From 0541a132333aadcaa0960bfb426e40b936a86533 Mon Sep 17 00:00:00 2001
From: Rodrigo Nascimento <rodrigoknascimento@gmail.com>
Date: Thu, 10 Aug 2017 20:21:46 -0300
Subject: [PATCH] Load more messages. Closes #15

---
 app/lib/rocketchat.js | 14 +++++++++++---
 app/views/room.js     | 37 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/app/lib/rocketchat.js b/app/lib/rocketchat.js
index c6c261c9..980ae3c1 100644
--- a/app/lib/rocketchat.js
+++ b/app/lib/rocketchat.js
@@ -104,10 +104,14 @@ const RocketChat = {
 		});
 	},
 
-	loadMessagesForRoom(rid, cb) {
-		Meteor.call('loadHistory', rid, null, 50, (err, data) => {
+	loadMessagesForRoom(rid, end, cb) {
+		Meteor.call('loadHistory', rid, end, 20, (err, data) => {
 			if (err) {
 				console.error(err);
+				if (cb) {
+					cb({ end: true });
+				}
+				return;
 			}
 
 			realm.write(() => {
@@ -119,7 +123,11 @@ const RocketChat = {
 			});
 
 			if (cb) {
-				cb();
+				if (data.messages.length < 20) {
+					cb({ end: true });
+				} else {
+					cb({ end: false });
+				}
 			}
 		});
 
diff --git a/app/views/room.js b/app/views/room.js
index b3058f01..78eca59b 100644
--- a/app/views/room.js
+++ b/app/views/room.js
@@ -27,6 +27,12 @@ const styles = StyleSheet.create({
 		margin: 5,
 		textAlign: 'center',
 		color: '#a00'
+	},
+	header: {
+		transform: [{ scaleY: -1 }],
+		textAlign: 'center',
+		padding: 5,
+		color: '#ccc'
 	}
 });
 
@@ -57,7 +63,7 @@ export default class RoomView extends React.Component {
 		const late = setTimeout(() => this.setState({
 			loaded: false
 		}), 1000);
-		RocketChat.loadMessagesForRoom(this.rid, () => {
+		RocketChat.loadMessagesForRoom(this.rid, null, () => {
 			clearTimeout(late);
 			this.setState({
 				loaded: true
@@ -70,6 +76,22 @@ export default class RoomView extends React.Component {
 		realm.removeListener('change', this.updateState);
 	}
 
+	onEndReached = () => {
+		if (this.state.dataSource.length && this.state.loaded && this.state.loadingMore !== true && this.state.end !== true) {
+			this.setState({
+				...this.state,
+				loadingMore: true
+			});
+			RocketChat.loadMessagesForRoom(this.rid, this.state.dataSource[this.state.dataSource.length - 1].ts, ({ end }) => {
+				this.setState({
+					...this.state,
+					loadingMore: false,
+					end
+				});
+			});
+		}
+	}
+
 	getMessages = () => realm.objects('messages').filtered('_server.id = $0 AND rid = $1', RocketChat.currentServer, this.rid).sorted('ts', true)
 
 	updateState = () => {
@@ -129,6 +151,16 @@ export default class RoomView extends React.Component {
 		);
 	}
 
+	renderHeader = () => {
+		if (this.state.loadingMore) {
+			return <Text style={styles.header}>Loading more messages...</Text>;
+		}
+
+		if (this.state.end) {
+			return <Text style={styles.header}>Start of conversation</Text>;
+		}
+	}
+
 	render() {
 		return (
 			<KeyboardView style={styles.container} keyboardVerticalOffset={64}>
@@ -140,6 +172,9 @@ export default class RoomView extends React.Component {
 					extraData={this.state}
 					renderItem={this.renderItem}
 					keyExtractor={item => item._id}
+					onEndReached={this.onEndReached}
+					onEndReachedThreshold={0.1}
+					ListFooterComponent={this.renderHeader()}
 				/>
 				{this.renderFooter()}
 			</KeyboardView>