// How often to query the server?
const REFRESH_INTERVAL_SEC = 60;

// Storage for the spot data that the server gives us.
var spots = []
// Storage for the options that the server gives us. This will define our filters.
var options = {};
// Last time we updated the spots list on display.
var lastUpdateTime;

// Load spots and populate the table.
function loadSpots() {
    $.getJSON('/api/spots', function(jsonData) {
        // Store last updated time
        lastUpdateTime = moment.utc();
        updateRefreshDisplay();
        // Store data
        spots = jsonData;
        // Update table
        updateTable();
    });
}

// Update the spots table
function updateTable() {
    // Populate table with headers
    let headers = Object.keys(spots[0]);
    let table = $('<table class="table table-striped table-hover">').append('<thead><tr class="table-primary"></tr></thead><tbody></tbody>');
    ["UTC", "DX", "Frequency", "Mode", "Comment", "Source", "Ref.", "DE"].forEach(header => table.find('thead tr').append(`<th>${header}</th>`));

    spots.forEach(s => {
        // Create row
        let $tr = $('<tr>');

        // Show in red if QRT
        if (s["qrt"] == true) {
          $tr.addClass("table-faded");
        }

        // Format a UTC time for display
        var time = moment.utc(s["time"], moment.ISO_8601);
        var time_formatted = time.format("HH:mm")

        // Format the frequency
        var mhz = Math.floor(s["freq"] / 1000.0);
        var khz = Math.floor(s["freq"] - (mhz * 1000.0));
        var hz = Math.floor((s["freq"] - Math.floor(s["freq"])) * 1000.0);
        var hz_string = (hz > 0) ? hz.toFixed(0) : "";
        var freq_string = `<span class='freq-mhz'>${mhz.toFixed(0)}</span><span class='freq-khz'>${khz.toFixed(0).padStart(3, '0')}</span><span class='freq-hz'>${hz_string}</span>`

        // Format sig_refs
        var sig_refs = ""
        if (s["sig_refs"]) {
            sig_refs = s["sig_refs"].join(", ")
        }

        // Format DE flag
        var de_flag = "<i class='fa-solid fa-question'></i>";
        if (s["de_flag"] && s["de_flag"] != "") {
            de_flag = s["de_flag"];
        }

        // Populate the row
        $tr.append(`<td>${time_formatted}</td>`);
        $tr.append(`<td><span class='flag-wrapper'>${s["dx_flag"]}</span>${s["dx_call"]}</td>`);
        $tr.append(`<td>${freq_string}</td>`);
        $tr.append(`<td>${s["mode"]}</td>`);
        $tr.append('<td>' + escapeHtml(`${s["comment"]}`) + '</td>');
        $tr.append(`<td><span class='icon-wrapper'><i class='fa-solid fa-${s["icon"]}'></i></span> ${s["source"]}</td>`);
        $tr.append(`<td>${sig_refs}</td>`);
        $tr.append(`<td><span class='flag-wrapper'>${s["de_flag"]}</span>${s["de_call"]}</td>`);
        table.find('tbody').append($tr);
    });

    // Update DOM
    $('#table-container').html(table);
}

// Load server status
function loadStatus() {
    $.getJSON('/api/status', function(jsonData) {
        $('#status-container').html(jsonData); // todo implement
    });
}

// Load server options. Once a successful callback is made from this, we then query spots and set up the timer to query
// spots repeatedly.
function loadOptions() {
    $.getJSON('/api/options', function(jsonData) {
        options = jsonData;
        console.log(options); //todo remove
        loadSpots();
        setInterval(loadSpots, REFRESH_INTERVAL_SEC * 1000)
    });
}

// Update the refresh timing display
function updateRefreshDisplay() {
    if (lastUpdateTime != null) {
        let count = REFRESH_INTERVAL_SEC;
        let secSinceUpdate = moment.duration(moment().diff(lastUpdateTime)).asSeconds();
        updatingString = "Updating..."
        if (secSinceUpdate < REFRESH_INTERVAL_SEC) {
            count = REFRESH_INTERVAL_SEC - secSinceUpdate;
            updatingString = "Updating in " + count.toFixed(0) + " seconds...";
        }
        $("#timing-container").text("Last updated at " + lastUpdateTime.format('HH:mm') + " UTC. " + updatingString);
    }
}

// Utility function to escape HTML characters from a string.
function escapeHtml(str) {
    if (typeof str !== 'string') {
        return '';
    }

    const escapeCharacter = (match) => {
        switch (match) {
            case '&': return '&amp;';
            case '<': return '&lt;';
            case '>': return '&gt;';
            case '"': return '&quot;';
            case '\'': return '&#039;';
            case '`': return '&#096;';
            default: return match;
        }
    };

    return str.replace(/[&<>"'`]/g, escapeCharacter);
}


// Startup. Call loadOptions(), this will then trigger loading spots and setting up timers.
loadOptions();
// Update the refresh timing display every second
setInterval(updateRefreshDisplay, 1000);