async function startApp() {
    await printPage();
}

async function printPage(){

    // Load data
    console.log("___printPage()___");

    // Print HTML
    let html = "";
    html += "<h1>Volvo XC60</h1>\n";
    html += "<p>Schedule Volvo rechanging</p>\n";
    html += "<h3>Schedule per left percentages in battery</h3>\n";
    html += "<p>How much there is battery left in the car?</p>";
    html += "<form action=\"\" method=\"post\" onsubmit=\"scheduleWithBatteryChargePercentage(); return false;\">\n";
    html += "<label for=\"batteryleftpercentageelement\">Battery left percentage</label>\n";
    html += "<input id=\"batteryleftpercentageelement\" class=\"percentage\" type=\"text\" width=\"20px\" name=\"batteryLeft\" value=\"3%\" placeholder=\"3 %\">\n";
    html += "<label for=\"readytimeelement\">To be ready at</label>\n";
    html += "<input id=\"readytimeelement\" class=\"time\" type=\"text\" width=\"60px\" name=\"readytime\" value=\"07:00\" placeholder=\"07:00\">\n";
    html += "<input type=\"submit\" value=\"Schedule\">\n";
    html += "</form>\n";
    html += "<h3>Active schedulings</h3>\n";
    html += "<div id=\"volvoschedules\"></div>\n";
    document.getElementById('center').innerHTML = html;

    await updateVolvoSchedules();
}

async function updateVolvoSchedules() {
    let schedules = await readVolvoSchedules();
    let totalCount = schedules["schedules"].length;

    // Create schedule table HTML and do calculations
    let scheduleTableHtml = "";
    scheduleTableHtml += "<table><tr><th>Schedule date</th><th>Energy price</th><th>Total cost (cents)</th></tr>";
    if (totalCount === 0) {
        scheduleTableHtml += "<tr><td colspan='2'>No schedules found</td></tr>";
    }
    let totalPrice = 0;
    for (let key in schedules["schedules"]) {
        let scheduleDate = schedules["schedules"][key].scheduleDate;
        let calculatedPrice = parseFloat(schedules["schedules"][key].calculatedPrice);
        let energyPrice = parseFloat(schedules["schedules"][key].energyPrice);
        scheduleTableHtml += "<tr>";
        scheduleTableHtml += "<td>" + scheduleDate + "</td>";
        scheduleTableHtml += "<td>" + energyPrice + "</td>";
        scheduleTableHtml += "<td>" + calculatedPrice.toFixed(3) + "</td>";
        scheduleTableHtml += "</tr>\n";
       console.log("\tSchedule : " + scheduleDate);
       totalPrice = totalPrice + calculatedPrice;
    }

    let hours = Math.floor(totalCount/4);
    let minutes = 15 * (totalCount % 4);
    let totalCost = (totalPrice/100).toFixed(2);

    scheduleTableHtml += "<tr><td><b>" + hours + " h " + minutes + " min</b></td><td><b>" + totalCost + " €</b></td></tr>\n";
    scheduleTableHtml += "</table>";

    let html = "";
    html += "<p>There is total of <b>" + hours + " hours and " + minutes + " minutes</b> of changing! Total cost for charging is <b>" + totalCost + " €</b></p>";

    if (totalCount > 0) {
        html += "<form action=\"\" method=\"post\" onsubmit=\"deleteSchedules(); return false;\">\n";
        html += "<input type=\"submit\" value=\"Reset schedulings\">\n";
        html += "</form>\n";
    }
    html += scheduleTableHtml;
    document.getElementById('volvoschedules').innerHTML = html;
}

async function scheduleWithBatteryChargePercentage() {
    let element = document.getElementById('batteryleftpercentageelement');
    let readyTime = document.getElementById('readytimeelement');
    console.log("Scheduling Volvo per battery percentage left " + element.value + " and to be ready at " + readyTime.value + "...");
    let response = await createVolvoScheduleByLeftPercentage(element.value, readyTime.value, true);
    console.log("Response : " + response.message);
    alert(response.message);
    await updateVolvoSchedules();
    return false;
}

async function deleteSchedules() {
    console.log("Deleting Volvo schedules...");
    let response = await deleteVolvoSchedules();
    console.log("Response : " + response.message);
    await updateVolvoSchedules();
    return false;
}

async function readVolvoSchedules() {
    const response = await fetch("/schedule/read/volvo");
    const data = await response.json();
    console.log("==> fetchSchedules: " + JSON.stringify(data));
    return data;
}

async function createVolvoScheduleByLeftPercentage(leftPercentage, readyTime, activateScheduling) {
    const response = await fetch('/schedule/create/volvo/leftpercentage', {
        method: 'POST',
        headers: {
            'Accept': 'application/json',
            'Content-Type': 'application/json'
        },
        body: JSON.stringify({leftPercentage: leftPercentage, readyTime: readyTime, activateScheduling: activateScheduling})
    });
    const data = await response.json();
    console.log("==> createVolvoScheduleByLeftPercentage: " + JSON.stringify(data));
    return data;
}

async function deleteVolvoSchedules() {
    const response = await fetch('/schedule/delete/volvo', {
        method: 'POST',
        headers: {
            'Accept': 'application/json',
            'Content-Type': 'application/json'
        },
        body: JSON.stringify({delete: true})
    });
    const data = await response.json();
    console.log("==> deleteVolvoSchedules: " + JSON.stringify(data));
    return data;
}