window.onload = () => {
    const table_elem = document.getElementById("table");
    const last_change = document.getElementById("last_change");
    const last_ping = document.getElementById("last_ping");
    const connected = document.getElementById("connected");
    const free_ports = document.getElementById("free_ports");

    const timeout_duration = 10*1000;
    const retry_timeout = 5*1000;

    let reconnect_timeout;
    let ping_timeout;
    let evtSource;
    let table = [];

    let last_update = new Date();

    let direction = -1;
    let oldkey = "last_change";

    table_elem.firstChild.firstChild.lastChild.className = "sort sort-down";


    let time_ago = ms => {

        let value = ms / 1000;
        // let prev = 0;
        let unit = 0;

        let factors = [
          [1, 'Sekunde', 'n'],
          [60, 'Minute', 'n'], 
          [60, 'Stunde', 'n'], 
          [24, 'Tag', 'en'],
          [7, 'Woche', 'n'],
          [4.348214, 'Monat', 'en'],
          [12, 'Jahr', 'en'],
        ];

        for (let i in factors) {
            let factor = factors[i][0];
            let new_value = Math.floor(value / factor);
            if (new_value == 0) break;

            // prev = Math.floor(value % factor);
            value = new_value;
            unit = i;
        }

        let factor = factors[unit];
 
        return [value,  factors[unit][1] + (value == 1 ? "" : factor[2])];
      }

    sort = (element, key) => {

        console.log(key, oldkey, direction);

        if (key == oldkey) {
            direction *= -1;
        } else {
            oldkey = key;
            direction = -1;
        }

        for (let child of table_elem.firstChild.firstChild.children) {
            console.log(child);
            child.className = ""
        };

        element.className = `sort ${direction > 0 ? "sort-up" : "sort-down"}`;

        do_sort(oldkey, direction);
    };

    let do_sort = (key, direction) => {

        let is_number = !!~(["port", "number", "last_change"].indexOf(key));

        console.log("is number:", is_number);

        table = table.sort((a, b) => (direction * (
            is_number ? a[key] - b[key] : ('' +a[key]).localeCompare(b[key], "de-DE")
        )));

        print_table();
        console.log(table);
    };

    let fmt = Intl.DateTimeFormat('de-DE', { dateStyle: 'medium', timeStyle: 'medium' });

    let format_date = date => fmt.format(date).replace(', ', ' ');
    let format_time = date => fmt.format(date).split(', ', 2)[1];

    let print_table = () => {
        while(table_elem.children.length > 1) {
            table_elem.removeChild(table_elem.lastChild);
        }

        for (let row of table) {

            let tr = document.createElement("tr");

            let values = [
                row.name === null ?  "?" : row.name,
                row.number,
                row.port,
                row.status,
                time_ago(last_update - row.last_change)
            ];

            let names = [
                "name",
                "number",
                "port",
                "status",
                "last_change"
            ];

            for(let i in values) {
                let value = values[i];
                let name = names[i];

                let td = document.createElement("td");
                td.className = name;

                if (name == "last_change") {
                    let [number, unit] = value;

                    let span = document.createElement("span");
                    // span.className = "value";
                    span.innerText = number;
                    td.appendChild(span);

                    span = document.createElement("span");
                    span.className = "unit";
                    span.innerText = unit;
                    td.appendChild(span);
                } else {
                    td.innerText = value;
                }
                tr.appendChild(td);

            }

            table_elem.appendChild(tr)
        }
    };

    let update_table = data => {
        console.log(data);

        const allowed_ports = data.allowed_ports.map(x => x.end - x.start + 1).reduce((a,b) => a + b, 0);
        free_ports.innerText = `Freie Ports: ${allowed_ports - Object.keys(data.allocated_ports).length - data.errored_ports.length}`;
        
        // last_change.innerHTML = `Letzte Änderung: ${format_date(new Date(+data.last_update * 1000))}`;

        table = [];

        for(let number in data.allocated_ports) {
            let port = data.allocated_ports[number];
            number = +number;
            let {status, last_change} = data.port_state[port];

            let rejector = data.rejectors[port] || null;

            if (rejector && rejector instanceof Array) {
                rejector = rejector.map(x => "0x"+x.toString(16).padStart(2, 0)).join(" ")
            }

            last_change = new Date(last_change * 1000);

            let name = data.names[number] || null;

            switch(status) {
                case "disconnected":
                    status = rejector ? `getrennt: ${rejector}` : "getrennt";
                    break;
                case "idle":
                    status = "bereit";
                    break;
                case "in_call":
                    status = "anruf";
                    break;
            }

            table.push({port, number, status, last_change, rejector, name})
        }

        for (let [timestamp, port] of data.errored_ports) {
            table.push({port, number: null, status: "Fehler", last_change: new Date(timestamp * 1000), rejector: null, name: ""})
        }

        console.log(table);

        do_sort(oldkey, direction);

        print_table();
    };


    let format_event = (event, method) =>  (method || format_date)(new Date(+event.data * 1000));

    let display_disconnected;

    let connect_event_source = () => {

        clearTimeout(reconnect_timeout);
        clearTimeout(ping_timeout);
        ping_timeout = setTimeout(connect_event_source, timeout_duration);

        evtSource && evtSource.close && evtSource.close();
            
        evtSource = new EventSource("/events");
        evtSource.addEventListener("change", event => {
            last_ping.innerText = `Stand: ${format_event(event, format_time)}`;

            last_update = new Date(+event.data * 1000);
           
            fetch("/data")
                .then(res => res.json())
                .then(update_table);
        });

        evtSource.addEventListener("ping", event => {
            clearTimeout(ping_timeout);
            ping_timeout = setTimeout(connect_event_source, timeout_duration);

            last_update = new Date(+event.data * 1000);

            last_ping.innerText = `Stand: ${format_event(event, format_time)}`;
            connected.className = "visible";

            print_table();

            clearTimeout(display_disconnected);
            display_disconnected = setTimeout(() => connected.className = "hidden", 5000);
        });


        evtSource.onerror = () => {
            clearTimeout(reconnect_timeout);
            reconnect_timeout = setTimeout(connect_event_source, retry_timeout);
        };
    }
    

    connect_event_source();

};