"use strict";

const Promise = require("bluebird");
const React = require("react");
const create = require("create-react-class");
const sanitize = require("sanitize-html");
const { expression } = require("dataprog");

const Event = require("./events/Event.js");
const Info = require("./info.js");
const Input = require("./input.js");
const User = require("./events/user.js");
const Loading = require("./loading.js");

const generateJdenticon = require("../lib/generate-jdenticon");
const generateThumbnailUrl = require("../lib/generate-thumbnail-url");
const groupEvents = require("../lib/group-events");
const parseMXC = require("../lib/parse-mxc");

let eventFunctions = {
	plaintext: function() {
		if (this.type == "m.room.message") {
			if (this.content.format == "org.matrix.custom.html") {
				return sanitize(this.content.formatted_body, {allowedTags: []});
			} else {
				return this.content.body;
			}
		} else if (this.type == "m.room.member") {
			if (this.content.membership == "invite") {
				return `${this.sender} invited ${this.state_key}`;
			} else if (this.content.membership == "join") {
				return `${this.state_key} joined the room`;
			} else if (this.content.membership == "leave") {
				return `${this.state_key} left the room`;
			} else if (this.content.membership == "kick") {
				return `${this.sender} kicked ${this.state_key}`;
			} else if (this.content.membership == "ban") {
				return `${this.sender} banned ${this.state_key}`;
			} else {
				return "unknown member event";
			}
		} else if (this.type == "m.room.avatar") {
			if (this.content.url.length > 0) {
				return `${this.sender} changed the room avatar`;
			}
		} else if (this.type == "m.room.name") {
			return `${this.sender} changed the room name to ${this.content.name}`;
		} else {
			return "unknown event";
		}
	}
};

let chat = create({
	displayName: "Chat",

	getInitialState: function() {
		return {
			ref: null,
			loading: false
		};
	},

	getSnapshotBeforeUpdate: function(_oldProps, _oldState) {
		let ref = this.state.ref;

		if (ref != null && (ref.scrollHeight - ref.offsetHeight) - ref.scrollTop < 100) {
			// Less than 100px from bottom
			return true;
		} else {
			return null;
		}
	},

	componentDidUpdate(prevProps, prevState, snapshot) {
		let ref = this.state.ref;

		if (ref != null && snapshot) {
			// scroll to bottom
			ref.scrollTop = (ref.scrollHeight - ref.offsetHeight);
		}
	},

	setRef: function(ref) {
		if (ref != null) {
			this.setState({ ref: ref });
		}
	},

	onReplyClick: function(e) {
		this.setState({ replyEvent: e });
	},

	paginateBackwards: function() {
		if (!this.state.loading) {
			let client = this.props.client;
			let timeline = client.getRoom(this.props.roomId).getLiveTimeline();
			
			this.setState({loading: true});

			return Promise.try(() => {
				return client.paginateEventTimeline(timeline, {backwards: true});
			}).then(() => {
				this.setState({loading: false});
			});
		}
	},

	render: function() {
		let client = this.props.client;

		let empty = <div className="main" />;

		if (this.props.roomId == null) {
			//empty screen
			return empty;
		} else {
			let room = client.getRoom(this.props.roomId);
			if (room == null) {
				return empty;
			} else {
				let liveTimeline = room.getLiveTimeline();
				let liveTimelineEvents = liveTimeline.getEvents();
				
				let events = liveTimelineEvents.map((item) => {
					let event = item.event;

					return Object.assign(
						event,
						eventFunctions,
						(event.sender == null)
							/* Whether this event is a local echo */
							? { local: true, sender: event.user_id }
							: null
					);
				});

				let eventGroups = groupEvents(events);

				//TODO: replace with something that only renders events in view
				return (
					<div className="main">
						<Info room={room} />
						<div className="chat" ref={this.setRef}>
							<div className="events">
								<div className="paginateBackwards" onClick={this.paginateBackwards}>
									{this.state.loading ?
										<Loading/> :
										<span>load older messages</span>
									}
								</div>
								{(eventGroups.map((group) => {
									return <EventGroup key={`${this.props.roomId}-${group.events[0].event_id}`} events={group.events} client={this.props.client} room={room} onReplyClick={this.onReplyClick}/>;
								}))}
							</div>
						</div>
						<Input client={client} roomId={this.props.roomId} replyEvent={this.state.replyEvent} onReplyClick={this.onReplyClick}/>
					</div>
				);
			}
		}
	}
});

function EventGroup({ events, room, client, onReplyClick }) {
	let [ avatarRef, setAvatarRef ] = React.useState();

	React.useEffect(() => {
		if (avatarRef != null) {
			generateJdenticon(user.userId).update(avatarRef);
		}
	}, [ avatarRef ]);

	let user = client.getUser(events[0].sender);

	let avatar = expression(() => {
		if (user.avatarUrl != null) {
			let url = generateThumbnailUrl({
				homeserver: client.baseUrl,
				mxc: parseMXC(user.avatarUrl),
				width: 128,
				height: 128
			});

			return <img id="avatar" src={url} />;
		} else {
			return <svg id="avatar" ref={setAvatarRef} />;
		}
	});

	return (
		<div className="eventGroup">
			{avatar}
			<div className="col">
				<User user={user}/>
				{events.map((event, key) => {
					return <Event event={event} key={key} client={client} room={room} onReplyClick={onReplyClick}/>;
				})}
			</div>
		</div>
	);
}

module.exports = chat;