageResult => {
			const message = messageResult.val();
			const deviceTokenFinder = admin.database().ref(`/Users/${user_id}/device_token`).once('value');
			return deviceTokenFinder.then(result => {
				const deviceToken = result.val();
				const uidChecker = admin.database().ref(`/Messages/${user_id}/${dest_uid}/${message_id}/from`).once('value');
				return uidChecker.then(uidResult => {
					const tempUid = uidResult.val();
					console.log(tempUid,'-Equals-',dest_uid);
					if(tempUid == dest_uid) {
						const payload = {
							notification : {
								title : `${name} messaged you`,
								body :  `${message}`,
								icon : "default"
							}
						};
						admin.messaging().sendToDevice(deviceToken,payload).then(response => {
				 			console.log('This was notification feature for..',deviceToken,' xx',result);
				 		});
					}
				});
			});
		});
	});
});