import tui from './httpRequest'

const socket = {
	connected: false,
	task: null,
	heartbeatTimer: null,
	subscriptions: {},
	connecting: false,
	messageHandlers: [],
	ackHandlers: [],
	presenceHandlers: [],
	roomEndHandlers: [],
	offlineHandlers: []
}

function wsUrl() {
	return tui.interfaceUrl().replace(/^http/, 'ws') + '/ws/websocket'
}

function frame(command, headers = {}, body = '') {
	const lines = [command]
	Object.keys(headers).forEach(key => {
		lines.push(`${key}:${headers[key]}`)
	})
	lines.push('')
	lines.push(body)
	return lines.join('\n') + '\u0000'
}

function parseFrame(raw) {
	const text = raw.replace(/\u0000/g, '')
	const splitIndex = text.indexOf('\n\n')
	const head = splitIndex >= 0 ? text.slice(0, splitIndex) : text
	const body = splitIndex >= 0 ? text.slice(splitIndex + 2) : ''
	const lines = head.split('\n')
	const command = lines.shift()
	const headers = {}
	lines.forEach(line => {
		const index = line.indexOf(':')
		if (index > -1) headers[line.slice(0, index)] = line.slice(index + 1)
	})
	return { command, headers, body }
}

function emit(list, payload) {
	list.forEach(handler => {
		try { handler(payload) } catch (e) { console.warn('ie socket handler error', e) }
	})
}

function send(destination, body = {}) {
	if (!socket.connected || !socket.task) return false
	socket.task.send({
		data: frame('SEND', {
			destination,
			'content-type': 'application/json'
		}, JSON.stringify(body))
	})
	return true
}

function subscribe(destination, id) {
	socket.task.send({
		data: frame('SUBSCRIBE', { id, destination, ack: 'auto' })
	})
}

function subscribeRoom(roomId) {
	if (!socket.connected || !socket.task || !roomId) return false
	const id = 'ie-room-' + roomId
	if (socket.subscriptions[id]) return true
	socket.subscriptions[id] = true
	subscribe('/topic/ie/room/' + roomId, id)
	return true
}

function bindSubscriptions() {
	subscribe('/user/queue/ie/ack', 'ie-ack')
	subscribe('/user/queue/ie/message', 'ie-message')
	subscribe('/user/queue/ie/presence', 'ie-presence')
	subscribe('/user/queue/ie/room-end', 'ie-room-end')
	subscribe('/user/queue/ie/offline', 'ie-offline')
	send('/app/ie/connect')
}

function handleMessage(raw) {
	if (raw === 'h') return
	const data = parseFrame(raw)
	if (data.command === 'CONNECTED') {
		socket.connected = true
		bindSubscriptions()
		startHeartbeat()
		return
	}
	if (data.command !== 'MESSAGE') return
	let payload = data.body
	try { payload = JSON.parse(data.body) } catch (e) {}
	const dest = data.headers.destination || ''
	if (dest.indexOf('/queue/ie/ack') > -1) emit(socket.ackHandlers, payload)
	if (dest.indexOf('/queue/ie/message') > -1 || dest.indexOf('/topic/ie/room/') > -1) emit(socket.messageHandlers, payload)
	if (dest.indexOf('/queue/ie/presence') > -1) emit(socket.presenceHandlers, payload)
	if (dest.indexOf('/queue/ie/room-end') > -1) emit(socket.roomEndHandlers, payload)
	if (dest.indexOf('/queue/ie/offline') > -1) emit(socket.offlineHandlers, payload)
}

function startHeartbeat() {
	clearInterval(socket.heartbeatTimer)
	socket.heartbeatTimer = setInterval(() => {
		send('/app/ie/heartbeat')
	}, 25000)
}

function connect() {
	if (socket.connected || socket.connecting) return Promise.resolve()
	socket.connecting = true
	return new Promise((resolve, reject) => {
		socket.task = uni.connectSocket({
			url: wsUrl(),
			header: { accessToken: tui.getToken() },
			success: resolve,
			fail: reject
		})
		socket.task.onOpen(() => {
			socket.connecting = false
			socket.task.send({
				data: frame('CONNECT', {
					'accept-version': '1.2',
					'heart-beat': '10000,10000',
					accessToken: tui.getToken()
				})
			})
		})
		socket.task.onMessage(res => handleMessage(res.data || ''))
		socket.task.onClose(() => {
			socket.connected = false
			socket.connecting = false
			clearInterval(socket.heartbeatTimer)
		})
		socket.task.onError(() => {
			socket.connected = false
			socket.connecting = false
			clearInterval(socket.heartbeatTimer)
		})
	})
}

function close() {
	clearInterval(socket.heartbeatTimer)
	if (socket.task) socket.task.close()
	socket.connected = false
	socket.task = null
}

function resetHandlers() {
	socket.messageHandlers = []
	socket.ackHandlers = []
	socket.presenceHandlers = []
	socket.roomEndHandlers = []
	socket.offlineHandlers = []
}

export default {
	connect,
	close,
	resetHandlers,
	subscribeRoom,
	sendMessage(data) { return send('/app/ie/message', data) },
	sendPresence(data) { return send('/app/ie/presence', data) },
	onAck(handler) { socket.ackHandlers.push(handler) },
	onMessage(handler) { socket.messageHandlers.push(handler) },
	onPresence(handler) { socket.presenceHandlers.push(handler) },
	onRoomEnd(handler) { socket.roomEndHandlers.push(handler) },
	onOffline(handler) { socket.offlineHandlers.push(handler) }
}