// A couple of constants that must match what's in CSS. We need to know them before the content actually renders, so we
// can't just ask the elements themselves for their dimensions.
BAND_COLUMN_HEIGHT_EM = 62;
BAND_COLUMN_CANVAS_WIDTH_EM = 4;
BAND_COLUMN_FONT_SIZE = 16;
BAND_COLUMN_HEIGHT_PX = BAND_COLUMN_HEIGHT_EM * BAND_COLUMN_FONT_SIZE;
BAND_COLUMN_CANVAS_WIDTH_PX = BAND_COLUMN_CANVAS_WIDTH_EM * BAND_COLUMN_FONT_SIZE;

// Load spots and populate the bands display.
function loadSpots() {
    $.getJSON('/api/v1/spots' + buildQueryString(), function(jsonData) {
        // Store last updated time
        lastUpdateTime = moment.utc();
        updateRefreshDisplay();
        // Store data
        spots = jsonData;
        // Update bands display
        updateBands();
    });
}

// Build a query string for the API, based on the filters that the user has selected.
function buildQueryString() {
    var str =  "?";
    ["dx_continent", "de_continent", "mode_type", "source", "band"].forEach(fn => {
        if (!allFilterOptionsSelected(fn)) {
            str = str + getQueryStringFor(fn) + "&";
        }
    });
    str = str + "max_age=" + $("#max-spot-age option:selected").val();
    // Additional filters for the bands view: No dupes, no QRT
    str = str + "&dedupe=true&allow_qrt=false";
    return str;
}

// Update the bands display
function updateBands() {
    // Stop here if nothing to display
    var bandsContainer = $("#bands-container");
    if (spots.length === 0) {
        bandsContainer.html("<div class='alert alert-danger' role='alert'>No spots match your filters.</div>");
        return;
    }

    // Do some harsher de-duping. Because we only display callsign, frequency and mode here, the previous
    // de-duplication could have let some through that don't look like dupes on the map, but would do here.
    // Typically that's a person activating two programs at the same time, e.g. POTA & WWFF.
    spotList = removeDuplicatesForBandPanel(spots);

    // Convert to a map of band names to the spots on that band. Bands with no
    // spots in view will not be present.
    const bandToSpots = new Map();
    options["bands"].forEach(function (band) {
        const matchingSpots = spotList.filter(function (s) {
            return s.band === band.name;
        });
        if (matchingSpots.length > 0) {
            bandToSpots.set(band.name, matchingSpots);
        }
    });

    // Build up table content for each band
    var table = $('<table id="bands-table">').append('<thead><tr></tr></thead><tbody><tr></tr></tbody>');
    bandToSpots.forEach(function (spotList, bandName) {
        // Get the colours for the band from the first spot, and prepare the header
        table.find('thead tr').append(`<th style='background-color:${spotList[0].band_color}; color:${spotList[0].band_contrast_color}'>${spotList[0].band}</th>`);

        // Get the band data to fetch start and end frequencies
        let band = options["bands"].filter(function (b) {
            return b.name === bandName;
        })[0];

        // Print the frequency band markers. This is 41 steps to divide the band evenly into 40 markers. One in every
        // four will show the actual frequency, the others will just be dashes.
        bandMarkersDiv = $('<div class="band-markers">');
        const freqStep = (band.end_freq - band.start_freq) / 40.0;
        for (let i = 0; i <= 40; i++) {
            if (i % 4 === 0) {
                bandMarkersDiv.append("&mdash;" + ((band.start_freq + i * freqStep)/1000000).toFixed(3) + "<br/>");
            } else if (i % 4 === 2) {
                bandMarkersDiv.append("&ndash;<br/>");
            } else {
                bandMarkersDiv.append("-<br/>");
            }
        }

        // Print the spots on the band. Each one is a div with the details, shifted down if necessary to prevent
        // overlap
        bandSpotsDiv = $("<div class='band-spots'>");
        // Sort by frequency so we print higher frequencies later, and can bump them further down the track to prevent
        // overlaps
        spotList.sort(function(a, b) { return a.freq - b.freq; });
        var lastSpotEmDownBand = -999;
        // Iterate through the spots list
        spotList.forEach(s => {
            // Work out how far down the div to draw it
            var percentDownBand = (s.freq - band.start_freq) / (band.end_freq - band.start_freq) * 0.97; // not 100% due to fudge, the first and last dashes are not exactly at the top and bottom of the div as some space is needed for text
            var emDownBand = percentDownBand * BAND_COLUMN_HEIGHT_EM;
            if (emDownBand < lastSpotEmDownBand + 1.6) {
                emDownBand = lastSpotEmDownBand + 1.6; // Prevent overlap
            }
            lastSpotEmDownBand = emDownBand;
            // Calculate how many px down the band div the label appears, and store it with the spot, so we can use it
            // later for drawing the lines.
            var pxDownBandLabel = (emDownBand * BAND_COLUMN_FONT_SIZE) + (0.015 * BAND_COLUMN_HEIGHT_PX);
            s["pxDownBandLabel"] = pxDownBandLabel;

            // Add spot div to DOM
            bandSpotsDiv.append(`<div class="band-spot" style="top: ${emDownBand}em; border-top: 1px solid ${s.band_color}; border-left: 5px solid ${s.band_color}; border-bottom: 1px solid ${s.band_color}; border-right: 1px solid ${s.band_color};"><span class="band-spot-call">${s.dx_call}</span><span class="band-spot-info">${s.dx_call} ${(s.freq/1000000).toFixed(3)} ${s.mode}</span></div>`);
        });

        // Work out how tall the canvas should be. Normally this is matching the normal band column height, but if some
        // spots have gone off the end of the band markers and stretched their div, we need to resize the canvas to
        // match, otherwise we have nowhere to draw their connecting lines.
        var canvasHeight = Math.max(BAND_COLUMN_HEIGHT_PX, (lastSpotEmDownBand+1.6) * BAND_COLUMN_FONT_SIZE);

        // Draw horizontal or diagonal lines to join up the "real" frequency with where the spot div ended up
        var bandLinesCanvas = $(`<canvas class='band-lines-canvas' width='${BAND_COLUMN_CANVAS_WIDTH_PX}px' height='${canvasHeight}px' style='height:${canvasHeight}px !important;'>`);
        spotList.forEach(s => {
            // Work out how far down the div to draw it
            var percentDownBand = (s.freq - band.start_freq) / (band.end_freq - band.start_freq) * 0.97; // not 100% due to fudge, the first and last dashes are not exactly at the top and bottom of the div as some space is needed for text
            var pxDownBandFreq = (percentDownBand + 0.015) * BAND_COLUMN_HEIGHT_PX; // same fudge but add half to put the left end of the line in the right place
            var pxDownBandLabel = s["pxDownBandLabel"];

            // Draw the line on the canvas
            var ctx = bandLinesCanvas[0].getContext('2d');
            ctx.beginPath();
            ctx.lineWidth = 2;
            ctx.lineCap = "round";
            ctx.strokeStyle = s.band_color;
            ctx.moveTo(0, pxDownBandFreq);
            ctx.lineTo(BAND_COLUMN_CANVAS_WIDTH_PX, pxDownBandLabel);
            ctx.stroke();
        });

        // Assemble the table cell
        td = $("<td>");
        container = $("<div class='band-container'>");
        container.append(bandLinesCanvas);
        container.append(bandMarkersDiv);
        container.append(bandSpotsDiv);
        td.append(container);
        table.find('tbody tr').append(td);
    });

    // Update the DOM with the band HTML
    bandsContainer.html(table);

    // Desktop mouse wheel to scroll bands horizontally if used on the headers
    table.find('thead tr').on("wheel", () => {
        bandsContainer.scrollLeft(bandsContainer.scrollLeft() + event.deltaY / 10.0);
        return false;
    });
}

// Iterate through a temporary list of spots, merging duplicates in a way suitable for the band panel. If two or more
// spots with the activator, mode and frequency are found, these will be merged and reduced until only one remains,
// with the best data. Note that unlike removeDuplicates(), which operates on the main spot map, this operates only
// on the temporary array of spots provided as an argument, and returns the output, for use when constructing the
// band panel.
function removeDuplicatesForBandPanel(spotList) {
    const spotsToRemove = [];
    spotList.forEach(function (check) {
        spotList.forEach(function (s) {
            if (s !== check) {
                if (s.dx_call === check.dx_call && s.freq === check.freq && s.mode === check.mode) {
                    // Find which one to keep and which to delete
                    const checkSpotNewer = check.time > s.time;
                    const keepSpot = checkSpotNewer ? check : s;
                    const deleteSpot = checkSpotNewer ? s : check;
                    // Aggregate list of spots to remove
                    spotsToRemove.push(deleteSpot.uid);
                }
            }
        });
    });
    // Perform the removal
    return spotList.filter(s => !spotsToRemove.includes(s.uid));
}

// 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/v1/options', function(jsonData) {
        // Store options
        options = jsonData;

        // Add CSS for band toggle buttons
        addBandToggleColourCSS(options["bands"]);

        // Populate the filters panel
        generateBandsMultiToggleFilterCard(options["bands"]);
        generateMultiToggleFilterCard("#dx-continent-options", "dx_continent", options["continents"]);
        generateMultiToggleFilterCard("#de-continent-options", "de_continent", options["continents"]);
        generateMultiToggleFilterCard("#mode-options", "mode_type", options["mode_types"]);
        generateMultiToggleFilterCard("#source-options", "source", options["spot_sources"]);

        // Load settings from settings storage now all the controls are available
        loadSettings();

        // Load spots and set up the timer
        loadSpots();
        setInterval(loadSpots, REFRESH_INTERVAL_SEC * 1000);
    });
}

// Method called when any display property is changed to reload the map and persist the display settings.
function displayUpdated() {
    updateMap();
    saveSettings();
}

// React to toggling/closing panels
function toggleFiltersPanel() {
    // If we are going to show the filters panel, hide the display panel
    if (!$("#filters-area").is(":visible") && $("#display-area").is(":visible")) {
        $("#display-area").hide();
        $("#display-button").button("toggle");
    }
    $("#filters-area").toggle();
}
function closeFiltersPanel() {
    $("#filters-button").button("toggle");
    $("#filters-area").hide();
}

function toggleDisplayPanel() {
    // If we are going to show the display panel, hide the filters panel
    if (!$("#display-area").is(":visible") && $("#filters-area").is(":visible")) {
        $("#filters-area").hide();
        $("#filters-button").button("toggle");
    }
    $("#display-area").toggle();
}
function closeDisplayPanel() {
    $("#display-button").button("toggle");
    $("#display-area").hide();
}

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