'use-strict';

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);

exports.sendNotification = functions.database.ref('/{teacherId}/{classId}/{notificationId}').onWrite((change, context)=>{
    const teacherId = context.params.teacherId;
    const classId = context.params.classId;

    return admin.firestore().collection("Users").doc(teacherId).collection("Subjects").doc(classId).get().then(doc=>{
        const className = doc.data().Name;

    }).then(result=>{

        return admin.firestore().collection("Users").where(classId,"==","Added").get().then(queryResult=>{
            queryResult.forEach(documentSanpshot =>{
                const tokenId = documentSanpshot.data().token;
                const payload ={
                    notification: {
                        title : "New Announcement",
                        body : "Subject: "+className,
                        icon: "default"
                    }
                };
                return admin.messaging().sendToDevice(tokenId,payload);
            });
        });
    });
});