From 1cde39461ad965b71983629a1aa9f2b38cba6a67 Mon Sep 17 00:00:00 2001
From: Simon Huang <shuang85497@gmail.com>
Date: Sun, 16 Aug 2020 19:12:11 -0400
Subject: [PATCH] set up listener to retrieve messages fixed listener
 unsubscriptions in Room.tsx

---
 src/components/Chat.css |  17 +++---
 src/components/Chat.tsx | 113 ++++++++++++++++++++++++++++------------
 src/pages/Room.tsx      |  16 +++---
 3 files changed, 101 insertions(+), 45 deletions(-)

diff --git a/src/components/Chat.css b/src/components/Chat.css
index a6d0288..2427fdf 100644
--- a/src/components/Chat.css
+++ b/src/components/Chat.css
@@ -1,9 +1,3 @@
-ion-grid {
-  border-left: solid 1px #bbb;
-  border-right: solid 1px #bbb;
-  height: 100%;
-}
-
 ion-col {
   padding: 10px;
   border-radius: 10px;
@@ -20,6 +14,17 @@ ion-textarea {
   justify-content: flex-end;
 }
 
+.message-grid {
+  padding-left: calc(100vw - 100%);
+  margin-right: 0;
+  height: 100%;
+}
+
+.message-input {
+  margin-right: 0;
+  border: solid 1px #bbb;
+}
+
 .my-msg {
   text-align: right;
   background: var(--ion-color-primary);
diff --git a/src/components/Chat.tsx b/src/components/Chat.tsx
index e402a2a..c7f5d3b 100644
--- a/src/components/Chat.tsx
+++ b/src/components/Chat.tsx
@@ -1,6 +1,6 @@
 import { IonButton, IonCol, IonContent, IonFooter, IonGrid, IonRow, IonTextarea } from '@ionic/react';
-import React, { useState } from 'react';
-import { db, timestamp } from '../services/firebase';
+import React, { useEffect, useState } from 'react';
+import { currTime, db, timestamp } from '../services/firebase';
 import './Chat.css';
 
 type ChatProps = {
@@ -8,53 +8,102 @@ type ChatProps = {
   userId: string;
 };
 
+type Message = {
+  id: string;
+  senderId: string;
+  sender: string;
+  content: string;
+};
+
 const Chat: React.FC<ChatProps> = ({ roomId, userId }) => {
-  const [message, setMessage] = useState('');
+  const [room] = useState(roomId);
+  const [message, setMessage] = useState(''); // Message to be sent
+  const [prevMessages, setPrevMessages] = useState<Message[]>([]); // Track previous messages for updating useEffect
+  const [newMessages, setNewMessages] = useState<Message[]>([]); // Newly retrieved messages
+  const [chats, setChats] = useState<Message[]>([
+    { id: '', senderId: userId, sender: '', content: 'You have joined the room.' },
+  ]); // All received messages
+  const [loading, setLoading] = useState(true);
+
+  // Listen for new messages
+  useEffect(() => {
+    const chatUnsubscribe = db
+      .collection('rooms')
+      .doc(room)
+      .collection('messages')
+      .orderBy('createdAt')
+      .where('createdAt', '>', currTime)
+      .onSnapshot(async (querySnapshot) => {
+        let newMsgs: Message[] = [];
+        const changes = querySnapshot.docChanges();
+        for (const change of changes) {
+          if (change.type === 'added') {
+            const data = change.doc.data();
+            const user = await db.collection('users').doc(data?.senderId).get();
+            newMsgs.push({
+              id: change.doc.id,
+              senderId: data?.senderId,
+              sender: user.data()?.name,
+              content: data?.content,
+            });
+          }
+        }
+
+        if (newMsgs.length !== 0) {
+          setNewMessages(newMsgs);
+        }
+      });
+
+    setLoading(false);
+    return () => {
+      chatUnsubscribe();
+    };
+  }, [room]);
 
+  // Only update array containing all messages when there are new messages
+  useEffect(() => {
+    if (prevMessages !== newMessages) {
+      setPrevMessages(newMessages);
+      setChats([...chats, ...newMessages]);
+    }
+  }, [prevMessages, newMessages, chats]);
+
+  // Send message to database and reset textarea field
   const sendMessage = async () => {
-    const messageId = await db.collection('rooms').doc(roomId).collection('messages').add({
+    await db.collection('rooms').doc(roomId).collection('messages').add({
       createdAt: timestamp,
       senderId: userId,
       content: message,
     });
-    console.log(messageId);
+
+    setMessage('');
   };
 
   return (
     <>
       <IonContent>
-        <IonGrid>
-          <IonRow class="right-align">
-            <IonCol size="auto" class="my-msg">
-              <b>Simon: </b>
-              <span>Hello!</span>
-            </IonCol>
-          </IonRow>
-          <IonRow>
-            <IonCol size="auto" class="other-msg">
-              <b>Manuel: </b>
-              <span>They are all asking me about what I'm going to do next</span>
-            </IonCol>
-          </IonRow>
-          <IonRow>
-            <IonCol size="auto" class="other-msg">
-              <b>Amaria: </b>
-              <span>Probably riding on</span>
-            </IonCol>
-          </IonRow>
-          <IonRow class="right-align">
-            <IonCol size="auto" class="my-msg">
-              <b>Simon: </b>
-              <span>my photo jet</span>
-            </IonCol>
-          </IonRow>
+        <IonGrid class="message-grid">
+          {!loading ? (
+            chats.map((chat) => {
+              return (
+                <IonRow key={chat.id} class={chat.senderId === userId ? 'right-align' : ''}>
+                  <IonCol size="auto" class={chat.senderId === userId ? 'my-msg' : 'other-msg'}>
+                    {chat.sender !== '' ? <b>{chat.sender}: </b> : <></>}
+                    <span>{chat.content}</span>
+                  </IonCol>
+                </IonRow>
+              );
+            })
+          ) : (
+            <></>
+          )}
         </IonGrid>
       </IonContent>
       <IonFooter class="ion-no-border">
-        <IonGrid>
+        <IonGrid class="message-input">
           <IonRow>
             <IonCol size="9">
-              <IonTextarea onIonChange={(e) => setMessage(e.detail.value!)}></IonTextarea>
+              <IonTextarea onIonChange={(e) => setMessage(e.detail.value!)} value={message}></IonTextarea>
             </IonCol>
             <IonCol size="3" class="send-msg">
               <IonButton expand="block" color="primary" onClick={sendMessage} class="send-button">
diff --git a/src/pages/Room.tsx b/src/pages/Room.tsx
index bc3de26..d1ee778 100644
--- a/src/pages/Room.tsx
+++ b/src/pages/Room.tsx
@@ -13,7 +13,6 @@ const Room: React.FC<RouteComponentProps<{ roomId: string }>> = ({ match }) => {
   const [userId, setUserId] = useState('');
   const [loading, setLoading] = useState(true);
   const [userCount, setUserCount] = useState(0);
-  const [didConnect, setDidConnect] = useState(false);
 
   // Verify that the roomId exists in db
   useEffect(() => {
@@ -49,7 +48,7 @@ const Room: React.FC<RouteComponentProps<{ roomId: string }>> = ({ match }) => {
 
   // Subscribe listeners
   useEffect(() => {
-    if (!didConnect && userId !== '' && validRoom) {
+    if (userId !== '' && validRoom) {
       const populateRoom = () => {
         const roomRef = rtdb.ref('/rooms/' + roomId);
         const availableRef = rtdb.ref('/available/');
@@ -68,7 +67,7 @@ const Room: React.FC<RouteComponentProps<{ roomId: string }>> = ({ match }) => {
         });
 
         // Re-add room into /available/ if the room was deleted
-        availableRef.on('child_removed', async (snapshot) => {
+        availableRef.on('value', async (snapshot) => {
           if (!snapshot.hasChild(roomId)) {
             await availableRef.child(roomId).set({
               name: 'Room Name',
@@ -77,7 +76,7 @@ const Room: React.FC<RouteComponentProps<{ roomId: string }>> = ({ match }) => {
           }
         });
 
-        setLoading(false); // Ready when connection to rtdb is made
+        setLoading(false); // Ready when connections to databases are made
 
         // Unsubscribe listeners
         return () => {
@@ -87,10 +86,13 @@ const Room: React.FC<RouteComponentProps<{ roomId: string }>> = ({ match }) => {
         };
       };
 
-      populateRoom();
-      setDidConnect(true); // Run this useEffect only once
+      const unsub = populateRoom();
+
+      return () => {
+        unsub();
+      };
     }
-  }, [userId, validRoom, roomId, userCount, loading, didConnect]);
+  }, [userId, validRoom, roomId]);
 
   // Handle disconnect events
   useEffect(() => {