import { createApp } from 'petite-vue'

import { domain, nopoll } from '@params'

type Config = {
	apiurl: string
	pollurl: string
	domain: string
	itemid: string
	sid: string
	iid: string
	nopoll: boolean
}

export function config (api, polling): Config {
	const pu = polling ? `${api.path}/${polling.msgbase.join('/')}` : ''
	const urlparams = new URL(location.href).searchParams
	return { 
		apiurl: api.path, 
		pollurl: pu, 
		domain: domain,
		itemid: urlparams.get('id'),
		sid: getSid(),
		iid: createRandString(1),
		nopoll: nopoll
	}
}

export const pvapp = {
	run(conf: Config) {
		appdata.conf = conf
		createApp(appdata).mount()
		if (appdata.conf.pollurl && !appdata.conf.nopoll) {
			appdata.poll()
		}
	}
}

const appdata = {
	$delimiters: ['{|', '|}'],
	conf: {} as Config,
	components: {},
	output: '',
	handle,
	poll,
	mounted(name: string) {
		console.log('app mounted: ', name)
	},
	Data
}

// components
// (move to separate module(s))

function Data(name, action, domain: string): object {
	domain = domain || this.conf.domain
	const comp = {
		name: name, // -> class of incoming/outgoing message
		action: action, // (default) action of outgoing message
		domain: domain, // domain of incoming/outgoing message
		data: {}, 	// model (2-way data store)
		data_bak: {}, // backup copy when leaving view or edit mode
		meta: {},	// metadata (params) for each data field
		mode: 'view',
		mounted,
		chmode,
		copynew,
		exec		// default function to execute upon button click
	}
	this.components[name] = comp
	return comp
}

// appdata and component method definitions

function mounted(name: string, meta: any) {
	if (meta.defexpr) {
		meta.default = eval(meta.defexpr)
	}
	this.data[name] = meta.default || ""
	this.meta[name] = meta
}

function chmode(action: string) {
	if (this.mode == action) {
		return
	}
	if (this.mode == 'view') {
		Object.assign(this.data_bak, this.data)
	}
	switch(action) {
		case 'query':
			setQuery(this)
			break
		case 'new':
			setNew(this)
			break
		default:
			Object.assign(this.data, this.data_bak)
	}
	this.mode = action
}

function copynew(action: string) {
	Object.assign(this.data, this.data_bak)
	this.data.id = ''
	this.mode = 'new'
}

function exec(action: string) {
	action = action || this.action
	const data = this.data
	const conf = this.conf
	let value = ''
	for (const k of Object.keys(data)) {
		value += `${k}: ${data[k]}, `
	}
	this.output += '\n' + value
	console.log('exec:', value)
	sendMsg(conf, [this.domain, action, this.name, data.id], data)
}

function handle(msg) {
	const data = JSON.parse(msg.payload)
	const [ domain, action, class_, item ] = msg.path.split('/')
	// TODO: check action => select handler fct
	const comp = this.components[class_ || 'data']
	if (domain && domain != comp.domain) {
		return
	}
	if (comp) {
		Object.assign(comp.data, data)
	}
}

function poll() {
	dopoll(this)
}

// helper functions for data manipulation

function setQuery(obj) {
	for (const key in obj.data) {
		obj.data[key] = ''
	}
}

function setNew(obj) {
	for (const key in obj.data) {
		obj.data[key] = ''
		const meta = obj.meta[key]
		if (meta) {
			obj.data[key] = meta.default || ''
		}
	}
	obj.data.id = ''
}

// basic functions - move to api.ts

async function sendMsg(conf: Config, basemsg: string[], data: any) {
	const url = `${conf.apiurl}/${basemsg.join('/')}`
	await send(url, conf, data)
}

async function send(url: string, conf: Config, data: any) {
	data._interaction = conf.iid
	const body = JSON.stringify(data)
	const headers = {}
	headers['X-Integrator-Session'] = conf.sid
	return fetch(url, {
		method: 'POST',
		headers: headers,
		body: body
	})
}

function createRandString(size: number): string {
	const arr = new Uint32Array(size)
	crypto.getRandomValues(arr)
	const result: string[] = []
	arr.forEach((x) => result.push(x.toString(36)))
	return result.join('')
}

function getSid(): string {
	const sid_key = 'api.sessionid'
	let sid = localStorage.getItem(sid_key)
	if (!sid) {
		sid = createRandString(2)
		localStorage.setItem(sid_key, sid)
	}
	return sid
}

//console.log("sid: ", getSid())
// TODO: clear sid - when?
//localStorage.setItem('api.sessionid', '')

async function dopoll(app: typeof appdata) {
	const wait_time = 10000
	while (true) {
		try {
			const res = await(send(app.conf.pollurl, app.conf, {}))
			const msg = await res.json()
			console.log(msg)
			switch (msg.status) {
				case 'idle':
					break
				case 'data':
					app.handle(msg)
					break
				default:
					console.log('poll response: ', msg)
					await sleep(wait_time)
			}
		} catch (error) {
			console.log(error)
			await sleep(wait_time)
		}
	}
}

const sleep = (delay: number) => new Promise(r => setTimeout(r, delay))