"use strict";

class trserver {
    #rpcurl;
    #authHeader;
    #sessionHeader;
    #requests = [];
    #torrents = {};
    #isOnline = false;

    #logger = function(msg) {};
    #torrentCallback = function(hash, torrentInfo) {};

    constructor (initdata, logger, tcb) {
        this.#rpcurl = initdata.rpcurl;
        if (logger != null) {
            this.#logger = logger;
        }
        if (tcb != null) {
            this.#torrentCallback = tcb;
        }
        this.#authHeader = initdata.auth;
        this.#sessionHeader = null;
    }

    #rpccall_prepare(method, args) {
        let request = {
            'payload': {
                'method': method,
                'arguments': args
            }
        };
        let tag = this.#requests.push(request) - 1;
        return tag;
    }

    #rpccall(tag) {
        let request = this.#requests[tag];
        //this.#logger(`[${tag}] >> ${request.payload.method}`);
        let rpc = new window.XMLHttpRequest();
        rpc.tag = tag;
        rpc.open('POST', this.#rpcurl);
        if (this.#authHeader != null) {
            rpc.setRequestHeader('authorization', this.#authHeader);
        }
        if (this.#sessionHeader != null) {
            rpc.setRequestHeader('X-Transmission-Session-Id', this.#sessionHeader);
        }
        rpc.setRequestHeader('content-type', 'application/json');
        rpc.addEventListener('readystatechange', this.#handler.bind(this));
        rpc.addEventListener('timeout', this.#handler.bind(this));
        rpc.addEventListener('error', this.#handler.bind(this));
        rpc.timeout = 10000;
        try {
            rpc.send(JSON.stringify(request.payload));
        } catch (error) {
            this.#logger(error);
        }
    }

    rpccall_debug(method, args) {
        var tag = this.#rpccall_prepare(method, args);
        let request = this.#requests[tag];
        request.success = console.info;
        this.#rpccall(tag);
    }

    #handler(e) {
        switch (e.type) {
            case 'readystatechange':
                if (e.target.readyState == 4) {
                    let tag = e.target.tag;
                    let request = this.#requests[tag];
                    switch (e.target.status) {
                        case 200:
                            if (!this.#isOnline) {
                                this.#logger('Server API connection estabilished');
                                this.#isOnline = true;
                                this.#forceUpdateTorrents();
                            }
                            //request.response = JSON.parse(e.target.responseText);
                            if (request.success != null) {
                                request.success(JSON.parse(e.target.responseText).arguments);
                            }
                            else {
                                //this.#logger(e.target.responseText);
                            }
                            break;
                        case 409:
                            this.#sessionHeader = e.target.getResponseHeader('X-Transmission-Session-Id');
                            this.#rpccall(tag);
                            break;
                        default:
                            request.response = {'code': e.target.status, 'content': e.target.responseText};
                            //this.#logger(JSON.stringify(request.response));
                            break;
                    }
                }
                break;
            case 'timeout':
                if (this.#isOnline) {
                    this.#logger('Server API connection timed out');
                    this.#isOnline = false;
                    this.#forceUpdateTorrents();
                }
                break;
            case 'error':
                if (this.#isOnline) {
                    this.#logger('Server API refuses connection');
                    this.#isOnline = false;
                    this.#forceUpdateTorrents();
                }
                this.#logger(JSON.stringify(e));
                break;
        }
    }

    refreshSession (){
        //let tag = this.#rpccall_prepare('session-get', null);
        //this.#rpccall(tag);
    }

    #parseTorrents(response) {
        // mark everything as deleted but clean
        for (const [key, value] of Object.entries(this.#torrents)) {
            value.wasDeleted = value.deleted;
            value.deleted = true;
            value.dirty = false;
        }
        // Update torrent data
        for (const torrent of response.torrents) {
            let hash = torrent.hashString;
            if (!(hash in this.#torrents)) {
                this.#torrents[hash] = {'dirty': true};
            }
            let knownTorrent = this.#torrents[hash];
            for (const [key, value] of Object.entries(torrent)) {
                let parsedValue = undefined;
                switch (key) {
                    case 'hashString':
                        break;
                    case 'percentDone':
                        parsedValue = Math.floor(value * 100);
                        break;
                    default:
                        parsedValue = value;
                        break;
                }
                
                if (parsedValue != undefined && knownTorrent[key] !== parsedValue) {
                    knownTorrent[key] = parsedValue;
                    knownTorrent.dirty = true;
                }
            }
            knownTorrent.deleted = false;
        }
        //check for changes
        for (const [key, value] of Object.entries(this.#torrents)) {
            if (value.deleted != value.wasDeleted || value.dirty) {
                // call UI update
                this.#torrentCallback(key, value);
            }
        }
    }

    #forceUpdateTorrents() {
        for (const [key, value] of Object.entries(this.#torrents)) {
            // call UI update
            this.#torrentCallback(key, value);
        }
    }

    refreshTorrentList() {
        let tag = this.#rpccall_prepare('torrent-get', {'fields': ['id', 'hashString', 'name', 'status', 'percentDone', 'comment', 'magnetLink']});
        this.#requests[tag].success = this.#parseTorrents.bind(this);
        this.#rpccall(tag);
    }

    torrent_add_url(url, dontstart, path) {
        let args = {
            'filename': url,
            'paused': dontstart
        };
        if (path != null) {
            args['download-dir'] = path;
        }
        let tag = this.#rpccall_prepare('torrent-add', args);
        this.#rpccall(tag);
    }

    torrent_start(hash) {
        let tag = this.#rpccall_prepare('torrent-start', {'ids':[hash]});
        this.#rpccall(tag);
    }

    torrent_pause(hash) {
        let tag = this.#rpccall_prepare('torrent-stop', {'ids':[hash]});
        this.#rpccall(tag);
    }

    getInstanceData() {
        return {
            'rpcurl': this.#rpcurl,
            'auth': this.#authHeader
        };
    }

    isOnline() {
        return this.#isOnline;
    }
};