const database = require('../database/database')
const not_found_error = require('../../lib/src/http/errors/not_found_error')
const {get_fastest_session_server, run_session} = require('../modules/session_server')

const create_session = async (req, res, next) => {
    const {title} = req.body

    var free_servers = await database.get_free_session_servers(title)

    if (!free_servers) {
        next(new not_found_error('no free session server or title not exists'))
        return
    }

    var session_server = await get_fastest_session_server(free_servers)
    
    if (!session_server) {
        next(new not_found_error('all session servers are not available'))
        return
    }

    var session_id = await database.generate_session_id()
    if (!session_id) {
        next(new not_found_error('can not generate session id'))
        return
    }

    var websocket_url = await run_session(session_server.url, session_id, title)

    if (!websocket_url) {
        next(new not_found_error('websocket_url not valid'))
        return
    }
    
    var add_active_session_result = await database.add_active_session(session_server.url, session_id, websocket_url)

    if (!add_active_session_result) {
        next(new not_found_error('add_active_session error'))
        return
    }
    res.json({session_id:session_id})
}

const connect_session = async (req, res, next) => {
    var websocket_url = await database.get_session_websocket_url(req.query.session_id)
    if (!websocket_url) {
        next(new not_found_error('session not exists'))
        return
    }
    res.json({websocket_url:websocket_url})
}

const schedule_session = async (req, res, next) => {
}

module.exports = {
    create_session,
    schedule_session,
    connect_session
}