// Enable delays
const delay = ms => new Promise(res => setTimeout(res, ms));

init()

/* Supporting Functions */
async function init() {
    var stn = await getQuery("stn");
    log(`init: Looking up: ${stn}`);
    var sv = await getQuery("sv");
    log(`init: Staff Version: ${sv}`);
    if (sv === 'true') {
        log("init: Staff Version not supported yet.")
        log("init: Unable to proceed.")
    } else {
        try {
            var data = await publicLdb(stn)
            log("init: Fetched LDB Data")
            parseLdb(data)
        } catch (err) {
            var data = null
            log("init: Unable to fetch LDB data")
        }
    }
}

async function getQuery(param) {
    var params = new URLSearchParams(window.location.search)
    var query = params.get(param)
    if (query) {
        return query
    } else {
        return 'false'
    }
}

async function publicLdb(stn) {
    var url = `${window.location.origin}/api/v1/ldb/${stn}`;
    var resp = await fetch(url);
    return await resp.json();
}

async function setHeaders(title,time) {
    var prefix = `OwlBoard - `
    document.title = `${prefix}${title}`
    document.getElementById("station_name").innerHTML = title
    document.getElementById("fetch_time").innerHTML = time.toLocaleTimeString()
}

async function parseLdb(data) {
    if (data.ERROR == "NOT_FOUND") { // Station not found
        clearLoading();
        document.getElementById("error_notice").style = "display: block;";
        document.getElementById("err_not_found").style = "display: block;";
        setHeaders("Not Found",new Date())
    } else if (data == false) {  // No data for station
        clearLoading();
        document.getElementById("error_notice").style = "display: block;";
        document.getElementById("err_no_data").style = "display:block;";
        setHeaders("No Data",new Date())
    } else if (data == "err") {  // Connection Error
        clearLoading();
        document.getElementById("error_notice").style = "display: block;";
        document.getElementById("err_conn").style = "display: block;";
        setHeaders("Connection Error",new Date())
        await delay(5000);
        log(`parseLdb: Waited five seconds, reloading`)
        location.reload()
    } else {
        buildPage(data);
    }
}

// Build and Display Functions
async function buildPage(data) {
    var stationName = data.GetStationBoardResult.locationName;
    log(`buildPage: Data ready for ${stationName}`);
    var generateTime = new Date(await data.GetStationBoardResult.generatedAt);
    log(`buildPage: Data prepared at ${generateTime.toLocaleString()}`)
    setHeaders(stationName, generateTime);
    // Check for notices and if true pass to function
    if (data.GetStationBoardResult.nrccMessages) {
        displayNotices(data.GetStationBoardResult.nrccMessages.message)
    }
    if (typeof data.GetStationBoardResult.trainServices == 'undefined') {
        displayNoTrains()
    } else {
        displayTrains(data)
    }
}

async function displayNotices(notices) {
    // Input: data.GetStationBoardResult.nrccMessages.messages
    // Processing: For each message, create a <p> inside #notices.
    //             If there is more than one notice, scroll between them.
    // Output: Only to DOM.
    //document.getElementById("notices").innerHTML = notices;
}

async function displayNoTrains() {
    document.getElementById('no_services').style = "display: block;";
    clearLoading();
}

async function displayTrains(data) {
    log(`Inserting data in DOM`)
    for(var i = 0; i < data.GetStationBoardResult.trainServices.service.length; i++) {
        // Reset Vars
        var svc = data.GetStationBoardResult.trainServices.service[i];
        displayService(svc);
    }

    clearLoading();
    log(`Insertion complete`)
}

async function displayService(svc) {
    var table = document.getElementById("output");
 
    // Determine Time Message
    var sta = await parseTime(svc.sta);
    var eta = await parseTime(svc.eta);
    var std = await parseTime(svc.std);
    var etd = await parseTime(svc.etd);
    // Determine Platform Message
    //if (svc.platform != undefined){var plt = svc.platform} else {var plt = "-"};
    var plt = await parsePlatform(svc);
    // Define Table Row
    var row = `
    <table>
      <tr>
        <td class="name">${svc.origin.location.locationName}</td>
        <td class="name">${svc.destination.location.locationName}</td>
        <td class="plat">${plt.num}</td>
        <td class="time">${sta.data}</td>
        <td class="time ${eta.changed}">${eta.data}</td>
        <td class="time">${std.data}</td>
        <td class="time ${etd.changed}">${etd.data}</td>
      </tr>
    </table>`
    // Put Table Row
    table.insertAdjacentHTML("beforeend", row)
    // Parse cancelReason & delayReason
    if (svc.cancelReason) {
        var cancelRow = `<p class="msg">${svc.cancelReason}</p>`
        table.insertAdjacentHTML("beforeend", cancelRow);
    }
    if (svc.delayReason) {
        var delayRow = `<p class="msg">${svc.delayReason}</p>`
        table.insertAdjacentHTML("beforeend", delayRow);
    }
    
}

async function parsePlatform(svc){
    if (svc.platform != undefined) {
        var platform = svc.platform;
    } else {
        var platform = "-";
    }
    if (svc.platformChanged) {
        var changed = "changed";
    } else {
        var changed = "";
    }
    return {num: platform, change: changed}
}

async function parseTime(string){
    switch (string) {
        case "Delayed":
            var output = "LATE";
            var change = "changed";
            break;
        case "Cancelled":
            var output = "CANC";
            var change = "changed";
            break;
        case "On time":
            var output = "RT";
            var change = "";
            break;
        case "":
            var output = "-";
            var change = "";
            break;
        case undefined:
            var output = "";
            var change = "";
            break;
        default:
            var output = string;
            var change = "changed";
    }
    return {data: output, changed: change};
}

async function parseName(){
}

// Log Helper
function log(msg) {
    var time = new Date().toISOString();
    console.log(`${time} - ${msg}`)
}